Zdawg

I would like to run a BMX drivetrain (AKA a freestyle drivetrain) on my fixed gear so I can have a feel for the spline-drive cranks and maybe get into some basic FGFS tricks without going all the way to buy a micro-drive hub.
What lockrings do you guys recommend that don't interfere with the chain when running a 12t fixed cog? If I try running my current regular lockring with no recess, the plates of the chain rest against the lockring which won't allow for full contact around the cog.

I know there is an old Campagnolo one and that the Phil Wood track lockring seems to have the recess to accommodate for a 12t cog. Also, is 12t the lowest tooth count for a cog you can go on a traditional track hub? I haven't seen 11t so I'm assuming that's the case.


@thebackwardwiz and his BMX freestyle drivetrain on a fixie



Both the crank and the chainwheel must be 48 splined for fixed gear (or so I heard)



NOS Vintage Campagnolo NJS Track Lockring for 12t (out of stock and also expensive, £40)



Phil Wood lockring and the recess



Profile track lockrings seem to clear it as well.



Halo do, too.


Does anyone have experience with the quality of any of the above or suggest some other more affordable alternatives?

I don't mind the fact the drivetrain is going to wear out a bit faster and that power transfer won't be as efficient as with big sprockets since I'll be riding the bike mostly for tricks and therefore would like to have a smaller (31t, 32t) chainwheel. I already have the half-link chain. I'm missing the special lockring, the cranks and the chainwheel (drop some suggestions on 48t-splined chainwheels as well if you know any)

Many thanks

veganbikes

Would not go campy for that purpose but Phil Wood is good quality as is Profile Racing (and they are a BMX company). Sugino also makes their Gigas lockring for 12t. There is a Fixed Gear Freestyle Subforum here I would say you didn't do wrong posting here because this is way way way way more active but the other one does exist.

Zdawg

I hear you. I've posted there before but didn't get much traction. I'm trying to have builds tailored more for tricks but with a bit of track bling, if you know what I mean, so I might post the same questions there and here. Can you get in trouble for double posting under two subforums?

Dylansbob 

When I first built this up, there was still some FGFS stuff for cheap on ebay. This is a 12t with the stepped lockring. SD sprockets are hard to find above 36t. I broke down and bought a 104bcd SD spider.... then I ended up selling the bike.

Zdawg

That's a sick build! I can't believe you sold it?!

What frame is that? It reminds me of those volume FGFS (thrasher or cutter). Are those 26in wheels? Do 104BCD 1/8" chainrings exist?

Myself, I can't seem to find spline-drive sprockets at 31t, a 31/12 would be a really decent ratio.

Russ Roth

I've dealt with Halo, not that popular a brand but decent and reliable in my experience.

You should be able to find a 31t 1/8 104bcd sprocket, something like this https://olsenbikes.us/products/olsen...0-40b9d768cbea

31t spline drive will be a whole different story. Spline drive is a more modern concept and is closely related with the 1x systems, with that they want narrow/wide rings which require even number rings.

BMX cranks on a track bike is usually an easy fit, all three of my kids are riding 2 piece bmx race cranks on their track bikes since the driveline works out fine. Just make sure you're buying one designed for a pro sized bike to avoid the weight limits that the Jr, expert cranks will have.

diricks0n

You could try to find a Specialized P.Fix rear hub, which has a 10T bolt on cog. Beware, the axles are 14MM. Or you could buy the whole bike if you find one, should be pretty cheap.

Zdawg

Thanks, Russ Roth, this info is really helpful. I'll be sure to have a look at it.

When checking the link I also found the spider for the 104BCD 31t front sprocket but that one seemed to be compatible with those MTB direct-mount cranks rather than the 48t spline-drive from BMX.


I heard that if you're going to run BMX cranks on a fixie, it's got to be 48 spline-drive (both cranks and sprocket).
So my understanding of fixed gear drivetrains are:I picked this up from videos online so I wouldn't be surprised if I'm missing any other standard? (I know technically you could use multi-speed chainrings but I'm only counting single-speed ones that are designed to go with 1/8").
P.S. I'd love to see some pictures of those track bikes with BMX cranks if you could upload them

Many thanks

Dylansbob 

It's a SE Us v Them FGFS frame with a Brev M fork. The stock Landing Gear had ***** tire clearance. It had a Mid bb, so it was made for 48spline. At this point, Profile Racing is the only ones still supporting anything SD. Check out the BMX "racing" section for larger sizes. Tree made some weird sizes, they might have made a 31t.

Actually, if you don't mind used, PM me. I have a few different rings left...

Dylansbob 

Zdawg I dug through my fixie stuff. No small cogs or stepped lockrings. I do have this S&M 30t for sale.

JohnDThompson 

Be aware that Campagnolo and Phil lockrings are 1.32" x 24tpi LH thread rather than English/ISO 1.29" x 24tpi LH thrad.

Zdawg

Since you brought these different standards I would like to ask about the Miche and Mavic lockrings. What standard are those? Are they the same as Campy and Phil?

And which standard is my formula hub? I currently have those no name lockrings on it.

diricks0n

Expanding on my post above, you could also run an ISO front disk hub and a bolt on cog. I don't know how small bolt on cogs go, but the one on my aforementioned P.Fix is 10T and is the same bolt pattern as an ISO disk hub.

Here is an older thread with some info: https://www.bikeforums.net/singlespe...bolt-cogs.html

veganbikes

It is not really smiled upon. However that is a sadly less used sub-forum but maybe you can help revive it.

JohnDThompson 

Not sure about Mavic, but Miche is the same as Campagnolo; I like them as an affordable alternative on Campagnolo and Phil hubs. I think the last one I bought was less than US$10.

Formula almost certainly will be English/ISO thread spec.

Jax Rhapsody

I'm actually planning a SS klunker that'll have bmx cranks, I just need to find a 38 or 40 tooth sprocket to pair with a 17cog.

grant40

It has been done before. There is nothing out of the ordinary at this point.

Zdawg

I didn't find a subforum on it. Can you link it here?

grant40

https://www.bikeforums.net/fixed-gear-freestyle/

grant40

Here is a singlespeed I built from a road bike with 1 piece cranks using a BMX crankset.