Disc brake caliper installation

[Alma]

I have a front disc brake set Shimano GRX 600 lever with 400 caliper flat mount, do I need to buy a mount to fix the caliper too?
This is for the front brake.

 

[Cycleops]

What type of mount do you have on the fork? If flat mount you’ll be fine (obv). You can get an adapter if you have post mount. A pic might be useful but you may not be able to post one just yet, maybe a link to your bike then.

Hello and to CC

 

[C R]

What type of mount do you have on the fork? If flat mount you’ll be fine (obv). You can get an adapter if you have post mount. A pic might be useful but you may not be able to post one just yet, maybe a link to your bike then.

Hello and to CC

I'm not sure you can find adaptors from flat mount to post mount.

 

[Alma]

Hi, it is a flat mount I have attached a couple of pics, so you should be able to see them.
It is Merlin GX2 gravel frame that I am building up.

 

[C R]

Hi, it is a flat mount I have attached a couple of pics, so you should be able to see them.

The caliper is flat mount, but what is the mount in the fork? What the distance between the mounting holes in the fork?

Have a look here for an explanation of caliper mounting "standards".

https://bicycles.stackexchange.com/...-s-post-and-flat-mount-disc-brake-mounting-st

 

[Cycleops]

I'm not sure you can find adaptors from flat mount to post mount.

Yes sorry, thats right it’s the other way around

 

[fossyant]

You need a post mount to flat mount adapter like on these GRX callipers. What size discs - standard default is 160mm

https://www.bikester.co.uk/shimano-..._G659ys7HstA1vGoTo6NFk5y0FxoicWBoCZvgQAvD_BwE

 

[fossyant]

These

https://www.bikester.co.uk/shimano-...brake-adapter-for-flatmount-black-474090.html

 

[fossyant]

You need a mount specific to disc size. Road bikes usually start with 160mm as standard. MTB's vary between 160 to 180 as standard. If you are fitting a larger disc you need a bigger adapter.

 

[C R]

@fossyant are those for flat mount caliper onto post mount frame? I was under the impression that you could only do the other way around.

 

[fossyant]

@fossyant are those for flat mount caliper onto post mount frame? I was under the impression that you could only do the other way around.

Take a look at those GRX's - they have a funny fitment - not traditional flat mount like on MTB's. You need that adapter as the screws screw into the GRX calliper from the underside, then the adapter is bigger to line up with the post mounts on the fork.

 

[C R]

Take a look at those GRX's - they have a funny fitment - not traditional flat mount like on MTB's. You need that adapter as the screws screw into the GRX calliper from the underside, then the adapter is bigger to line up with the post mounts on the fork.

Are those fairly new releases? I checked recently and everyone seemed to imply they didn't exist, like in the stack exchange post.

 

[fossyant]

Are those fairly new releases? I checked recently and everyone seemed to imply they didn't exist, like in the stack exchange post.

No Idea - I just googled them. I'm post mount on the MTB's.

 

[Alma]

thanks for all your input, the front disc brake has come with the mount, and I have now ordered my rear adapter mount using the link you provided.
Thanks a lot

 

[si_c]

thanks for all your input, the front disc brake has come with the mount, and I have now ordered my rear adapter mount using the link you provided.
Thanks a lot

Both the bike and calipers are flat mount so you'll need the front adapter regardless of rotor size used, for the rear you only need an adapter if you are planning on using a 160mm rotor otherwise you can mount the caliper directly onto the frame.

One point to note is that you will need to get the caliper mounts faced properly - judging from the photos you posted above this hasn't already been done. If you don't then it won't be possible to get the calipers aligned properly. You can do it yourself to an acceptable degree with fine gauge files, but it takes quite a bit of trial and error to get it right, your LBS should be able to do this and I'd recommend you ask them to.