Are they a must on PM caliper adapters? Ran my last one without but adapter bolter to fork, caliper bolted to adapter. On my new forks, caliper bolts through adapter straight to forks. I cannot for the life of me line it up properly and not get the horrific scraping sounds. Unfortunately this wombat ordered bolts to fit through the caliper and adapter, and i dont have any conical washers. They wouldn’t fit regardless now. Are they really necessary or i am having a moment??

Bump incase its not showing…

I’ve only ever used them with SRAM/Avid brakes. Never with Hope, Shimano or Magura.

Is it possible that your mounts need faced?

Shimanos in question. I think ive just solved it and my answer is i need longer bolts and some washers. From the look of it the lower bolt doesnt fit flush with the caliper either so im presuming the conicals act as an angular spacer to allow for an even tightening load, plus all the other bikes in the garage that have through adapters all have the washers fitted.

Some mounts that work as a bolt straight through spacer are angled so require the washers otherwise the bolts are sitting at an angle against the spacer. Just think of the angle of the bolts directly out of the fork vs the angle the caliper sits at.

I run Hope brakes with Hope mounts and never needed any conical washers. They all either have one set of through holes to fasten the mount, then threaded holes to mount the caliper, or, if the caliper bolt goes through the mount, the top and bottom faces are parallel.

On one frame, the rear caliper is on the chain stay and the Hope mount I wanted wouldn’t fit so had to use a Shimano mount (rear 160-180PM). The faces on that mount were NOT parallel so conical washers were needed.

I did warn you, bolt through adapter type needs conical washers on top of the caliper under the bolt head, this adds about 7mm including a normal washer, you’ll need about 10mm of thread going into the fork mounts after the washers, caliper and adapter, I have some unused sram ti bolts, one is 32mm two are 38mm and one is 43mm and come with the conical washers so I might be able to come to your rescue for a £5 a pair including postage if those lengths are a match.

Depends on the adaptor. Also, even when the adaptor comes with them, you don’t always need to use them- I experimented with some that were supposed to have them under the bolt head and found it didn’t make any practical difference (though it’s a bit bodgy obviously)

Going off his previous post he has bought an uberbike 180mm to 203mm adapter which is much higher on one side so the tops have to slope, without conicals you’ll be able the get a feeler gauge under the bolt head on one side, so more than a bit dodgy IMO.
NSB or Hope rule when it comes to adapters, anything else is inferior, uberbikes look good being CNC but the platform lacks material so it’s a bit of a skinny perch for the caliper to sit on.

All sorted with the correct length bolts and some washers. Uber mount is nice and shiny too! So far the brakes are working as well as they did previously so no gripes as purpose served. At least i have matching Ti bolts front and rear now 🤣

robo89
Free Member

NSB or Hope rule when it comes to adapters, anything else is inferior

Eh, Shimano are as good as it gets. Formula are good too. Both forged and machined rather than just cnc’d from solid.

Arguing over which brake caliper mount is best has to be close to peak STW.

Fair point 🙂 I don’t know what’s best but this “everything but NSB or Hope is inferior” bugged me especially when neither is really especially good. It’s a wider thing, a lot of mountain bikers are convinced that CNC from billet is automatically good… even when Hope upgraded to forgings for a load of their parts, they left all the “machined from billet” stuff on the website, I guess because they’d spent so much effort convincing people that was the better way to do it.

Its an uberbike mount and bolts, it works, thats good enough for me!

I’ve actually thrown away shimano bolt through style mounts due to being unimpressed by the amount of material either side of the hole and the rounded edges leaving little contact with the caliper, I’ve also binned cheaper forged mounts when I could see daylight coming through gaps when I rested the caliper against them, I’ve tightened up one bolt and the caliper has floated above the adapter at the other end leaving a gap big enough to swipe a credit card through ( clarks cheap crap ) so I think cnc is way to go for adapters if you want precise perpendicular fitment and a good base for the caliper to sit on, a lot of brake rub and squeal could be down to poorly finished adapters. I have NSB adapters on my bikes and some might say an irrational hatred of bolt through type adapters.

I don’t like straight through type adapters as I don’t want to have to keep threading a steel bolt into magnesium fork lowers if my brakes need adjusting.