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  1. #1
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    torn between titanium and steel

    I am going to get a steel or titanium bike. Having trouble making up my mind. I have heard that titanium gives a more compliant ride on rougher roads which is what I mainly ride on. But a friend of mine says that titanium bikes don't do well with riders around 200 pounds. I weigh 195. He is steering me towards steel. I went and rode a custom steel and loved it. Nowhere to test ride a titanium. So if I go with steel, he told me NOT to get powdercoat. He says you can't touch up a powdercoated frame very well. I have a hard time believing that but could be wrong. Please share your expertise on frames and paint finishes. Thanks

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    With lacquer you can melt in new material, though your chance of getting a seamless match are pretty low unless it goes back to a painter. Powder is good stuff, and it can be patched with other materials, I use crazy glue, which is very shear, and not too noticeable. There are those who say powder doesn't seal against water as well as other finishes, but that doesn't seem to be a problem in normal custom frame use. You want a beater to leave chained to a pipe out of doors...

    Ti isn't my thing, but I do think it is tough to get enough compliance out of a solid material. One extreme you have oodles of fork travel , on another you get a material with a little buzz difference. Even if the material has properties that are beneficial, there are still many other variables. I think if you want a particular ride, the only way to be sure is to test it in advance. That is the single problem with custom. Unless you get to ride an identical bike, you can't really be sure what you are getting. You should get a better frame custom, but which better frame can be tough to determine in advance.

    If your roads are rough rely on your tires. Torquing up your tires so they have theoretical rolling resistance advantages, when your body is getting hammered, is inefficient in direct relation to the amount of punishment you are taking. Large amount of punishment equals large amount of energy not going to forward motion. It turns out that on rough surfaces the lost energy from smoothing out the road with tires is less than from taking the beating.
    Last edited by NoReg; 11-22-10 at 04:05 AM.

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    Quote Originally Posted by jerrypare View Post
    I am going to get a steel or titanium bike. Having trouble making up my mind. I have heard that titanium gives a more compliant ride on rougher roads which is what I mainly ride on. But a friend of mine says that titanium bikes don't do well with riders around 200 pounds. I weigh 195. He is steering me towards steel. I went and rode a custom steel and loved it. Nowhere to test ride a titanium. So if I go with steel, he told me NOT to get powdercoat. He says you can't touch up a powdercoated frame very well. I have a hard time believing that but could be wrong. Please share your expertise on frames and paint finishes. Thanks
    Your friends titanium frame opinions are incorrect. Titanium bikes with properly sized tubes can and do work great for those over 200 pounds.

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    any recommendations on titanium frame brands? Lynskey, Habanero, Everti?

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    Hampsten and Eriksen would be on my short list if I was ordering custom titanium.

    My wifes frame and my frame have very different diameter tubes as mine was designed around supporting a fattie and hers was a stock size.

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    Quote Originally Posted by jerrypare View Post
    But a friend of mine says that titanium bikes don't do well with riders around 200 pounds.
    Your friend doesn't know very much about frame construction.

    Titanium, like steel, is just a material. The tubing that the builder picks, and the method of construction, are important.

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    I tend to agree with your friend's assessment of Ti and steel. I think Ti is an ideal material for smaller and lighter riders and that bigger riders may find it lacking. It's true what was said above that Ti bikes can be made stiffer using larger tubes - but not entirely true.

    Most of the tubes on a bike have no practical limit to the diameter of the tube that can be used so it's easy to design and build the frame with large main tubes - but the issue boils down to chainstays. Because we need to squeeze the chainstays into a small space left between the chainrings and the tire the size of the chainstays is limited to about 7/8" in most cases. This is what is used on most steel bikes and getting anything larger in their is near impossible without some serious stiffness stealing dents to give clearance. So when you combine this with the fact that Ti is much more flexible than steel you end up with the rear end of the Ti bike being much softer than the rear end of a steel bike.

    Some will counter by saying that you can use ovalized Ti chainstays to get more material in there to make it stiffer - but it has little effect. If you make the Ti stays 20 mm wide and say 30 mm tall (a big assed stay!) it will not be as laterally stiff as a round 22.2 mm steel stay. This is for two reasons. First is the obvious that Ti flexes much more than steel does. The second reason is that the oval stay is still not as large in diameter horizontally that the steel stay is. Any oval tube has the bending stiffness roughly equivalent to a round stay of the same diameter. So an oval Ti c-stay will behave in lateral flex about the same as a round Ti tube whose diameter is the same as the minor diameter of the oval. ........... I don't think I said that well. How about this? - a tall oval Ti c-stay that is 20 mm wide will flex about the same as a round Ti c-stay that is 20 mm in diameter.

    So you end up with a oval Ti stay that is stiff vertically and about the same laterally as a round Ti stay. There is very little to be gained here with diameter as long as the chainrings and tire are competing for space. But when you look at a steel stay you have the same amount of room so can fit the same diameter c-stay in there and because it's steel it will be MUCH stiffer.

    You will also see folks argue that if you put a big down tube in the bike that it will be stiff. It doesn't really work that way IMO. There are only two tubes that can and do transfer the power from the BB to the rear wheel and those are the chainstays. You can remove the down tube and make a bike that transfers power very well - i.e. the "Slingshot" bikes what have a cable instead of a down tube. The Slingshots had very stiff BB's because the chainstays were designed to do the job. Since the chainstays do the work of getting the power from the BB to the rear wheel they are the tubes that will make or break the power transfer of the bike. The chainstays see a combination of three loads - compression end to end, torsion, and bending. The compression loads are small and can for the most part be set aside while the other two are very dependent on diameter. And since the diameter that can be used is limited by the space to put the tube in then you really need to have a stiff material to get the job done and Ti just isn't stiff enough if you are a big guy.

    This is the reason I think Ti isn't great for big guys and that other materials like carbon or steel can be better. IMO big guys would be best off getting a steel or carbon bike designed with a big guy in mind and leave Ti to smaller and lighter riders.

    Thanks for reading all the above - I got wordy.

    Dave

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    Touching up a powder coating frame is not that difficult. If you stick with a standard non metallic color like red or orange then it's easy...black is easy to touch up. The trick to making a touch up look good is taping off the area around the scratch and then carefully priming the raw area. Steel will oxidize slowly as long as your not riding in the damp or salty areas. Touching up the frame is always a wise idea.

    In theory powder is stronger than paint. A powder coat is a great way to save money on your new frame.

    I'd love to have a titanium frame but it is rather cost prohibitive. The cost of a custom steel can likely be the same as the titanium because most titanium frame builders do not make a titanium fork to match the bike. Today it seems a lot of steel frame builders are not expressive in a good fork bend.

    I'd go with a steel frame because the artful interpretation of the lugs is more eccentric than the flat brushed look of titanium. Overized tubing and lugs would be the way to go in my opinion. Consider the builder to allow your frame to allow bigger tires.

    Running a 35C tire at reduced pressure in the 55-60PSI range offers a good feeling on smooth pavement. Most people are running tiny tires on bad pavement these days. A good plush tire sure beats the heck out of a racing tire with a minimal diameter and harder casing.

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    As far as I know, with my degree in not-an-engineering, ovalizing a round stay increases it's stiffness in direct proportion to the increase in width perpendicular to the load . A racetrack oval or squarish section will add a lot to stiffness, around 60%. But whatever can be done in Ti can be done in Steel, so

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    Quote Originally Posted by Peterpan1 View Post
    As far as I know, with my degree in not-an-engineering, ovalizing a round stay increases it's stiffness in direct proportion to the increase in width perpendicular to the load . A racetrack oval or squarish section will add a lot to stiffness, around 60%. But whatever can be done in Ti can be done in Steel, so
    I think you are right on. Making the stay ovalized makes it stiffer in one direction (against the major axis) and less stiff in the other direction (against the minor axis) as compared to a round tube. If there was room for the stay to be ovalized with the major axis being horizontal than there would be much to gain but since this is the direction where we are very limited in room its not really feasible.

    You are also correct that the profile and shape of the oval would have a large effect. In fact if the stay was rectangular or square you could get more lateral stiffness from it in a given amount of room. The issue here is one of failure. With a round or even oval stay you can flex it a good long ways without issue but with a tube with flat sides (or squarish oval if you will) you put a tremendous load on those flat sides and they become very prone to beer-canning/buckling. To alleviate this one needs to make the tube walls very tick and any weight savings one gains from the material is long gone. This is why we so seldom see tubes other than round or oval in a bike.

    Time for bed here. Lots of fresh snow to play in in the morning.

    Dave

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    Quote Originally Posted by Dave Kirk View Post
    I tend to agree with your friend's assessment of Ti and steel....

    This is the reason I think Ti isn't great for big guys and that other materials like carbon or steel can be better. IMO big guys would be best off getting a steel or carbon bike designed with a big guy in mind and leave Ti to smaller and lighter riders.

    Thanks for reading all the above - I got wordy.

    Dave
    Very interesting, and counter to my own experience (as a rider, not a builder). I'm big - I have a Ti bike w/fat chainstays - and don't see any problems w/flex. Could be that I'm just a weakling (?).


    Dave - what would be your cut-off point if a customer came to you and said they were indifferent between steel and Ti - by "cut off", I mean, at what weight would you recommend someone favor steel over ti? (recognizing that you may not have an absolute rule).
    Last edited by BengeBoy; 11-27-10 at 06:28 PM.

  12. #12
    Have bike, will travel Barrettscv's Avatar
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    I have several steel bikes in Reynolds 531 and Tange Prestige and a made-by-Lynskey Ti bike.

    Hands down, The Lynskey bike is stiffer by a large margin. I'm 210+ lbs.


    Michael
    Last edited by Barrettscv; 11-27-10 at 06:10 PM.

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    Quote Originally Posted by BengeBoy View Post
    Very interesting, and counter to my own experience (as a rider, not a builder). I'm big - I have a Ti bike w/fat chainstays - and don't see any problems w/flex. Could be that I'm just a weakling (?).


    Dave - what would be your cut-off point if a customer came to you and said they were indifferent between steel and Ti - by "cut off", I mean, at what weight would you recommend someone favor steel over ti? (recognizing that you may not have an absolute rule).
    Hey,

    Thanks for the reply. You are right, there is no hard and fast cut off where if you weigh a given amount Ti is fine and if you gain 10 pounds that it will suddenly suck and steel will be your only choice. If the rider is big and powerful an aggressive I think that a steel bike can be made that will outperform a Ti bike. Note I said a steel bike 'can be made' and not 'any steel bike would be better'. One can make stiff or soft steel bike just as one can make stiff or soft Ti bikes - it's just that the stiffest steel bike will be stiffer than the stiffest Ti bike due to the properties of the materials and the size constraints of the chainstays.

    If on the other hand the rider is big and not aggressive and rides at a steady pace and doesn't climb or sprint a lot then the Ti can be great...... it's light and tough and gives a very nice ride..... But if this guy gets fitter and more aggressive and wants to climb and sprint a lot he may find the Ti bike lacking.

    I'd hesitate to put a number to it. I've known strong racers who are big for racers at 180 pounds and they could not get a Ti bike to work well for them. So I think it all depends. If someone came to me and wanted my advice as to what material would be best I'd get their size and weight and have them answer lots of questions about how they ride and how the bike will be used and only then could the most appropriate material be chosen.

    This is IMO, like most things in life and it is nuanced. There is no one right answer and anyone who tells you otherwise is wrong. Does that make sense?

    Dave

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    Quote Originally Posted by Barrettscv View Post
    I have several steel bikes in Reynolds 531 and Tange Prestige and a made-by-Lynskey Ti bike.

    Hands down, The Lynskey bike is stiffer by a large margin. I'm 210+ lbs.


    Michael
    Hey Michael,

    I think it's important to remember that I'm not comparing all (or any) Ti bikes will all (or any) steel bikes. I'm talking about designing bikes for a big guy and what can be done with the two materials. No doubt your steel bikes have 531 or prestige stays and they are most likely ROR (round-oval-round) in profile as most stays were made back in the day. They are also very thin and therefore not very stiff. I have no doubt that a modern Ti bike can be made stiffer then either of these. But with modern steel stays using a constant round profile and a thicker wall could be made stiffer than most any Ti chainstay that will fit between the tire and the chainring.

    It all comes down to the design,the material and the tube diameters and walls chosen. One can't say bikes of one material are heavy/stiff/flexi or what ever and that bikes made of another material are the opposite. It's not just the material but what the builder choses to do with it.

    Way back in the day I built the bikes that Davis Phinney and the Coors Light team used and I could never put a Ti bike under Mr. Phinney that he liked because they were never stiff and responsive enough in the rear end for him. So even though it was heavier he opted for a custom steel bike with beefy chainstays that was painted to look like a Ti bike to race on (Serotta was the sponsor and wanted to promote the Ti bikes).

    So, in the end, saying your Ti bike is stiffer then your steel bikes means just that - that your Ti bike is stiffer the the steel bikes that you have experience with and is not an indication of the materials but one on the designs. One can't effectively compare materials that way IMO.

    I hope that makes sense - I'm too tired and hungry after skiing all day so my words might not be the goodest.

    Dave

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    Dave,

    your argument makes sense, but is it not the case that when presented with a rider profile for which you would choose a heavier guage chainstay in steel (say 1.0 mm instead of 0.7 mm) you could use a heavier guage Ti tube (say 1.6mm wall rather than 0.9). The Ti tube will still be something like 20% less stiff than the steel one but when combined with the higher stiffness of the other Ti main frame tubes (due to their larger diameters) the overall stiffness would be OK.

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    Quote Originally Posted by Dave Kirk View Post
    Hey Michael,

    I think it's important to remember that I'm not comparing all (or any) Ti bikes will all (or any) steel bikes. I'm talking about designing bikes for a big guy and what can be done with the two materials. No doubt your steel bikes have 531 or prestige stays and they are most likely ROR (round-oval-round) in profile as most stays were made back in the day. They are also very thin and therefore not very stiff. I have no doubt that a modern Ti bike can be made stiffer then either of these. But with modern steel stays using a constant round profile and a thicker wall could be made stiffer than most any Ti chainstay that will fit between the tire and the chainring.

    It all comes down to the design,the material and the tube diameters and walls chosen. One can't say bikes of one material are heavy/stiff/flexi or what ever and that bikes made of another material are the opposite. It's not just the material but what the builder choses to do with it.

    Way back in the day I built the bikes that Davis Phinney and the Coors Light team used and I could never put a Ti bike under Mr. Phinney that he liked because they were never stiff and responsive enough in the rear end for him. So even though it was heavier he opted for a custom steel bike with beefy chainstays that was painted to look like a Ti bike to race on (Serotta was the sponsor and wanted to promote the Ti bikes).

    So, in the end, saying your Ti bike is stiffer then your steel bikes means just that - that your Ti bike is stiffer the the steel bikes that you have experience with and is not an indication of the materials but one on the designs. One can't effectively compare materials that way IMO.

    I hope that makes sense - I'm too tired and hungry after skiing all day so my words might not be the goodest.

    Dave
    Hi Dave,

    I agree with your general point and wish I was skiing too!

    While my vintage 531 framed bikes were excellent for the day, it is no surprise that a modern Ti bike out-performs a vintage bike. BTW I have a 1973 Schwinn Paramount and a 1987 Trek 400. I also have a modern 2008 Soma that is made from Tange Prestige.

    My 2008 Lynskey is well crafted and is also an improvement on earlier Ti bikes I have seen.

    I've seen some of the better modern steel Waterfords and would like to do a side-by-side comparison of a $2000 - 3000 ti bike frame and a $2000 - 3000 steel bike frameset from a high end fabricator.

    What steel framed bikes would you compare to a Lynskey Sportive, which is one of their more basic framesets?


    Michael
    Last edited by Barrettscv; 11-27-10 at 08:06 PM.

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    Quote Originally Posted by Dave Kirk View Post
    If on the other hand the rider is big and not aggressive and rides at a steady pace and doesn't climb or sprint a lot then the Ti can be great...... it's light and tough and gives a very nice ride..... But if this guy gets fitter and more aggressive and wants to climb and sprint a lot he may find the Ti bike lacking.
    Dave,

    Thanks for taking the time to reply.

    I think the description above probably describes me: "big and not aggressive." I'll just have to be careful not to get too fit. Time to go grab another beer...

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    Quote Originally Posted by Mark Kelly View Post
    Dave,

    your argument makes sense, but is it not the case that when presented with a rider profile for which you would choose a heavier guage chainstay in steel (say 1.0 mm instead of 0.7 mm) you could use a heavier guage Ti tube (say 1.6mm wall rather than 0.9). The Ti tube will still be something like 20% less stiff than the steel one but when combined with the higher stiffness of the other Ti main frame tubes (due to their larger diameters) the overall stiffness would be OK.
    I see your point and it comes down to degrees I think. Will the bike work even with stays that are 20% less stiff? Of course it will and the rider would probably love it. I look at it a slightly different way and when I design a bike never rely on the main tubes to contribute the the drivetrain stiffness. The main tubes are very ineffective in stiffening up the drivetrain. It's so often overlooked but the chainstays are the only tubes that can transfer the power from the BB to the rear wheel. If the stays are flexi then drivetrain will be flexi and the size of the down tube will make no difference.

    Again - going back toe OP's question. He's a big guy and wonders what material would be best for him. I contend he could be happy with most any material while at the same time think that he could be better served by a bike with a stiffer drivetrain......... and making the drivetrain stiffer with Ti is more difficult and less effective.

    I make steel bikes but I love all bikes regardless of material. I have an engineering friend who once told me "there is no such thing as a bad material, just a bad application" and to me this makes sense. Riders of different weights and sizes can benefit from different materials and designs. I just like seeing people get bikes that are best for them based on the mechanics and properties of the bike and to not get hung up on a specific material or fad. And of course 'best' or 'better' is a matter of degrees and two things can be great while one of them is a bit better. For a big guy I think steel is better. On the other hand if you are 4'11" and weigh 95# then I think you might be better served with Ti.

    Time for leftover pie!

    Thanks again for reading.

    Dave

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    Quote Originally Posted by Barrettscv View Post
    Hi Dave,

    I agree with your general point and wish I was skiing too!

    While my vintage 531 framed bikes were excellent for the day, it is no surprise that a modern Ti bike out-performs a vintage bike. BTW I have a 1973 Schwinn Paramount and a 1987 Trek 400. I also have a modern 2008 Soma that is made from Tange Prestige.

    My 2008 Lynskey is well crafted and is also an improvement on earlier Ti bikes I have seen.

    I've seen some of the better modern steel Waterfords and would like to do a side-by-side comparison of a $2000 - 3000 ti bike frame and a $2000 - 3000 steel bike frameset from a high end fabricator.

    What steel framed bikes would you compare to a Lynskey Sportive, which is one of their more basic framesets?


    Michael

    The skiing was very good for any time of year let alone November - it was awesome for November.

    I'm sorry but I don't know enough about the Lynsky to speak with any intelligence about it. So rather than make a guess I leave this answer blank.

    Time for pie!


    Dave

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    I'm 6"3 and 250 lbs and am a big powerful guy. I've been riding high end road bikes for 30 plus years and have owned just about everything. I have had a Moots VaMoots going on 5 years or so and love it. I expect I will have it for a very long time. No reason at all that big guys can't ride Ti. I like seeing steel make a comeback but good Ti frames have a special ride quality, they don't corrode, they don't chip or ding, and they are still pretty light which is not a big issue for me but nice to have.

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    Quote Originally Posted by Dave Kirk View Post
    I just like seeing people get bikes that are best for them based on the mechanics and properties of the bike and to not get hung up on a specific material ...
    I agree with this and feel that proper tubing choice and design can take care of differences in the material properties. Your concerns about the stiffness of the rear triangle of a Ti frame would seem to apply at least as much to Al frames, yet I don't hear any complaints about inadequate stiffness of Cannondales and Kleins when used by big strong riders.

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    I continue to think that a modern titanium frameset made from oversized tubes is more than stiff enough for a big rider who is not racing.

    Based on my own experience, I cannot agree with the idea that lighter riders only should consider titanium.

    I consider my Soma to be a well made steel bike, Tange Prestige is a very good quality heat treated steel. Yet the bike simply does not accelerate or climb as well as the ti bike. I could not get the steel bike up to higher speeds in the 25 to 35 mph range unless I was on a slope. The titanium bike, on the other hand, is much better at climbing and will sprint to 33 mph without assistance from wind or gravity. The two bikes could not be more different in this respect.

    Some of my century rides feature 15 to 22% grades and the titanium bike allows me to make the most of every pedal stroke. The steel bike will also climb the grades, but with more effort and less speed. On a 200k, ride the small differences do add up.

    I somewhat disagree that the chainstays provide all the power to the wheels. The chain provides the power, and the frameset may flex, which will reduces some of that power. All that is required is that the BB and rear axle be able to hold the bearings in place without unwanted flex. Its not especially important if the bearings are held rigid by the chainstays, seattube or down tube. All that matters is that the bearing housing not flex in a way that absorbs power.

    I have seen 75hp chain driven systems in industrial application where the motor and the material handling systems were set on two different structures. As long as both structures are rigid, the only power loss is the 2% mechanical loss in the chain itself.

    I'm planning on replacing the Soma to get a stiffer frame that can also be used for light touring. I'll use steel or ti. Based on experience, ti has all the advantages.
    Last edited by Barrettscv; 11-28-10 at 08:24 AM.

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    Quote Originally Posted by prathmann View Post
    I agree with this and feel that proper tubing choice and design can take care of differences in the material properties. Your concerns about the stiffness of the rear triangle of a Ti frame would seem to apply at least as much to Al frames, yet I don't hear any complaints about inadequate stiffness of Cannondales and Kleins when used by big strong riders.
    I agree - you rarely hear people complaining about aluminum frames not being stiff enough. If you hear any complaints they concern ride comfort due to the very large tubing diameters most often used in aluminum bikes. If the OP asked what material, aluminum or steel, would be best for him based on his size I would have given much the same answer as I did with Ti. It all comes down to optimization. While there are many materials that will make for a very good bike that will make the rider happy for many years I still think that there are some materials that are a bit better for a given application and rider. This is not to say that if you are big that you should not like your Ti bike. If you have one and you like it what could be wrong? On the other hand if you go into this will a blank slate and ask what would be the absolute best for the big rider Ti might not end up being the ultimate choice.

    Dave

  24. #24
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    Quote Originally Posted by Barrettscv View Post
    I continue to think that a modern titanium frameset made from oversized tubes is more than stiff enough for a big rider who is not racing.

    Based on my own experience, I cannot agree with the idea that lighter riders only should consider titanium.

    I consider my Soma to be a well made steel bike, Tange Prestige is a very good quality heat treated steel. Yet the bike simply does not accelerate or climb as well as the ti bike. When I started riding with a group, I could not get the bike up to higher speeds in the 25 to 35 mph range unless I was on a slope. The titanium bike, on the other hand, is much better at climbing and will sprint to 33 mph without assistance from wind or gravity. The two bikes could not be more different in this respect.

    Some of my century rides feature 15 to 22% grades and the titanium bike allows me to make the most of every pedal stroke. The steel bike will also climb the grades, but with more effort and less speed. On a 200k, ride the small differences do add up.

    I somewhat disagree that the chainstays provide all the power to the wheels. The chain provides the power, and the frameset may flex, which will reduces some of that power. All that is required is that the BB and rear axle be able to hold the bearings in place without unwanted flex. Its not especially important if the bearings are held rigid by the chainstays, seattube or down tube. All that matters is that the bearing housing not flex in a way that absorbs power.

    I have seen 75hp chain driven systems in industrial application where the motor and the material handling systems were set on two different structures. As long as both structures are rigid, the only power loss is the 2% mechanical loss in the chain itself.

    The Soma is a better light touring bike, while the ti bike does not accept racks of fenders. I'm planning on replacing the Soma to get a stiffer frame that can also be used for light touring. I'll use steel or ti. Based on experience, ti has all the advantages.

    I agree with you. I think that a Ti bike can be more than stiff enough for a big rider and I certainly never said, nor meant to imply, that only small riders should consider Ti. My only point, which I seem to not be so good at making , is that if a big rider is asking what would be the ultimate best choice for them that for many the answer would be steel. And again, not all Ti is created equal just as all steel isn't created equal........... meaning you can make appropriate or inappropriate bikes from either and it's not a matter of one material being better than the other.

    I think that there is an optimum design and material for every rider. The key word(s) being 'optimum' and not 'one and only'. If someone owns a Ti bike, and loves it, that kicks butt and I never said that you shouldn't love it. And at the same time if a big guy were to come to me and ask for my professional opinion, based on my over 20 years of designing and building with both Ti and steel, I would lean toward steel for him.

    There is one place I disagree with you and that is your thoughts on the tubes that transfer power from your feet to the rear wheel. It seems overly simple to some but the reality of the situation is that while the down tube does give a feeling of stability to the BB is does nothing to provide efficient transfer of power from your feet, through the crank, into the chain and then into the rear wheel. The only tubes that have a mechanical advantage and are in a position to transfer the force from the BB to the rear wheel are the c-stays. In fact you can remove the down tube altogether and still have a very stiff BB and great energy transfer from the BB to the rear wheel (i.e. the Slingshot bikes). The down tube, along with the top tube, provides torsional rigidity to the front of the bike which will make it steer and handle as it should but contributes little to the efficiency of the rear end of the bike and power transfer from your feet to the rear wheel.

    Lastly, I think it's very important to not lump all similar materials in with one another. You have real world experience showing that your Ti bike is better for you than your steel bike and I would never argue with your findings or conclusion. I would however question if either of these materials were designed and used in the optimum way for you, your weight and how you will use the bike. Meaning that, as a big rider, a custom builder would pick specific tubes for you and your needs and I'll bet that both your Ti and steel bikes could be improved upon if you had a good custom builder design and build the bikes for you.......... and I think that if the designs were both optimized for you, your size, and how you ride that you would find that the steel bike would have a slight advantage over the Ti bike. The admittedly difficult thing in this is the fact that since they are custom built bikes you can't test ride them nor will most riders go as far as having two bikes built with differing materials so that they can compare them. This leaves the rider needing to ask the pro builder what they think would be best for them and then taking a small leap of faith and trusting them. If you are going to have a new bike built to replace your Soma I would suggest that you go to a builder like Tom Kellogg who offers both top shelf Ti and steel bikes and ask him what he feels would be best for you based on your needs. Only then can you be as sure as you can be that you will have the best thing for you.

    All the best,

    Dave

  25. #25
    Have bike, will travel Barrettscv's Avatar
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    Quote Originally Posted by Dave Kirk View Post
    I agree with you. I think that a Ti bike can be more than stiff enough for a big rider and I certainly never said, nor meant to imply, that only small riders should consider Ti. My only point, which I seem to not be so good at making , is that if a big rider is asking what would be the ultimate best choice for them that for many the answer would be steel. And again, not all Ti is created equal just as all steel isn't created equal........... meaning you can make appropriate or inappropriate bikes from either and it's not a matter of one material being better than the other.

    I think that there is an optimum design and material for every rider. The key word(s) being 'optimum' and not 'one and only'. If someone owns a Ti bike, and loves it, that kicks butt and I never said that you shouldn't love it. And at the same time if a big guy were to come to me and ask for my professional opinion, based on my over 20 years of designing and building with both Ti and steel, I would lean toward steel for him.

    There is one place I disagree with you and that is your thoughts on the tubes that transfer power from your feet to the rear wheel. It seems overly simple to some but the reality of the situation is that while the down tube does give a feeling of stability to the BB is does nothing to provide efficient transfer of power from your feet, through the crank, into the chain and then into the rear wheel. The only tubes that have a mechanical advantage and are in a position to transfer the force from the BB to the rear wheel are the c-stays. In fact you can remove the down tube altogether and still have a very stiff BB and great energy transfer from the BB to the rear wheel (i.e. the Slingshot bikes). The down tube, along with the top tube, provides torsional rigidity to the front of the bike which will make it steer and handle as it should but contributes little to the efficiency of the rear end of the bike and power transfer from your feet to the rear wheel.

    Lastly, I think it's very important to not lump all similar materials in with one another. You have real world experience showing that your Ti bike is better for you than your steel bike and I would never argue with your findings or conclusion. I would however question if either of these materials were designed and used in the optimum way for you, your weight and how you will use the bike. Meaning that, as a big rider, a custom builder would pick specific tubes for you and your needs and I'll bet that both your Ti and steel bikes could be improved upon if you had a good custom builder design and build the bikes for you.......... and I think that if the designs were both optimized for you, your size, and how you ride that you would find that the steel bike would have a slight advantage over the Ti bike. The admittedly difficult thing in this is the fact that since they are custom built bikes you can't test ride them nor will most riders go as far as having two bikes built with differing materials so that they can compare them. This leaves the rider needing to ask the pro builder what they think would be best for them and then taking a small leap of faith and trusting them. If you are going to have a new bike built to replace your Soma I would suggest that you go to a builder like Tom Kellogg who offers both top shelf Ti and steel bikes and ask him what he feels would be best for you based on your needs. Only then can you be as sure as you can be that you will have the best thing for you.

    All the best,

    Dave
    Hi Dave,

    Thank you for the detailed reply. And yes, the chainstays are very important to creating a rigid structure. I agree that the chainstays are also more important than the seattube or down tube in providing a stable support for the crankset and rear wheel. However, even if the downtube is in tension, the lateral rigidity of the downtube is critical to a rigid housing for the crankset. A BB without a rigid downtube would rock uncontrollably.

    I certainly think that steel can be as very rigid in the hands of a skilled builder. However titanium can be rigid, I have no doubts about that.

    I'll take a hard look at steel for my next bike. If the frame is truly stiff and meets my needs, I'll go with steel.

    Michael
    Last edited by Barrettscv; 11-28-10 at 09:26 AM.

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