Truing a disc rotor

So I have my beautiful new spirit cranks all set up. Formula caliper and an avid 180mm disc

My problem is I’m having real trouble stopping the disc from rubbing

I spend half as long truing the disc as i am riding the damn thing

I get it pretty true, then take it out to use, and its
Working really well. next time ( I guess after cooling down) it’s warped again

I’m right at the edge of the adjustment range with the caliper and have some 0.25mm shims on order, I hope if I can get a bit more wiggle room with the caliper may work better ( I suspect my pads are not perfectly facing
The disc)

I domt have much experience with disc brakes, any top tips

It could be a couple things, including a bad disc, bad pads, air in your lines, or a bad caliper. The discs are designed to get hot, so they shouldn’t warp, but I suppose one could if it was a bad disc. Have you spun the wheel to see how far out the disc is before and after riding? It could also be the caliper, sometimes a caliper won’t retract the pads well, either due to dirt in the caliper, air in the lines, or just a defective brake. So next time you go for a ride, with a trued the rotor, spin the wheel and see if you can spot a pattern of rubbing. Formula brakes have good reviews, except you may want to check your serial number for this:


I had a feeling the disc was just really warped. When trying to het
It true it wasn’t just rubbing in 1 or 2 spots it was rubbing
Inside pad for 1/2 rev and outside pad for the rest

So Ive given up on this rotor (avid hsx titanium)
Gone with a hope disc

The difference is night and day. It took a little
Fettling but after 2-3 minutes truing spins really quietly

Thankyou Ben

Hope disk are super nice. i have a had a few.