Racing Dan

Power to overcome air drag increases by the CUBE of the speed. Double the speed and power increases eight (!) fold. That is, as base2 alludes to, the reason wheel manufacturers like to quote watt savings referencing very high speeds. Often 40km/h. Assuming a 10W saving* at 40, but if riding speed is 30km/h you are only saving 4.2W, at best.

*Also the saving is usually measured against the worst box rim you can imagine. That may not be what you have on the bike. Lots of alloy rims have semi aero shaping, further eroding the achievable gain switching to a aero wheel.

Polaris OBark

I have a steel bike with a set of aluminum rims (700C HED Belgium+). The widest tire I can fit in my frame is 38mm.

I have a second set of wheels with carbon 650B rims, and although they are not "aero," they have a bit more of a cowling shape to them, so I am assuming that because the wheels are smaller in diameter, the rims are carbon and designed like they are, and the spokes are significantly shorter, these wheels are likely stiffer. Despite this, the ride is more plush. I assume this is because I have wider tires on these wheels (42mm rear, 48mm front).

If my interpretation is correct, then tire width/inflation >> rim material.

The deep dish pizza aero carbon rims have the indirect effect of making the wheel significantly stiffer, as the spokes are shorter and the rim itself is likely more rigid. I cannot pedal my bicycle fast enough to entertain the idea of these kind of aero wheels, and although they look cool, they presumably weigh a bit more than they have to, and can be challenging in strong cross-winds.

The steel bike frame is more comfortable than any carbon one I have tried. Even with wide tires, I feel the difference (fewer pains on long rough gravel rides).

popeye

Get out of the saddle and sprint and you will notice a diff, more so with a stiff bike. That and the speaker effect.

DaveSSS 

Try the pressure calculator at zipp.com. It takes into account the internal rim width, tire size, pavement and tire construction. For 140 rider, 28mm tubeless tires on pavement, 19mm internal width rims, it suggests 62/65. If you're running 25mm tires, on narrower rims and tubes, it will suggest quite a bit higher. I've run 25mm on 17mm internal width zondas at 72 with no problem. Be sure that your pressure gauge is accurate.

ctak

28mm gp5000s may actually fit your frame, particularly if it is one of the newer Nitros.
Hunt makes quality carbon rim brake wheelsets. These, in particular, will have considerably better dampening than the Hunt Aero Wide Sprints I have on my Davidson. I'm a fan of the ride quality of shallow-ish 36-40mm carbon wheels on vintage and modern steel tubes.

signalnc

It's a 2016. I'll try a 28 to see if it fits. Thanks

Kapusta

Yes. Although “more” obvious implies it was obvious to start with… which it was not.

bruce19

My GURU Sidero (steel) is also built with Columbus Spirit. I put Mavic tubeless wheels/tires on it and it is lighter, faster, and more comfortable.

signalnc

Which Mavic do you have?

cxwrench

Ride quality has nothing to do w/ the wheels he has.

bruce19

Mavic Ksyrium Elite UST w/ Yksion tires. They come as a package and the wheelset cost me under $500.

chaadster

I disagree with that!

There are many different types of bicycle wheels out there, and even if you maybe haven’t experienced the range of constructions and materials used to make wheels, it’s quite a stretch, from the materials and mechanical properties perspective, to presume none of it makes any difference.

cxwrench

You obviously don't know as much about wheels as you think you do. Consider that you have a pneumatic tire mounted on the wheel and it's inflated to somewhere between say 80-100psi. This is a normal road size tire, 25-28mm. If you sit on the bike you'll see the tire squish a bit. If you squeeze it with your thumb and finger it'll squish a bit. This happens ALL the time when you're riding, the tire is constantly squishing a bit. Now look at your wheel. The spokes are under a LOT of tension, normally 100-120kgf. For you to feel any difference in ride quality between wheels you can guess what might have to happen. The tire would have to squish to a degree that the rim would be hammered into the tire, much like what happens when you get a pinch flat. Then you'd have to have a rim that would be flexible enough to result in spoke tension going down to near zero or even less than zero and somehow be able to return to exact and proper tension every revolution of the wheel. Do you really think this is what happens? Now look at carbon rims. Even low profile carbon rims are very very stiff radially. I've built hundreds and hundreds of wheels, both aluminum and carbon rims. You don't even build them the same way. They don't get the radial hops that alloy rims do because of the stiffness. Some people talk about carbon wheels damping vibration better than alloy rims. Do you honestly think you'll notice that difference with the pneumatic tire and it's soft tread between you and the road?

bruce19

I think this depends on your definition of "ride quality." If it means comfort, a lot of that is in the tires. If it's about ability to spin up quickly then weight comes into the picture. You get the point. When I went from Mavic Ksyrium Elite clinchers to UST's I got better comfort, quicker spin up and lighter weight. So, for me, ride quality was improved. FWIW both wheelsets ran on 25mm tires.

chaadster

You’ve made a *lot* of assumptions in that comment which I don’t make and wouldn’t agree with, but the most disagreeable is the notion that a pneumatic tire works on the road independently of the wheel and is an impenetrable barrier to feel.

chaadster

Yes, for sure.

base2 

A big part of comfort is spoke length & elasticity.

A relatively low number of Alpine 3's or CX Ray spokes on a large ERD box section 700c or single wall 27 (630mm bad) rim are going to load up a lot more like a spring & have a lot more give than say, 36 12 gauge straight spokes on a deep 20 inch rim.

That extra "give" directly leads to ride quality.

Kapusta

This is a classic example of relying on armchair predictions and ignoring real-world results.

A few years ago I replaced a wheelset on my road/gravel bike. Same bike, same tires. Noticeably different ride quality, even though they were both aluminum.

In the MTB world the difference between CF ans Al wheel is incredibly obvious, and those tires are being run at very low psi.

The fact that you can’t see the spokes bend or collapse does not mean there is no difference in ride quality.

If you want to apply engineering to this question, then use it to explain why things are the way they are… using it to explain why things should be other then the way they is a waste of time.

ctak

Couldn't agree more

Trakhak

The only test data I was able to locate regarding wheel stiffness represent measurements of lateral deflection. If someone can find similar data for vertical deflection, please post them.

Note that there's not a single mention of vertical deflection in that report. I wonder why.

Actually, I don't wonder. I believe that people truly believe that there's such a thing as significant vertical deflection in modern bike wheels. However, none of them have tested those wheels and found measurable vertical deflection, or else they'd be reporting numbers and not impressions.

ctak

Very similar to Bill Mould's findings, thanks for sharing: "Some believe that a wheel built with tighter spokes is stiffer. It is not. Wheel stiffness does not vary significantly with spoke tension unless a spoke becomes totally slack."

Another point which runs contrary to conventional thought is that deeper rims = more lateral flex. The deeper the rim, the greater the leverage... which certainly can impact a host of variables related to "ride quality".
https://www.velonews.com/gear/deep-w...s-beyond-aero/

cxwrench

What difference? Ride quality? Please.

Because...feels?
You guys are so sure of your opinion but can't provide any proof of why...how come?
^This^.
^And this^

SoSmellyAir

To harmonize above posts #38 through #45 (excluding #39 and #41):

A tire (within its stated range of inflation pressure) is of course more compressible than the wheel on which the tire is mounted, by many orders of magnitude, but to conclude that the wheel has no effect on suspension (e.g., handling, comfort, etc.) is to ignore the interaction between the wheel and frame. The frame and the fork also function as components of the suspension, and even if you replace one wheel with another wheel which is exactly as stiff but weighs more or less, that affects how the suspension works because it affects attenuation.

chaadster

You’re the first person to bring up “vertical deflection” in this thread.

Trakhak

The test that I linked to refers to side-to-side movement of bike rims in a built wheel under load as "lateral deflection." If the people attempting to describe differences in comfort among wheels mean something other than "vertical deflection," I hope that they'll clarify what they mean and provide data from a reputable source that quantify that which they are describing.