(05-18-2020, 08:30 AM)ManBearPig Wrote: @CharleyFarley very useful information, highly appreciated! I am not a top level athlete yet and need those extra teeth for hills that we have around here. 11-32 and 11-34 ... would two teeth make a big difference? I am afraid that after few months, once my legs are super duper fit, 34t will be pointless.
Will this work with my cassette?
https://www.parktool.com/product/cassette-lockring-tool-fr-5-2
You was talking about going from a 30T to a 34T. That might be a bit of a stretch for your existing chain, that's why I said to put it on a bike work stand where you can turn the pedals and watch the chain as it moves to each larger cog. Or if you can support the back wheel in some other way to get it off the ground and turn the pedals to watch the chain. You might get away with two extra teeth but four could cause a problem. Personally, I wouldn't put the 34T cog on, and then ride the bike to try it out because the force of turning the pedals could do damage. I'd want to watch the chain to see what happens when it gets to the large cog.
You can calculate the difference two extra teeth, or four extra teeth would make over your 30T cog. Here is how to calculate the gear inches, plus an example of my own Elektra cruiser:
CALCULATE GEAR INCHES
Divide chain ring teeth by rear cog teeth. Multiply by tire diameter.
Example: My Elektra Cruiser - 44 chain ring teeth, divide by 28 sprocket teeth. = 40.85 gear inches. That's the distance in inches traveled by the bike for each revolution of the pedals.
So count the teeth on your chain ring and then go from there. It will tell you how far the bike will travel with the gears you are using. It's not as difficult as it may look.
Let's say you have 44 teeth on your chain ring, and you have 26" wheels. Your calculation for the current 30T will be:
Chain ring: 44 teeth
Rear cog teeth: 30
Divide 44 by 30. Multiply by 26 = 38 gear inches of travel. The bike will move 38" with each revolution of the pedals.
Now try it with 34T cog.
Divide 44 by 34 = 1.29. Multiply by 26. That's 33.6 gear inches of travel for each revolution of the pedals.
The lock ring tool should do the job you want. As far as I know, cassettes are standard mounting on the freehub, as long as you match the brand of cassette to the freehub - Shimano for Shimano. Or you might get an equivalent other brand that will fit the freehub. The splines on the freehub can be different between the brands. If you currently have a Shimano cassette on the bike, then another Shimano cassette will fit.
Let us know how you get along with your project.
EDIT: I don't know where my head was when it came to the gear inches calculation. I have now corrected it. It was way out!