Jur: No sweat. Feel free to edit your post if needed, I'll stick to mechanics & clarifications etc.


Although I accept that tire properties are significant, I'm not sure why you make this claim.

For example, it's widely accepted that smaller wheels are stronger than larger wheels; e.g. 26" are more common on MTB's because of the increased strength. This in turn makes the smaller wheel stiffer. Since you're using the same materials, increased stiffness also increases transmission of vibrations -- as does the lower mass of the wheel, assuming the materials are of the same type. In this respect, "flex is flex" - it doesn't matter which direction the material moves, what matters is how efficiently the "wheel system" dampens vibrations.

Similarly, wheels with fewer spokes also tend to be harsher. The rims need to be stiffer, lacing patterns are different, there are fewer spokes to absorb shock, tension needs to be higher, and so forth.

Separately, the smaller diameter results in a harsher response to bumps, divots and holes in the road. I hope it's quite clear that a sufficiently large enough wheel can cruise over certain sized holes, while a smaller wheel would dip into the same size hole. The angle of attack of a given hole is also harsher, and that may make a difference.

Changing the rim composition has the same effect as changing the frame composition. If you switch to a carbon rim, that material will absorb more vibrations.

If we were dealing with a small change in tire size (e.g. 650c to 700c) and keeping all other properties identical (i.e. same rim composition, same spoke type and count, same lacing pattern etc), I'd agree that alterations in tire properties will overwhelm structural properties. However 700c to 406 is a much bigger change, therefore structure takes on a much larger role.

Or to put it another way: why isn't the mechanical suspension on a Moulton, a Pacific Reach, a Dahon Speed Pro, an Air Friday, or a Birdy utterly superfluous? These are all essentially road bikes, a category which in 700c almost never has mechanical suspension. Why don't 26"/700c folders like the Dahon Jack, the Pacific iF, the Montague CF "Comfort" use suspension? Or from the opposite tack: Why add suspension to ANY non-MTB bike, if all you need to do is lower the PSI of the tire?

Something just doesn't add up about the "it's only the tires" theory.


Not really following you here. There are quite a few tire widths that are in the 100psi range for 406. E.g. Stelvios are narrow, Marathon Slicks were a tad wider, Marathon K's are much wider, all are around the same PSI range. With 700c, tire sizes can easily range from 21c to 28c for the same tire and PSI. AFAIK the PSI range doesn't change based on tire size, either.

Also, I'm quite aware that "comfort" will be based on not just wheel size, but the overall design of the bike. One thing that reinforces my experience in that respect is riding a Dahon for about a year or so. That bike in particular had a steel frame (good dampening properties), no top tube (more flex), a long seat post (more flex), a long handle post (yet more flex) a few hinges (even more flex) and a substantial heft (28 lbs). Despite all these structures and properties, the Dahon had a bumpier and harsher ride than several 700c steel road bikes, especially on cobblestones, gravel and dirt roads -- even when comparing 65 PSI tires to 100 PSI 700 x 28c's. I'm not sure what can account for this, other than wheel properties.

You can disregard my subjective experiences -- in which case, all such subjective claims need to be tossed....


You may have misunderstood my point here. I am not saying "more people ride 700c, therefore it's better." I'm pointing out that makeinu is inappropriately disparaging the legitimate cycling purposes, preferences and enjoyment of millions of people solely because he doesn't engage in those activites.