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Wheels(5 posts)

WheelsQ
Jul 30, 2001 3:46 PM
My wife recently purchased a Cannondale with 650cm wheels. Does anyone know whether we adjust the bike to accomodate a 700 cm wheel in the rear? Ideally, I would like to keep the 650 cm in the front for her. Any help will be greatly appreciated.

Thanks
Marlon
What are you trying to accomplish?Spoke Wrench
Jul 31, 2001 2:32 PM
Unless she is spun out in her highest gear a high percentage of the time, you won't be gaining anything. If she is that strong, she can probably body slam you and you might want her to have the smaller wheel so that you can escape.

If you are just curious, you could try to fit your 700c wheel onto her bike, but my bet is the brakes won't line up.
What are you trying to accomplish?Q
Jul 31, 2001 4:10 PM
On long rides, she tends to lag behind (even though we are keeping similar cadence). I'm hoping that a 700 c wheel in the back will keep her on pace. She used to ride with 700 c wheels and we were at about the same pace. I realize she can just increase her cadence frequency but if switching to a 700c wheel does the trick than that may be a better option. Any thoughts?
What are you trying to accomplish?grzy mnky
Jul 31, 2001 4:37 PM
Well unless she's spinning out then the limitations are power and efficiency. If she's spinning out then increase the large chainrign to something like a 56 or 57 (do the math first). By power I mean what she can produce - since you have a base line from her previous ride I'd say unless her conditioning changed we're looking at the efficiency thing. The 650 wheels have to rotate faster to get the same speed as a set of 700's. As you decrease the diameter the rolling resistance increases due to things like tire deflection, possibly increased drag from the spokes (we could debate this one for a while), bearings, etc. Dunno why you went with a 650 setup if 700 worked and you don't have a fit issue. Most likely you're not going to get a set of 700 wheels to fit the bike. The tri-folks are all over the 650 bikes, but they don't make much sense for the rest of us. You may also want to check out the tires - there can be considerable difference in rolling resistance of tires but 650 really limits your choices.

I'd look at getting some "faster" tires and if that doesn't work get her back on a 700C wheeled bike. There are some women's bikes that will run a regular 700C rear wheel, but a smaller front wheel (Terry, Wylder, etc.) which works reasonably well since most of the weight is on the rear wheel.
why change wheels?Rusty McNasty
Aug 2, 2001 8:38 AM
You would be much better off increasing the gearing, either by getting a smaller cog, or a larger chainring. Why would you want to spend the money for a whole wheel (which probably won't clear the bridge, and will never line up with the brake pads) when the solution is GEARING? The ONLY time a wheel size makes any difference is during acceleration, and even then, it's damn little. In this case, it would be detrimental.