Rear axle advice

The over-lock-nut distance should be 135mm but the overall length of the actual axle should be 145mm if your GT is a mountain bike. If you measure the distance from the inner edge of one of the dropouts to the inner edge of the other dropout, you should find that it's 135mm. You then need an extra 5mm at each end of the axle for the dropouts to sit on, taking the overall length to 145mm.

The Hanna Cycles one you linked to in your opening post is the correct one. The ebay one is not well described but it reads like the overall length is 135mm, which is not long enough.
 
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Back
Top