Old 05-09-21, 11:48 PM
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Join Date: Feb 2018
Posts: 1,216

Bikes: 2017 Specialized Allez Sprint Comp

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If you're in 8-9-10 80% of the time, maybe you need something bigger than a 48T top end. Or maybe you just need to shift to the big ring more often? Or are you saying that you're in your big ring and little cogs 80% of the time?

Step 1 is to figure out your spinout cadence. How fast can you spin downhill before you can't put out useful power? At what speed do you hit that cadence?

Step 2: Figure out what you want your top speed to be. For example, do you have a good reason to be able to pedal past 40mph?

Step 3: Use bikecalc.com to figure out what gear ratio allows you to hit your target speed.

Step 4: Get the chainrings (or even new cranks?) you need. Any 10 speed 110mm 5 bolt ring should work. You can try to just get a bigger big ring. Your front mech probably won't be able to handle it. Thus, you'll need a bigger little ring. If you need easy gears, you'll need a bigger cassette. If your rear mech is a short cage, you'll need a new rear mech. And you'll also need a new chain to accommodate the larger gears. And you'll need to readjust the front mech.

Alternatively: get better at spinning. I can put down useful power well beyond 45mph if I want to using a 50:11, which is pretty standard gearing. It's usually far more beneficial to tuck than to continue to pedal at those speeds anyway.

With a 46:11, at 130rpm, you're doing 43mph rather than 46.5mph. Not a huge difference IMO.

Those are your options.

Last edited by smashndash; 05-09-21 at 11:54 PM.
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