Singlespeed & Fixed Gear - Double fixed hubs.

It seems like a comical idea because even if you flip your wheel over to a different size cog, you will have too much or too little chain to run the other side, so whats the point. Or perhaps I am missing something here?

I believe with true track ends, you do have enough lateral freedom to accommodate a one- or two-tooth cog difference.

The whole point is that you can run more than one ratio by flipping.

Or, bugger up the threads on one side and not have to buy a new hub.

If you keep it within 1-2 teeth, you shouldn't have any problems. I have 16t and 17t on mine.

i have a 4 tooth spread on my flip flop with room to spare on my iro's dropouts.

It seems like a comical idea because even if you flip your wheel over to a different size cog, you will have too much or too little chain to run the other side, so whats the point. Or perhaps I am missing something here?

ride to the velodrome on 48/17 then flip the wheel around and ride 48/14 ;)

If you keep it within 1-2 teeth, you shouldn't have any problems. I have 16t and 17t on mine.

Exactly. 14t and 15t for me. Ride hard one day on the flats and the next ya wanna make it easier or it might be really windy, just flip it and make it easier. No chain problems for me. Of course if you are at the end of the track end with the bigger cog and flip it then it might be a problem.

It seems like a comical idea because even if you flip your wheel over to a different size cog, you will have too much or too little chain to run the other side, so whats the point. Or perhaps I am missing something here?
Track ends allow you to move the wheel back or forth for good chain tension. So if the cogs are within 2 or so teeth, you will be able to get correct tension with no problem.

i'm running a 13-17 flip flop

Also gives you the most versatility for a flip-flop since you can run a freewheel or a fixed cog on either side. (Sure, you can run a fixed cog on both sides of a fixed/free hub, but you're sans lockring on one side.)

It seems like a comical idea because even if you flip your wheel over to a different size cog, you will have too much or too little chain to run the other side, so whats the point. Or perhaps I am missing something here?

yes

Also gives you the most versatility for a flip-flop since you can run a freewheel or a fixed cog on either side. (Sure, you can run a fixed cog on both sides of a fixed/free hub, but you're sans lockring on one side.)

A fixed cog, sans lockring is not a good idea, especially since the aim is versatility. I'd get a fixed/fixed, if they were cheaply available.

A fixed cog, sans lockring is not a good idea, especially since the aim is versatility. I'd get a fixed/fixed, if they were cheaply available.

u dont need a lockring if u are riding at the track.

wat?

yeah i run a 17t on the street and a 15t on the track with no need for additional/fewer chain links

u dont need a lockring if u are riding at the track.
if you show up as a new track racer and you don't have a lockring on your hub, i'd advise keeping your mouth shut about it.

as to what does and does not fit, let's be quantitative about it.

1 tooth on a cog engages 1/2 link of a chain or 1/2 inch of chain. but the chain only wraps around half the cog, so 1 less tooth on the cog means 1/4 inch of extra chain.

that extra 1/4 inch, though, is shared between the sections of chain above and below the chainstay, so the axle only moves 1/8 inch back in the dropout.

the axle is about .4 in thick, so if your dropouts are 1.4 inches long you can theoretically deal with an 8 tooth difference. in practice you have to account for space for the track nuts to grip and things don't always line up as you'd like them to, but a 4 tooth spread is usually no problem.

just remember that if you have a rear brake it'll probably not line up and may rub the tire or spokes because the rim's position will have changed along with the axle.

Fixed/free flip flop hubs are a foolish buy IMO seeing as how you can run a freewheel on the fixed threads.

Also gives you the most versatility for a flip-flop since you can run a freewheel or a fixed cog on either side. (Sure, you can run a fixed cog on both sides of a fixed/free hub, but you're sans lockring on one side.)

I beg to differ. A fixed/fixed hub will yield the greatest versatility as one could use 2 fixed cogs, 2 freewheels, or a fixed cog and freewheel. From what I understand, the few threads not utilized by a freewheel on the 'fixed' side aren't a problem.

I've run a 48/18 and 48/15 on my fuji, with just enough space in the drop outs.

I beg to differ. A fixed/fixed hub will yield the greatest versatility as one could use 2 fixed cogs, 2 freewheels, or a fixed cog and freewheel. From what I understand, the few threads not utilized by a freewheel on the 'fixed' side aren't a problem.

A fixed/fixed will also allow all those combination, and you will be able to have a lockring for your fixed cogs. Fixed/free, if you run double fixed cogs, one side won't have a lockring.

I like the double fixed hub. 15t for flats and low wind conditions or 14t for towing a trailer or strong headwinds.:D

Provided you're not running a "magic ratio" on a bike with vertical dropouts there should be enough room to swap one side or the other without chain problems.

Croscoe is talking about fixed/fixed.

And Plecks, it is ill advised to run fixed on the freewheel side. No threads at all for a lockring so too much back pressure and you've got yourself a mess of trouble.

Croscoe is talking about fixed/fixed.

For some reason I read it as "fixed/free will offer the greatest versatility". D'oh!

I love my Shimano DA fixed/fixed, merely because of the security if I accidentally strip the threads on one side. But I rarely keep a cog on the non-drive side because of the added rotational weight.

^ Really? The weight of a cog that close to the point of rotation is insignificant.

I suppose you COULD run a rotafixed cog on a freewheel thread with a BB lockring without too much trouble at the track.

But only the track.

As dirtyphotons pointed out, most if not all velodromes have rules that specify you must have a lockring installed on your bike.

Also gives you the most versatility for a flip-flop since you can run a freewheel or a fixed cog on either side. (Sure, you can run a fixed cog on both sides of a fixed/free hub, but you're sans lockring on one side.)

I use double stepped hubs that have a lock ring on both sides for a fixed and fixed set up and even on a conversion with horizontal drops you usually have room for a 3 tooth difference in cogs.

Although I could run a freewheel I prefer the fixed / fixed set up on all my bikes.

I suppose you COULD run a rotafixed cog on a freewheel thread with a BB lockring without too much trouble at the track.

But only the track.

If you want to take a bike like this out on the road you really need to make sure things are set up right... besides the rotafix the cog and lock ring will need red loctite and one should be running a brake.

My Peugeot has been rocking a suicide hub for well over 10,000 km with nary a problem and removing the last cog required the use of a torch and a few extra hands since it was so solidly affixed.

If you want to take a bike like this out on the road you really need to make sure things are set up right... besides the rotafix the cog and lock ring will need red loctite and one should be running a brake.

My Peugeot has been rocking a suicide hub for well over 10,000 km with nary a problem and removing the last cog required the use of a torch and a few extra hands since it was so solidly affixed.

You're absolutely right about the additional steps for road use. I was just assuming track use. Personally I'd never run a suicide hub.

this post got me my senior membership status...

It seems like a comical idea because even if you flip your wheel over to a different size cog, you will have too much or too little chain to run the other side, so whats the point. Or perhaps I am missing something here?

Older frames with long dropouts have plenty of room for 4 or 5 tooth difference. You'll rarely ever want such a spread in real life. Maybe 2 tooth difference.

http://gallery.mac.com/bbattle/100187/P1010025/web.jpg

http://gallery.mac.com/bbattle/100187/P1010027/web.jpg

Formula fixed/fixed hub with 16/18 Surly Dingle and 16T freewheel. Yes, freewheel cog fits nicely on the hub. If you look closely, you can see an old bottom bracket lockring I put on the hub first as a spacer.

Dingles are the shiat! So glad the lbs set me up on my remodel.

Older frames with long dropouts have plenty of room for 4 or 5 tooth difference. You'll rarely ever want such a spread in real life. Maybe 2 tooth difference.

http://gallery.mac.com/bbattle/100187/P1010025/web.jpg

http://gallery.mac.com/bbattle/100187/P1010027/web.jpg

Formula fixed/fixed hub with 16/18 Surly Dingle and 16T freewheel. Yes, freewheel cog fits nicely on the hub. If you look closely, you can see an old bottom bracket lockring I put on the hub first as a spacer.
Looks like you should drop a link. You can't move the wheel any farther back in the dropout, and you'd need to if you wanted to use the smaller cog.

this post got me my senior membership status...

Congratulations :lol: .

...4 or 5 tooth difference. You'll rarely ever want such a spread in real life.

If for some reason you wanted more spread than your dropouts could handle, it wouldn't be a big deal to carry an little bit of extra chain and a 2nd master link. Might add 30 seconds to the gear change process.

^that works.

the bike polo crowd tend to desire a normal street gear and a super low polo gear. one setup that has become popular has been to run a surly double cog (17/21) and a double chainring (say, 46/38). that gives a whopping spread of 47.6 and 71.1 gear inches with one chain.

this can also be accomplished with a freehub for a singlespeed. or a regular flip flop hub, creative use of spacers and a double crankset.

Looks like you should drop a link. You can't move the wheel any farther back in the dropout, and you'd need to if you wanted to use the smaller cog.

It looks like he has a double chainring. He probably uses the smaller cog with the bigger chainring.

It looks like he has a double chainring. He probably uses the smaller cog with the bigger chainring.

You're right. I didn't notice the second ring in the chainline shot. :o