Singlespeed & Fixed Gear - SS Build - flip flop hub question

Happy new year folks.

It is time for me in the new year to build my long awaited single speed bike. I have had a track geometry frameset for a while and this Xmas I bought Vuelta Track Zerolite wheelset. The rear wheel features a flip flop hub where one side has two sets of distinct threads, and the other side has just one. I suppose the former is for cog and lockring and latter for freewheel.

However, I would like to put freewheel on both sides. Based on google searches, I think that this is possible, but just wanted to make sure before I went out and bought the parts.

Assuming this is possible, I would like one free wheel to be helpful in riding substantially steep mountains (6-15% grade). I have a century coming up in May 2012 and would like to have a regular freewheel on one side (say 16T) and a climbing friendly freewheel on the other. Should I choose 17T or 18T for that? My chainring is going to be 46T.

I will have more questions coming up soon, but thats it for now. Thank you for any feedback.

I'm no expert, but I believe you can not put a freewheel/freewheel on a fix/free hub. They make them threaded specifically for the application indicates. Also, you're better off with a cog (http://surlybikes.com/parts/dingle_cog) setup like this or a double on the crank. I believe Paul or White Industries makes a double-chainring that allows you to have the variability you're looking for without having to switch to a different chain, or break down and flip a wheel. It's a bit expensive, but the crank option would allow you to stick with the SS, obviously the cog variant will not.

I believe you can not put a freewheel/freewheel on a fix/free hub.

Incorrect.

Incorrect.

Yep. You can put a freewheel on a fixed hub, but you can't put a fixed gear and lock ring on a freewheel hub. Fixed/free can be set up as free/free.

I'm pretty positive that you can use the freewheel on either side, if it fits, there's no problem.... the only difference between the fix and free side, are the threads for the lockring...

Incorrect.

Incorrect. You can most certainly install a freewheel on the fixed side of a hub without any problems whatsoever.

That's great news. Now I feel more confident about doing a century on a single speed. This ride features 10K feet of climbing and I could certainly use lower gears by just flipping the wheel.

Are there any recommendations for freewheels?

Incorrect. You can most certainly install a freewheel on the fixed side of a hub without any problems whatsoever.

He was actually correcting me, so I was the one that was wrong. For some reason, I assumed fixed/free had different threading.

I totally missed the word not in your post. Derp.

Are there any recommendations for freewheels?

as in brands? or tooth count?

I personally would be pretty unhappy with a low gear of 46x17 or 18 for any significant climbs. Especially when talking about 15% grades... I'd have to walk. Back in the days when the Tour de France was ridden on flip-flop bikes, gearing for mountain stages would typically be a 24 cog on one side and a 20 cog on the other, with a chainring of 42, 43, or 44 teeth.

I live in the mountains, and I'm not in Tour de France shape, so my flip-flop bike uses a 40 ring with a 24 tooth freewheel on one side and a 15-18-21 freewheel on the other. This only works because the dropouts are a bit more than twice as long as average, and angled so that the brake pads hit the rim regardless of where the hub is positioned. Without that option, I simply would not be using any kind of a SS/flip-flop bike here.

Six jours: Thanks for the feedback. Currently, I live in Texas, so I guess 46x18 or x17 will work fine here, since it's mostly flat. But I want to do this century in the hills later this year, which is when I will need comfortable setting. 40x24 sounds like it will do the trick, but that will be hard to find.

I'm not aware of any modern maker of 24 tooth freewheels, but they're actually pretty common on Ebay - if you trust 50+ year old bike parts. So far I've had no problems...

<edit> Because it's been years since I last looked for large SS freewheels, I took another good look around. Turns out a place called Circle A Cycles in Rhode Island appears to have 24, 26, 28, and 30 cog models in stock for $85 a throw.

Six jours: Thanks for the feedback. Currently, I live in Texas, so I guess 46x18 or x17 will work fine here, since it's mostly flat. But I want to do this century in the hills later this year, which is when I will need comfortable setting. 40x24 sounds like it will do the trick, but that will be hard to find.

beware that if you run two single speed freewheels on a flipflop hub there is a max amount of cog teeth difference that a frame's rear track forks or horizontal dropouts can compensate for as far a chain tensioning is concerned.

BTW, texas hill country climbs can be as tough as any in the U.S.

if you go with a single speed freewheel, i have found that the newly redesigned ACS Crossfire is nice at a reasonable price. this is not your father's ACS Claws freewheel.

Huey: Interesting info. What is the max difference in tooth number that a track frameset will compensate for? At the moment, I am considering 46T chainring and 18T/20T freewheels on the flipflop hub. This is with 165mm cranks. On my geared road bike, I use 42T chainring and I find myself to be riding mostly with 17T cog on the cassette.

You need to move the hub axle approximately 1/8" in the dropout for each tooth change, so in your example with 18/20T freewheels it would be 1/4". You will need about 1/4" clearance to the inside of the dropouts to get enough slack in the chain to remove it from the chainring so you can remove the rear wheel. So, you can actually accomodate a significant change in ratio with at typical track dropout.

If you use a rear brake you'll find that on horizontal dropouts or track ends, moving the rear wheel means the brake pads won't line up with the rim anymore. On race bikes from the 20s and 30s, when flip-flop hubs were standard equipment, the dropouts were angled so that the pads would line up with the rim regardless of hub/wheel position.

Incorrect. You can most certainly install a freewheel on the fixed side of a hub without any problems whatsoever.

eh you can, but what iv seen, there is not enough threading for the freewheel, and can cause major stripping.


I personally would Not do this

OP get a white industries DOS hub, its a freewheel with two cog sizes to run different gearing,. put that on your free side and you can still run fixed.

If the threads are adequate enough to deal with the torque of a rider using a fixed cog, why would they not be enough to deal with the torque of a rider using a freewheel?

look at the amount of threads on a fixed side / cog verses the amount for a freewheel, I pulled a freewheel a kid had on a fixed side and it was toast, the freewheel was only threaded on halfway.

What is the max difference in tooth number that a track frameset will compensate for? At the moment, I am considering 46T chainring and 18T/20T freewheels on the flipflop hub. This is with 165mm cranks. On my geared road bike, I use 42T chainring and I find myself to be riding mostly with 17T cog on the cassette.

The range is a function of the length of the dropout slot. Generally a 2-3 tooth difference will work.

Shimano makes good, inexpensive single freewheels.

If you use a rear brake you'll find that on horizontal dropouts or track ends, moving the rear wheel means the brake pads won't line up with the rim anymore.

Yeah, but if you're going through the bother of flipping the wheel, another couple seconds to adjust the pads is trivial.

Huey: Interesting info. What is the max difference in tooth number that a track frameset will compensate for? At the moment, I am considering 46T chainring and 18T/20T freewheels on the flipflop hub. This is with 165mm cranks. On my geared road bike, I use 42T chainring and I find myself to be riding mostly with 17T cog on the cassette.

you might ask this question on the "track" forum they deal with this issue all the time. they are pretty knowledgeable and don't mind a non-trackie question now and then if you are nice about it.

edit: not that your question hasn't received some informative responses already.

oh, and with track dropouts, i imagine you can get any gearinch value you want, providing you are willing to purchase additional cogs and/or chainrings and adjust the chain as necessary.

look at the amount of threads on a fixed side / cog verses the amount for a freewheel, I pulled a freewheel a kid had on a fixed side and it was toast, the freewheel was only threaded on halfway.

That still doesn't answer the question. If the threads are adequate for the torque of a fixed cog, why are they not adequate for the torque of a freewheel?

Yeah, but if you're going through the bother of flipping the wheel, another couple seconds to adjust the pads is trivial.

It takes me 10-15 seconds to flip a wheel, which is consistent with the times posted by the old racers. I don't know what the world record for brake pad adjustment is, but I'm sure it takes me at least a minute or two, not counting time to fish around for the tool.

That still doesn't answer the question. If the threads are adequate for the torque of a fixed cog, why are they not adequate for the torque of a freewheel?

um, a fixed side is designed for a fixed cog and has the amount of threading needed to fully screw on, It does Not have enough for a freewheel to fully screw on and will only screw on about half way with the rest of the freewheel hanging over the lockring threading. This will be flexy and is bad.

I have seen someone do this and it stripped and messed up the fixed side of the hub. Put a freewheel on the freewheel side.

If you look at six and seven speed freewheels you'll note that they are only supported by about half their width too.

Moreover, I have seen fixed cogs strip threads designed for fixed cogs. I have also seen freewheels strip threads designed for freewheels. So the fact that threads sometimes strip isn't a very good argument.

Regarding "flex", I'm assuming you know this because you have measured it or have access to the research of someone else who did. I'm very interested in those measurements and hope you will publish them here.

Personally, I have "researched" the issue to my own satisfaction through extensive use of freewheels on fixed threads. I have never had a problem.

um, a fixed side is designed for a fixed cog and has the amount of threading needed to fully screw on, It does Not have enough for a freewheel to fully screw on and will only screw on about half way with the rest of the freewheel hanging over the lockring threading. This will be flexy and is bad.

um, you don't really know what you're talking about.

um, you don't really know what you're talking about.

Well if you want to put freewheels on the wrong side on the hub, I won't argue :)

I just won't go to any shop you work at

If you look at six and seven speed freewheels you'll note that they are only supported by about half their width too.

Moreover, I have seen fixed cogs strip threads designed for fixed cogs. I have also seen freewheels strip threads designed for freewheels. So the fact that threads sometimes strip isn't a very good argument.

Regarding "flex", I'm assuming you know this because you have measured it or have access to the research of someone else who did. I'm very interested in those measurements and hope you will publish them here.

Personally, I have "researched" the issue to my own satisfaction through extensive use of freewheels on fixed threads. I have never had a problem.

Neat, the Shimano freewheel I took off a wheel was only able to screw half way on to the fixed side, and while test riding it, I can tell it was flexing and it skipped under load, being it was not able to fully thread on. Maybe I'm talking about something else then you, bit that was my finding on a freewheel on a fixed side threading.

Well if you want to put freewheels on the wrong side on the hub, I won't argue :)

Unless you've actually done it and had it fail, you shouldn't be talking at all. I know plenty of people who have used freewheels on fixed hubs with zero problems.

scrod is correct.

Ok, you got it dood.

I know I do.

Watchubinsmokinmikeetow ?

why would a freewheel be more stressful to the threads compared to a fixed cog?
I've never heard of anyone stripping threads with a freewheel.

Watchubinsmokinmikeetow ?

Some bad stuff I guess :/

why would a freewheel be more stressful to the threads compared to a fixed cog?

It wouldn't be.


I've never heard of anyone stripping threads with a freewheel.

And you won't.

All hail bike king.

No one is trying to be "bike king", you're just wrong. It's okay dude, really.

why would a freewheel be more stressful to the threads compared to a fixed cog?
I've never heard of anyone stripping threads with a freewheel.

It isn't. Mike is arguing (I think) that the typical fixed gear threads don't extend far enough out to adequately support the typical SS freewheel. I can understand how someone could be concerned about it, but the reality is that it works just fine.

FWIW, I have seen several instances of stripped freewheel threads (all of them with multispeed freewheels mounted on hubs designed for them) but in all those cases there was some other issue - either a really old hub, a thread incompatibility, or incorrect installation.

That still doesn't answer the question. If the threads are adequate for the torque of a fixed cog, why are they not adequate for the torque of a freewheel?


It takes me 10-15 seconds to flip a wheel, which is consistent with the times posted by the old racers. I don't know what the world record for brake pad adjustment is, but I'm sure it takes me at least a minute or two, not counting time to fish around for the tool.

You don't need to perform a full adjustment, just align the pads so they meet the rim properly when you apply the brakes. It shouldn't take more than a few seconds.

My lady has a freewheel on fixed threading, she does fine.
Generally anytime someone says you can't do something to a bicycle, or anything else, they are wrong.

I know I do.

HAHAHAHA I love it.

I can't imagine any normal cyclist hammering that hard to mess up threads using a freewheel. Unless you mount an internal combustion engine.

You don't need to perform a full adjustment, just align the pads so they meet the rim properly when you apply the brakes. It shouldn't take more than a few seconds.

Well, I can't do it that fast. Maybe you can put up a video of you doing it so that I can see where I'm going wrong.

Well, I can't do it that fast. Maybe you can put up a video of you doing it so that I can see where I'm going wrong.

I agree entirely that (semi) horizontal dropouts are preferable for a single speed application with a rear brake. In fact, both of my single speeds are set up that way and all my track frames are fixed w/o a rear brake. Since a single speed can coast through turns, a high BB is not needed, and a road style frame works well. I certainly would not want to have to constantly readjust the rear brake pad position every time I flipped the wheel to change gearing. Also, it can take longer if the pads include toe-in adjustment, which always seems to change when the pads are readjusted.