So, I fitted new floating rotors and the spider was rubbing the brake mounts on the fork. Usual Chris King/Hope/Fox problem. Could have went with the standard ones, but wasn’t too fussed about removing a bit of material from the mount, as the fork lowers already have plenty of dings/scratches (as they should have!).

Anyway, I’m now looking at it thinking ‘Hmmm, might have gone a bit far there’. Seems fine with caliper installed etc. So the question is, have I left enough of it to hold the bolt, or am I heading for grizzly death?

Plenty meat left there, carry on riding. Just don’t horse the bolt in, stick to recommended torque.

It might be close enough to weaken the thread/bolt interface but I can’t see it being any risk when braking. Wouldn’t bother me. Don’t gorilla the bolt though!

I was expecting the first answer to be ‘yes, you will die!’, in the standard STW fashion. 🙂

Grand, will be extra careful with the torque wrench, to be sure not to overtighten it.

have I left enough of it to hold the bolt,

I suspect not. I can easily see that cracking over time, based on other stuff I’ve seen crack rather than anything scientific.

Will keep an eye on it for any hairline cracks appearing and replace the lowers if any do. Catastrophic failure under braking is my main concern.

If it brakes off you’ve still got a rear brake so you’ll be fine. I rode a single braked hard tail off rode for years. It’s not as easy to modulate braking but you’ll survive

That looks a bit close. I had the same combination of fox/hope/king and just filed a small amount off and it was fine, but it was far less than the photo suggests

You’ll go sailing over the bars when you pull the front brake and it all gets mangled up in the front wheel.. just make sure you are wearing a wing suit

Usual Chris King/Hope/Fox problem

I’ve not heard of this before

It’s actually a Hope Floating twin disc/ Fox issue I run Mavic SX wheelset. I found just by thumbs on the floating bit to free them up to move again solved the issue of rubbing…..that and I will let it rub the little away it needs to rather than my ham fisted file intervention 😆

Why would it crack it’s made of metal not cheese loads of meat left on that you will be fine just don’t over tighten ,bloody arm chair engineers 😈

What did you use to remove the metal, a belt sander?

😆

🙄

I was looking it it from a different angle when I was filing and didn’t notice the file wasn’t quite flat, so more came off at the bottom than it seemed, from my vantage point. Bit annoying, since I frequently stopped to check progress. Will be checking from several angles the next time I have to file something.

Wing suit ordered 🙂

If it makes you feel any better I did that to my Reba forks. Calliper fell off and wrapped itself around the wheel. Don’t underestimate the power of the claiming action on the disk.

I’m alive and well by the way

Got a will sorted OP?

So does it get thicker further towards the fork leg?

if so I would think about carefully seeing how deep the thread is and what the maximum length machine screw you can get in there – allow 2mm or so to prevent the screw bottoming out and stripping the thread. I would then possibly counterbore the hole slightly so there are no threads in the weakened bitto reduce the chance of cracking but only if you have plenty of thread left lower down.

I take no responsibility if it doesnt work, makes it worse or you get injured or die.

Another solution could be bond a stud in there and use a nyloc nut to secure the caliper. Your forks are pretty much worth sod all 2nd hand now anyway.

Yeah, it does get thicker. Thought of putting in longer bolts, but wasn’t sure if it’d make a difference. Will have a dig about in the spares box and see what I have.

i’d be concerned about cracking under heavy braking. When it does, it could go between the spokes and lead to an OTB crash.

So you may or may not have a very slightly increased risk of someday going over the bars

Just ride! – I go over the bars all the time, its great fun 🙂

The load will be going in the opposite direction to the side you have filed. I doubt it would just fail. You may develop a crack from the threads to the filed bit over time, but a longer bolt should help.

Nice to see someone solving the problem with a tool rather than raving that it’s not ‘fit for purpose’ and demanding the lynching of the retailer.

andyl – Member

So does it get thicker further towards the fork leg?

if so I would think about carefully seeing how deep the thread is and what the maximum length machine screw you can get in there – allow 2mm or so to prevent the screw bottoming out and stripping the thread. I would then possibly counterbore the hole slightly so there are no threads in the weakened bitto reduce the chance of cracking but only if you have plenty of thread left lower down.

This would be the method I’d use, provided your cack handed filing isn’t uniform down the length of the mounting post.

Measure the depth of the threaded hole and use a bolt of this length and all should be good.

You’re still going to die though, just not because of a snapped brake mount……probably 😀

i like using hopefoating rotors but have found issues with rubbing forkleg,only get out for me and safty is non floating or a different hub to allow for the spacing
it is a pain in the arse when all your nice expensive shinny do not play together but cheaper shonky does ( and i love expensive shinny kit).

So which bit is out of ‘spec’; the Fox forks, CK hub or Hope floating discs?

Why did you file the actual fork? Am I reading that right?!! I always file the adaptor. That way if you go too far you can shim back up or bin and spend another tenner buying a new one. The fork mount though?!!!!

It must be the wonderful CK hubs, Ive run Hope floating disks on Fox, RS and Magura forks without issue using Pro2 hubs. The rivets did rub on an old Hope M4 post mount caliper though….

Id feel nervous about that myself.

The forces (and fore/aft slight flex) over (what?) time would cause fine cracks- at what point does a bolt unwind? TBH you’d still have one bolt in. I lost a bolt on the rear and on descending Jacobs Ladder I heard a loud metal on metal slapping noise as the caliper slapped back and forth when I wasn’t breaking. I carried on until halfway when I thought I’d better check.

i find you can never tell till you put all your nice shiny bits together its only then i get pissed off. my salsa hubs floating rotors and carbon forks would not play together was taking no chances with that so boring standard hopes on to be safe.

So the OP filed the forks to fit a floating rotor?

Yay! My first Picard meme! It’s like a badge of honour. 🙂

So far, I may or may not die and it may or may not be related to my forks. It might crack or fail catastrophically and I’m a fud.

Measured the hole and it’s not really much deeper than the bolts I’m currently using, but will see if I have any bolts that size. I compared the amount of meat left on the mount with that on the Revs on my hardtail. Seems the Rockshox mounts are nowhere near as beefy as the Fox ones. The amount of meat that’s on the Revs as standard is pretty comparible to what I’ve left on the Fox brake mount.

So which bit is out of ‘spec’; the Fox forks, CK hub or Hope floating discs?

There’s a few threads over on MTBR about it. The spider on the Hope rotor is slightly thicker and there’s less clearance on Fox forks. If I remember correctly, someone even got CK to admit that their hubs were slightly out of spec. I’ll see if I can find the thread.

Why did you file the actual fork? Am I reading that right?!! I always file the adaptor.

It was rubbing the fork and adaptor. The spider was hitting the fork and preventing wheel from turning and the rivets were fouling the adaptor too. That also got the file treatment, but done a little more carefully.

Worst case, there’s plenty of Fox forks out there with gubbed stanchions, so should be able to pick up a 2nd hand set of lowers easilly enough.

Edit: Here’s that thread, post #45 seems most relevant.
Clicky

there’s less clearance on Fox forks.

Are they made of a weaker material?

Are they made of a weaker material?

I have no idea.

Edit: Here’s that thread, post #45 seems most relevant.

I’ll be honest, if I’d fitted the parts together and something caught the last thing I’d do is take a file to them.

And ride it now? Must be crackers as it will always be in the back of my mind, especially when going OTB…