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monospaced / bike

Bug tracker for my bike
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setup my fixed/fixed hub with different sized cogs on each side #18

Closed monospaced closed 9 years ago

monospaced commented 10 years ago

The desired result is 2 useful ratios that can be switched without having to alter the chain. One ratio close to what I'm currently running, and a lower ratio for spin to win. Both with a decent amount of skid patches.

Currently running a 49 link chain, 48T chainring and a 17T cog on one side, nothing on the other. The chain is stretched, chainring is worn, and the cog/lockring from LBS seems sketchy. So inclined to replace all of that.

These are the 2 ratios I think could work:

47/18, 69.9 gear inches, 18 skid patches 47/17, 74 gear inches, 17 skid patches

The key is finding a chain length that will work with both cogs. May require a half link.

Currently running a stretched 49 link chain, with has the 17T towards the front of the dropout, and an 18T barely in the dropout. It's possible that simply reducing the chainring by a tooth will be enough to get the correct fit with a 49 link chain.

Tools required:

Shimano Sprocket Remover Tool

Parts required (if sticking with 3/32):

Surly 47T chainring Surly 17T & 18T cogs 2 x Surly lockring Shimano Dura Ace chainring bolts KMC Z610 HX silver chain and possibly a KMC half link

My main concern is getting the old chainring bolts off, as they're worn and #14…

monospaced commented 9 years ago

All parts arrived and successfully installed this weekend!

(After some drama, in which I over shortened the chain by half a link—getting my male and female links muddles—and had to get another one!)

Was able to get correct tension on both sides with a new 49 link chain. Also checked with the old stretched 49 link chain, and was able to tension both sides with this too (though the 17T was right back in the dropouts). So if/when I can no longer tension the 17T, it will be time for a new chain. Quite a useful indicator.

Chainring bolts came off easily. Didn't need the tool in the back, just the allen key. However, the tool did work to properly tighten the new bolts, so #14 can be closed.

The 'sketchy cog from LBS' turned out to be a Miche Cog Carrier system. Nothing inherently sketchy, I guess the lockring just needed extra tightening after riding had tightened the cog some more. Need to watch out for that with the new cogs too - check those lockrings. But I did attach the cogs with rotafix method, so that may have been enough. Going to keep the lockring tool in my bag for the time being.

Good job!