Originally Posted by
Duke of Kent
Yeah, I'm good with tools. I've built all 3 of my mountain bikes and my CX bike from a bare frame, built all 10 of my wheels from hubs/spokes/nipples/rims, etc.
My last question, given budgetary constraints:
I have friends selling wheels of various vintages, and some options from eBay. Some first-edition, paired spoke Bonty Aeolus, some Reynolds DV46s, some Easton EC90s. None of them are super aero, current generation, U-shaped rims.
Do you think any of those would give much to a modern, U-shaped open mold rim on DA or DT Swiss hubs? Leaning towards that option vs. used, old model wheels. Aero seems more important than weight, to me, if it's 100-150g difference.
I'm building this bike under $2500; aiming for 7kg or less. I'm small, and small bikes are light.
100-150g difference isn't much at all. However, weight does matter at some point - my 3+ lbs difference between my Jets and my Stinger 6s made me ditch the Jets for the local Tuesday Night Worlds on a 1k 3-corner flat course.
I think there's a small difference between the DV46 (raced/trained on them for a couple years) and the not-quite-U shaped Stingers (2010, before U shaped, but they are 28mm wide). However I don't have any power/objective data to back it up. I also have cognitive dissonance working against me as I replaced my DV46 clinchers and tubulars with 3 (and now 4.5) sets of wider HED wheels (Stinger 4 front, pair 6s, 7 front U shaped, 9 rear U shaped, Jet 6 front, Jet 9 rear, Bastogne/Ardennes). Therefore I'd be stupid if I concluded that the Stingers aren't better, therefore cognitive dissonance
I basically gave my DV46s to a teammate who just returned them as he's not racing anymore, and I got to use them twice in races, when I flatted my front wheel (Stinger 6 both times). The DV46 felt slow back to back with the Stinger 6 (not-U-shaped), but again, no data to back it up.
A sort of friend who tolerates my questions and who often worked with companies and pros in a wind tunnel doing bike data told me that technically a narrow wheel will be faster but you have to use a narrower tire, with all a narrow tire's disadvantages. The wide rims come into play when you want to use wider tires.
A few other points.
First, a tall wheel is faster in a cross/tailwind kind of situation, where it can sail. Shape isn't as critical. I don't use tall wheels for the headwinds, where everyone is going slow. I use them for the cross tailwind bits where I pick up noticeable speed. On windy courses tall wheels can make a big difference in top speed, and that's what concerns me. For a long time I favored my Specialized TriSpokes, aka HED3, and a rear disc wheel, especially in the really windy flat courses. In less windy but super technical courses I'd use my lightest wheels, not really aero (Zipp 340s), but super jumpy. I had Zipp 440s (58mm tall) but usually put the TriSpokes on instead. For road races, which I still did back then, I'd use a super light front non-aero (280g Campy rim or 330g FiR rim wheel) with a 440 rear (for the sail effect after I got shelled on whatever hill).
Second, the differences between an older narrow V shape wheel set and a newer U shape rim is not as much as a non-aero wheel to an aero wheel. If I was to try to do a bike for less money I'd use my DV46s. If I could I'd get a set of 66s and a whatever the 32mm tall front Reynolds wheel was called (KOM?). Short front wheel for courses where it's super windy or I'm descending fast, 66s for everything else. 66 rear is good for most everything, I'd even go taller if I could without gaining much weight.
Third, tires. I've only used 19 and 21 mm tires on narrow tubular rims. I don't know how they'd fare with a 23 or 25mm tire. I use 23mm tires with my Stingers, used 21mm initially with the 6s (first set I got). I think the 21mm are supposed to be faster than 23mm due to aero profile but they made me nervous in hard corners as the carbon stuck out so much.
Gotta go help Junior with his train tracks.