Wheel weight vs. aerodynamics

[Fibre-Lyte]

good to see you back Adrien

[Fourthbook]

A follow-up question concerning the effect of lower wheel and overall bike weight on handling: My old ride was an '91 Eddy Merckx (753) w/Fulcrum Racing Light wheels that weighed just over 17 lbs. When I updated to a Wilier Cento Uno w/MV32UL wheels that weighs a bit over 14 lbs., I'm buffeted more by the wind and passing trucks, presumably because of the lighter weight as opposed to the slight difference in wheel aerodynamics. Is it simply a case of less weight = less momentum and mass = less stability?

If so, what are your thoughts on finding one's best balance of light weight, aerodynamics (drag and cross-wind), and handling both for wheels as well as the overall bike?

[j0m]

Damn Pritch. Just realized that I've been riding around in gales, feeling comfortable, with Cosmics and Edge 65's. Are you implying that I should go deeper?

I don't think there's a universal best balance of parameters. For me the 18xxg Cosmics feels slightly more stable than the 1200g Edge wheels but I get blown around more on the CX with box rims and fat tires. The CX feels more stable in general but when it's bad it's worse. I believe it's all about personal preference and riding conditions. I know it might become interesting meeting lorries in certain wind conditions but as it's quite uncommon I don't feel I need to spec my bikes accordingly.

[Fourthbook]

Clearly there's no universal recipe that fits all riders/conditions; and certainly personal skill/experience/comfort riding in cross winds is a critical determinant; however, I'm wondering how much of the instability is related to bike weight and frame cross section verses rim depth/shape. For example, comparing my steel tubed Merckx to my carbon fiber Wilier, the Wilier (like most/all CF frames) presents a substantially greater cross-section and is thus far more subject to cross winds than the relatively thin tubed Merckx. Do we worry too much about mm-range differences in rim depth when the real determining factor is frame X-section/width???

[pritchet74]

Rim depths are hugely influenced by rim shape. A better shape will allow you to ride a deeper rim. If you have friends with different wheels that you might like then just borrow them for a test ride.

My friends have been borrowing my Jet 9's a lot lately.

[rustychain]

When comparing wheels like this I think bearings are often an important yet neglected factor. As already stated the fun is really why most of us ride. The conditions you ride in, your riding style, personal preferences can all weigh in to the decision more then what is fastest under specific conditions IMO

[Ypsylon]

Clearly there's no universal recipe that fits all riders/conditions; and certainly personal skill/experience/comfort riding in cross winds is a critical determinant; however, I'm wondering how much of the instability is related to bike weight and frame cross section verses rim depth/shape.

I would add bike fit to that list and how much "instability" goes back to equipment will obviously vary from case to case. I'd think most differences in how your two bikes react are due to different geometry/fit and have very little to do with cross section.

There are two equipment related things I can think of that can happen in wind gusts. Your front can be pushed further to the side than the rear which will lead to going into a different direction than you originally were.

Or your entire bike can be pushed to the side and, if the wind is just strong enough, disappear from under you.

For all I know the latter is a lot less likely to happen, so it's more important where the cross section is and how much it differs from your weight distribution. Having a little shallower front makes sense in that regard, be it with a set of SMART/ENVEs or any other mix n match.

Since the shape of the ENVE wheels is different front/rear, that should help as well.

[marcusweaver03]

While it may be tantamount to heresy on this Forum, aero almost always trumps weight in real-world racing conditions.

[pritchet74]

Either you are a little hung over or just don't know which forum you are on, but most people 'round these parts know aero is king.

And welcome to the forum by the way.

[mdeth1313]

Either you are a little hung over or just don't know which forum you are on, but most people 'round these parts know aero is king.

And welcome to the forum by the way.

It is?

[pritchet74]

Hey, I know your favorite wheels to ride are your aero ones!

[mdeth1313]

Hey, I know your favorite wheels to ride are your aero ones!

yeah, but secretly I lust for my old reynolds dv46t's - w/ non-bladed spokes! I just love the hed wheels for the cool sound they make- well that and when a nail goes thru them they still make the ride home and are easily repairable!

[ToddC]

Thought I'd join in on the aerowheel party... I rode Bontrager carbon climbing clinchers for a while.(1320g) Bought a set of HED Stinger 6's 2011(1430g) model with Conti Competitions. Loved the Heds, But only rode them twice a week on the fast rides. After becoming lazy I wanted an aerowheel for everyday. (sold the Heds) I decided on the 2012 Bontrager Aeolus D3 50mm clincher.(1550g) 27mm wide at brake track. Mounted up a set of Veloflex Corsa 22's(tire is narrower than rim like the Stinger set up) with lightweight tubes and I can honestly say I don't miss my Heds or my climbing wheels which I still have on the back up bike. I am 160 lbs. with a bike weight under 15 lbs. and I hardly ever feel them push me around. The Heds do have a loud unique sound. To my surprise the D3 50's are very quiet unless sprinting(which is still not very noisy) They feel fast like the Heds did. Climbing, I can't comment on because I have no plans to use the climbing clinchers anyday soon to compare. Aerowheels just add fun factor! In my opinion what little is lost in the climbs is more than made up everywhere else. Good luck choosing!

[BMANX]

Get the lightest aero wheels you can get. Zipp or ENVE built up as light as possible is the way to go. While Aero trumps weight, both matter and you are trying to lower your time to the finish. Whether you are trying to save minutes or seconds both help. If I was building up a set of race wheels right now I would be going with the ENVE 3.4 with aero spokes and Rob English Aero hubs. I think this gives you the best aero qualities with a great low weight.

Using the same rims, you could have a 1300g wheelset or a 1600g wheelset once you add in different tires, tubes, cassette, hubs and spokes. The lighter one will be faster.

[Fibre-Lyte]

I'm going to dispute that a little bit. For general riding you're quite right, lighter is better. However, I've always held the belief that if you are doing a flat, fast, time trial or even a ride that is predominantly flat and straight, then a heavy rim is better than a light one from a momentum point of view. Once you have a heavy rim up to speed it is easier to keep there than a light rim. Of course, that works the other way around if the course is twisty as it is easier to accelerate a light rim than a heavy one. I still like your wheel choice, just offering another opinion