Road Bike Racing - New Rear Wheel: Another 50mm, or 82mm?

Well, my mom knocked over, then ran over my rear race wheel last night. I was surprisingly nonchalant about it, too.

So, I'm going to be replacing said race wheel, and I'm wondering what I should get. I do a good amount of crit-ing, and rolling road races. The two rims I'm looking at are 50mm, which would match my front wheel in terms of depth, and 82mm, which would be significantly deeper, without much of a weight penalty.

So, gents (no ladies here, let's not delude ourselves), what should I get?

The 82mm will cost about $100 more than the 50mm wheel, by the way.

I'd get the 80mm. Tall rims (or discs) in the rear are always fine in strong wind.

If I had my druthers I'd be getting such a rear wheel too, but I'm stuck with my 46mm rim for now.

Now just find a better place for them in the garage :)

cdr

Zipp says 808 in the back is worth 2 sec vs 404 in back at 300watts/40km.

Not sure that really amounts to much.

I have 60's and 90's. My only problem is the 90 steers "almost" like a disc in turns. I love it for RR's, but it feels strange repeatedly burying it into a corner during crits. Kind of an understeering feeling like it wants to keep going straight when I want it to turn. Another guy I was talking with this weekend felt the same way about his 808's, but he said he just deals with it.

I wonder how much of a difference that extra 32mm makes for the one or two minutes you're pulling on the front during a crit.

Hmm, if it's really only 2 seconds, I would go with the smaller rim, just for the cross-wind difference.

I'd go with the 50 mm as I'd be concerned about cornering with a deeper section rim. Also, even though the smart guys say rotational weight (i.e. rim weight) doesnt matter, I still think it does matter when you're acclerating out of corners over and over again in criterium style racing.

I would get flowers for my mother for giving me an excuse to buy new wheels.

Hmm, if it's really only 2 seconds, I would go with the smaller rim, just for the cross-wind difference.

Here's the link - it's 8 seconds for the front wheel (808 vs 404)

http://www.zipp.com/Portals/0/Technology/Documents/ZippAeroEdgeFlyer_2.pdf

He's strictly talking rear wheel here, folks. He'll still be rockin' the 50mm up front.

I'd go with the 82mm. So PRO.

I'd go with the 50 mm as I'd be concerned about cornering with a deeper section rim. Also, even though the smart guys say rotational weight (i.e. rim weight) doesnt matter, I still think it does matter when you're acclerating out of corners over and over again in criterium style racing.

Yeah, it matters, but not much. Between a 404 and an 808, it's only going to be ~0.05% of the energy required during the race for crit style accelerations. So if your average power is 300W, the 808s would cost you 1.5W more than the 404s.

I'd still probably go with the 50mm hoops, myself. If you want more aero than that, then get covers from Wheelbuilder for TTs.

I wonder how much of a difference that extra 32mm makes for the one or two minutes you're pulling on the front during a crit.

In the last "smaller" race I did, i.e. less than 80 guys, I was first or second wheel for ~10min, maybe more, of the 90min race.

Blocking, chasing and riding tempo will do that.

How did your mother end up running over your wheels?

Here's the link - it's 8 seconds for the front wheel (808 vs 404)

http://www.zipp.com/Portals/0/Technology/Documents/ZippAeroEdgeFlyer_2.pdf

Actually, it's less than that, as they're assuming 30 MPH (and only 300 watts! ProTour here I come).

How did your mother end up running over your wheels?

He had it propped against her rear bumper, of course.;)

I would get flowers for my mother for giving me an excuse to buy new wheels.


+1 I need to put my old wheels under my mom's car too.

Although the front will make more of a difference, I don't find there's a lot of accelerating in the crits I do. I mean, yeah, there's more than in a TT, but a lot of times it's just flat out and you have to do a little jump here and there.

In a top speed sprint I think the taller wheel will make a difference. Up front more, but in the rear a bit too. My ideal setup would be a tall (66+ mm) rear rim and three front rims - sub 30 mm, 45-50 mm, and 66+ mm. All with the same braking surfaces.

cdr

Although the front will make more of a difference, I don't find there's a lot of accelerating in the crits I do. I mean, yeah, there's more than in a TT, but a lot of times it's just flat out and you have to do a little jump here and there.

In a top speed sprint I think the taller wheel will make a difference. Up front more, but in the rear a bit too. My ideal setup would be a tall (66+ mm) rear rim and three front rims - sub 30 mm, 45-50 mm, and 66+ mm. All with the same braking surfaces.

cdr

yeah - I have carbon 404s (braking sucks when wet) and Kysriums. Swapping wheels means swapping brake pads, which is a royal pain (i've read that brakes pads used on aluminum wheels will have metal fibers that will shred carbon wheels).

Personally, if there's a large chance of rain, I'd be running aluminum anyway just because of the crash risk.

yeah - I have carbon 404s (braking sucks when wet) and Kysriums. Swapping wheels means swapping brake pads, which is a royal pain (i've read that brakes pads used on aluminum wheels will have metal fibers that will shred carbon wheels).


Swiss Stop Yellow Kings have all the answers.

Seriously, Kool Stops(IMO) are junk compared to my Swiss Stops.

I ran a 606 setup once in a crit. Never felt right to me and also had by far my worst outing of the year. I still like the setup for road races though.

I'm also making the jump to a 90mm rear and 60mm front (HED jet C2's). Let's keep in mind that it would look badass...
http://bp0.blogger.com/_VOv6-TpOlN0/RzMeDKc7EPI/AAAAAAAAAAw/v9wize-VtuU/s1600-h/T16-Red+web.jpg

Any opinions on the 82mm rim and it's acceleration feel? Is the extra weight noticeable or do the aero benefits seems to help with acceleration?

-L

so...jealous....