I was told at the LBS today that i was too big for a 650c wheel, I have a Scott Tri-Bike that was
equipped from the factory with Mavic CXP-14's 650c. I am 240lbs, I have road the bike a little and

the tires seemed wobbly but strong.

So upon finding out I'm too fat, I started asking question that I know a little about.

1. If I get a 700c rim can i just bolt it in?
2. what do I need to do with the rear casseset after installing the 700c?
3. Whats the true benefit to getting a 700c?

1. yes your frame(I didn't have the bike with me) will accept a 700c rim you just need to adjust the brake and move them up.

2. just pull the old casseset off and install it onto the 700c hub??? O'REALY what if the hub is different?

3. You'll go faster

So i had a fuji before with a 27x1 1/4 wheel on it, to go to a 700c I had to bend the rears and change the front fork- is that not so with going from a 650c to a 700c?

How can I find out what my rear hub is so I can order a 700c and not have to change my casseset out?

I dont give 2 sh|ts about going super fast I am doing Tri-s to get fit not win a million dollars, so why change them?

How much are Mavic CXP-14's even worth?

1) Highly doubt it
2) Not relevant due to above
3) Not relevant due to above

700c is substantially larger in size over 650c. 622 vs 571

operator is spot on. Unlike the other wheel size thread, this one is pretty definitive. Mountain bikes have lots of clearance, which can (sometimes) allow for a larger wheel to be used. Tri-bikes are usually built with very tight clearances.

And anyway, smaller wheels are faster. Less rotating weight, and less aerodynamic drag.

Time to find a different LBS.

Agree with the above responses that they won't be compatible. 700c is a full inch larger in radius than 650c, so it's highly unlikely that the brake pads could be adjusted up by that amount. And you'll probably to run into clearance problems with the basic frame and fork as well.

It's not clear what you're trying to solve. Are you having some specific problems with your current wheels and tires?

no none thats the bad part, the problem I'm having is I have never had wheels with these funky valve stems, the screw out and then will release the air, but how do you put air back in them?

I was trying to buy a pump, but after all the crap he talked I left. I still need a pump!!!!

I guess if I start breaking spokes I'll worry but I am also on the hunt for some carbon wheels, and thought if he was right I need to start looking for a 700c but I like the 650c's I have and will use them to train and use the carbon for racing.

What do you think Mavic cxp 14's are worth?

Did you have tires fully inflated? Sound like that could be part of the problem, given you don't have a pump. I have to add air (top off) to my bike tires just about every day.

Go to the clydedale forum, and you can find some awesome advice on wheel choice.

+1 Find another shop, depending where you live, there should be several decent choices. And the shop doesn't have to be that close to where you live or that convenient, as you probably won't be going there that much anyway. My favorite shop is 75 miles one way from my home.

What is your goal with the tri bike? Depending on how serious you are about it, a decent road bike might meet your needs just fine.

I would like to see a picture of your valve stem, as you may just want to change out the tubes? Are your tires tubulars or clinchers? Most decent bikes come with presta tubes. If thats what you have, thats not really a funky tube, thats normal. Get a bicycle floor pump, you will need one regardless.

If you are at 250 lbs you needn't worry about lightweight wheels just yet. You can get by with 650's if they are built up with enough spokes. 32 might work, but 36 is much better.
700 wheels will not fit a bike designed for 650. There is too much difference in diameter for the necessary clearences.

All you guys responding with eloquent English literature excercises are really wasting time and bandwidth...

Urbanknight said it best...I'll make is even shorter with fewer characters...


0:00 2 =>-) a != LBS

Depends on the hubs, and the condition of the rim/total mileage/how beat up the wheelset is.

That's a presta valve by the sound of it. It's the typical standard on road bikes these days with clincher tires. You can get a pump with a two sided head if you like that will allow you to pump up tires with a schrader valve or presta. The pump with a presta head will simply press onto the open (unscrewed) presta valve, and should have a lever on the head to lock it in place.

There are a lot of 650 wheels out there, that was once really common for tri bikes. I second whoever said check out the clydesdale forum, I imagine there is something out there that will work.