Playing on the local bmx track with a friend, i noticed that his dirtjump bike rockets forward whereas my 4x bike seems incredibly sluggish compared to his.

They are both of a similar weight and gearing, is it safe to assume that the tyres could make this much difference?

I had high rollers on mine (yes i know that they arent for skateparks) and he was using some sort of x country tyres.

Is the difference in rolling resistance that big?

Maybe it’s his legs vs yours? 😉

Can be. What pressures are you running.? Makes a massive difference on the right surface.

Why on earth would you run a highroller on a 4x bike? Yes they are slow rolling
DJ bike should have a slick or semi slick rear too.
Pressures also make a massive difference on the bmx track don’t be afraid to run 60psi

Guessing you are a beginner and your mate not much more experienced but possibly a better rider?

forgot to mention, we swapped bikes for a few runs and his felt incredible agile. I was running 2 gears higher and was leaving him for dead.

The only reason I was using highrollers is thats what was on the rims at the time, after a winters ride on the local downhill tracks.

When you say he rockets forwards when is that happening? Is he not just pumping more than you?

Which highrollers? Can make a huge difference that, fat supertacky dualplies roll about as fast as continental drift on tarmac

nope, on the downslope his bike is simply more easy to accelerate then mine, proven after we swapped for a few runs. I’m pumping, he’s jumping and I am working very hard to keep up. Once again, I can beat him hands down when i ride his bike, even though he is fitter then i am.

A difference in forks assuming they are both hardtails. Less travel, more air, stiffer spring, more low speed compression damping. All these things must be able to stop the fork eating the energy put in a via a pump..