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650C vs 700C(7 posts)

650C vs 700Cyt
May 14, 2001 11:08 AM
Are there any short riders out with EXPERIENCE with riding 700C and 650C bikes? I understand all about tire selection and the theoretical benefits of less rotational inertia, but I want to know if someone could say, "Yes, I switched to a 650C-wheeled bike for road-racing and I love it."

Can you say that the smaller wheels improve acceleration without detriment to handling, especially when sprinting out of the saddle?
So....grz mnky
May 14, 2001 11:33 AM
Why stop at 650C, why not 600C, 550C, etc.?

If you understand the theoretical benifits, yet continue to observe that elite road racers don't use them what is your point? Are you trying to prove something to yourself? The tir-guys will extoll their virtues, but that's about it. If there were even a minute actual advantage they would be used by now. Not to say that people don't come along and knock the established mindset for a loop, but it just doesn't happen that often. The whole thing about acceleration and the reduction of rotational moment of inertia is fine in theory and on paper, but eventually it mostly comes down to the rider. Equipment doesn't win races, but it can lose them.

You could have a road racing bike designed around them and this could make sense based upon your physical size (common in some of the women's bikes), but one problem will be that you will run out of gearing unless you do something about the large chainring. This may or may not be an actual problem.
So....yt
May 15, 2001 12:54 AM
>>If you understand the theoretical benifits, yet continue to observe that elite road racers don't use them what is your point?

Most elite road-racers are taller than me (5'3"). Most elite road-racers are on sponsored teams, and unless they are the star rider or the entire team switches bikes, they will ride 700C-wheeled bikes because the team needs everyone to have common equipment, among other reasons. Most elite riders don't use sub-49cm frames, wear size 39 Sidis, nor have to special order XS jerseys. THAT'S my point.

>>Are you trying to prove something to yourself?

Well, no. If I were trying to prove something to myself, I'd have two bikes custom made with different size wheels, build them both up with D-A, and then go ride them back-to-back. But that would be rather expensive. What I AM doing is asking others to relate their experiences.

>>Equipment doesn't win races, but it can lose them.

That statement is a gross simplification, and I can always point out that Laurent Fignon didn't think that was true after the '89 Tour.

It is a physical fact that a 650C wheel has less rotational inertia than a 700C with the same hub and rim model. Tests prove that 650C wheels are laterally stiffer than comparable 700C wheels (see damonrinard.com).

My question is whether or not these physical facts can be utilized to an advantage. I have limited the range of conditions to sprinting, though I am somewhat intrigued by the purported climbing advantage. i am more interested in a 650C track bike for sprint events. The advantage in acceleration is highly desirable so long as there are no handling issues. My working assumption is that if roadbikes with 650C wheels are good for sprinting, then a well-designed 650C trackbike should sprint well, too.

>>Why stop at 650C, why not 600C, 550C, etc.?

Why stop at 700C, why not an 800C? Moser used a whopping-big wheel in 1984, why not something bigger than 700C? It should be obvious that 700C is merely a size derived from a compromise of structural goals, later deeply entrenched to become a standard. It's not like God created 700C on the sixth day, then cast Adam out when Eve bought a tri-bike.

Why stop at 650C? ---because 24" discs, rims, and tubulars are nearly impossible to acquire easily or cheaply. But I can always find used 650C aero wheels.

If you can say from personal experience that 650C wheels are an excellent or poor choice for a 46cm sprintbike, then please elaborate. Otherwise, please respond if you are a short rider with personal experience with 650C-wheeled roadbikes and can make a qualitative statement regarding their sprinting qualities.

Thanks
So....Abbs
May 15, 2001 11:40 AM
grz mnky is a jerk. He thinks he knows all. He posts more than anybody else here-just to show how "smart" he is (to feed his little ego). He will criticise recklessly and be proud of it. (He thinks it is his "signature"). He is also a racist who stereotypes others. He posts frequently about his drinking and drug use (my aren't we impressed).

He is the epitome of all that is bad about road cyclists. A snobbish bore. He has a lot of mental/emotional problems.

There are many other knowlegeable posters here who will give good, correct advice without all the insults. If you read this forum often, you will soon know who to respect. Grz mnky is NOT one of them.

I've seen others who feel this way too.
handling on 650sBecky
May 14, 2001 12:42 PM
I'm not about to discuss acceleration and rotational intertia, etc. since I'm not a physicist or a racer. I ride a 650-wheeled aluminum road bike and it's been my experience that, while it handles a little *differently* than my 700-wheeled steel ride, it doesn't handle poorly. That said, I love the way this bike handles and don't consider the smaller wheels to be a detriment.
a LITTLE input.boy nigel
May 14, 2001 1:29 PM
I know of an elite (Cat 1 or 2) woman racer who's about 5'7 or so. She can ride any bike out there, sizewise, but chooses to have her frames made to accept 650cc wheels. I've not had the opportunity to ask her why she digs these wheels more, but she does very well at races (Granted, she can toast most local men on rides) and trains constantly. Must be something to it.

Note to Grz: take it easy on YT, mate. They asked a question that they'd like answers to; nothing more, nothing less. Maybe they can get either on a bike but are wondering about the pluses and minuses. I had similar questions at one point, being 5'5 (I thought I'd have to get a 650cc-wheeled bike before I hopped on a small Giant TCR).

The bottom line is that, I feel, if you choose one or the other and this is your only/main road bike, you'll have nothing to compare it to, and your body will adjust quickly and comfortably.

As Akirasho sagely says, "Be the bike."

Cheers,
Nigel
re: 650C vs 700Cdough
May 14, 2001 8:34 PM
I wouldn't classify myself as short (5'8"), at least not REAL short, but I have ridden both 650 & 700 and I've settled for the 650's. I posted some info about this awhile back but I can't find it, so here goes again:

I have had the very unique opportunity to ride the same EXACT frame with both size wheels to compare the difference. I don't mean the same brand and model in different wheel sizes. I mean the very same frame. I have a Softride PowerV, which can be fairly easily switched back and forth between the two sizes. Here are some of my observations:

1. 700c seems a tiny bit faster going downhill
2. There is no noticeable difference between the two on flat roads
3. 650c is WAY better for climbing – the difference is like night and day
4. 650c accelerates quicker (which is likely the reason for the improvement in climbing)
5. 650c handling is just a little "quicker" but this may be somewhat frame dependent
6. It can be a real pain in the butt finding tires and tubes – keep some spares on hand!

I don't think there is any "detriment" to the handling of my bike with the 650c wheels. It is different but it handles great. To be honest, the main reason I decided on the 650c size is for climbing. That's the only significant difference I found - and a VERY significant difference it was.

One small piece of advice before I shut-up: If you decide to go with 650c, KEEP SPARE TUBES AND TIRES HANDY. There are at least dozen bike shops in my area and only one of them ever has them in stock and they are constantly running out of them.