Caliper adapters 160 to 180 and rotor doesn't fit

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Caliper adapters 160 to 180 and rotor doesn't fit
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flag Tomzah
Posted: Jan 3, 2021 at 12:45 Quote
I have a Giant Talon 2 (2021) and I ordered a Shimano 180mm to replace the 160mm Tektro rotor fitted as standard. In order to do so I ordered a Shimano XTR Post to Post mount adapter 160 to 180. I've fitted the new rotor and installed the adapter and the rotor does not fit in the caliper (touches the caliper and will not freely turn). Is there something I am missing here?

The frame has a 74ish mm bolt spacing and is Post mount and the same for the caliper.
flag Reaperactual
Posted: Jan 3, 2021 at 13:02 Quote
Maybe you fitted the adaptor back to front? The adaptor should have a white arrow and that should be pointing forward/same direction as the rotor spins.

The two 'blocks' the bolts go through are different heights so if the shorter block is on the front instead of the back the caliper will interfere with the rotor.

If this is the problem then make sure the longer of the two bolts is fitted through the front 'block' and into the front post mount too.
flag Tomzah
Posted: Jan 3, 2021 at 13:22 Quote
Hi, thanks for your response, the adapter had a white arrow on saying UP. I aligned that so the arrow pointed upwards and the text was the right way.
flag Reaperactual
Posted: Jan 3, 2021 at 13:34 Quote
Hi Pal. Smile Can you show a pic of the set up either on a post or your profile's photo album?
flag Tomzah
Posted: Jan 3, 2021 at 13:54 Quote
Hi, I've uploaded some photos. I've tried switching the adapter around and it looks like it may fit. Will see if I can calibrate it now.
flag Reaperactual
Posted: Jan 3, 2021 at 13:54 Quote
Hello again. Yes the adaptor is back to front on pic 3? EDIT: in the top right hand corner. Your pic is at a strange angle. The adaptor can be used on the front and the rear so when it's fitted to the forks the arrow points up but where it's fitted on the rear that arrow should face forward and down towards the ground.
flag Tomzah
Posted: Jan 3, 2021 at 14:01 Quote
Cheers for letting me know that. I'm just trying to align the caliper now but not having much luck. I think the scraping has stopped now though and the rotor fits now. Cheers.
flag Reaperactual
Posted: Jan 3, 2021 at 14:08 Quote
Fitting the silver aluminium cupped washers under BOTH the bolt heads will be needed and will also help with alignment. Trial and error when centering calipers, frustrating sometimes too so take your time Buddy. Wink
flag Tomzah
Posted: Jan 3, 2021 at 15:10 Quote
The bolt wasn't long enough to fit the washers on the larger block of the adapter. I have managed to align it with no brake rub and only a single washer on the large one. Is this OK or should I redo with a larger bolt?

P.s. I just used the bolts that came with the adapter set.
flag Tomzah
Posted: Jan 3, 2021 at 15:44 Quote
Reaperactual wrote:
Fitting the silver aluminium cupped washers under BOTH the bolt heads will be needed and will also help with alignment. Trial and error when centering calipers, frustrating sometimes too so take your time Buddy. Wink

Took me a while to align it but done now. The bolt provided by shimano wasn't long enough to have both the silver washers and then reach the frame mount. I've just used the black washer that also came in the adapter set.
I've uploaded a picture of what it looks like now, I think it will be under my profile. From a bit of online research the silver washers are helpful if the bolt isn't flush to the adapter but I think in my case (see on images) I don't have that problem. Please correct me if I'm wrong.

If I need those washers I'll need a longer bolt, otherwise I can take it out for its bedding in the brakes session.
flag Reaperactual
Posted: Jan 3, 2021 at 22:43 Quote
Tomzah wrote:
Reaperactual wrote:
Fitting the silver aluminium cupped washers under BOTH the bolt heads will be needed and will also help with alignment. Trial and error when centering calipers, frustrating sometimes too so take your time Buddy. Wink

Took me a while to align it but done now. The bolt provided by shimano wasn't long enough to have both the silver washers and then reach the frame mount. I've just used the black washer that also came in the adapter set.
I've uploaded a picture of what it looks like now, I think it will be under my profile. From a bit of online research the silver washers are helpful if the bolt isn't flush to the adapter but I think in my case (see on images) I don't have that problem. Please correct me if I'm wrong.

If I need those washers I'll need a longer bolt, otherwise I can take it out for its bedding in the brakes session.

Hi Tomzah. The adaptors are supplied with two bolts and one is always longer than the other so maybe they are mixed up and need swapping around?

When you look at the bolt with the aluminium washers underneath (first few pics) you can clearly see the bolt head isn't at a straight angle. The other bolt is the same and will not be straight and therefore clamping too tightly on one small area of the caliper under the bolt head.

Your caliper isn't being clamped down fully and this could damage/stress the caliper, move it out of position or even crack it around the hole where the bolt goes through.

I'd undo both bolts and double check their lengths and position. If for some strange reason the bolts are the same length you should definitely source the correct length bolt to make sure those washers are in place as they should be.

Not worth taking any chances with brake mounts for your own safety and I'd highly recommend being 100% sure the job is done properly Buddy.
flag Spangoolies
Posted: Jan 5, 2021 at 5:30 Quote
I love this forum, you can pretty much guarantee a problem once solved, will be solved again by a number of different people.
I want in on this:
The white arrow saying up is the orientation for the bracket when used on the forks. Have it facing forwards when used on the frame. There should be a longer bolt in the pack.
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