Hi Guys,

Just wondering if anyone can help.

Last year I upgraded the brakes and forks on my Giant XTC. I Upgraded with RockShox Reba’s and Shimano XT M755 brakes. The shimano brakes that I bought came standard with 160.0mm discs.

I recently decided to upgrade the front disc to 180.0mm diameter to increase braking performance. Since I bought the disc I have struggled to find a suitable bracket that will pick up the standard flange IS mounting on the Reba’s and enable the 180.0mm disc to be used.

I have searched through the Shimano Spares brochures and the only bracket I can find is Shimano bracket SM-MA-F180S/S which is intended for Shimano XTR discs.

I can’t seem to find any UK distributors that sell this bracket and I’m not sure it’s suitable. I have found one German website that sells it.

http://www.bike-discount.de/shop/k612/a3963/adapter-vr-auf-180mm-sm-ma-f180s-s.html.

Can anyone tell me if this is suitable or if they have any other ideas for me finding a bracket?

Thanks.

im runninig a 180 on my 2008 revelations which have a IS mount. this is the bracket i bought and works fine. here

CRC are your friend. I got a couple of the adapters from them.

Hi Tang,

The adapter you mentioned is for the IS Boss Type mountings (Bolt is at 90 degrees to the front wheel axle), there are lots of these available. I need something that picks up of the flange style mountings (Bolt is in same direction as the Front Wheel Axle)

I have looked on Chain Reaction but they do not seem to have that type that allows use of the IS Flange to 180.0mm Rotor.

See my link.
http://www.bike-discount.de/shop/k612/a3963/adapter-vr-auf-180mm-sm-ma-f180s-s.html.

Thanks.

Look on CRC for the Hope IS +20mm adaptor – that will do it

is your front caliper IS fitting? or are there two types of IS mounts (thought there was IS and post mount only, worth knowing as im thinking of rebas for my soul) my caliper is postmount hence fitting to that adaptor. also i didnt know that xt calipers came in IS version, both of mine were postmount(know the xtr does)

Hi Tang,

Sorry I probably confused you slightly. Yes there is only one type of IS mount (Flange type), the other type is the Post Mount or boss type. My 2008 reba;s came with IS mount and my XT Brakes came with IS mounts also so they fitted straight on with no bracket. I noticed that the latest 2009 Reba;s seem to use the post mount type fixing and so the bracket you were talking about would be correct for your application.
Thanks

James

Tang.

Although just noticed some websites call both types of brackets IS type fixing. Compare your link you sent me to the one I added in my original email, they are both called IS brackets, its confusing!

This is the mount you want Shame it’s out of stock….

Your XT M775 are post mount, they have an adapter to fit 160mm rotors, the one above is for for 180mm discs, just change over the mount. Part number is as you say in your OP. XTR caliper dimensions are the same as XT.

He didn’t say he had 775, he said he has 755 and they were IS.

james, got you now! if the 09rebas are post mount(as opposed to my 08 revs with IS mount) ill need a different bracket to the above link to run the 180s i think.

Are we talking the really ancient 4 pot Grimica XT brakes?

If they’re standard IS (51mm) then any IS to IS +20mm mount will do the job. Hope do one you can get them from CRC as well.

This will work:
http://www.chainreactioncycles.com/Models.aspx?ModelID=13736

Your fork is IS mount, your brakes are IS mount.

Hi Guys, that Hope bracket looks like it is just the job. I’ll get onto Chain Reaction later and order one.

Tang – I think you have the same forks as me so you’ll probably need a similar bracket for your discs.

My brakes are the 4 pot XT brakes, just out of interest does anyone know much about them? / what year are they are from etc? They seem to perform a lot better than some Hope / Avid brakes that my mates use on their bikes – they have always been impressed with how sharp & how well they modulate.

You can get a black version of the Hope one from eBay for less – Bikefridge is the seller

Really old but pretty good quality brakes maybe 2000/01. MTBR has loads of reviews of them.

ive not been reading very well! ive got the new 775’s and they are post mount hence the bracket i linked, 4 pot 755 are IS hence you needing that part! im such a dumb ass….good luck with the part and enjoy the increased power!

You must need this adaptor:

Shimano SMMAF180SSA