Postmount fork + IS caliper? Possible?

Is there an adaptor to fit a IS brake calliper to a post mount fork? And if so, can you leave the disc size the same?

Thanks in advance! 🙂

Ye they are availible. Only seen +20mm ones though so you’ll need a bigger disc.

e.g. http://www.hopegb.com/voir_ADAPTMANAV.html

Looking into this with some Hope mono mini’s. Yes there is an adaptor but not one that will keep the disc the same size….However i believe Ashima do one, but cant say i’ve looked for it yet.

EDIT – Balfa beat me to it. 😀

there was a giant one for giant mph brakes for IS mount down to 160mm – so same size rotor
It has to fit around the caliper, though giant MPH-3 calipers are pretty fat, I’d guess most should also fit

Jejames (rotherham) had them in stock when I asked about them in I think 2007?

Not aware of any others, not that I’ve looked

Balfa, cheers for that. I can do a bigger disc, but I’d just rather not if you get me? 🙂

http://www.ashima.com.tw/products_02_14.html

I think its the Au22 on here.

If you’re currently using 180 IS with a +20 adaptor, you can switch adaptors and stay at 180. If you’ve got 160 with the caliper bolted directly to the fork, you’ll have to go to 180 to accommodate the post-to-IS adaptor.

Is the J mount suitable?

http://www.wiggle.co.uk/hope-step-up-mounts/

kcnc do a postmount 160 – is 160
http://cgi.ebay.co.uk/KCNC-Disc-Brake-Adapter-POST-Anodised-RED-160mm-/270688863666?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item3f065045b2
would normally say get from andy at clee-cycles but he’s out of the 160, does have the pm160 – is 180 and is203, plus the hope ones,
hth.

This is what I used to fit my mph calipers to rebas:

http://www.cyclestore.co.uk/productDetails.asp?productID=11716

and other adapters (going through bookmarks – I’m a hoarder):

http://www.ukbikestore.co.uk/product/219/hbsm20h/hope-brake-mount—is-caliper-to-post-mount–20mm.html

http://www.wiggle.co.uk/a2z-adapter-is-to-pm-to-keep-160mm/

I’ve found that it’s impossible to eliminate brake squeal with this set up. I try not to use the brakes much anymore.

PP, I have that A2Z you can have for small donation to STW towers.

The ones at XC Racers shop seem to imply they are 160-160.

I ended up with a hope adapter and a 180 disc.

I’ve got 180mm calliper and disc (Magura Louise FR) with no adaptor on the calliper. I love the brakes and really don’t want to change them, but the new forks I’ve seen are PM.

Bruneep, d’ya think yours will work with this? It’s not 100% clear from the Wiggle description. 🙂

I just got the KCNC adaptor from Clee and it’s fitted and working perfectly.

I used it to fit a Hope Mini Mono IS mounts to a 2011 Revelation with Post Mounts. I use a 180 Magura Venti Disc.

The pinky red doesntt clash too much with the Lime Green Heckler either!!

I bought that A2Z from Wiggle a couple of weeks ago. It definitely does not fit an IS caliper to a PM fork, despite one of the “reviews” saying that it does.

Kcnc one from xc racer worked for me. I changed forks to new SIDS and thought I would need new brakes but with the kcnc mount it just bolts straight on and I kept the original 160 disc size. No rubbing problems and easier to set up rather than shims

Only just seen this thread.. looking to do the same so I ordered one of these Brake Authority adapters yesterday.. will report back on whether it works!

Frogstomp, Nice link thanks! 🙂

Which one did you order and what is the size of your calliper?

I can’t work out if the adaptors are all based on a 160mm caliper (so a 180mm adaptor would take a 160mm caliper to a 180 disc) or not?
My brakes are already 180mm…. Wild guess I need the 160mm calliper as it’s intended to keep the disc the same size??

If you understand me? 🙂

frogstomp,
that adapter am pretty sure if it Is the one in the picture Wont work, its meant for is-pm not pm-is, the main difference is that it Wont sit flush on the fork pm, i picked up a shimano one almost the same from crc when trying something out on mine and had the same problem,
is either the hope one with a 20mm bigger disk or the kcnc one with the same disc,

All Post-IS adaptors (IS calliper on post-mount fork) are +20mm
The only way to get around it is if you have old Hopes for example, to change the calliper half.
I had a problem when I got my Magura Thors, which are post-mount for a 180mm calliper, but I had IS Hope M4s for 180 calliper. The Post to IS on the forks, takes it up to 200, and the Hope calliper half, would have taken it to 220mm, which would void the forks warranty! so i sold the brakes and got post-mount Shimano XTs.

PeterPoddy – Which one did you order and what is the size of your calliper?

I ordered the main one in the link.. for a 160mm caliper (no change)

Timmo – that adapter am pretty sure if it Is the one in the picture Wont work, its meant for is-pm not pm-is

Looking around a bit more I think you are probably right, but unfortunately it has already been dispatched.. will probably send it back (or keep it in the spares box!) and try the KCNC one..

that adapter am pretty sure if it Is the one in the picture Wont work, its meant for is-pm not pm-is

Ahh. I see. 🙁

But that got me wondering…. PM and IS are just two different standards. What about using a normal adaptor like that one and turning it upside down? Hmmmmmm

No. the lateral spacing is wrong isn’t it? Forget I said that. 😳

do the forks have a 8″ PM or a 6″ PM one Peter?

If it’s the latter surely a standard +20 PM to IS adapter will fit, if it’s the former there is a Giant +0mm PM to IS adapter available.

Looks like the KCNC one is the one I need 🙂

EDIT
WWASWAS – Dunno mate! Not got them yet… 2011 Revelation RLTs 🙂

That AU22 adapter says suitable for 180mm but as it doesn’t say what IS calliper you start with it’s a bit misleading/useless.

I’m gonna need one soon, got a few 180mm IS callipers and my IS forks are getting a little tired – don’t really fancy a hop up to 200mm discs on an xc bike.

Interested is someone does get a +0mm IS to PM (should do for any size IS calliper shouldn’t it? +20mms work for any size calliper afaik)

if yo uhave a quick look at the two pictures you can see the difference between the is-pm and the pm-is in the machining aroound the pm area,
brake authority,

kcnc

the kcnc is also offset to allow for the caliper to be mounted in the correct place, if you tried withg the BA mount then the caliper would be too far in,
hope that makes sense!!

Just got one of the KCNC ones (the second one above) today and it certainly seems to work fitting an IS XTR caliper to a Post Mount (Fox) fork without changing the 160mm rotor size..

(sorry about the image quality.. only had my phone to hand)

Many thanks to Ant at XC Racer for confirming it was what I wanted and ordering it in even though they don’t do them any more..

Apparently the ones for larger discs just use spacers to pad it out.

excellent, just what I need. Cheers for the follow up frogstomp.

Just a quick note.. the adapter (left-hand side as shown above) sits very tight against the fork and seems in some cases (e.g. Revs) to foul the fork stanchion when the size of disc is not being changed.. spacing it out with a thin washer might help though..

Frogstomp …I think you mean fork leg or lower rather than stanchion.

Frogstomp …I think you mean fork leg or lower rather than stanchion.

Indeed I do!

i have one of these if anyone needs one.

I used one of these to successfully attach my Hope xc 180mm to my Rock Shox Reba’s this morning. No issue with it fouling the fork.

First ride out this afternoon and I have to say it’s good to have my Hope’s back on the bike!

well i got one of the kcnc ones and it wont fit on my marzocchi 66s

trouble is if i use the spacers it pushes the disc out
and its already at 203mm so cant go bigger 🙁

anyone wanna swap their 180mm mono m4 caliper for my 203mm one???????

PeterP, did you resolve this? I’m doing the same build (rev rlt + mag louise fr) and would like to keep my 180mm rotors.

I had this exact same problem when I changed my 2007 SID’s for 2011 ones.
I had XTR brakes IS mounted to the original SID with 160mm rotor. When I got the new forks they had post mount, so calliper wouldn’t fit.

I bought the Giant converter as suggested above but it wouldn’t go around the calliper. Tried the KCNC Red one s well but same problem, carefully ground some metal away but calliper was only sweeping about half the pad.

Contacted Shimano who said the easiest way it can be done is by going to 180mm rotor. On a lightweight XC race bike I didn’t fancy that, they then said Shimano do a converter and 170mm rotor as a kit which would do the job. Didn’t fancy that either as expensive and Ctr lock only.
In the end I bit the bullet and bought a post mount calliper, it fits directly with no spacers and was lighter as well.!

Hope that helps.

thanks, I was getting the vibe that it wasn’t possible – maybe I’ll just have to go big and get a whopper 200mm rotor – endotastic