Tomforsyth24

I’m wanting to convert my front and rear rotors from 160mm to 203mm. I know for the front I need the post mount to post mount +43. I was wondering what the link or product code for the is to is mount +43 was

cobba

This is a 160 to 203mm post to post adapter.

https://www.jensonusa.com/Shimano-F2...-Brake-Adapter

Is your fork rated to use a 203mm rotor?

Tomforsyth24

If I was to convert the rear to 203 from 160, what adapter would I need. I ordered the sm-ma-r203 s/s and it’s the right adapter but the calliper doesn’t fit on the adapter. The fixing for the calliper is on the chain stay not the seat stay and the up label on the adapter isny facing up

cobba

Wouldn't the caliper fit if it was the right adapter?

Does the frame have IS mounts?
Does the caliper have post mounts?

Do you need a 203 on the rear, could there be any possible issues with attaching a 203 on the rear?
What's your frame?

Tomforsyth24

The frame is IS mount and the calliper is also IS mount. The frame is a cube aim race 2020 The adapter would fit but the calliper won’t sit flat on the adapter and only one hole lines up with the adapter and calliper

dsaul

None of this makes any sense. What holes are you trying to mount where? The holes that mount to the frame are 51mm apart and are located where the Shimano name is written on the adapter. The holes that mount to your post mount brakes are 74mm apart and are located at the top of the two posts that stick up. The arrow does not have to face up. It faces forward on a chainstay mounted brake.

By the way, 203mm brakes are way overkill on that bike. They are only used on Downhill bikes and tandems. There is also a good chance that there will not be room for the brake caliper to fit under the seat stay with that size adapter.

cobba

This is a IS mount brake attached to a IS mount frame.....

https://www.flickr.com/photos/kyomor...phy/4933408196

Specs say you have Shimano brakes, they haven't made a IS mount brake for over 10 years.
SR Suntour recommends a maximum rotor size of 180mm for the fork on your bike.
Cube says you won't have any warranty if you put on larger rotors then they supplied.

Are you actually having any problems with slowing down or stopping?

bikeme

I had 160s F and R and upsized the front to a 180 and it's plenty. I ride XC/Trail not enduro or DH. I can tell the diff with the 180 (the max for my fork)

Trevtassie

Then there is the issue that Suntour XCM forks are only rated for 180mm...

Leebo

What kind of riding do you do? 180 front and rear should be plenty. Current brake setup?