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Originally Posted by JoeyBike
(Post 5833100)
I weigh 150lbs. I am a very "light" rider as far as the abuse suffered by my road bike components. I don't normally just slam into things and stay light in the saddle all the time. I don't put much weight on the saddle, esp on rough surfaces and usually pedal a very tall gear to help keep my arse safe from the hammering saddle.
Vredestein Fortezza Tri-Comp tires. 700x23. No (undeserved) pinch flats. I run between 120 and 130psi on some very old Mavic Reflex 36 spoke conventional wheels. Not all that light, but bombproof - and not total slugs by any means. The tires are not "Race Day" tires, but one step heavier. The "Tri" stands for Three elements - 1. Hard center strip for speed going straight, 2. Gooey side strips for a-m-a-z-i-n-g cornering even on wet roads. The tires are billed as All-Weather tires. 3. A strip of "kevlar" type flat prevention that works well at holding the tread together even after a nasty gouge. I have three flats since August, two of them last week. Rare otherwise. The August was a pinch flat on the front tire from hitting the gate track at my old apartment complex waaaaay to fast. I shot a gap in traffic and wacked the sharp edge at 19-20mph. Went flat overnight. The next two flats were glass bits and both on the front tire! (hence, my new sig line). Never had three front flats in a row before. Got the last two flats on wet streets, so probably some broken glass that I continue to not see and run through. I try to stay in the auto tracks. Too much broken glass and building materials on the road in New Orleans to ride in the "gutter". I almost never use the lower gears. But when I do, it's nice to have them. There are some sweet short cuts around town that require a bit of off road riding through mostly mowed grass, but it varies. Probably could make due without the 26. BTW...no snow and ice down here pretty much EVER. If the streets where a mess with frozen precipitation tomorrow morning I would ride my Pugsley to work and ditch the 23s big time. I wasn't able to find any info on older Reflex clincher rims, currently Reflex is tubular only. but the setup yeilds a number of around 12 in the "intertia" calculation assuming 450g rims, which i suspect is pretty reasonable. a trick you might try to avoid small pinch & glass punctures: squirt a little Stan's sealant in your tubes. maybe 1oz or so - not much needed in 23's. You have to finagle with the valve stem a bit, but I find it's worth the hassle. I haven't gone completely flat on the road bike since doing this: might go down to 80psi or so, but retains enough pressure to finish the ride. Cheers |
Originally Posted by roadfix
(Post 5830433)
Unlike members of this forum, most commuters are not bike enthusiasts. They just want to get to work and lock up their $49 mountain bikes at their usual parking spot.
As a bike enthusiast, I take bike efficiency and practicality into consideration when choosing and setting up my bike as a commuter.......whether it be a mountain bike, road bike, or whatever....:) |
Originally Posted by cyccommute
(Post 5835869)
I don't know if that's valid. Considering the low number of bicycle commuters in the US (somewhere around 5 million), I'd suspect that most of them bicycle to work because they want to...not because they have to. In other words, enthusiasts. There are a few people that ride their $49 bikes to work but I see far more expensive bikes then cheap ones.
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Originally Posted by HiYoSilver
(Post 5827136)
3. they are not as choice of a thief target as a road bike
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There are far more of them to steal and more of a market for them.
I'm thinking bents are stolen the least. |
Originally Posted by cyccommute
(Post 5835869)
I don't know if that's valid. Considering the low number of bicycle commuters in the US (somewhere around 5 million), I'd suspect that most of them bicycle to work because they want to...not because they have to. In other words, enthusiasts. There are a few people that ride their $49 bikes to work but I see far more expensive bikes then cheap ones.
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Originally Posted by acroy
(Post 5832011)
sure, all points are valid, 'cept the "average" mtb commuter hasn't voiced up yet, so i don't know what they use! I took a guess based off what i've used & seen used. personally i've gone all the way down to 195g, 1" tires, and up to 600g 2" tires.
feel free to plug this into your own spreadsheet & play around. it's facinating seeing how much of a difference lowering the rotating mass makes. if you have numbers for your setup I can plug them in. We'll see. |
Originally Posted by DataJunkie
(Post 5836003)
There are far more of them to steal and more of a market for them.
I'm thinking bents are stolen the least. |
Originally Posted by tjspiel
(Post 5836509)
I'll let you know when I can track down numbers for rim and tire weights. Comparing my Specialized RockHopper with stock wheels and tires to my Specialized Allez with stock wheels and tires will I'm guessing favor the road bike. The wheel diameter (including tires) of the two bikes is almost the same when I eyeball them and I would guess the substantially heavier MTB tire will tip the balance toward the Allez. It's admittedly skewed though because I doubt many roadies commute with 23's. On the other hand the stock rims on the Allez are on the hefty side for a modern road bike.
We'll see. |
FWIW, on the acceleration/inertia etc. subject here's my admittedly subjective/non-technical experience. 'Roadified' mtb: Mavic 717xc disc on XT hubs, Panaracer Pasela TG folding, 1.5" (about 410 grams), latex tubes; roadie: Mavic Open Pro on 105 hubs, Panaracer Pasela TG folding 25c, latex tubes. All up weight of the mtb is about 22 -23 lbs, using standard mtb front rings w/ Ultegra 9 sp. road cassette; roadie 50/34 compact with usual cassette, all up about 19/20lbs. Ride position on the mtb mimics 'relaxed on the hoods' on the roadie.
1.Acceleration from stop: BluePig(mtb), hands down. Whether intrinsic to the bike differences, or to do with the fact that BluePig just suits my abilities better, for me the difference is pretty startling. This remains the case through low to middling speeds. However, 2. Once moving along well, this changes to favour the roadie, which I guess stands to reason -- roadies are optimized to handle well/accelerate at speed, xc mtb's to do the same at (relatively speaking) slow to moderate speeds. 3. The other major difference I've observed time/time again is that once up to speed, it is easier to maintain consistency on the roadie, i.e. over rolling roads etc. Here I think the same thing that creates effect #1 creates this: the greater inertia of the larger wheel, due not so much to all-up weight as to the distance of that weight (rim/tire/tube) from the rotating centre, and to the fact that a larger diameter wheel does have slightly less rolling resistance to sharpish-edged surface irregularities (the 'angle of attack' effect). So, for me/my conditions: BluePig in the city/MUP etc., roadie on longer rides out on open road. |
[QUOTE=Sawtooth;5829710]
Originally Posted by badger1
(Post 5829562)
"My roadbike is sooooo much faster than a mtb". Is that so, 'Lance'? Maybe slightly better elapsed time/distance on a long commute over open roads (and/or into a headwind), but otherwise not likely: laws of physics etc. are rather against this one. (We're not talking group rides/paceline here -- those are different conditions). All depends on the rider, and on prevailing conditions on one's commute. I know, beyond doubt, that my blue-pig atb is in fact slightly quicker over my route than my roadie; if my route were different (more 'open'), the converse might well be true -- it all depends. In either case, for MOST OF US, there's not a h_ll of a lot in it.
QUOTE] Yeah, I am going to have to agree with this one. I am almost solely a road/cross bike commuter. My friend commutes on his mid 1990's raleigh mtb with slicks and fenders. We rode 13 miles home together the other day at 25 mph and he had no problem whatsoever keeping up. I think the key to making an mtb fast is to drop the handlebar relative to the seat and put some good slicks on there. Presta......a fast mtb commuter. In another instance, we like to consider ourselves some hard core roadies but we rode the last 100 miles of a 200 mile day (Seattle to Portland 2006) at 21-23 mph with a GIRL on a gary fischer MTB with slicks. She did not hang on the front very much but neither did most of the folks in our group. She was incredibly strong, but that gave me a new respect for the versatility of the mtb chasis a foundation for all kinds of possibilities. For me, I simply prefer the drop bars and I like the bigger wheels. My cross bike can do just about anything as well. Heck, for that matter, my 23 mm road tires actually perform pretty well off road as long as I maintain reasonable expectations about their traction in turns. There is no doubt in my mind that the lower rolling resistance and lighter weight of the road bike make a big difference to the amount of effort I have to put in to ride to/from work quickly and efficiently. |
Yeah, I'll echo SDRider's comments. My observations come from me trying both(well, mtb, cross bike, road bike and hybrid) on my commute. I can almost drop my friend on my cross bike while he rides a Tarmac SL2. Does that mean the $7500 Tarmac is slow? This isn't an apples to apples comparison.
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Originally Posted by SDRider
(Post 5836918)
There is no doubt in my mind that the lower rolling resistance and lighter weight of the road bike make a big difference to the amount of effort I have to put in to ride to/from work quickly and efficiently.
So small that I basically just pick a bike at random in the morning (provided they are all actually functional). Your point about dropping/not dropping people being a meaningless comparison is correct, however. |
Originally Posted by tjspiel
(Post 5836509)
I'll let you know when I can track down numbers for rim and tire weights. Comparing my Specialized RockHopper with stock wheels and tires to my Specialized Allez with stock wheels and tires will I'm guessing favor the road bike. The wheel diameter (including tires) of the two bikes is almost the same when I eyeball them and I would guess the substantially heavier MTB tire will tip the balance toward the Allez.
mtb: 22" rims road: 622mm (24.5") rims so anyway: say a speed-oriented commuter used 25c tires on his 700c wheels, the diameter of his wheel would be 26.5in. If the same guy used 1" tires on his mtb, the wheel diameter would be 24 inch. using equivalent rims etc, the smaller wheel would have around 20% less inertia. this is just a guesstimate. the road bike not only has the heavy parts of the wheel farther away from the axis, but since the rim & tire are also physically larger, everything else being equal, they weigh more too! anyway, this is mostly conjecture. road bikes are obviously more fit for the road than any mtb, and if smaller wheels made road bikes faster, they probably would have adopted them. Smaller wheels have higher rolling resistance also, which comes becomes a bigger factor the longer the rides are. as it is, wth rough roads & a lot of starts & stops, the mtb feels more suited for my situation. if i ever get smoother roads & fewer stops, you can bet I'll be on a road (or cross) bike. |
Originally Posted by NoRacer
(Post 5802006)
I think your "sample" is skewed. Many of us commuters ride something like this:
http://img.photobucket.com/albums/v2...D/DSC00622.jpg http://i253.photobucket.com/albums/h...et/lilMule.jpg |
Originally Posted by acroy
(Post 5837268)
<snip>
so anyway: say a speed-oriented commuter used 25c tires on his 700c wheels, the diameter of his wheel would be 26.5in. If the same guy used 1" tires on his mtb, the wheel diameter would be 24 inch. using equivalent rims etc, the smaller wheel would have around 20% less inertia. this is just a guesstimate. the road bike not only has the heavy parts of the wheel farther away from the axis, but since the rim & tire are also physically larger, everything else being equal, they weigh more too! <snip> The rim on a typical road bike obviously has a larger diameter but they are usually thinner than MTB rims. Typical MTB tires I would guess are MUCH heavier than a typical road bike tire and I might just throw my tubes on a scale because I bet the MTB tubes are heavier too. I think you can make the argument that you could get an MTB wheel/tire combo that has less inertia than a typical road bike wheel/tire combo but then again you can also get some very light road rims and tires or for that matter there are road bikes that use 650C rims. In other words by choosing certain tire/rim combos you can stack the deck one way or another. Unless you're using typical sizes I'm not sure what value the argument has. |
Originally Posted by tjspiel
(Post 5838028)
The problem I have with the numbers you're using is that while 25c is a common size for a road tire, 1" is NOT a common size for a MTB tire. By choosing a tire that small you're eliminating the softer ride, the go anywhere capability and the flat resistance that many here claim as MTB advantages.
The rim on a typical road bike obviously has a larger diameter but they are usually thinner than MTB rims. Typical MTB tires I would guess are MUCH heavier than a typical road bike tire and I might just throw my tubes on a scale because I bet the MTB tubes are heavier too. I think you can make the argument that you could get an MTB wheel/tire combo that has less inertia than a typical road bike wheel/tire combo but then again you can also get some very light road rims and tires or for that matter there are road bikes that use 650C rims. In other words by choosing certain tire/rim combos you can stack the deck one way or another. Unless you're using typical sizes I'm not sure what value the argument has. for rim weights, take a look at Mavic or any other rim co's site. Their CXp rims are 470g+. Open Pro is 435. For mtb, their xc717 disc is 395g. xm 317 is 440. Assuming 26" rims are heavier than 700c rims is not valid - good general-purpose rim weights are pretty close mtb vs. road. And, this is a kicker, the 700c rims is bigger, so more inertia.... Of course, heavy duty mtb rims meant for freeride or whatever are heavy. So are 700c rims meant for touring or whatnot. standard Performance road tube is 117g. mtb tube is 176g. I'll give ya that - tho I bet a lot of mtb riders on skinnier slicks are using the smaller 26" tube, 129g. I sure was - couldn't stuff that fat tube in a skinny tire. fwiw, i converted my tires to tubeless early this year. On to tires - the $8 Forte City ST is 455g. The Slick City is 350, Fast City is 400, Michelin TransWorld are 700, my Conti Sport Contact are 370g, and my new Marathon Supremes are 595. so.... kinda hard to say what the "typical" is, as all are popular! For road bike commuter tires - i doubt many road bike commuters are using 200g uber-tires. I'll bet most are in the 26-32c range - and 300+ grams. The popular Gatorskins are 300g. so please plug your numbers in there & see what ya get. the math is straightforward & eye-opening. Really makes you want to take weight out of your wheels. On my personal bikes, the mtb has less inertia, more rolling resistance. On the road bike, I accelerate slower, but to a higher cruising speed. since my commute involves no more than about 1/2 mile of continuous cruising, and many stops/starts, i ride the mtb.... among other reasons. results may vary, and past performance does not guarantee future results ;) |
All this math is funny, it's like we're trying to numerically prove that one is better than the other. It's what ever you prefer. I think trying to argue the numbers is a waste of time. it's like trying to prove that red is better than blue.
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Originally Posted by Domromer
(Post 5838746)
. it's like trying to prove that red is better than blue.
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If smaller, heavier MTB tires were better in terms of efficiency/speed, then road bikes would use them... period. Racers look for any advantage they can get.
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Y'all are missing the point. What is easiest to track stand on trumps everything.
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Originally Posted by matthew_deaner
(Post 5833730)
It's usually about 40-miles, round trip. I mentioned this earlier - but my normal commuter is a Surly Long Haul Trucker with full racks.
The LHT is an awesome bike! If I could only own one bike, that would be it. Sweet. I built a LHT "prototype" years before Surly came out with their entry. I converted a 1989 Marin Pine Mountain ATB with no suspension. Recently I changed out the fork to a LHT fork and a King threadless headset. It is still going strong. Check it out on the Lewis and Clark trail in Iowa 1n 1995: My LHT prototype 1989 Marin Pine Mountain conversion |
Originally Posted by acroy
(Post 5835582)
a trick you might try to avoid small pinch & glass punctures: squirt a little Stan's sealant in your tubes. maybe 1oz or so - not much needed in 23's. You have to finagle with the valve stem a bit, but I find it's worth the hassle. I haven't gone completely flat on the road bike since doing this: might go down to 80psi or so, but retains enough pressure to finish the ride.
Cheers |
Originally Posted by JoeyBike
(Post 5838876)
Nice route. 40 miles is a hump. I know....my 18 month post-Katrina commute was 36 miles round trip at the shortest. Are you riding that route five days a week, or just when you can?
The LHT is an awesome bike! If I could only own one bike, that would be it. Sweet. I built a LHT "prototype" years before Surly came out with their entry. I converted a 1989 Marin Pine Mountain ATB with no suspension. Recently I changed out the fork to a LHT fork and a King threadless headset. It is still going strong. Check it out on the Lewis and Clark trail in Iowa 1n 1995: My LHT prototype 1989 Your LHT "prototype" really does look like a LHT! That's quite a load you have on there. If you ever get a chance to get a LHT, don't hesitate. It's a fantastic bike. One of the few bicycle-related purchases that I don't have some regrets or second thoughts about. It has been reliable and low maintenance, rides like a dream, carries incredible weight without a problem... I couldn't be happier. |
Originally Posted by matthew_deaner
(Post 5839128)
If you ever get a chance to get a LHT, don't hesitate. It's a fantastic bike. One of the few bicycle-related purchases that I don't have some regrets or second thoughts about. It has been reliable and low maintenance, rides like a dream, carries incredible weight without a problem... I couldn't be happier.
As for your commute, smart move cutting down to 4 days and getting that extra rest day. When I was stuck with the 18 miles each way I tried every trick in the book including switching to 4 days @ 10 hours a day working instead of 5 days @ 8 hours. That third rest day is key when you can get it. Keep on Truckin' ! |
Originally Posted by JoeyBike
(Post 5838944)
I use Stans in my Pugsley tires and it works awesome! Stans works best on low pressure tires, never thought of trying it on road tires. (Pugs can run 5 - 30 psi) And the presta valve is a real bugger to use with Stans.
now push the stem back into place, you might have to finagle it some. air it up a bit, then take the pump off the tube, let the air pressure help push the stem back into place. put the cap back on. ta-da! the cap will come all the way off again if you let it. hopefully you won't have to mess with that tube for a LONG time. the stan's will seal small holes (like thorns & glass) even at hi pressures. sounds worse than it is - first time i did it took about 10 min on one tube, now 2-3 min per tube. Time i'd much rather spend in the garage with my bike than on the road with a patch kit ;) i've been running this for the last year in all my tubed tires. road bike (100+psi) & wife's cruiser 60psi. had no ride-stopping flats! |
Originally Posted by acroy
(Post 5842123)
well here's the trick: using a set of wire cutters, lop off the very end of the Presta stem so you can unscrew the cap all the way off.
Originally Posted by acroy
(Post 5842123)
i've been running this for the last year in all my tubed tires. road bike (100+psi) & wife's cruiser 60psi. had no ride-stopping flats!
Originally Posted by acroy
(Post 5842123)
Time i'd much rather spend in the garage with my bike than on the road with a patch kit ;)
Yes...Stans rocks! |
Originally Posted by Domromer
(Post 5838746)
All this math is funny, it's like we're trying to numerically prove that one is better than the other. It's what ever you prefer. I think trying to argue the numbers is a waste of time. it's like trying to prove that red is better than blue.
Just say no the quantification of speed via mathematics. No matter what I wear, no matter what I ride, be it a 10,000$ BMC, or a 600$ used MTB, somewhere out there is a guy in jeans work boots and a leather jacket who can crank (with his heels seemingly) his 150$ wallymart bike, while smoking and carry a 12 of beer such that I have to work to catch him on my ride home at night. I think most of you know this guy, or his cousin. |
I've used a HRM and monitor my effort (or at least used to). With my summer mtn bike set-up, I typically cruise at around 14-15 mph on the road bike at a given level of effort. That same level of effort on my road-setup cyclocross bike is about 16-17 mph. Increases in effort are more evident on the cyclocross bike also. If I increase my effort by 10% (meaning up the Heartrate by 15 beats), I can get 18-19 mph out of the cross bike, but only improve to 15-16 on the mtn bike.
With a winter setup, the same level of effort nets me about 9-11 mph. So, if efficiency (speed per unit of power) was my primary concern, I'd always use the road bike setup. But its not. I like to cruise to work in my upright position on my cushy tires. I like to be more upright to see traffic, and with all the lights and batteries and such on my helmet, the more upright position eases strain on my neck. But, I only have a 5 mile commute. If I had a 10+ mile commute, I'd switch. |
Originally Posted by acroy
(Post 5831777)
I can't resist: here's an Inertia calculation:
I=MR^2 Diam Diam MTB 22 Road 24.5 Mass (atb/road): rim 400 rim 450 tube 150 tube 150 tire 350 tire 300 total 900 total 900 MTB Inertia 10.89 Road Inertia 14 road = 124% mtb This shows the road bike has 20-25% more inertia in the wheels. Assumptions: -Discounts the spokes, nipples, hub, etc. Inertia is related to the square of the radius, so stuff close to the center of rotation doesn't matter much anyway. -uses the "true" diameter of mtb rims (22") and 700c rims (24.5") -rim: nice mtb rim of around 400g, nice road rim of around 450g. -tube: i figure about the same for each, around 150g -tire: i used the "Nashbar Slick" wire bead 26x1.25 and Duro Road folding bead 700x26c tires. about what the *average* commuter uses... just a guess cause I havta put something there. the "inertia" number is just an index to compare one to the other. feel free to plug into your own spreadsheet & play around. edited for readability - copy/paste from execl to bf is iffy. Entry level Specialized Allez (2005) Rim: Alex DA-16 @ 540 g Tire: Conti Super Sport 25c @ 300g (actual tire is a Mondo 23c but few commute on 23c) Tube: 122 g Wheel Diameter: 27 inches (includes tire) Older Specialized Rockhopper Rim: Araya GP-710 @ 520 g Tire: Specialized Hardrock'r 1.95 @ 600g Tube: 192 g Wheel Diameter: 26.5 inches (include tire) The wheel inertia for the Allez is 17.53 and for the Rockhopper is 23.03 I used these bikes because they're what I have and have commuted on. I realize that with either bike you can do a lot better but I'm more interested in what's typical than what's possible. Putting really skinny tires and ultra-light rims on an MTB is messing with one of the identifying characteristics of that type of bike The main differences from your calculations is that I used a more typical MTB tire and used the diameter of the entire wheel including the tire instead of just the diameter of the rim. Any advantages with respect to interia the smaller MTB wheel rim gives is more than nullified by the larger tire. I'd also contend that you'll find lighter wheels on the road bikes of people who really care about such things than you will on MTBs. I don't think you'll see many sub 300g tubular rims on an MTB. |
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