crypticlineage

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.

Santaria

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 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.

TejanoTrackie 

Incorrect.

Doohickie

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.

Nagrom_

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...

Scrodzilla

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

crypticlineage

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?

Santaria

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

Scrodzilla

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

Nagrom_

as in brands? or tooth count?

Six jours

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.

crypticlineage

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.

Six jours

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.

hueyhoolihan

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.

crypticlineage

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.

TejanoTrackie 

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.

Six jours

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.

mikeetow

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.

Six jours

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?

mikeetow

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.

JohnDThompson 

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.

JohnDThompson 

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

hueyhoolihan

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.

Six jours

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?

Six jours

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.