Road Cycling - wheel size

I will be purchasing a new road bikeand have it narrowed down to a couple. One is a 52 that comes with 650's and a 54WSD that comes with 700's. How much difference is there on 40-60 mile rides. I don't want to start out with a handicap of not traveling as far per rpm as my road crazy husband.

I will be interested in seeing the answers to this thread! I can't answer this one, but I know that a local lady rider is always complaining at her lack of top speed due to the smaller tires. I don't know if that can be made up with gears or not! We'll both learn something!

By the way, congrats on getting a road bike, they are loads of fun!

Same here, one of my friends who rode the smaller wheels complained about the lack of speed, but recently she purchased a bike with 700's. If this is anything, I would go for the 700's as long as the bike still fits you.

velo

I'll bet 700c tires are a lot easier to find (and less expensive) than 650's.

Aren't 650's used on triathalon bikes?

a 650 is used on some track bikes and triathalon bikes... it is really close to 26"

I have a question myself then...

I bought a fork that I love yet.... it is a 650 fork and I am using 27" in the back.. so I am forced to use 26" in the front.... I wonder how it will go..???

I'll say it before anyone else does! Always downhill, should be FAST! :D

650 wheels are popular on smaller bikes because they weigh less. With proper gearing, you can get exactly the same gear ratios with either. &00 tyres are much more common than 650 tyres are, so that's a very good reason not to go with 650's.
for JP King:
As for the 650 fork and the 27" rear-what a mongrel! Your front rim will be 571mm diameter, and you rear is 630 mm diameter. Assuming that the bike was originally designed for the 27" (630mm) rims, you will be sitting 29.5mm (1.16") lower at the front than the bike was designed for. This will throw off the headtube angle, and reduce the amount of trail needed for high-speed stability. The shorter the wheelbase is, the worse this will be. My prediction is that this bike will be impossible to control at higher speeds. You will likely find this out the hard way on your first steep hill, at about 30 mph.
For the sake of safety, stop this project now, and get the right fork for the bike. The setup you describe could only be called dangerous, and could very possibly be lethal.

I've heard that 650's are used on tri bikes for better acceleration. Is this true?

Yes.
The advantage is small, though.

I've heard this debate numerous times, as the shop where I work sell mostly high end road and tri-bikes. IMHO the difference in acceleration is more cycle-logical, and you can compensate the top end speed with gearing ratios. The benefits of a 650 wheel it allows more room for aerodynamic tube shapes, and a more forward and lower position on the bike!

BTW how many times do you accelerate in a triathlon? ONCE! As soon as you're up to speed, you rarely accelerate more than 5 mph at a time!

The benefits of a 650 wheel for acceleration, in my mind are negligible! However, the most important factor is bike fit! Many companies use the 650 wheels on their smaller sized and women specific designs to keep the frame geometries relative. I would worry less on the wheel sizes and concentrate more on how each bike "feels".

The women specific designs usually have a shorter top tube and the "reach" may be better. Test ride both and buy the one that's more comfortable.
L8R G8R:D

Scubagirl; Whichever bike fits you best. Which one do you feel the most comfortable on? That is the only criteria that should concern you.
Are you able to ride year round in TX? If not, do you use an indoor trainer? I've been told by some that 650 wheels and indoor trainers are not as comfortable as 700's. Why I don't know.
Again, the most important thing is that the bike fits you and you feel comfortable upon it. Good Luck.

The above threads are generally right:
700c tires and rims are easier to find and more choices are available.
The acceleration, weight and aerodynamic advantages of the 650c wheels are reduced by the increased rolling resistance of the smaller diameter. The 700c wheel WILL have "smoother" ride.
If you are too small to fit a bike with 700c wheels properly, then a 650c wheel bike, designed for 650c wheels, would be advantagous.
Ride Smart
Pat

Originally posted by Oscar
I'll bet 700c tires are a lot easier to find (and less expensive) than 650's.

Aren't 650's used on triathalon bikes?
Yes you are right but sometime they are using I mean the traithlon bike are now using the 700c wheels, but a 650 wheel set on a bike is very good for climbing..

The other reason triathletes use 650 wheels is to get shorter top tube that allow them to seat forward over front wheel, what is ok for time trials but otherwise if person is tall enough 700 makes more sense.

700c/27" is the largest wheel size which will comfortably fit inside a normal sized frame.
Since you need a small sized frame, 700c wheels are going to be too big.
Framebuilder mess with the steering geometry to make it fit, and some of them handle OK.
If you want a small bike, then you really want proportionally smaller wheels. The arguments about weight vs rolling resistance are simply side-issues to the one of correct fit and bike handling.


You also need smaller cranks and a lower bottom bracket , but that is wishfull thinking in todays market.

Racso!!! Nice to see you back, it's been a while!