My guesstimate is that it would drop about 3 inches on the front, which would allow me to go to a normal stem and get down where I want. I have a 650c fork and wheel with which I can try it, but I am wondering if anyone has already done it. Mostly I wondered if the resultant change in handling would render the bike so quick on the front end as to be unrideable.
Chad
What frame?
It is my Yaqui Mariola (DE model, 81.5 seat tube, shallow head angle). I’m embarking on some testing, comparing the times over a fixed course with a P2 I borrowed back from HH. The P2 has VT one-piece bars and a very deep QR Carboaero fork. The Yaqui has a Reynolds Ouza (not aero, 50mm rake) and regular round pursuit bars. I had given some thought to switching those out after the first round of testing to isolate how much affect, if any, I could detect for only the aero frame/wheel cutout.
Chad
At least one guy has…
It is my Yaqui Mariola (DE model, 81.5 seat tube, shallow head angle). I’m embarking on some testing, comparing the times over a fixed course with a P2 I borrowed back from HH. The P2 has VT one-piece bars and a very deep QR Carboaero fork. The Yaqui has a Reynolds Ouza (not aero, 50mm rake) and regular round pursuit bars. I had given some thought to switching those out after the first round of testing to isolate how much affect, if any, I could detect for only the aero frame/wheel cutout.
Chad
Not a good idea. You’ll have a bike with an almost vertical seat-tube. Works well for road frames with a shallow head-tube angle.
Not a good idea. You’ll have a bike with an almost vertical seat-tube. Works well for road frames with a shallow head-tube angle.
Is that a problem of itself, though? In coversations I’ve had with Ves, he said he built his first steep bikes for pursuit with 85 degree or steeper seat tubes and he said it really worked for the riders trying to get low in front.
I just finished up a month of riding a 51cm P2C with a 40 degree downsloping stem in a 130 length, so I’m not sure how much worse the handling could be than that.
This morning I completed the P2 and when I am out on the bars I am looking down about 2 inches in front of the hub. The handling was actually a lot better than I remember from when I was racing it a few years ago.
Chad
Email Ves and ask him what he thinks about the idea. Don’t forget to post here his email 
I try not to bug him much these days; he’s trying to build a house and it seems to be an overwhelming project.
I was hoping someone could provide me with some pearls of wisdom. I know, I know, this IS slowtwitch.
Chad
isn’t it sort of a moot point, since it would be illegal to race on anyway?
also, i wonder if crank clearance would be an issue. i think the BB is think higher off the ground on a 650c bike.
I seemed to recall AC posting regarding this.
http://forum.slowtwitch.com/gforum.cgi?post=957219;search_string=650;#957219
http://forum.slowtwitch.com/gforum.cgi?post=999315;search_string=650;#999315
I didn’t read these threads carefully so I don’t know if they will help.
I any event you should have your answer soon. Paulo said no. If AC disagrees, I’m sure he’ll educate the SAC.
.
I think I remember Inside out sports having some 650 P3s (Alu)at really good prices (LIke $8-900) for the frame–and maybe some P2k, too.
No, it is not a moot point, because it is legal to race with wheels of different sizes. I checked for this issue specifically before I asked the question. Crank clearance is not something that bothers me either, since I already ride with 190mm crankarms. What will being a little closer to the ground hurt?
Chad
Check the footage of the 1996 ironman. Luc Van Lierde raced on a Colnago with dual wheel sizes. I believe that in 1997 Hellriegel also raced on a duel wheel sized bike - the red Centurian. Seemed to work for these guys - although both went back to bikes with the same size wheels. Im sure there are a host of other examples.
Chad, love to see you are pushing the limits, and trying new stuff!!!
Keep us informed as your results come in.
Dave
The bike I had for it, Elite custom made for me using 26" front end geometry. You have to be careful about changing headset angle when you drop the front end of a standard frame. You are also losing pedal clearance because the bike will go down. The change in the headset angle will effect the bike handling drastically.
They are fast and f designed properly, it will handle as well as any other TrI bike.
Prior to that I rode 24" front wheels, one Nishike and a custom design bike. The biggest problem with 24" is finding high end, light bike equipment. It is not mass produced at racing quality.
The bike would be triathlon specific. Proportional wheels are not allowed for bike races.
Joe Bonness
don’t do it. it won’t work and its a stupid idea. it’ll throw off the geometry of your bicycle to the point that it will be near unrideable. get a look ergo stem if you must or a new bike. funny bikes were the rage because no one had yet figured out a way to make a seatpost longer than a 200mm…your bike wouldn’t be funny, it’d be dumb.
jerk
Hello Cdw and All,
I tried it on my P3C - just 650 wheel in front - same 700c fork - brakes on tire (although) I wouldn’t want to race with the brakes that way.
It rode just fine, (with only a 1 inch drop) but it put a lot of weight on the front of my saddle and was not comfortable and I would have to carry 2 tire size spares - so I discarded the idea.
With some saddle tinkering I think that set up would work. With a 650 fork and the additional drop perhaps it would affect handling - try it and see what you think, the proof is in the pudding.
Cheers,
Neal
my bad. it IS legal for triathlons after all. it’s the UCI races that demand that both wheels must be of equal sizes.
I think you’ve spent a little too much time in that 29 Palms sun, Chad! Please step AWAY from the workstand!