I have a GT Pro Series 26" BMX crusier.. it came with 36t/16t gearing. I recently changed the freewheel to a 17t. I have a 33t front sprocket/chainring arriving tomorrow. My bike has pretty long rear dropouts, and tight now my axle is tight right in the middle as far as how forward/backward it sits. I'm wondering how much of a difference it will make by dropping down 3 teeth in the front. I'm hoping I don't have to shorten my chain. Any knowledge would be greatly appreciated. Here is a pic of where my rear axle sits now. I guess my question is how much further back will my rear axle move by dropping 3 teeth?
by AcceptableNorm
1 Comment
Reducing the size of front gear ring will result in three extra chain links, making the chain too long. Measure the length of three links from pin center to pin center (i.e. four consecutive pins) and add this length to present position of rear axle. The rear wheel axle will fall out from drop outs. Therefore it is necessary to shorten the chain as you said. It’s quite simple with the chain breaking tool and a quick link