180mm rotor- do I need a spacer for my brake caliper?
 

I’ll be building my Slalsa Fargo as soon as the frame arrives. Bought TRP Spyke brakes (flat bar bike) and will be mounting to the Firestarter fork. To properly space out the brake from the typical 160mm rotor spacing to 180mm, will I need some sort of spacer? Does TRP make standard parts for this?

thanks.

Google "disc brake adapter". Very standard part. Lots of manufacturers.

thanks!l

next question: front brake spec is a post mount, no problem.

rear brake mount spec says 51mm I.S. What is “I.S.” ?

"Industry Standard". That's the kind with the flat metal part at the bottom of the fork that the adapter bolts to. Then the calipers bolt to the adapter. All I.S. mounts need an adapter of one size or the other.

I.S. is post mount, but it's the post mount type that needs the dogbone shaped adaptor, as opposed to the post mount that has conical washers that sit upon posts with long bolts to hold it all together.

You'd want to buy an I.S. adaptor for 180mm. As noted above, very standard part. Front & rear require different adaptors...180 front=160 rear or some such thing. Maybe I have it backwards.

You want a post mount to post mount +20 adapter, like this one from Shimano. There are others from other brands, any +20mm most mount adapter will do.

What IS mount adapter you need for the rear depends on the OEM size of the rear rotor. The mount will look like this, but you can't always trust the description. If the bike "natively" takes a 140mm rear rotor, you would need a 180mm adapter (essentially a +20) to mount a 160mm rotor.

Thanks everyone, this all makes sense and confirms what I had expected. Just wanted some confirmation before I purchased components.

A free beer to everyone who responded ;)

THX for the info