Beerope

I want to upgrade my aluminium clinchers to a deep profile carbon wheel but only have the budget of getting either the front or the rear. Which would affect aerodynamics more and be a more significant upgrade?

Xherion

front

nycphotography

put the money aside until you can afford both. you dont actually need deep wheels and if you can't afford both, you probably cant afford one either... at least not without leaving yourself too tight on funds to respond to unforeseen emergencies.

mvnsnd

Both answers are correct. The front is more significant, but if you cant afford a pair, well, then just wait.

If you want to buy right now, this is a good deal:

Reynolds R Four

$1100 on sale with additional 20% off is about $880 for the pair.

shafter

I'd hold off. But don't be ashamed of only 1 carbon wheel. If it were me, I'd put it on the front. The front bears less weight and stress and is lighter regardless. Keep the more trustable alloy in the back.

PepeM

Front. It is also the one more affected by crosswinds. If money is tight I wouldn't bother, unless you are losing races by fractions of a second. Even then, plenty of places where you can gain more speed without spending as much/at all.

joejack951

Keep in mind that the majority of your braking power comes from the front brake and based off everything I've read, carbon rim braking has merely matured from crap to almost ok.

69chevy

Drag isn't simple.


People usually think of aerodynamic drag as the force that pushes back as you "hit" the air. It's much more complicated than that. There are air pressures and velocities that change as the air flows around you. The changes in this flow are what generates the force known as drag. Drag is greatly affected by the manner in which the air recombines (or doesn't) as it passes around you (and your bike).


Since drag occurs all around you (as the flow of air recombines) there is a force pushing against you and a force pulling you from behind (you create a separated flow of air behind yourself). The smaller this area of separated flow, the less force pulls on you.


There is no way of knowing with certainty which wheel would "help" more, because it would depend on the bike design, the rider position, the wind direction, the speed of the bicycle, etc...


Logic would tell you that the front wheel would have more impact, but the truth is, without any testing of you on your bike in your normal position, at your normal speed, any answer you get will be a guess.

asgelle

When logic fails, there's always direct measurement to fall back on. There's been enough testing to know that improving the front wheel always gives a greater benefit than the same improvement to the rear (there may be some extreme cases where this is not so, but I've never seen one). Zipp has published that putting the improved wheel on the rear gives about 75% of the improvement seen by the same wheel on the front.

wphamilton

I checked this 5 or 6 years ago, more of a casual not very rigorous coast test so details are a little hazy. I didn't use expensive carbon fiber wheels, but attached some disk covers fashioned from Coroplast. The rear disk improved somewhere around 1-2% of my total drag and the front a little better. These weren't big enough numbers for me to put much more effort into it so I mothballed the whole thing.

Seattle Forrest

... on the other hand, the front wheel is (as already mentioned) more vulnerable to cross winds, a situation that's improved by a shallower front wheel, and stabilized to a degree by a deeper rear wheel.

rmfnla

Mis-matched wheels are slower, regardless...

caloso

Bending your elbows more is more effective and cheaper. Do that while you save up for new wheels.

Beerope

Heres the drop on my bike, cutting the steer tube soon. but there is absolutely no way you can ride without elbows bent

asgelle

I must be missing it, so maybe you can help. Where did the OP say his or her elbows weren't already bent optimally? (and bending elbows too much can be as bad as bending them too little.)

woodcraft

Why not just get a cheaper set?

Lots of used wheelsets available for $ as folks upgrade the latest and widest.

Buying a single wheel doesn't seem like a very good plan, unless you are a tri-geek.

fietsbob

A Solid, full carbon disc, Rear wheel , is time trial Choice of the Pros ..

indyfabz

Not to mention stoopid looking in virtually every case.

Clipped_in

This mismatched wheel set seems to go pretty fast... How it looks is subjective. I have a mismatched set of Crit racing wheels--60mm front/90mm back. Fellow racers are apparently hiding their disdain quite well. Good think I came to the 41 to get set straight!

Dan333SP

In Froomey's case, the mismatched wheels were merely offsetting the tremendous advantage he was gaining from those asymmetrical chainrings. He wanted to be subtle about it, so he had to go for slower, mismatched wheels. Seemed to balance perfectly for him.

rmfnla

Good think, indeed...

Seattle Forrest

... emaciated ...

himespau 

Drop your cash on an aero helmet instead. If that's too spendy, drop it on some duct tape to cover the vents in your current helmet. Oh and buy some shoe covers.

Beerope

Perhaps I should upgrade my chainring to get the advantage like froome? What is recommended?

Dan333SP

You'll want to buy some of these-

Welcome to Osymetric USA -

They'll give you 10% more power and 30% greater endurance, as proven by science in multiple probably-peer-reviewed studies that were reasonably comprehensive and paid for by the manufacturer, so you can trust the results.