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02-08-13, 10:27 AM
#26
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Aluminum can break before steel with the same amount of force applied. I recently had a rear derailuer go into my spokes. I fortunately had a very good back wheel, the frame wound up bending before my spokes gave out. We were able to bend the frame back, I have to watch that area of the frame now, but aluminum would have either cracked or caused more stress on the wheel. I can't say the aluminum would have failed, but the mechanic though it would have. I am not trying to dis aluminum frames I think they are great, I think the higher up in weight you go the better steel is for the frame. I'm not sure where the switching point is that makes aluminum better than steel, but there is definately a point somewhere along there.
Getting strong rims, is not A classic mistake. 350 lbs riders hitting potholes with an average strength rim is not a good idea.
Cycocommute you can leave the Condescension at home, you can have your opinion, but that doesn't make mine wrong or worth belittling. Why comment on an opinion that doesn't even state why I chose the way I did? Your post would have been valid without quoting my comments and definitely without "Classic Mistake" and "Let's just stop right there". Your points are good, but I think you are looking at the problem from a different angle than I am. The last line kinda sums up your viewpoint where mine would be more of:
You can build a tank that most heavy riders never have to worry about. I'm not sure what the goal is for the OP, but I was coming from that perspective.
Getting strong rims, is not A classic mistake. 350 lbs riders hitting potholes with an average strength rim is not a good idea.
Cycocommute you can leave the Condescension at home, you can have your opinion, but that doesn't make mine wrong or worth belittling. Why comment on an opinion that doesn't even state why I chose the way I did? Your post would have been valid without quoting my comments and definitely without "Classic Mistake" and "Let's just stop right there". Your points are good, but I think you are looking at the problem from a different angle than I am. The last line kinda sums up your viewpoint where mine would be more of:
You can build a tank that most heavy riders never have to worry about. I'm not sure what the goal is for the OP, but I was coming from that perspective.
02-08-13, 11:09 AM
#27
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Hi guys --
Interesting project.
An idea on targeting -- why not market strength and toughness, rather than targeting "obese"?
As for me, following the format you like:
Strength
- steel, triple-butted, high quality (Reynolds, Dedacciai, Columbus), preferebly oversized on DT
- lugged for strength
- King headset (amazing durability)
Seat comfort
- VERY personal. I like almost no padding, flatish profile. I've settled on a charge knife.
- stop calling it a seat. You're into biomechanics -- it's a saddle. It should be a perch, not a seat
Gearing
- road, Pro-compact crank (52/36) and a tight cassette (12-25). Much closer gear ratios
Brakes
- long reach ultegra do fine for me
Tires / wheels
- tires -- contis, either GP4000s or GP 4000 all-seasons. 700X25 for a little cushion
- v-style rims, 28-36 spokes. I have Velocity deep-vs on ultegra hubs, DT Swiss RR585s on King hubs, and Ambrosio FCS28s on Dura-Ace track hubs.
Pains
- none
I should point out that I dropped from 250 to 205. My BMI is now right around 25. No idea if I'm the target demographic or not.
Oh, and I would not ride a step-through frame. Unless I couldn't ride a standard frame.
Interesting project.
An idea on targeting -- why not market strength and toughness, rather than targeting "obese"?
As for me, following the format you like:
Strength
- steel, triple-butted, high quality (Reynolds, Dedacciai, Columbus), preferebly oversized on DT
- lugged for strength
- King headset (amazing durability)
Seat comfort
- VERY personal. I like almost no padding, flatish profile. I've settled on a charge knife.
- stop calling it a seat. You're into biomechanics -- it's a saddle. It should be a perch, not a seat
Gearing
- road, Pro-compact crank (52/36) and a tight cassette (12-25). Much closer gear ratios
Brakes
- long reach ultegra do fine for me
Tires / wheels
- tires -- contis, either GP4000s or GP 4000 all-seasons. 700X25 for a little cushion
- v-style rims, 28-36 spokes. I have Velocity deep-vs on ultegra hubs, DT Swiss RR585s on King hubs, and Ambrosio FCS28s on Dura-Ace track hubs.
Pains
- none
I should point out that I dropped from 250 to 205. My BMI is now right around 25. No idea if I'm the target demographic or not.
Oh, and I would not ride a step-through frame. Unless I couldn't ride a standard frame.
Thank you so much for your input. This is exactly the kind of response I was looking for. Picture this...... a largely obese person has a hard time mounting his/her bicycle. So a step through frame is in order.... But to keep a traditional look there is a snap in top bar. What are your thoughts? -Gabe
02-08-13, 11:22 AM
#28
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I think everyone here mentioned 700c wheels but it seems that 26" wheels might be a better choice. I've always read and been told that the real weak point in a bike ridden by a very heavy person is the wheels. If a person is just doing normal riding on pavement or hard packed dirt, modern production frames are plenty strong enough. I ride a 1995 Trek hybrid and I weigh 400 lbs. I have no issues whatsoever with the strength of my frame.
Also, check out Peter White's website and the Tout model bicycles he carries. Even though they are only rated to 300 pounds (I think that's very conservative but I'm sure it's a result of lawyer's input) that's what I think of when I think about a bike for very heavy people.
Here is a link to the bike I'm talking about:
https://www.peterwhitecycles.com/tout-terrain.asp
Also, check out Peter White's website and the Tout model bicycles he carries. Even though they are only rated to 300 pounds (I think that's very conservative but I'm sure it's a result of lawyer's input) that's what I think of when I think about a bike for very heavy people.
Here is a link to the bike I'm talking about:
https://www.peterwhitecycles.com/tout-terrain.asp
Thanks so much for your input. This helps a lot- Gabe
02-08-13, 11:27 AM
#29
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As mentioned before a clearer definition of the target will help. Obese is not well defined.... over 300 lbs over 400 ??? and there is the skil set of the rider...new rider, returning after 30 years.....etc
and it might help if posters put there height/weight there.
and recognize it is an opinionated group. An example is the the step through frame. Many people who are experenced cyclist don't see the need, but a new cyclist at 450 lbs might consider this a godsend.
I am 6" and 270. I ride steel frame road bikes (drop bar and priest/postino style bars....not flat bards) with 32 spoke rims and have no problems with breakage.
if it were me I would build a city bike style
Step throught or mixte frame (maybe be off setting to some, but would be unisex, and has benefits for those with limited mobiliyt or concern about being able to put foot down and not hit frame)
nortth road styel bars (think english 3 speed )
700 cc wheels, 36 spoke able to take at least a 35mm tire
Brakes to cleare above.
thinks about simple gear setup.... single up front, many on rear (sram has a new mountain 1 x 11 setup)
make sure frame has eylets etc
avoid overpadded saddles
and it might help if posters put there height/weight there.
and recognize it is an opinionated group. An example is the the step through frame. Many people who are experenced cyclist don't see the need, but a new cyclist at 450 lbs might consider this a godsend.
I am 6" and 270. I ride steel frame road bikes (drop bar and priest/postino style bars....not flat bards) with 32 spoke rims and have no problems with breakage.
if it were me I would build a city bike style
Step throught or mixte frame (maybe be off setting to some, but would be unisex, and has benefits for those with limited mobiliyt or concern about being able to put foot down and not hit frame)
nortth road styel bars (think english 3 speed )
700 cc wheels, 36 spoke able to take at least a 35mm tire
Brakes to cleare above.
thinks about simple gear setup.... single up front, many on rear (sram has a new mountain 1 x 11 setup)
make sure frame has eylets etc
avoid overpadded saddles
02-08-13, 11:35 AM
#30
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I have read the above and agree with some of the points made. I would re-define clydesdales to BMI. There are many people greater than 200 pounds that are not carrying excess body fat. Easy on frames are a great asset for those who have BMI's >35. If this is a dream of yours to get into bicycle manufacturing, pursue it. I just watched Paulo's video on the catrike website and he tells of his dream to build bicycles in America. He was a mechanical engineer living in Brazil at that time. Look at him now.
I am a 340 pound guy with a BMI > 40. I have never purchased a special frame because of my size. My trek 5500 is carbon fiber and I rode several RAGBRAI's on it without any special wheels or any frame problems. Now I have a recumbent - catrike and exceed the weight recommendation by 65 # and load the bike with 20-25pounds of gear and do long distance rides. I did ride 4500 miles between May 2012 and 12/2012. I gave up the DF bike because of pressure on my perineum and subsequent numbness. This is not a problem with my trike. I think a crank forward design has merit, but remember that a very obese person may have difficulty getting going with a 2 wheel recumbent. Have fun, don't re-invent the wheel if you don't have to.
I am a 340 pound guy with a BMI > 40. I have never purchased a special frame because of my size. My trek 5500 is carbon fiber and I rode several RAGBRAI's on it without any special wheels or any frame problems. Now I have a recumbent - catrike and exceed the weight recommendation by 65 # and load the bike with 20-25pounds of gear and do long distance rides. I did ride 4500 miles between May 2012 and 12/2012. I gave up the DF bike because of pressure on my perineum and subsequent numbness. This is not a problem with my trike. I think a crank forward design has merit, but remember that a very obese person may have difficulty getting going with a 2 wheel recumbent. Have fun, don't re-invent the wheel if you don't have to.
02-08-13, 11:47 AM
#31
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Lots of good advice already, here's my two cents worth:
Even very large Clydes don't need radically redesigned frames, just a good sturdy frameset. A more relaxed geometry may be beneficial for comfort and stability. I like double butted high quality steel in a touring geometry. Lugged is an option but not an absolute. For extremely heavy riders and off road use you might want to include some gussets in high stress areas. Like Cyccomute said, it doesn't have to be a tank to be strong. I personally prefer steel as I find it comfortable at a reasonable cost, but AL and CF have also been used successfully for Clyde bikes. Step through designs have inherently weaker geometry and may require additional reinforcement. They will also appeal to a very narrow market. The frame must accommodate wider tires than some main stream road bikes. 32mm width would be the least I would accept on a road bike for a Clyde, 40+ on a trail or commuter bike. Not that everyone will use tires that wide, but they should have the option. Depending on the intended use, you will also have to look at mounting points for fenders, racks and accessories. Maybe even disk brakes.
Saddle comfort has way more to do with frame geometry and proper rider fit than it does with the saddle itself. The big point I want to make here is, it's a bike, not a barstool. An excessively upright seated "barstool" position on a wide cushy saddle is inefficient to pedal, more difficult to balance, and uncomfortable for anything other than occassional short cruises. Remember that saddle width is based on the width of the ischial tuberosities, not the size of the person's butt cheeks.
Gearing will depend on the intended use of the bike. If you are looking at general road riding, touring or offroad/trail riding, I'm a fan of a triple chainring with a fairly wide range cassette, something like a 12-28 in a 9-speed. Look at durable drivetrain components like Shimano Deore, LX, or XT (personal preference for my touring and trail bikes, there are other options). The triple chainring is an advantage over a compact double for Clydes as it gives you a low bailout ring for climbing.
Disc brakes would be a nice addition but any good solid double-pivot calipers or cantilevers would work just fine. Again, I picked Deore and LX for my most ridden bikes. I've got older double-pivot RX100s with Tektro levers on my roadie. Ultegra brake pads all around but again some people like Kool Stop or other brands/models.
You don't need battle cruiser wheels but quality and proper design/build are extremely important. My personal preference is 36 butted spokes on Deore LX hubs with double-wall eyeletted rims. The rims I chose were Salsa Delgado which are slightly wider than most road rims and are designed for touring or cyclocross. They take a wider tire nicely. I suggest you stick with either 26" or 700c/29er wheels for maximum tire availability and selection. As far as tires, that again will vary with rider weight and desired riding style. I'd stay away from anything under 28mm wide for morbidly obese riders. 28s are still just fine as a road or light touring tire. 32mm-38mm make good touring or commuter tires, trail and offroad will get beefier yet. I'm a fan of Specialized All Condition Armadillo Elites for road and touring and Schwalbe Smart Sams for trail riding and mixed surface touring. My local wheelbuilder also sold me on building 36 or more spoke wheels in a 4X pattern for both strength and comfort. For extremely heavy riders you might want to consider a 40-spoke + rear wheel on a tandem hub. The front wheel carries less weight and doesn't deal with drive train stresses, so 36-spokes on a touring or MTB hub should be strong enough.
As far as aches, pains, discomforts, you need to look at adaptability to fit the riders' needs. Some might need extensions to move the pedals slightly wider, different stem lengths and angles, setback seat posts, etc. Bike fit is very individualized and your design will have to be adaptable.
One part of your original post that concerns me is that you are planning to build "a" better bike for obese individuals. The problem there is that there is no one type of obese rider. You will need a range of bikes to suit various purposes and preferences. I know morbidly obese riders who are roadies, others who are endurance riders or tourists, utility/commuters, fitness riders, recreational cruisers, off road trail and MTBers.
Take a look at the offerings from Workman, Surly, and several other companies that have become the mainstays of bikes for obese riders. You might find that you are reinventing the wheel, so to speak. Of course, if nobody ever reinvented the wheel we'd all be driving around on wooden rims.
Contact your local bike shops and try to get in touch with a cross section of obese riders. Find out what they are riding and do a survey of what they do and don't like. Don't base your designs on what skinny or athletic people think that obese people need, go ask the big guys (and gals). Is anyone in your project group and avid cyclist? Are any of you obese cyclists? What experience does your group have in bicycle building and design in general?
Even very large Clydes don't need radically redesigned frames, just a good sturdy frameset. A more relaxed geometry may be beneficial for comfort and stability. I like double butted high quality steel in a touring geometry. Lugged is an option but not an absolute. For extremely heavy riders and off road use you might want to include some gussets in high stress areas. Like Cyccomute said, it doesn't have to be a tank to be strong. I personally prefer steel as I find it comfortable at a reasonable cost, but AL and CF have also been used successfully for Clyde bikes. Step through designs have inherently weaker geometry and may require additional reinforcement. They will also appeal to a very narrow market. The frame must accommodate wider tires than some main stream road bikes. 32mm width would be the least I would accept on a road bike for a Clyde, 40+ on a trail or commuter bike. Not that everyone will use tires that wide, but they should have the option. Depending on the intended use, you will also have to look at mounting points for fenders, racks and accessories. Maybe even disk brakes.
Saddle comfort has way more to do with frame geometry and proper rider fit than it does with the saddle itself. The big point I want to make here is, it's a bike, not a barstool. An excessively upright seated "barstool" position on a wide cushy saddle is inefficient to pedal, more difficult to balance, and uncomfortable for anything other than occassional short cruises. Remember that saddle width is based on the width of the ischial tuberosities, not the size of the person's butt cheeks.
Gearing will depend on the intended use of the bike. If you are looking at general road riding, touring or offroad/trail riding, I'm a fan of a triple chainring with a fairly wide range cassette, something like a 12-28 in a 9-speed. Look at durable drivetrain components like Shimano Deore, LX, or XT (personal preference for my touring and trail bikes, there are other options). The triple chainring is an advantage over a compact double for Clydes as it gives you a low bailout ring for climbing.
Disc brakes would be a nice addition but any good solid double-pivot calipers or cantilevers would work just fine. Again, I picked Deore and LX for my most ridden bikes. I've got older double-pivot RX100s with Tektro levers on my roadie. Ultegra brake pads all around but again some people like Kool Stop or other brands/models.
You don't need battle cruiser wheels but quality and proper design/build are extremely important. My personal preference is 36 butted spokes on Deore LX hubs with double-wall eyeletted rims. The rims I chose were Salsa Delgado which are slightly wider than most road rims and are designed for touring or cyclocross. They take a wider tire nicely. I suggest you stick with either 26" or 700c/29er wheels for maximum tire availability and selection. As far as tires, that again will vary with rider weight and desired riding style. I'd stay away from anything under 28mm wide for morbidly obese riders. 28s are still just fine as a road or light touring tire. 32mm-38mm make good touring or commuter tires, trail and offroad will get beefier yet. I'm a fan of Specialized All Condition Armadillo Elites for road and touring and Schwalbe Smart Sams for trail riding and mixed surface touring. My local wheelbuilder also sold me on building 36 or more spoke wheels in a 4X pattern for both strength and comfort. For extremely heavy riders you might want to consider a 40-spoke + rear wheel on a tandem hub. The front wheel carries less weight and doesn't deal with drive train stresses, so 36-spokes on a touring or MTB hub should be strong enough.
As far as aches, pains, discomforts, you need to look at adaptability to fit the riders' needs. Some might need extensions to move the pedals slightly wider, different stem lengths and angles, setback seat posts, etc. Bike fit is very individualized and your design will have to be adaptable.
One part of your original post that concerns me is that you are planning to build "a" better bike for obese individuals. The problem there is that there is no one type of obese rider. You will need a range of bikes to suit various purposes and preferences. I know morbidly obese riders who are roadies, others who are endurance riders or tourists, utility/commuters, fitness riders, recreational cruisers, off road trail and MTBers.
Take a look at the offerings from Workman, Surly, and several other companies that have become the mainstays of bikes for obese riders. You might find that you are reinventing the wheel, so to speak. Of course, if nobody ever reinvented the wheel we'd all be driving around on wooden rims.
Contact your local bike shops and try to get in touch with a cross section of obese riders. Find out what they are riding and do a survey of what they do and don't like. Don't base your designs on what skinny or athletic people think that obese people need, go ask the big guys (and gals). Is anyone in your project group and avid cyclist? Are any of you obese cyclists? What experience does your group have in bicycle building and design in general?
02-08-13, 11:48 AM
#32
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I am a personal trainer and an avid cyclist so I have an appreciation for what you guys are trying to do. There are so many variables that come in to play, many have already been mentioned. One thing that never gets mentioned is the biomechanics of individuals. I see many obese individuals who's biomechanics are so screwed up simply because they have gotten so obese that their thigh rub together and they need to externally rotate their legs. When cranksets on bikes are made, most of them are designed for the biomechanical movement of a lance armstrongs sized cyclist. While it is a myth that people are "big boned" and/or have massive differences in their structure, there are certainly going to be some tangible differences for the morbid obese. There is something known as "Q-Factor" within cranksets that has to do with the width of cranks but is an area that rarely gets discussed. Other areas for you to investigate would be bikes with "crank forward" designs and recumbents as another issue is often having a large belly impede with the ability to pedal.
From a materials standpoint, there are still a lot of myths about carbon fiber and that would be another area to investigate. I've seen video footage of Santa Cruz MTB's being tested for strength and their aluminum frames fail WAY before their carbon ones do yet there is a perception in the clydesdale world that we shouldn't ride carbon bikes.
As for my personal experience 6'3" 250lbs so not obese but heavy for a cyclist and my athletic background means I put a lot of power to the pedals. I've had no major issues with bike parts failing due to my weight. I've ridden 20/24 spoke carbon wheels and had them flex enough to hit the brake tracks with each pedal stroke on a hard climb but no breakage issues
From a materials standpoint, there are still a lot of myths about carbon fiber and that would be another area to investigate. I've seen video footage of Santa Cruz MTB's being tested for strength and their aluminum frames fail WAY before their carbon ones do yet there is a perception in the clydesdale world that we shouldn't ride carbon bikes.
As for my personal experience 6'3" 250lbs so not obese but heavy for a cyclist and my athletic background means I put a lot of power to the pedals. I've had no major issues with bike parts failing due to my weight. I've ridden 20/24 spoke carbon wheels and had them flex enough to hit the brake tracks with each pedal stroke on a hard climb but no breakage issues
02-08-13, 11:53 AM
#33
You gonna eat that?
Department of Integrative Physiology
I think that's what they're trying to do here.
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I stop for people / whose right of way I honor / but not for no one.
Originally Posted by bragi "However, it's never a good idea to overgeneralize."
02-08-13, 11:56 AM
#34
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Thank you so much for your reply. Do you think you would need a special bike if you were upwards of 400 lb.? even 500 lb.? I am going to redefine my audience right away to better to fit these criteria. We considered a recumbent at first, but it seems it has been done. We feel that people will still prefer to ride a traditional bicycle. You mentioned perineum pain... Do you think this could have been solved with a better saddle? -Gabe
Yes, people upwards of 400 and 500 lbs need special bikes. Someone like Shaq who is probably awfully close to 400lbs still needs a special bike because of his 7 foot height. Someont 6 feet and 400 lbs is pretty darn obese and may need something like a step through bike as you mentioned because swinging their leg over the seat is difficult. As for a drop in top tube to make the bike look like a traditional bike, that could be a cool concept for the image conscious I suppose but if I were 500lbs I may not care if my bike was a step through; I probably already know people are going to be looking at me funny just seeing me getting on a bike.
Something else to think about. Downhill MTB's have dropper posts. When you are climbing on a mtb you want your seat up high as it's the best position mechanically to generate power but when descending tough and steep hills, you want your seat low so that you can get your weight back and stay in balance and not go over the bars. A dropper post on a regular bike may be all that someone obese needs to be able to swing the leg over the seat and mount the bike. The issue however, would be having a dropper post durable enough to support that weight. I know presently there is only one on the market that gets good reviews from bigger guys.
02-08-13, 12:29 PM
#35
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Aluminum can break before steel with the same amount of force applied. I recently had a rear derailuer go into my spokes. I fortunately had a very good back wheel, the frame wound up bending before my spokes gave out. We were able to bend the frame back, I have to watch that area of the frame now, but aluminum would have either cracked or caused more stress on the wheel. I can't say the aluminum would have failed, but the mechanic though it would have. I am not trying to dis aluminum frames I think they are great, I think the higher up in weight you go the better steel is for the frame. I'm not sure where the switching point is that makes aluminum better than steel, but there is definately a point somewhere along there.
Getting strong rims, is not A classic mistake. 350 lbs riders hitting potholes with an average strength rim is not a good idea.
Cycocommute you can leave the Condescension at home, you can have your opinion, but that doesn't make mine wrong or worth belittling. Why comment on an opinion that doesn't even state why I chose the way I did? Your post would have been valid without quoting my comments and definitely without "Classic Mistake" and "Let's just stop right there". Your points are good, but I think you are looking at the problem from a different angle than I am. The last line kinda sums up your viewpoint where mine would be more of:
You can build a tank that most heavy riders never have to worry about. I'm not sure what the goal is for the OP, but I was coming from that perspective.
Getting strong rims, is not A classic mistake. 350 lbs riders hitting potholes with an average strength rim is not a good idea.
Cycocommute you can leave the Condescension at home, you can have your opinion, but that doesn't make mine wrong or worth belittling. Why comment on an opinion that doesn't even state why I chose the way I did? Your post would have been valid without quoting my comments and definitely without "Classic Mistake" and "Let's just stop right there". Your points are good, but I think you are looking at the problem from a different angle than I am. The last line kinda sums up your viewpoint where mine would be more of:
You can build a tank that most heavy riders never have to worry about. I'm not sure what the goal is for the OP, but I was coming from that perspective.
What you've said now is true and I have no issue with that statement. My issue is with your previous statement that steel bends and aluminum snaps. The failure mode isn't what you stated. Yes, aluminum is weaker than steel but being weaker doesn't mean that it is going to snap. The material just doesn't react that way. I've broken both materials in frames and I've broken both materials in parts. If anything, steel is the one that snaps off without warning. I've never experienced a failure of a steel part where it bent before breaking.
It's not the material that is the problem but the way in which it is used. Aluminum...properly designed and utilized...is a perfectly suitable material for a bike with a heavy load or for severe duty cycles. I have an aluminum touring bike...I don't worry about it. I have aluminum mountain bikes...I don't worry about them. There is no need to go to a steel frame just because the bike is designed to carry lot of weight.
As for wheels, worrying about the rim strength is a classic mistake, but you are in good company because nearly everyone makes the same mistake. Look at the wheel more closely. The rim doesn't hold up the rider. The rim is just a convenient place for the spokes to pull against. But the spokes are free to slide up and down on the rim because the rim is only under tension. You can put the lightest or heaviest rim you like on a wheel and the strength won't really vary.
But if the spokes are weak, the wheel will be weak. Let's say you built a wheel with Velocity Chukkers rims. Build it with 1.8/1.5/1.8mm spokes. It would be a scary wheel to ride but not because the rim isn't strong enough. It would be a scary wheel to ride because the spokes aren't strong enough. On the other hand, build up a set of wheels with Mavic XC-717 rims and 2.3/1.8/2.0mm spokes. The wheel is a joy to ride because it is strong and lightweight. I know this because I have exactly that wheel...and I've ridden it (hard) off-road for about 10 years without issue.
I stand by my statement that you can build a bike for a heavy rider without it having to be a tank. And the rider won't have to worry about it, either.
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Plan Epsilon Around Lake Michigan in the era of Covid
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Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
02-08-13, 01:12 PM
#36
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Thank you so much for your input. This is exactly the kind of response I was looking for. Picture this...... a largely obese person has a hard time mounting his/her bicycle. So a step through frame is in order.... But to keep a traditional look there is a snap in top bar. What are your thoughts? -Gabe
As I read this thread, I think the real issues are:
- really define the target. It seems to be obese below a certain threshold of flexibility -- fit enough to ride a 2-wheel traditional bike (no trikes, balance required), but not so fit as to be able to get on a traditional frame with a Top tube. That seems very narrow to me.
- geometry, given the above -- things like wheelbase, rake, trail and ST and HT angle will have a lot of impact on bike stability
- components, especially with an eye to durability / reliability and adjustment to body dynamics -- like the Q factor of the BB / crank / pedals, maybe stem adjustability, etc.
Seems your solution is some sort of frame (which, as other have pointed out, has been done) plus a careful selection of available parts, all of which exist, but tend to be sourced individually by folks on this board. Depending on what they need, what they want, and what the budget is, I could see it being things like:
- wheels. Very important once you're over 200.
- saddle
- bottom bracket and cranks / pedals. Buy for durability, length of crank arm and Q factor (including pedal width)
- brakes
- stem / bar combo
- headset. Nothing worse than a bad one, and a tricky part of a bike to get right
(and then, but only then, frame)
02-08-13, 01:17 PM
#37
You gonna eat that?
Not sure what you mean by that at all. It's just a bearing; what would make a "bad" headset?
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02-08-13, 11:43 PM
#38
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When you talk about people like Shaq you are talking about a very, very small percentage of people and the only way they are likely to get a bike that fits is custom.
Now if we are talking about morbidly obese people of more or less "average" skeletal frame and height you have a much larger population (not a pun as that would be in bad taste) to which you could market a mass produced or semi-custom product. Now you have to look at for whom in this group the product would be practical. There are lots of riders of average height in the 250 to 400 pound range who are physically capable of riding a bicycle. Once you get past 450 pounds, the percentage of people in that super morbidly obese range who are healthy enough and physically capable of riding a bicycle dwindles. I'm not saying there are none, just that many in that weight category have limited or no ambulation ability and health issues as well as body mechanics are often a limiting factor in the types of physical activity that can be tolerated. If a man can only walk 20 yards with a cane before becoming so winded he has to sit down, a bicycle really isn't appropriate, no matter how it is constructed. You have to pick a target market that you actually have a reasonable chance of helping. There is a point where a bicycle simply is no longer the answer, at least until other measures have been taken.
Now if we are talking about morbidly obese people of more or less "average" skeletal frame and height you have a much larger population (not a pun as that would be in bad taste) to which you could market a mass produced or semi-custom product. Now you have to look at for whom in this group the product would be practical. There are lots of riders of average height in the 250 to 400 pound range who are physically capable of riding a bicycle. Once you get past 450 pounds, the percentage of people in that super morbidly obese range who are healthy enough and physically capable of riding a bicycle dwindles. I'm not saying there are none, just that many in that weight category have limited or no ambulation ability and health issues as well as body mechanics are often a limiting factor in the types of physical activity that can be tolerated. If a man can only walk 20 yards with a cane before becoming so winded he has to sit down, a bicycle really isn't appropriate, no matter how it is constructed. You have to pick a target market that you actually have a reasonable chance of helping. There is a point where a bicycle simply is no longer the answer, at least until other measures have been taken.
Last edited by Myosmith; 02-08-13 at 11:46 PM.
02-09-13, 07:23 AM
#39
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There are many things on a bike that can go wrong that are not going to ruin your day -- you can get home easily enough with a little caution. On the few occasions when I have had HS issues, it has forced me to stop, because I like my steering.
02-09-13, 07:38 AM
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Good Luck, hope you learn a lot and do well. I would suggest you make two frames. Make the step through but keep in mind cycling is steeped in tradition and there is a reason a double diamond design has remained successful for a 100 years, it works! Not all clydes have mobility issues and when your target audience becomes more fit and flexible they will want another bike and it may as well be your bike.
02-09-13, 08:13 AM
#41
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When you talk of a step=through design, I see what you want to do, because due to decreased mobility, an obese person may have problems swinging their leg over a top bar. But this is remedied by leaning the bike over, not by a step through frame. A step through frame takes away stiffness and strength right where you need it most, creating the need to apply more material (e.g.Steel or Aluminium) to the joints and critical stress points on a step through frame. Step Through Frames are also passe even among female cyclists. You need a person on your team to handle engineering issues, as well as a person to look at marketing as it applies to bicycles. Look at somebody like ZinnCycles . They try to make the clydesdale equipment look like everybody elses bikes and gear. This is for a reason- I think the large or obese person does not wish to stand out as different or uncommon or eccentric.
02-09-13, 08:20 AM
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The step-through frame is a great idea---whatever the arguments in favor of the traditional double-diamond frame may be, many obese people would prefer not to be seen struggling to get a leg over the top tube.
But forget about steel as a potential frame material---a steel step-through frame would carry a large weight penalty compared to an aluminum step-through frame with respect to strength and reliability. The maximum practical diameter for a high-strength metal tube works out to about 1 1/4" (given the standard materials science guideline that the ratio of diameter to wall thickness of a metal tube should not exceed about 200 to 1). For applications such as a step-through bike frame for obese riders, where more strength is needed than a 1 1/4" metal tube can safely provide, aluminum is clearly the superior material, since the tube can be configured in a much larger diameter while staying well within the 200-to-1 diameter/wall thickness limit.
But forget about steel as a potential frame material---a steel step-through frame would carry a large weight penalty compared to an aluminum step-through frame with respect to strength and reliability. The maximum practical diameter for a high-strength metal tube works out to about 1 1/4" (given the standard materials science guideline that the ratio of diameter to wall thickness of a metal tube should not exceed about 200 to 1). For applications such as a step-through bike frame for obese riders, where more strength is needed than a 1 1/4" metal tube can safely provide, aluminum is clearly the superior material, since the tube can be configured in a much larger diameter while staying well within the 200-to-1 diameter/wall thickness limit.
02-09-13, 08:45 AM
#43
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My thoughts for what they are worth (I started riding at about 280-290 pounds and as far as I know never went north of 300).
People who are very heavy tend to find exercise tiring. It takes a lot of work to shift that kind of body weight around. With few exceptions people don't get to that kind of size by exercising regularly so you're going to be dealing mostly with people who haven't taken any meaningful exercise for a long time.
I felt very self-conscious when I first took to two wheels. My bike was a mountain bike but that was a comical idea because I could barely do hills let alone mountains. So there I was, this big sweaty guy struggling to get his bike to do much of anything, being overtaken by just about everything else (including young teenagers on bikes that squeaked and rattled a lot), and doing my best impression of an asthmatic hippo after even a gentle incline. Although at the time I was obese by BMI definition, at 6'4 people said I carried the extra weight well - I was visibly overweight but we're not talking the same kind of overweight as someone who is maybe 5'6 and weighs 280.
I'd imagine people weighing 100+ pounds more than I did at my heaviest, especially if they are also shorter, would have the same kind of self-conscious issues but even more so. My speed and stamina said "fat unfit person" so one thing I wouldn't have touched with a barge pole was any product that broadcast "fat unfit person" with nothing more than its branding.
So for all there's undoubtedly a market for such a product you'll have to consider the strength of the product you offer, the branding of it, and the fact a lot of folks just don't have much to spend on discretionary purchases coupled with the issue that the overweight may be reluctant to spend much at all because we don't know if we'll enjoy a particular type of exercise.
The only reason I spent £700 on a bike rather than the £200 I'd originally planned was because of feedback I saw and heard that got me thinking a £200 bike was something I'd break within six months.
People who are very heavy tend to find exercise tiring. It takes a lot of work to shift that kind of body weight around. With few exceptions people don't get to that kind of size by exercising regularly so you're going to be dealing mostly with people who haven't taken any meaningful exercise for a long time.
I felt very self-conscious when I first took to two wheels. My bike was a mountain bike but that was a comical idea because I could barely do hills let alone mountains. So there I was, this big sweaty guy struggling to get his bike to do much of anything, being overtaken by just about everything else (including young teenagers on bikes that squeaked and rattled a lot), and doing my best impression of an asthmatic hippo after even a gentle incline. Although at the time I was obese by BMI definition, at 6'4 people said I carried the extra weight well - I was visibly overweight but we're not talking the same kind of overweight as someone who is maybe 5'6 and weighs 280.
I'd imagine people weighing 100+ pounds more than I did at my heaviest, especially if they are also shorter, would have the same kind of self-conscious issues but even more so. My speed and stamina said "fat unfit person" so one thing I wouldn't have touched with a barge pole was any product that broadcast "fat unfit person" with nothing more than its branding.
So for all there's undoubtedly a market for such a product you'll have to consider the strength of the product you offer, the branding of it, and the fact a lot of folks just don't have much to spend on discretionary purchases coupled with the issue that the overweight may be reluctant to spend much at all because we don't know if we'll enjoy a particular type of exercise.
The only reason I spent £700 on a bike rather than the £200 I'd originally planned was because of feedback I saw and heard that got me thinking a £200 bike was something I'd break within six months.
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02-09-13, 09:47 AM
#44
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some of you guys don't seem to have even read the initial post! it's not to say that they ever wont launch this as a potential business but lets be real, it's a school project. Have fun with the project and don't limit yourselves! try any and everything and hopefully find some real world data on what works and what doesn't and why. Heck, there are bike share programs popping up in cities all over the place and they are building super durable bikes because they know people will beat on them and many of the ones I've seen are step through frames. A step through frame can be made plenty strong if done right.
02-09-13, 10:12 AM
#45
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Unless university level projects have changed a lot since I was in school (think quill and ink) practical application is a significant part of the final analysis and grade. After all, the purpose of university study is to prepare you for a career in the real world.
You are absolutely right about the bike share programs though. Most of them are geared toward college students and other short distance commuters which has limited crossover to the morbidly obese looking for a way to improve fitness. That style of bike is also very limited in scope of use. I do want to state that I am a big supporter of bike share programs for green reasons and general public health concerns, but how many people would choose those public share bikes for daily personal use?
You are absolutely right about the bike share programs though. Most of them are geared toward college students and other short distance commuters which has limited crossover to the morbidly obese looking for a way to improve fitness. That style of bike is also very limited in scope of use. I do want to state that I am a big supporter of bike share programs for green reasons and general public health concerns, but how many people would choose those public share bikes for daily personal use?
Last edited by Myosmith; 02-09-13 at 10:21 AM.
02-09-13, 03:14 PM
#46
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Gabe,
Saw your post on Clydesdale forum. “obese individuals” might offend some people. Call them “Clydesdales” near 350#.
It is an interesting posting. I am 6’4”, 230# and about 14% Body Fat. Fully kitted, I will weigh about 245#.
I have ridden with ex-football players who are huge and not obese. Chronically obese people (I picture a very very fat guy with 50% body fat) probably wouldn’t ride a bike.
But your premise on larger than normal riders is great. there is a huge market there.
I race against guys that weigh about 120#-175# and that in itself is a challenge.
First, check out this podcast from Cycling360 which addresses some of the issues you want to work on.
https://www.cycling360media.com/clyde...hena-cyclists/
they state that bikes and bike components are not designed for over 250# of weight. They will fail with bigger riders.
I used to have bike wheels go out of round just from the strength of my legs. I currently ride mavic ksyrium sl’s which hold up for me fine.
I ride a Giant XL (pun intended) that is holdihg up fine for me. It has a strong frame and built up stronger near the crank very well. It took me a long time to find a bike that would hold up for me.
Ergonimcally it is a good bike and a bike fit is the best way to be comfortable on the bike.
But listen to the podcast, you will get a lot of information on this.
Saw your post on Clydesdale forum. “obese individuals” might offend some people. Call them “Clydesdales” near 350#.
It is an interesting posting. I am 6’4”, 230# and about 14% Body Fat. Fully kitted, I will weigh about 245#.
I have ridden with ex-football players who are huge and not obese. Chronically obese people (I picture a very very fat guy with 50% body fat) probably wouldn’t ride a bike.
But your premise on larger than normal riders is great. there is a huge market there.
I race against guys that weigh about 120#-175# and that in itself is a challenge.
First, check out this podcast from Cycling360 which addresses some of the issues you want to work on.
https://www.cycling360media.com/clyde...hena-cyclists/
they state that bikes and bike components are not designed for over 250# of weight. They will fail with bigger riders.
I used to have bike wheels go out of round just from the strength of my legs. I currently ride mavic ksyrium sl’s which hold up for me fine.
I ride a Giant XL (pun intended) that is holdihg up fine for me. It has a strong frame and built up stronger near the crank very well. It took me a long time to find a bike that would hold up for me.
Ergonimcally it is a good bike and a bike fit is the best way to be comfortable on the bike.
But listen to the podcast, you will get a lot of information on this.
02-09-13, 04:20 PM
#47
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The estimates say I have 31% body fat now, I have lost 30ish pounds since I started riding. Why would you think we wouldn't ride? Riding is way easier on us than jogging or hiking. One of the points of this is how someone in that shape should be starting out riding. I'm having a hard time thinking of a cardio workout that would be easier on a bigger person than riding. Swimming comes to mind, but I can't think of others at the moment.
02-09-13, 04:28 PM
#48
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There are more than one kind of Clyde or Athena. I was the obese kind. Many others here are or were also obese.
02-09-13, 07:45 PM
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I was 6'5" and 400 + when I started lurking here and riding my Huffy Cruiser around looking for a better bike . 2-3 guys in my club started out the same way, so I never felt alone in my endeavor to lose weight riding a bike. I'm down in the 290's now, by no means finished but much better than before . I'll have to modify a lot of diet and exercise issues to get lower, but I have to. My case does not seem to be an exceptional one . I think your research , Gabe, can do a lot of people a lot of good . Keep up the good work , get some wheels under this project. Engineering, marketing and research are all good directions for you to explore at this juncture.
02-09-13, 08:44 PM
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I guess you haven't hung around the C/A forum much. I am not the target market for this bike because I am short so was never was too heavy for a conventional bike, though I certainly had comfort issues due to weight. But as near as I can determine in retrospect I was over 50% over body fat when I was heavy. One estimate put me at 58%.
There are more than one kind of Clyde or Athena. I was the obese kind. Many others here are or were also obese.
There are more than one kind of Clyde or Athena. I was the obese kind. Many others here are or were also obese.
And this is a Clydesdale:
And these are Clydesdales:
And so are these:
So to talk about a "Clydesdale bike" or a "Clydesdale style of riding" isn't particularly useful IMO. Is said Clydesdale bike designed for Sayre Kulp, or Nerys, or Little Darwin or Neil_B or 2Klose or Bautieri?