What in cocking Nora am I supposed to do now? Brake disc won’t fit conundrum
Working on mini_s #3’s bike, found a lovely Goldtec Draco hub on the bay, built it up into a 24″ wheel… came to mount the disc and it doesn’t fit!
The “tabs” where the 6 bolts are, are too big to fit over the hub. By about 1.5mm each.
I’ve checked out a few of my in-stock discs, none of which will fit. Looks like I’ll have to grind the tabs down, but my angle grinder won’t fit in. Dremel?
Has anyone seen this before?
ThanksPosted 1 month ago
Dremel or just a small file will do it.Posted 1 month ago
You sound confident stumpy! I’ll practise on an old one…Posted 1 month ago
Is that red spacer/cap that the rotor is clashing with removable?Posted 1 month ago
With the forces going through those bolts under heavy braking, I wouldn’t be cutting anything away from the disc itself..
Looks to be more than a few thou to be shaved off and if the red surround isn’t a spacer of sorts, it may release bearings or grease if cut through.Posted 1 month ago
If its this https://www.mountainbikecomponents.co.uk/product/goldtec-draco-front-hub/
The. Somethings wrong there.
If it were me, i’d be trying path of least resistance first.
Washers behind the disc and see if you can space the caliper. If IS mount then you could put a washer between mount and frame. Post mount then hope you can slide the caliper across enough. Personally i wouldnt be filing down all the disc mounts. One or two of three you could get sway with not using. But All 6, that’d be praying on my mind the time.
Granted a nippers bike. Not for me though!Posted 1 month ago
File. Practice on an old one first. Bolts look like they’ll still have plenty of metal around them. Or look for another disk without the tabs.Posted 1 month ago
Hmm. I’ve attacked it with a file to no great effect. I’m wondering whether other makes may have smaller tabs which would be a much better place to start.
The red thing is the actual hub, so there’s no way around this problem.Posted 1 month ago
Definitely a Dremel job.Posted 1 month ago
Have you got a photo without the disc in front? You could try emailing betd with a photo and see if it is something that they have come across.Posted 1 month ago
Maybe one of these would workPosted 1 month ago
Rich I’ve done it once or twice before on my own bike and someone elses. Can’t remember which hubs they were but I know they were the same make.
Just file them down a bit and round the edges off once you are happy they are low enough, if it worked for my considerable heft I can’t see it being a problem for your little lass.
If you wan’t pop round as I have a stack of different make disks in the dinky size (unused 😉 ) that might fit betterPosted 1 month ago
Maybe one of these would work
Ah! That could well be the solution!
You could try emailing betd with a photo and see if it is something that they have come across.
Far too sensible a solution 😁
it worked for my considerable heft I can’t see it being a problem for your little lass.
Yeah, but F=mv^2 and she’s only ickle, but faster than you 🤪Posted 1 month ago
See edit RichPosted 1 month ago
Assuming that you could get the disc to fit in the brake then some washers ground on one edge would do it.Posted 1 month ago
See edit Rich
Thanks all. I’ll go see what’s in MrOvershoot’s emporium of shiny bits before I try out other options.Posted 1 month ago
Old original style hub ?
Years ago i had a similar problem and had to grind a bit off the inner bit of a rotor to make it fit.
there is an adaptor, which converts the 6 bolt to Hope 5 bolt, but as most 5 bolt rotors are the +5mm size, im not sure you could get a modern brake to fit it. Well an IS mount that is. Maybe if it was PM, you could slip a few washers between the IS-PM adaptor and the PM mount on the brake caliper and get it to fit that way. But if the caliper is IS mount, then it will only be the earliest hope calipers- DH4,first gen E4,C2,O2 and anything mini mono on wont fit(as far as i remember)
I do in the box have a goldtec to hope adaptor, and a mono 160mm rotor unusually flavoured in 5 bolt.
The adaptor is in this pic – middle bottom page two. – pic wont post on here, you’ll need to follow the link.
In the pic it says its directly compatible with magura gustav M disc and Louise disc brakes. see if you can find a pic of the Gusttav M rotor and it might look compatible.
Yeah, it’s the original style. Having seen MrOvershoot’s stocks are pretty much the same as mine, I’m going to try either the wiggle option above, or a cheap floating rotor. Thought there is with the centres being alu, it will be easier to dremel.Posted 1 month ago
What brake are you using with it ? As i said, ive the adaptor sitting in front of me and a 160mm 5 bolt hope mono rotor that fits it.Posted 1 month ago
It’s an slx m7000.Posted 1 month ago
Do you know anyone with a lathe?Posted 1 month ago
1) You need a bastard file, if you’re using a finishing file you’ll be there forever.
2) Grinding the tabs will probably be fine, the rotor isn’t centred so it looks worse than it is, the bottom tabs are barely in the way in that pic. If it was that important I doubt they would make floating spiders thinner and from aluminium.
3) Hope make adaptors for half sizes, have done for years. It’s probably easier to get one of those than a PM-IS adaptor these days. But 5 bolt disc is a niche pain in the arse.Posted 1 month ago
I would imagine the Clarks rotor would still foul the hub and need filing down, on that basis I’d stick with the current rotor as it has far more meat between the bolt holesPosted 1 month ago
Looking at it again I would be taking an angle grinder to the disc tabs and removing what I needed to slip over the hub. Given the direction of the forces I cant see this being an issue for long term safety.Posted 1 month ago
will the bolts fit without the disk or will the heads catch as well?Posted 1 month ago
£25 and i’ll send you this thing out, the 160mm mono rotor included. RM 1st class recorded costs a fiver so its really 20 quid im after.
Only stipulation is after little one outgrows it, please sell it back to the retro market, its a rare part.Posted 1 month ago
Minor update on this – I rang BETD to see what they said, and they were as baffled as I was. I’m going to send them a pic, but I’ve also ordered the Clarks discs in the meantime.
I asked Clarks to measure the width of their discs and I thinkit’s bang on – I might need to hoover off a gnat’s fart of metal on each tab, rather than the 1.5mm on the shimano ones.
Thanks dyna-ti – I’d already gone with the Clarks ones early this morning. If it’s OK, I’ll keep your offer in my back pocket and come back to you later in the week if this one goes all wrong.
Annoyingly I’ve sold her current bike a bit too quickly so I need to get this one up and running! This isn’t the only problem as I’m waiting a hub from China and some adapters from the outer rings of Uranus.Posted 1 month ago
I had something similar to this with a Hope rotor on an old set of Risse forks – the hub was a special width (I think) Risse jobbie and the hub caps had recessed slots where the tabs should have slid down. Had to file down a mm or so of the rotor tabs and it fit fine.Posted 1 month ago
Looking at it again I would be taking an angle grinder to the disc tabs and removing what I needed to slip over the hub
You must have more finesse with an angle grinder than me – I’d struggle to shave a fraction of a mm off thinking about how the disc would have to be clamped…Posted 1 month ago
I wouldn’t even attempt to do that sort of thing with an angle grinder, Accident waiting to happen, and a serious accident at that.
People seem to forget how dangerous an angle grinder actually is.
This is a job for a dremel, or a hand file, nothing more than that.
I’ll keep your offer in my back pocket and come back to you later in the week if this one goes all wrong.
I wish you the best of luck in that.Posted 1 month ago
Paul from BETD has advised that it’s a pre-betd model (which it is, it’s a Goldtec)
All the ones made by them aren’t like mine and he thinks the redesign would have been at the time ownership went to betd.
So I’m getting the dremel out.Posted 1 month ago
Final update. Clarks discs arrived today.
Got the ones linked by @StuE so thanks for that. Ended up getting a pair (cos matching) from Clarks on eBay for £11.99 posted.
They’re about 2.0-2.5mm wider across the middle, so *nearly* fit without assistance.
As it was, a couple of scrapes with a file on each tab and it slid on like a well lubricated slidey thing.
Posted 1 month ago
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