[Closed] disc brake mount widths & an OnOne Fatty carbon fork

Think the on one forks are RDS spacing - ha have you got a FDS hub?

hmmmm, no idea, like a total noob, I bought it second hand, not realising there was a difference.

bugger I do have an FDS hub.

is there some way of converting ?

Sorry didn't spot this - I think you've had a reply via the UK Fatbike Facebook thing now?

It's a bit of a pain. At least with RDS you can use spacers to push the disk out, with FDS it's more tricky.

I had the same issue. I machined down a brake adaptor in the end.

yeah cheers wwaswas - bit pissed off.

hypnotoad - I am thinking the same - I have a mate with all the milling gear so I might try this as an option first.

I have this issue too. Just tried to fit my on-one carbon fatty forks to my voodoo Wazoo only to find that the brake adaptor rubs badly against the disc.

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wwaswas - Member
Think the on one forks are RDS spacing - ha have you got a FDS hub?

Say what now?
Never heard of all that... 😕

RDS = Rear Disk Spacing
FDS = Front Disk Spacing

You probably didn't know that the disk on disk hubs isn't in the same place front and rear - until now. As fatbikes were evolving, there was a time when 135mm front hubs were just rear hubs (some folk ran a SS rear hub at the front for a bit of contingency in the back country) so forks were designed with a different disk spacing. Once fatbikes got more popular, some companies started to manufacture "proper" 135mm front hubs. Hence we ended up with two standards.

Pooh 🙁

RDS forks are the worst option. With a FDS fork you can convert the RDS hub to work with a simple converter.

http://problemsolversbike.com/products/fat_fork_disc_rotor_spacer

So the on-one carbon fatty fork is an RDS?

Yeah its stupid, but you can make it work with just a bit of filing~
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Looks great Lightman. I was thinking down that path, just reducing the width but the way you've done it keeping the integrity of the threads is great.

Lightman,

I have the same problem but my solution is handmade, not neat... You look like you have access to a milling machine....

You probably know what's coming next....

Can you make another one for me... ?

Cash, beer, baby robins, kittens.... ?

Got to work and got straight onto the overhead router, and milled away about 4.6mm a-la Lightman.

I know that woodworking cutters can cope quite well with aluminium, but it still makes me nervous every time... 😯

Hopefully it will fit now. I suppose you do lose some strength from the adaptor, but I'm relatively confident that it'll be ok. What's the worst that could happen?

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Ignore the bit where I accidentally buzzed the corner...I was rushing ok!.. 😳

Can someone do another for me please !

I overachieved with the file and had to put a washer between the adaptor and the fork mount...

I took 1mm off the inside of the fork mount, the rest off the adapter... but a bit too much!

On and working fine...

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Looks good, let us know if you die!

The pics above aren't mine, I was looking for a problem solver when I was after a new wheel for my fatty and thats what I came across. Luckily, I did manage to find a wheel which had the correct hub on it, so I didn't have to filing.

Looking around, it seems carbon straight steerer fat forks are as rare as hens' teeth, even looking at Chinese Ebay sellers. So far, I can only find the Carbon Fatty (~650g) or the Exotic (~950g with alloy steerer) as possible upgrades for my Wazoo.

Given I have no access to a lathe or the experience to file down the disc mount ~4.5mm, I'm wondering about a safer and more expensive option...

Buying one of those front Fatty wheels that are in the 40% PX sale for ~£41, which have RDS to fit the Carbon Fatty without any rotor headaches.

As I wrote in another thread, little niggles like this have made me question the Wazoo purchase a little, because it is locking me into old fatbike tech.