Without taking off the rotor that is, I don’t know if the threads are compatible could someone please help?! I’m building up a wheel but want the ability to change from a freewhel to fixed, but without compromising the disc brakes. If anyone could advise I would be very greatful! 🙂

I didnt find a way so took the disc off and used a bolt on cog. Didnt need back brake when fixed anyway 😉

It will thread on, but could potentially unscrew if you resist pedalling due to the lack of a lockring.

yes you can, the threads for a freewheel and fixed cog are the same

you’ll need to put a lockring on there as well as the cog will unscrew when you stop pedalling, and you’ll need to Loctite the lockring on or similar as it will be using the same thread and want to undo as well, a proper fixed hub has a stepped-down and reversed thread section for the lockring to prevent this

they call it Suicide Fixed for a reason, but as you’ve got a back brake it’s less of a problem

Yes, kinda.

On a fixed gear hub there’s 2 threads so the cog can’t unscrew whilst ‘braking’ as the lockring is screwed on in the opposite direction on a slightly smaller thread .

If you put a fixed cog on a freewheel hub it will unscrew under braking, you can screw on two fixed cogs (they need to both be offset against each other so the chain doesn’t catch) and do them up tightly against each other (like the locknuts on cup and cone hubs) and they should stay put, but I’d avoid doing skids with it just in case.

Alternatively, just get a fixed gear disk hub rather than a singlespeed one.

http://www.bike24.com/p234595.html

Thanks all 🙂 I won’t bother with that then, but alternatively, is there a way to put a freewheel on the fixed hub?

Yes, they just screw on (hence my recommendation of the surly hub). The big thread is the same on fixed and SS hubs, it’s only the additional smaller lockring thread that’s different.

Awesome, so if I get a fixed, I can just screw on a freewheel? Sounds a bit too good to be true! Thanks for the Surly reccomendation, but a lot of people are not saying good things about them….can anyone else chip in? 🙂

Theres only really 2 bearings in them, theres no moving parts other than those to go wrong so if you do go down that route any hub will be much the same, the quality being purely dependant on what bearings are fitted (and the freewheel).

Its a very niche thing, so only really served by the niche brands like surly, pauls components, white industries, etc. What frame are you using?

Thank you for your reply 🙂 I’m using a Surly 1×1 with 65mm Rob’s Son rims which are 32h hole, and the weirdest thing is, I’ve been googling for an hour, and I cannnot find a single 36h fixed disc hub??? I already have hope brakes on it so I want to keep those, but I can’t find ANYTHING?? Even Surly only make the 36h hub in freewheel, not even fixed? And the downside is the Rob’s son rims only come in 65mm in 36h, and they are about £30, the next 60mm odd rim is the Marge Lite which is £130 :S

It will be fine, since you have a rear brake, you won’t be needing the locking. If you still feel you must lock the sprocket down, the old fashioned way was to use the locking ring from a traditional bottom bracket.

It wouldn’t worry me. Once you’ve stamped on that fixed sprocket, it will be o n tight. I have a fixed wheelset for winter that I gave up trying to remove the sprocket – the lockring has been off for ages.

TiRed – Member

It will be fine, since you have a rear brake, you won’t be needing the locking. If you still feel you must lock the sprocket down, the old fashioned way was to use the locking ring from a traditional bottom bracket.

This +1 When i rode fixed I never managed to unscrew a fixed sprocket by kicking back, it used to be quite common to ride on the road without a lockring that way if the chain unshipped or somehow jammed the sprocket would unscrew allowing you to coast rather than locking the back wheel up – and it does work

Ahh so are you saying I should just get a singlespeed freewheel type hub and then run single speed on that? Because I literally cannot find a fixed 36h hub with disc mounts at all :S