chaadster

A current thread about wheels, in one of the other sub forums, poses one of the prospective buyer's criteria as "comfort," which struck me as odd.

Well, maybe not odd, but unfamiliar, because whereas I perceive a difference between the feel of wheels, it's in such a narrow range that I don't perceive it as impacting comfort in one way or the other.

Not having thought about it much, I don't even see how, given the range of materials, design, and performance requirements, that there could even be any difference.

What do y'all think? Are different wheels more or less comfy than others? Why?

franswa

The width of the rim factors in to comfort to a certain degree. It dictates the form your chosen tires will take on, thus contributing to or subtracting comfort.

rpenmanparker 

Many folks believe that rim and spoke stiffness as well as low flange height (higher spoke length) contribute to rim comfort. That is a holdover from the past when roadies were nearly universally on very skinny tires, rims were fairly whippy, spokes were usually 2.0 mm straight gauge, there were 36 of them, and high flange hubs were still fairly common. So folks would announce that switching to the new-fangled low flange rims and only 32 double-butted spokes had made their wheels more comfortable. Who knows?

Today our approach is completely different: rims are stiff, flange heights are all over the place, and 20/24 very light gauge spokes are the norm. I believe that one should design a wheel for the desired performance attributes like durability relative to the rider's weight, cornering, aero (or not), weight, resistance to flexing, etc. We know so much more about using tire width and inflation to provide enhanced comfort. That is where I would go looking for it. Having said that, it is pretty clear that very deep rims, carbon or not, will ride more harshly than low profile ones. It is just that in comparison to the shock absorbance of larger tires inflated to lower pressure or narrower tires on a wider rim at lower pressure, how much difference will rim stiffness make. I think it must be overshadowed by the tires.

K.Katso

Never thought about it, but then again comfort isn't really a factor for me when talking about any bike or bike component that I buy.

Trsnrtr

Yep, what RP said. Tires and psi make the biggest difference.

datlas 

Exacty. If you want more "comfort" go slightly wider width tires and drop the PSI a bit.

StanSeven

Rim depth and spoke count makes a huge difference as well as RP mentioned. I had two Mavic wheels - box type Open Pro with 32 and deep CXP 30 with 18/24. The Open Pros feel like riding on marshmallows

chaadster

Yeah, I get the tire thing, but that's not what I'm talking about. I'm talking about discernible differences in comfort between wheels.

Deep section, whether carbon or aluminum, are clearly more harsh than low profile? Not in my experience, and currently I have alu rims ranging from about 17mm (Open Pro) to 30mm.

I mean, do rims flex up and down giving comfort or cushion? It doesn't seem likely to me.

Do long spokes absorb and dissipate shock more than a deep carbon rim? Do 32 spokes at 100kfg tension transmit less shock to the hub (and onto the frame?) than 24 at same tension? What about spoke width?

I dunno, but these are the dynamics I'd like to understand if they're factors.

tarwheel 

Tires can have a big effect on comfort, wheels not so much.

chaadster

Hmm, I notice a difference between my 32h Open Pros and my 18/24 30mm Argents, but it's in terms of responsiveness or liveliness, and I don't think the Pros feel softly comfy, just kinda vague.

Homebrew01

Unless someone has done well controlled tests of wheels, running identical tires, tubes and pressures, any differences in feel would seem to be tire & pressure related, much more than spoke diameter or rim width.

Rim depth is definately a factor in crosswinds though.

Psimet2001 

Rims flex. Thus RP's statements about how rims have changed.

What a lot of people don't seem to realize at first is that wheels can really be mostly about the rims. The correct spoking and hub dimensions are there to help the rim in doing it's job.

Shallow depth, thin walled rims ride "soft". To some this is annoying. To some it's called "comfortable".

Deeper section rims become stiffer in the vertical plane but if they are put together with too few spokes they can still be soft laterally. This gives the rider a stiff or harsh ride over bumps and such but makes the system feel like a wet noodle when they are out of the saddle and leaning the bike and/or when cornering.

Like chaadster mentioned - I too feel like the soft wheels aren't comfortable - rather they are "vague".

Psimet2001 

Spoke diameter is only really a factor in the longevity of the wheel with respect to the load it's carrying (fatigue life). Depth of the rim, as well as width of the rim and wall thickness, will change the area moment of inertia of the rim directly affecting stiffness. Just like it does for any other beam. Unsure of that then walk on a square beam and then walk on an i-beam of the same mass. It's why we use i-beams and they are the perfect illustration of the concept of area and mass moment of inertia.

Carbonfiberboy 

Tire width and pressure are irrelevant to this discussion. We are talking wheels and assuming that the rider would run the same tires and pressures on any wheel. I get that wider rims encourage lower pressures, but that's still not the issue. It's the behavior of the wheels themselves that is of interest. Psimet describes the issues very well. Some folks don't notice the difference, others do. There are similar individual sensitivity issues with frame design and construction.

Lazyass

No, it's actually true today and always will be. Butted spokes have more give than straight gauge, and they're the main thing holding your weight.

grolby

The difference in deflection between properly-tensioned single and double-butted spokes is infinitesimal. I don't think that's going to make a difference.

Still, there's no denying that wheels definitely feel different from one another. I think spoke count and the rim qualities (depth, construction, shape, material, etc etc) are the determining factors in comfort, if that's how you describe the difference, between varying wheelset. My own experience is that there can be a surprisingly noticeable effect. A 20/24 spoke wheelset with 30mm Kinlin rims felt significantly smoother to me than a 32/32 spoke wheelset with Velocity A23 rims. Same tires (literally the same, moved to the other wheels), same pressure. Very noticeable change in ride. And now that I've replaced the Kinlin rims with H Plus Son Archetypes, there are noticeable differences there, too. Not sure about the ride which is similar, but snappier and stiffer-feeling. More precise. It's good stuff.

Before I had experience with more wheels, I would have dismissed claims that wheels can noticeably differ in ride quality as placebo effect. It's not.

Lazyass

Yes, it does make a difference. I went from a 1900g wheelset to a 1400g one. Besides the weight, the main difference is the former had straight gauge spokes and the latter double butted. Riding the new wheels, the number one biggest difference I felt was in how much smoother the ride was.

Spoke Information - Wheelbuilder.com

grolby

Just because it's common lore and posted on Wheelbuilder doesn't mean it's necessarily true. I'm not discounting the possibility that spoke butting matters, I'm just saying the deflection difference in spokes is going to be smaller than differences between rims. Does your 1400g wheelset use the same rims as your 1900g wheelset? Same spoke count? I would consider both of those factors more likely to make a noticeable difference.

Lazyass

Once again, the main difference between my two wheelsets besides the weight were the spokes. The absolute biggest difference I feel between the two is the smoothness. I was expecting to feel a difference because I've had countless wheelsets with different spokes and I know they do not in fact ride the same (and this is the first thread I ever read where someone actually disputes it to degree), but it was bigger than even I expected. This is my personal experience.

Silvercivic27

Ride a set of deep section tubulars then a set of deep section carbon clinchers. You'll feel the difference! I definitely feel ride quality differences between all of my wheelsets, particularly as the rides get longer and bumpier.

rpenmanparker 

Just to be clear I did not mean to say that rim, hub and spoke characteristics were not factors in wheel comfort. My point is that unlike in the past when most people were riding very uncomfortable tires, that is not the case now. IOW I don't think those factors, real as they are, are nearly as important as they used to be.

chaadster

@Psimet2001 So, shallow rims are less vertically stiff than deep section, and wheels flex. My thought has been that the amount of deflection in shallow rims (which is resisted and controlled by the spokes?) is very little, and nowhere near the amount of displacement we see in comfort-giving items that flex like shocks, suspension posts, or big tires, or even under inflated skinny ones. Yet, we do feel that vagueness as both pedal inputs and road feedback is somewhat muted by the flex/displacement.

Am I thinking of this right?

My other question is whether full carbon, deep section rims behave with the material properties of CF we praise in other applications like forks, handlebars and seatposts, namely vibration damping. Though a deep CF wheel might be verticall stiff and flex less (esp. over big hits) than a shallow wheel, do those small, high-frequency impact shocks get soaked up by the carbon at all, yielding what is both a smother and more reactive ride over good condition roads (i.e. roads not torn up and potholed)?

Or do I have the whole wheel dynamic wrong?

I appreciate you sharing your expertise on the matter.

chaadster

I take it you're feeling the tire difference in that example, right? Or are you suggesting something else about rim construction?

emveezee

So, the rims are the same or different?

Silvercivic27

It's prob mostly tire/tube but prob also wheel. The rim shapes are a lot different, but I'd definitely say that there are differences in ride quality between wheels and they don't necessarily follow a pattern like the deeper wheels always ride harsher than the shallower wheels, etc.