Join Date: Jul 2011
Location: Birmingham, AL, USA
I think the ride height change is about 4 or 5 mm
I am not saying I can detect it in the handling of the bike, I think my problem was tires all along. But with the stock sprockets and stock chain, the eccentric is at about the 6 o clock position. If you install the 42 tooth rear, you either keep the stock 108 chain in which case you have to move the axle about 8mm forward, which raises the axle about 4 or 5mm, or, you install the 110 link chain, in which case the axle moves back about 8mm and up about 4 or 5. I'm not good at math, but its easy to see when you play with it on the bike. You have to rotate the eccentric a lot to get significant fore-aft axle movement, and as you are rotating it away from 6 o clock, the axle is moving up also. It could be a real effect to ride height depending on where the ideal original eccentric position was. I am not sure if the original position was truly 6 o clock or not. If you had perfect chain adjustment with the axle at 4mm to the rear of 6 o clock, and you installed the 42t and kept the 108 chain, your wheelbase would decrease by 8mm but your ride height wouldnt change.