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Adaptors for 6" tab and 7" posts from Jenson?

1K views 2 replies 2 participants last post by  Squash 
#1 ·
I'm trying to get the right adaptors (the first time) to mount my new brakes, and because I'm ordering other stuff from Jenson, I'd like to get them there if I can.

Front brake: Shimano XT M785 caliper (74mm hole spacing, post mount type)
Fork fork: 74mm posts
Front rotor: 180mm
Front adaptor: http://www.jensonusa.com/Shimano-F180PP2-Disc-Brake-Adaptor
Is this the right adaptor to use?

Rear brake: Shimano XT M785 caliper (74mm hole spacing, post mount type)
Rear frame mount: 51mm tabs
Rear rotor: 160mm
Rear adaptor: http://www.jensonusa.com/Shimano-74mm-To-51mm-Rear-Brake-Adapter
I think this is right, but it's out of stock till August, what else might work?

They have this which seems like a 51mm tab mount to 74mm post adaptor, but it says it's for forks (front) and I need a rear adaptor:
http://www.jensonusa.com/Shimano-F160PS-Disc-Brake-Adaptor

I'm starting to regret getting the 160mm rear rotor, I didn't think it would be such a long lead time to get adaptors for this? Should I try to return the rotor and get an easier to adapt 180mm rear rotor?
 
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#3 ·
"Front brake: Shimano XT M785 caliper (74mm hole spacing, post mount type)
Fork fork: 74mm posts
Front rotor: 180mm
Front adaptor: Shimano F180P/P2 Disc Brake Adaptor > Components > Brakes > Brake Adapters | Jenson USA Online Bike Shop
Is this the right adaptor to use?"

Yup, that's the one you'll need for the front.

"Rear brake: Shimano XT M785 caliper (74mm hole spacing, post mount type)
Rear frame mount: 51mm tabs
Rear rotor: 160mm
Rear adaptor: Shimano 74mm To 51mm Rear Brake Adapter > Components > Brakes > Brake Adapters | Jenson USA Online Bike Shop
I think this is right, but it's out of stock till August, what else might work?"

An yes that's the one you need for the rear. As to what else will work, you can try the one you link to in you'r follow on post. It looks about right. The only draw back to using another manufacturers adapter is that it might not work. Slight differences is caliper shape, pad position within the caliper etc. may cause slight alignment issues. But they'll usually work fine. There's just he chance they might not. The Hayes adapter looks good though.

"They have this which seems like a 51mm tab mount to 74mm post adaptor, but it says it's for forks (front) and I need a rear adaptor:
Shimano F160P/S Disc Brake Adaptor > Components > Brakes > Brake Adapters | Jenson USA Online Bike Shop"

And that one won't work, at least not for a 160mm rotor on the rear. It'd do a 140mm rear though. The tabs on a front IS mount fork are a bit longer than the tabs on the rear. So a front IS usually translates to one smaller rotor size than is listed on the adapter when used on the rear.

Anyway, don't get stuck on Jenson, there are other retailers out there that have them in stock I'm sure. Also check out the local shops, it's a common adapter and likely available locally. So shop around a little, you'll find the adapter somewhere. Yeah it'll cost you a bit more in shipping or about even up if you buy it locally. A 180/160 is a good set up, that's why it's so common and so often recommended. No reason to give it up just because the retailer where you intended to order everything doesn't have the rear adapter. So get it somewhere else or try the Hayes adapter.

Good Dirt
 
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