Disc brake – fork interface, help me I'm confused.

I’m about to buy some new forks.

My current forks have IS brake mounts.
My current brakes are Avid Elixirs with an IS mount with 160mm rotors.

The forks I’m looking at are post mount.

How can I mount my current brakes on the new forks?
I’ve seen some adapters but I can’t find any avid 160mm IS to PM adapters. Do you know what I need and where I can get it?

I think if using IS to PM adapter you have to go up a size in rotors. I may be wrong though as I’ve never had to do it myself.

You don’t use an adapter, just bolt the caliper straight to the fork

Your current brake is post mount. You want to change forks from IS to post mount. Simply bolt the caliper directly to the forks. Just leave the mount off.

Fitting an IS caliper to post mount forks needs a step up in size usually.

khani – Member

You don’t use an adapter, just bolt the caliper straight to the fork

+1

So I’ll need a new rotor instead?

No.

khani – Member

You don’t use an adapter, just bolt the caliper straight to the fork
Do explain how you mount an IS caliper to a PM fork without using an adaptor….. 🙄

In more helpful advice, try looking for a KCNC IS to PM adaptor, that should do the trick
HERE

thanks

Do explain how you mount an IS caliper to a PM fork without using an adaptor

Elixers are post mount 🙄 try to keep up…

As above just remove the the mount bracket from your current caliper and bolt the caliper inc washers straight to the fork leg.

No extra mount no new rotor

Ah, ok, didnt realise Exlirs were PM as std, apologies. In my defence the OP said they were IS…. 😳

Got the forks yesterday. Will fit tonight. I’ll let you know how I got on tomorrow.

Got the forks yesterday. Will fit tonight. I’ll let you know how I got on tomorrow.

if you don’t post I assume catastrophic brake failure occured?

So I managed some time to look at this over this weekend.

Just bolting the caliper to the post mount on forks didn’t work. The wheel wouldn’t go back in as the rotor butted up against the caliper.

The forks are 29er SID RL.
The brakes are Avid Elixr R.

What size rotor do you have? If it’s bigger than 160mm then you will need a post mount to post mount adaptor.

I thought it was a 160mm but I might be wrong, to be honest I didn’t check.

An adapter like this or this

Did you use the washers as well? As in my pic above,
Measure your disc too, we can’t tell you what adapter you need til you know what disc size you have..

The wheel wouldn’t go back in as the rotor butted up against the caliper.

Do you mean that the rotor goes too far into the caliper? i.e. the caliper would appear to be closer to the axle than previously?

In that case a) are you sure that the discs are 160mm? b) have you got the mounting hardware (i.e. washers) on in the correct order? c) can you space the caliper off slightly with an extra washer/s?

OMG

Patience Rob, we’ll get there eventually. To all those that have tried to help so far it appears that the op has pm elixirs on is fork. He must have had a pm to is adapter which adds 20mm. So now he has pm fork hell need either a pm pm plus 20 adapter to fit his 180 rotor, or treat himself to a 160 rotor. Scholarsgate, I have a 160 rotor you can gave for postage costs just email me your address

Or Scolarsgate has a 160mm rotor but has not fitted the Avid washers. If you’ve not done this, try fitting the washers you can see in the picture above. If you have a 160mm rotor then that should sort it.

http://cdn.sram.com/cdn/farfuture/m8eq5pbQbYNJ3tBGJ_1WNNkb9UfaTS2g7mkqu9au1sY/mtime:1338574414/sites/default/files/techdocs/avid_technical_specifications_my13_updates.pdf

That’s all for your help so far.

This is what I have

Yesterday I bolted the caliper straight to the fork. The rotor went way too far into the caliper preventing it from engaging the axle.

Did you include all of the washers in the same order as in your picture above (i.e. everything but the black PM-IS adaptor)?

Have you actually measured your rotor diameter?

If it’s an AVID rotor should be written on it

How far out of the drop-out is your wheel? If it’s about 10mm or so then you’ll need a +20mm PM-PM adaptor. If it’s about 5mm then it looks like you might be missing the extra washers below the caliper mount.

To be honest I didn’t include the washer stack when I bolted it to the forks. I’ve obviously misunderstood one of the earlier posts.

I’ll try it again with the washer stack and check the rotor size.

Thanks

http://cdn.sram.com/cdn/farfuture/awF-SxA7urE-VEaeKSQtWiogbnKYHtTFOESgGqisMq4/mtime:1351197847/sites/default/files/techdocs/95-5018-000-000_rev_a_disc_brake_caliper_mounting_0.pdf

the avid rotor is 165 or 185mm

To be honest I didn’t include the washer stack when I bolted it to the forks. I’ve obviously misunderstood one of the earlier posts.

There’s your answer :D!

solved.

added washer stack and everything is in the right place.

Cheers guys. Thanks for your patience.