Comfort - Tire Size v. Frame Material
 

Speaking with my LBS salesman, he was telling that the comfort of frame materials mostly only comes into play when riding a smaller tire like a 23 or 25. His assertion is once you get into the 28 and 30 size tires that aluminum is no diff than carbon or steel in terms of ride comfort. Agree/Disagree?

Agree.I have 5 aluminum bikes..Comfort comes from the PSI in tires.

Run tires from 700 X 18 to 700 X 40.

Call me skeptical (or even cynical), but I don't think frame material has any bearing on riding comfort. A standard bike is pretty close to a bridge girder in the vertical frame; it won't absorb any significant shock, so it won't make a difference in ride comfort. (Not I put that "significant" qualifier in; the possibility that someone can come along and use advanced engineering tools to calculate a 1 in a million difference is not significant.) Fork material might, but fork design is more likely (old, say 1960-70s road bikes had flexible forks that could soak up some shock).

disagree....there is a pretty good difference on the vibrations you actually feel that goes through the tires/wheels/frame/bars and seatpost. Plus there is the speed/efficiency lost when running fat tires beyond the 28c range.

If you can't feel the difference, then your roads are F'd up as bad as the ones here :lol:

tire size/volume and psi are going to make a much larger impact on the ride feel then the frame material will... but that isn't to say there isn't a difference in how each material will/can feel... even then not all frames of the same material are the same.

I have identical 700 x 25 tires on all my bikes, which I pump up to the same pressure. I also set up all three with pretty much the same fit, right down to identical saddles. I can tell you that there is a big difference not only between my carbon bike and my steel bikes, but also between the steel bikes. The CF bike just rides smoother over rumbly pavement, and even though the geometries are similar, the two steel bikes corner better than the CF, and one of them corners better than the other - like it already knows the best line, and the proper lean for each turn.

I agree with jsigone... frame material can make a difference - that said, doesn't mean one carbon frame is more comfortable than an aluminum one... depends on the bike, the actual material and the construction.

Tire size will help with comfort no matter what frame material. I ride on 25s or 28s which are way more comfortable than 23s and 32s are downright cushy but then - there is the rolling friction thing (although I have 32s on my commuter bike and that bike rolls just fine). But you can have the cushiest frame, tires even suspension but none of that makes up for actual conditioning. The more you ride the more comfortable you are on a bike...

edited to add: and fit... I think fit on a bike is the single most important element of being comfortable...

Bicycle tires provide more suspension than the flex of a bike frame. The larger the tire, the greater capacity to absorb road shock without pinch flatting.

Some frames transmit all the impact and vibration to the rider. Others reduce a small amount of impact, maybe 1 mm or less by flexing at the seat-stay. Some frames reduce vibration better than other frames.

The fork has real ability to flex under impact. Without some flex at the fork, most bikes would be unsafe and the front tire could bounce off of the surface when hitting surface damage.

Looking for places where a bike can absorb road impact, see below;

#1 - the rider's legs and arms can absorb several inches of impact.
#2 - the tires can absorb a few mm's of impact, depending on size
#3 - the fork can absorb a few mm's of impact.
#4 - the frame can absorb little to none of impacts from the road.

I have a Columbus Airplane frame and run 28 Continental 4 Season tires.

That frame is abusive. A kidney wrecker. It has a carbon fork but I dislike the ride quite a bit. Perhaps the least favourite of all the bikes I've ever owned next a shop-supplied Cannondale. I appreciate how light it is on the climbs and how stiff it it, again, on the climbs, but I'm in the process of building another bike up right now.

Tell your saleman he is talking complete bollocks unless you can fit a size 40 tire in that aluminum frame. As it is I have about 1.5 mm under the rear brake bridge and 2mm between the tire and the seat tube.

also another perspective, most roadie max out at 28c or even 25c tires. If you can't UP the circumference of the tire size due to frame design hitting fork or rear chain stays. You have to get wider rims at allow for more volume of air. HED C2, Velosity A23, Kinlin XC-279 or go tubeless w/ Stan A400, Shimano Ultegra tubeless or similar. Any of these wheels are in the $300-700 range pending your hub selection.

WIDE is the new AERO....and I'm a believer of the hype. Been on A23s w/ king hubs, now on tubeless Stans A400s and they are awesome + not having a flat tire in the past few thousand miles is an added perk or made me down right spoiled:thumb:

You're wrong on both counts, unfortunately.

High volume tires run at lower pressures flex enough to do a great job of absorbing "road noise" and minor pavement imperfections, just like carbon fiber frames. Trust me: I own a $5000 carbon fiber road bike and a cheap aluminum touring bike that wears 700x35 tires. The difference in comfort between the two is very, very minor.

In addition, it's possible to find larger tires that roll just as well as smaller tires. My power meter seems to think that there isn't much difference between a 700x32 Vittoria Voyager Hyper and 700x25 Continental Grand Prix 4000S, for example.

You might fall into the phrase of my post you left out. If you can't feel the difference then your roads aren't as f'd up as the ones around here :lol:

I can feel the difference between my super6 and my 87' Schwinn circuit with Columbus SL tubes. That bike is plush even on the 23c tires I have one it's box rims. But with flex designed into its curved fork and thin chain stays, its exactly perfect for the f'd up roads here, just not snappy fast like my super6.

Agree on general principle, but disagree as an absolute. IMO, tire diameter has a much greater impact on ride quality than any other factor. If a person is really interested in a great ride quality, then he needs to look into wide tires: 27+ mm for tubulars, 32+ mm for clinchers.

Having said that, a really comfortable frame is a really comfortable frame. Compared to an uncomfortable frame, it will always be more comfortable, all other things being equal. IOW, if you take a soft, compliant frame and mount it with the same tires (regardless of whether they are 19 mm or 42 mm) mounted on a stiff, harsh frame, the former will still be more comfortable.

Bzzzzt incorrect or errr ummmm DISAGREE! You LBS salesman is just that.... a salesman.

The comfort in a frame is not in the material. It is in the geometry of the frame and the tube profiles that are incorporated into it. You can easily get an ultra stiff kidney wrecking frame from carbon, just as you can get a soft supple riding frame from aluminium and vice versa. Aluminium is not often used for the purpose due to the weight concerns of new bike purchasers these days and the fatigue life assosciated with the material.

The ride of different tyres is the thing that a lot of people don't give enough props to, along with wheel types. If you are chasing a new bike, you should really ride each bike with the same wheel/tyre combo to effectively discern which rides better than the other. Small changes in PSI, tyre width and wheels can massively affect the way a bike rides.

I have a few too many glasses of wine in me but: frame material and geometry makes an enormous difference. I have a steel frame with 20.5c tires at high pressure, in many respects it's more comfortable to ride than my alum Specialized with 32c or my CF Roubaix at 25c. I'll opine it has to do with the frequency/wave of the vibration and the intensity when it gets to your bones. On the CF bike is has a delayed reaction, that deadened THUD, which I just don't like. On the alum bike its more of a long snap that radiates through-out the frame, even with larger tires. On the steel bike it has a fast, mellow, single jolt and then it's gone. On a long ride on bad roads, I'd take the steel bike and narrow tires. Except for the weight penalty, cr-mo steel / relaxed geometry is the plush ride, hi-ten even more so ....regardless of tire size.

Cr-mo frame and hi-ten fork -> budda ride.

I you are talking frame material you are missing the point. It's what the designer does with that frame material. Frame material being pretty minor with the exception of carbon which has better dampening properties than other materials. Your frame isn't going to save you from a pot hole, doesn't matter what it's made from. Ride comfort is a combination of a number of things. Besides tires and frame design, wheels are huge and I would submit that they are more important than tires. Tires are just the easy/cheap fix for a crappy frame/wheel combination.

I agree for the most part. Any tires that are 28mm+ will pretty much dampen any road "buzz" even at high pressures. You'll still feel the big bumps but that's pretty much unavoidable other than learning to ride a better line. I see a lot of people throwing in other variables like frame geometry and whatnot, but that's a completely different question.

Personally I think the whole thing is blown out of proportion. Yes, my high-end carbon bike does ride better than my mid-range aluminum one, but the difference is small and you get used to it either way. I would say your salesman was being pretty honest since a snake would have said that carbon makes all the difference in the world, even with fat tires.

My road bikes all ride Michelin Pro Endurance 25c tires. There is a significant difference in feel/comfort. The Klein pounds me. The Ti/carbon id8 spoils with plushness (even with Ksyrium wheels) and the Element 6 is right in the middle. My old De Rosa (Columbus SLX tubing, Mavic SUP's, Conti 23c tires) was amazing. My aluminum commuter, with 1.4" wide 26" wheels (Michelin Rubber) is still a "stiff" ride--sure, if I let out some air the ride gets "softer," but so does the handling; no thanks.

Frame material matters. To me, anyway. YMMV.

I've ridden a bicycle from San Francisco to Los Angeles, so I think I have a pretty good idea of what roads in California are like...

What you're feeling is not the difference in the frame material. Rather it's the difference between 20-year old technology and design versus current technology and design. In my case, I'm talking about two modern frames: a 2008 Cervelo RS and a 2009 Nashbar double-butted aluminum touring frame.

There is a lot of talk about frame material, but IMHO, a greater influence on comfort is frame design. You can't accurately make a blanket statment like "carbon fiber rides better than aluminum" because there are countless variables to take into account.

Unfortunately, due to market forces all designs tend to be pretty similar these days. In order to be cost competitive, you pretty much have to use the same materials as everyone else. If you want a special tubing shape or alloy or construction method it increases costs enormously. Frame designs and geometry also tend be be pretty similar, thanks to UCI rules that outlaw anything new and because unfamiliar designs just don't sell. How many disc brake-equipped road bikes did you see on your last ride? How many recumbents?

Interesting info so far, thanks.

Yes and No. Sure there are a limited number of frame manufacturers and many companies use similar or even the same frames as their competitors, but there is still a lot of variety in available frames, even in a given material. Add to that the innovations that show up every year and you get even more variety.