so the frameset is actually worth 25%, not 16, but still less than the handlebar. that's interesting, I didn't realize the handlebar is totally exposed compared to the frame..

where can i find tunnel data on v shape and u shape rims being compared?

The best compendium is Aeroweenie.com - Time Trial and Triathlon Aerodynamics Links and Data or just google it.

The other option is to go to slowtwitch and tell someone with a v shape rim his bike is slow compared to a u shaped rim (or visa versa). You'll get 300 replies worth of data.

i can't find it. all i see is qualitative data, which doesn;t really help.

also, is it a big deal to have an extra 100g in each wheel rim for accelerations? I'm considering selling my tubulars to race on clinchers. I never train with tubulars, and it makes no sense to me to have my best wheels sitting around waiting for big race days, which only comes around like once every 2 months. I don't even use them for the training series.

100g is my approximation on the weight difference of the rim, tires (and tubes)

Ok now you're just trolling!

I'm actually serious. the weight between clinchers and tubulars used to be a factor. now, it's much less so. I'm wondering if the difference is small enough for people to ignore.

also, is it better to have a deeper stiffer rim in the rear or a shallower, lighter rim?

To me 100g (about 1/4 lbs) wouldn't be super significant. However there's a 3 lbs difference between my similar height Jets and Stingers (60/90 and 75/90 respectively) due in large part to my tire selection on the Jets (same spokes, cassette, and almost identical hubs - with my Stinger 6s, 60/60, it's over 3 lbs and those use identical hubs). At 3 lbs I think it makes a difference when doing any kind of hard acceleration. In something, maybe Northeast Racing, I posted a power file from the P123 race last Sunday. I had numerous 500-700w spikes accelerating out of turns (I just looked for 5s intervals, there were 51 instances where I went over 500w for 5s). If those were a bit higher because I had to accelerate 3 more pounds of rim/tire weight, I think I'd have been making bigger efforts or I'd have gotten shelled. It's hard to calculate this stuff in a mass start type race because I could have accelerated a bit lighter (and kept the same power peaks) but that would have meant I would have had to have better position going into the turn. As it was I was dead last for a bit so I had no more drift back, no leeway, and with the pretty significant cross/headwind (depending on the straight), it was absolutely critical to get shelter. I corner well enough as someone pointed out elsewhere (at 2 to go I really moved up hard, and it was mainly through cornering technique/lines, not sprinting up the side of the field or whatever.

Once you go over a certain height a rim is no longer stiffer, it actually gets more flexible. The Stinger 7 (75mm) is advertised as being more of a sprinter rim with a stiffer rim overall. The 9 (90mm) has no such wording. Apparently (?) the 9 will flex a bit when out of the saddle. On the other hand a 45-60mm rim should be stiffer laterally than those.

All tall rims are pretty stiff vertically, but the tire really makes up for a lot of that.

For the sail effect I'd get a tall rear wheel. Just make sure it doesn't weigh too much.

V shaped wheels are fast, but they can be a ***** in a crosswind, forcing you to spend energy correcting. Toroidal and Firecrest shapes can be just as fast but they take a lot less correction in crosswinds. Little corrections add up.

i love my pacenti rims but jfc mounting tires on them with latex tubes might be my least favorite task ever.

New head units from Garmin with GPS, ANT+, BT in a small form factor. Sounds great... except no support for power meters. HR, cadence, speed, but no power. Obviously a designed-in software limitation for the sole purpose of creating product tiering. I hate that.

Everyone says that, but even with my relatively low weight (72kg), I rarely have any problems holding my line in 15-25mph gusty crosswinds. I ride 98% of the time on my November RFSC58 wheels and only really consider switching to a lower profile wheel when the gusts get above 25mph.

I posted basically this same comment on DC Rainmaker's blog. I understand why Garmin is doing this, preventing cannibalization, but I think they're overestimating that reality. Sure some people might buy this instead of a 510, but I could see myself getting one of these along with my 510 (if it supported power). I hate the idea of my 510 getting ripped off in a crash during a CX race. Something smaller/cheaper would be perfect for CX/MTB/etc where external damage is more common than Road. Also, for TT I could see this as a great small unit since I doubt many TT riders use much more than speed/time/power/HR during a TT.

I'll take the sort of contrary opinion, I have 90 mm planet x track wheels, and they're a bear in any meaningful wind. Maybe deeper than we're realistically talking about though.

Maybe they will support power later as a firmware upgrade. Though, I also see it doesn't have an altimeter, which is not ideal.

I just hope they don't stop manufacturing 500s (or have they?), or that somebody else puts out a device with that basic feature set.

without an altimeter I wouldn't know when to pull the ripcord.

I know. plus you would get the bends all the time.

Might be the tire as much as the rim. I've got a set of Challenge Paris-Roubaix tires that ride delightfully, but I've decided that I will never use them again. It's not worth the blisters on my thumbs and the fact that I ruin at least one inner tube every time I take them on or off. Plus I don't think the rubber is as sticky as my GP4000S IIs. If I want super-fast clinchers, I'll get the Specialized Turbo Cottons, maybe.

Your joking, right? This is Garmin we are talking about. They can hardly be bothered to fix bugs in current units.

hmm interesting. they are vittoria open corsa cx...anyone else have experience? i love them, have never mounted to other rims though.

Mikey are they "open tubular" style tires? Meaning that they basically lie flat when you get them, not curved into a U shape like a conventional clincher. That's how my Challenge tires are constructed. I'm not sure that's why they fit so badly on my wide rims, but I suppose it could be a common factor. Still, there are other tires that are a tight fit on wide rims, too, or at least I would bet there are.

So I ordered some Black Prince brake pads from XXcycle in France, $35 with shipping. Felt good about the price, about $15-20 cheaper than online here in the U.S. Then I tried to use that card for something else this morning- declined. The card company decided that a charge to France was suspicious and froze my card. It's unscrewed now, but boy that's irritating.

yes. fwiw, i've heard other people with these rims and presumably different tires complain about the same thing.

those rims have that problem - good rim, but it's an issue.

That's a bummer if it happens across lots of different tires. There are always some variations from rim to rim in terms of which side of the tolerances built into the ISO standard they tend to run. Same thing for tires. So some tires are always tight on certain rims. Usually most of them work well enough, though. For the record, the rims I've had trouble getting those Challenge tires onto are Velocity A23s, not Pacenti.