Next, grabbing a fixed part of the bike, lift the back end up to full extension. Write that number down too. Nowπ we can make sense of the numbers. Darren Wnukoski of MCT reckons we want 30mm from at rest to fully extended, plus or minus 5mm. We got 65mm from loaded to fully extended – close for this style of bike. A road bike would be more like 30mm.