So I got a Cotic Cascade frame and Salsa carbon forks last week. Had a few small issues with it already that has delayed the build, Cotic have sorted those out but I’m having a mare with the brakes!

It says it has flat mount +20 fittings on the rear stay, I thought I’d be able to use an adaptor to use the post mount caliper I have. Does anyone know if this is possible or not and what adaptor I need if it is?

I have an adaptor, for 160mm rotor, that should work but don’t know if the +20 thing is screwing things up, or actually, maybe I need a 140mm adaptor so the +20 makes up the difference. I can’t really afford to just keep throwing money at it, but I’ll have to if I need to buy a flat mount caliper. I’ve seen a GRX one on Winstanleys for £39 but then it says it comes without an adaptor, so am I going to end up back where I started…

I just want to ride the **** thing, and this is all just making me wish I had’t bothered!

Apologies if this all seems a bit overly dramatic but I have loads of other shit going on at the moment and this is just stressing me out. My head just hurts now.

I’d give Cotic a call first and foremost, they are super helpful folks and great to deal with.

Yeah they’ve been great sorting the other couple of issues. Just does my head in when ever you buy a new bike theres always something different. It shouldn;t be this hard….

I think the issue is that I need a 140mm post mount caliper to flat mount frame adaptor. Then the +20 thing will take up the difference. Deff won’t be riding it this week then…

I don’t know but, given how the spacing shifts the calipers a flat to post (140, no extra spacing) should work to put your Caliper in the correct position for a 160 rotor.

The caliper with a flat to post [140] adaptor should be a direct replacement for a flat Caliper.

Do you have a spare 180 you can check with? Stick a 180 rotor in with your current 160 adapter and, theoretically, it’ll fit there abouts – I wouldn’t ride it but it should look the part of not.

Just does my head in when ever you buy a new bike theres always something different. It shouldn;t be this hard….

In fairness if you bought the whole bike, there wouldn’t be this problem.

The something different isn’t that new, flat mount has been around for a good few years the problem is

I thought I’d be able to use an adaptor to use the post mount caliper I have.

And yeah, old stuff doesn’t always work with new, be that bikes or cars, imperial to metric.

It’s not a bad thing that “we” generally try and get the longest possible life from things but it’s always a bit more complicated trying to make a pile of things with together that are not specifically intended to and that’s always been the case.

Thats a good idea, yeah i should have a 180 rotor. Cheers.

Its just the +20 thing that has confused me, easily done at the moment as my head is a mess. Probably not the best time to building a new bike. I’ve got other bikes with Flat mount so used to those but just not with the +20 bit.

I think the issue is that I need a 140mm post mount caliper to flat mount frame adaptor.

I’d say so. In the same way that if you had a post mount caliper and (old) IS mount, you need to adapt the different format as well as the rotor size.

Yeah gonna check with a 180mm rotor and then order a 140mm adaptor.

I’m usually good at working on bikes, just got myself all confused and then inevitably angry with myself for being dumb!! 😃

(old) IS mount, you need to adapt the different format as well as the size.

And space it left or right, after double checking which is mount you have and so on.

What has been will be again, what has been done will be done again; there is nothing new under the sun.

Is there anything of which one can say, “Look! This is something new”? It was here already, long ago

Is as true now as when it was written plagiarised into a well known old book.