I’ve got a 20″ GT Aggressor 3.0 hardtail frame I built up as an XC bike. Shortish toptube and rear end. The seattube is slack putting me over the back wheel and the shocks going up the rear end are too much for me considering the brain injury I picked up 10 years ago, leading me to suffer side effects after long rides.

I bought a Raleigh 23″ XC bike in a sale to use as a commuter, then bunged the tyres off the GT on it when I got wider tyres for the GT to reduce the shocks. The Raleigh is surprisingly comfortable in the rear end with the tyres I had in the GT.

The Raleigh is of course larger, with a longer toptube, but the distance from BB to Fork QR is only about 1/2″ longer than the GT, and it has a steeper seattube and 2″ longer chainstay.

I didn’t particularly think the GT was that huckable, something wrong with its geometry. Not like other frames I’ve ridden that I could pop the front end up and then bunnyhop. The Raleigh with a 50mm stem fitted to suit is even less whippable due to that longer rear end. I used to ride a Kinesis Maxlight and that wasn’t whippable either. The short stem on the Raleigh frame means the front is very responsive though.

Can someone help me understand what it is about the rear end that is making it more comfortable? Is it solely about leverage, or is it the tubing/frame build?