Just got hold of a rear slx disc brake and its going on a brand new frame, lbs want 20 quid to fit it, is it essential to face it or am i throwing 20 quid away?

£20 sounds steep, but I’d say it’s pretty important to get done. Some frames don’t need any facing, some need loads. My current hardtail, a Steel Genesis Altitude, needed a fair bit of material removing to make the disc mount totally straight.

It’s more of an issue with IS mount brakes though, if you’re using Hayes mounts you can often get away without bothering.

its a shimano slx with shimano 160 disc mount, cant really afford 20 quid but if it needs doing it needs doing.

Never faced a disc mount in my life. Never had problems?

wot coffee king said, same experience, face it if you get problems if you dont and its ok then its money saved..

probably not if theres an addaptor. try it, if its noisy th it’ll need faceing.

Never had one faced and never had a problem. Shims on IS where needed and nowt for post mounts.

so post mount with the shimano 160 adapter should be ok? try it first and then spend yeah?

Fit it and then check that you can get both pads to hit the disc perfectly flat to it, if you can’t do this then it’ll need facing for them to work to their optimum performance.