|Cheap TT wheel build/project...||philippec|
Jun 2, 2003 2:25 AM
|I'm in the process of building a dedicated TT bike and have come to the thorny question of which wheels to use. Let me preface this by saying that this is a cheap build project -- I'm not interested in spending tons of money to get an especially light final product, esp. as most of the TT's I do are on flat courses. My question relates to improving the aero. profile of the bike through the wheels. I've thought of a few options, including slapping an aero cover on the back, building up some "more aero" deep/medium depth rims w/ a low spoke count (are deep/medium depth rims really more aero?) and/or keeping my current set-up (daytona/32h/Open Pros). Thanks for ideas and feedback.
|re: Cheap TT wheel build/project...||Marketing Dept|
Jun 2, 2003 4:48 AM
|IMHO, Sink all of your money into an aero front wheel. For the price, I like Spinergies. I see these for sell quite often for $150.00 or so for a front wheel.
If your course is flat and non-technical (only one turn around) see if you can find an old Specialized tri-spoke. They weigh quite a bit, but can be had for a decent price on the used market as well.
Good luck, and as far as the rear wheel, don't cover it, just pump up the tire to the max and leave as small a foot print as possible.
|Spinergies arent very aero||wilsonc|
Jun 3, 2003 6:50 PM
|I think I recall a John Cobb wind tunnel study saying that the old 8 spoke carbon spinergies were pretty poor in terms of aerodynamics. I agree on spending most of the money on the aero front, if not all of the money. Hed Jet 60, Hed Alps, Hed H3, and Zipp 404 are good recommendations, although some cheaper than others.
Make sure your body is as aero as possible/comfortable/powerful as possible... that alone can be worth 10X the aerodynamics of an expensive wheel set.
|re: Cheap TT wheel build/project...||Ye Olde Balde One|
Jun 2, 2003 6:09 AM
|I'd cruise Ebay.
You can pick up a set of Deep V/Edco wheels for about $200pr from listings I've seen recently, and have them as a spare road set of wheels as well, or get a Renn rear disc and pick up a front wheel (about $600 total).
If you have time, then you often find old Mavic Cosmic Pro's and Campy Shamal wheels going cheap too.
|Aero is always good.||jw25|
Jun 2, 2003 9:07 AM
|First off, I'd never TT on box-section rims, especially on a flat course. Above a certain speed (around 10 miles per hour, I think), wind resistance becomes your greatest obstacle. Aero wheels are fairly important overall.
However, there's no need to spend a lot of money on them. Ebay is definitely your friend here. I've seen older Mavic Cosmics and Campy Shamal/Ventos go for pretty cheap there. I TT on a set of Cosmic Pros I picked up at a swap - $150 for 2 pairs. 1 needed a spoke replaced, and they all needed a truing, but add in $15 for tools and spoke, and they're great.
I'd focus on the front wheel first, since that's what sees the wind first, before it's churned up by the bike, your legs, etc. Go fairly deep here, at least 30mm rims, but deeper if you can. The Cosmics are 38mm, I think, and Shamals are similar. If you can find a Zipp or Hed carbon, they go deeper, up to 58-60mm, but then you have tubulars to worry about, usually, and they cost more than alloy rimmed wheels.
Weight is of little concern here, especially on flat courses. Sure, they take slightly longer to accellerate, but they keep their momentum better, and once spinning, it's a moot point.
Tires are important, too. You really want a skinny tire, not much wider than the rim itself, at high pressure with no tread. The tire forms the top of an aerofoil, so you want a smooth transition with the rim. Heck, I've seen riders use silicone sealant to fill in the gap around the bead - makes for a tricky tube change, though. If you're light, definitely go 20mm, and try something that'll take 130 psi or more. Most of the time, you want softer tires for cornering, but TT's are the one time this doesn't matter. If you're over 180 lbs, I'd use a 23mm tire in the back, but keep the skinny one up front. Check the wheel specs for maximum pressure, too. Mavic has a 140 psi upper limit, which I respect.
Panaracer Stradius TT's look nice, if you can find them. I've used 20mm Stradius Pros, and they performed very well. The TT is lighter and smoother, but still goes to 150 psi. Hard to find for a decent price, though.
Conti Supersonics also treated me well, but they're fairly fragile.