First, the craftsmanship on the Serrota 650 project on the front page is impressive. Second, any chance we’re headed back to the funny bikes of the '80’s? They weren’t very comfortable but we were riding bullhorns with slack rather than steep positions. Felt like a push-me pull you and were tortuous to t’aint and low back. Did the Hamilton with (I think) 24" wheels that Paula Newby Fraser rode make more sense then anyone suspected? I’m a casual observer of bike tech and entirely unqualified to engage in Slowtwitch discussions of crr data, wheel spin up rates, frame aerodynamics etc. It seems to me that with the advancements in bearings, wheel and tire technology there are lots of good arguments for smaller wheels; less rotational weight and better aerodynamics due to less fork and wheel and more frame (is a stable aero profile headtube aerodynamically superior to a fork and spinning wheel?
On the topic of wheels size, very race dependant , and I will only talk on my car racing experience days… If you have a 300hp car, on the dyno meter you will get more power out put of a smaller wheel say 320 hp and quick to top end (120mph), while a bigger wheel might give 290hp but more top end speed (130mph). Now a smaller wheel has better chance of spinning out when you are putting more power to it if no spin and just right - you should have more initial acceleration - of course gearing can change this but to a certain degree. So currently Im wondering if I should switch from my 26" mtb to a 29 since I am spinning when biking up hill. Also the advatage is on the downhill when going over objects. Course I can be talking out of my ass but I would just like to bring the thought up.
There are some advantages and disadvantages of using 650 vs. 700. But they are not typically large enough to warrant bike and wheel manufacturers to tool up so they can make two differnent frames for the same bike size.
The business operations side of that dictates that for the mass produced bikes we need to stick with one standard wheel size. It looks like 700 is that standard.
p.s. my first Tribike was a 56cm Fuji Aloha with 650C wheels and I loved it. I wish my 54cm Cervelo P2 had 650 wheels as well.
I’ve been racing both a 650c bike and a 700c bike in various time trials for the last ten years. I’d say your observations hold up and translate quite well to the bike. I’ve always said that I pick between the two bikes based on the course. As your analysis would suggest, I find the 650c bike better suited to technical courses with lots of turns out of which I need to accelerate and with more hills. Flatter, less technical courses and I’m on the 700c bike.
For me, it’s all about position. Riding steep, that rear wheel needs to be tucked under in order to not need a mile of front center to get the weight off the front wheel. Chainstays can only get so short with a 700 wheel…
I’m actually designing a bike for my wife with 24" wheels… More of an all-road 1x10, but whatever…
After reading the article on the Serotta, and the linked article on the wheel size wars, I had to throw this out there…
Why not have the tri bikes go to the 559/MTB 26" wheel size instead? In fact, use disc brakes, add some tire clearance, and you could swap between the two with abandon! Hmm… I’m liking the idea.
I’m adding another project to my build queue – a long front center/long trail TRI bike, and instead of 650’s (as I’d originally planned), base it around MTB 26"ers with disc brakes, and have loads of clearance… I’d use my last build (as it’s already MTB 26" and disc brakes), but the STA was set at 73 degrees. Not too tri-friendly.
650 may be come even more popular as the kids / women series races are growing. When dealing with full grown women at 5’0" or less or child of similar height needing 42cm or less bike. Other option is the womens hybrid bike to be converted into road bike
Most if not all of the decisions on a “new” style bike (tri, mtb etc) come down to available tire choiice. When mtb started bmx and crusiers exited and the tires for them worked OK,
When small wheelsed tri bikes came out there were plenty of mtb bike tires in 26 inch format but really no tires. Just curious if you make a custom tri bike with 559 wheels what tire /rim will you use?
After reading the article on the Serotta, and the linked article on the wheel size wars, I had to throw this out there…
Why not have the tri bikes go to the 559/MTB 26" wheel size instead? In fact, use disc brakes, add some tire clearance, and you could swap between the two with abandon! Hmm… I’m liking the idea.
I’m adding another project to my build queue – a long front center/long trail TRI bike, and instead of 650’s (as I’d originally planned), base it around MTB 26"ers with disc brakes, and have loads of clearance… I’d use my last build (as it’s already MTB 26" and disc brakes), but the STA was set at 73 degrees. Not too tri-friendly.
I did something kinda-sorta like you mention… (but 700c):
http://www.slowtwitch.com/Tech/The_Uber_Training_Bike_3133.html
The Serotta actually has a longer front/center than my normal 700c tri bike, just with how it workout in rake/HTA/trail. That’s actually one of my favorite features that I wasn’t expecting to like, but I really do.
More exciting stuff in 650c to come. We’re going to review the hell out of everything we can find.
The business operations side of that dictates that for the mass produced bikes we need to stick with one standard wheel size. It looks like 700 is that standard.
p.s. my first Tribike was a 56cm Fuji Aloha with 650C wheels and I loved it. I wish my 54cm Cervelo P2 had 650 wheels as well.
I just think it’s funny (and unfortunate) how it turned out. If you’re going to pick one size, pick 650c (said to the industry at large). It’s always easier to fit a large person on a small wheel than the other way around. Sure it might look a little goofy having a big head tube on a 650c bike (or a flipped up stem, or high-stacked aerobars), but that’s better than a short person who can’t hit their proper fit coordinates - i.e. get low enough.
I’ll get more into the ‘ride review’ in part 2 of this article, but I honestly prefer the feel of 650c, now that I’ve ridden both. The only thing keeping me on 700 is tire and chainring choice.
Back in the early days of tri bikes one of the best TT riders in MI was tall and for whatever reason had a custome funny bike made with a 24 in front wheel. I forget how the headtube was made, I think it may have been a tandem tube but no headset tube was long enough.
SuperDave may remember the bike.
Just curious if you make a custom tri bike with 559 wheels what tire /rim will you use?
There are plenty of narrow 559 tires out there. A quick look in QBP yielded 3 choices in 25mm, and another 3 in 28. I’m fine with that for most road riding. But if I wanted to go to 23, then I could pop on a set of 650’s. Just a matter of building in enough clearance in the frame.
p.s. my first Tribike was a 56cm Fuji Aloha with 650C wheels and I loved it. I wish my 54cm Cervelo P2 had 650 wheels as well.
you can always scan fleabay. I saw a 54cm aluminum P3 with 650 wheels sell for under $700 in the dead of winter…plus you can absolutely steal race wheels. I got a zipp disc/404 combo for under $400 because they were 650’s.
Right. That’s why it seems that if there isn’t a rolling resistance disadvantage then frame designers and builders could really go to town to further improve aerodynamics and fit options. (I do think I understand the ‘spin-out’ concept for MTB’s and that in performance autos at high speeds larger wheels will carry more speed per power increment - but I would think those differences negligible at TT speeds, particularly for the front wheel). Ultimately, I think those who have posted about manufacturers needing to pick a standard size to be profitable, interchangeable, etc… state why we ride the wheels we ride. That said, rim and tire width have changed.
I was actually curious as to the specifics. Their are certainly lots of tire choices but very few if any fast tires are made for 559 tri bikes. Long ago Specialzed made one, a narrow road mtb sized tire. I suspect they could be found NOS but other than that you are likely looking at touring type tires.
Here’s mine. 73 STA, 69.5 HTA, 43mm rake yielding 80mm trail on 2.0 tires (it’s got 1.5’s now). BB drop was set to duplicate 80mm drop on 700x23’s, so it’s really low. This bike is THE most stable ride I’ve ever had. Love it.
Ritchey’s slick, and a couple wheelchair-specific ones would likely fit the bill. But my definition of “fast” may be different than yours. I’m not one to split hairs with minor differences in Crr. My roadies (and tri bikes) are running a bunch of Kenda Koncepts, training and racing, as I got them for $10 a pop. Good enough for me. I’m still at the top of my local AG, so I’m not complaining.
I’ve always wanted a 650 wheel time trial bike, closest I’ve gotten is a 650 front wheel bike. 
I have one of those
http://www.flickr.com/photos/kenneyc59/5456954099/in/photostream
.
Moser had a 24 inch front. A few years ago I saw and almost purchased one of the frames made for him