BobbyG

I haven't ridden a fixie, but as I was riding home last night I was on a long, gradual uphill section and I found myself wondering what a fixed gear bike would be like on such a section. Then as I passed the 7-11 Olympic Velodrome in Memorial Park, (here in Colorado Springs) I was spurred on again to consider fixed gear set-ups.

As a bike-commuter in a hilly city, I don't see many fixed-gear commuters (but I do see them).

But is there a system that allows you to switch between fixed-gear riding and freewheeling? I don't mean a dual-hub system where one needs to stop and reverse the rear wheel. I mean a system with a mechanical switch that could be engaged or disengaged on the fly.

My first thought was a hub with a cable or chain like on an internal gear-hub, but on the non-drive side.

I suppose the danger of a fixed-gear bike with variable ratios, would be downshifting into a lower gear and having your legs immediately accelerated into a hyper-speed cadence. That would be tough on hips and knees.

I think what I would like to see is a system that allows one to lock the rear hub on the fly, but would automatically switch to free-wheel when downshifting more than a couple gear steps, or shifting the front gears, or braking.

I realize a manually operated switch would allow a rider to engage/disengage at will, but flying down a hill in top gear and then accidentally downshifting would be disasterous in a fixed gear set-up, so the automatic switching would be nice. An electro-mechanical system would allow the system to be "smart" and use some logic for more flexibility, but a mechanical system should be possible also.

Does anybody have any thoughts on such a system as to feasability, practicality, or how it would be to use?

Lazyass

No.

thumpism 

Actually, there used to be a BMX product that was a switchable freewheel that could be made fixed but it was manual. There were two set screws on opposite sides of the device that could be turned inward to un-free the freewheel. Perhaps ACS made it, or it could have been done by one of the pros like R.L. Osborn. Getting something like this to operate remotely so you could switch while riding would be a challenge but there might be other (perhaps internally gears) rear hubs that can do this.

Here you go. Turns out I was right on both; it was a joint venture.

https://bmxmuseum.com/forsale/21147

wphamilton

https://www.amazon.com/Sturmey-Arche.../dp/B0042R51MY

The knocks in it, apparently, are price, weight, and "feels like a very slack chain"

fietsbob

Sturmey Archer S3X uses a splined cog for fixed, and the hub driver is also threaded for a freewheel ..

but you must choose in the shop, assembling it one way or the other.. it does have 3 speeds inside..

there is some gear lash in fixed mode, its not locked solid.

I recall a hub prototype, there was a long screw you tightened with many turns to lock it, I don't think it went past prototype.

So what remains is a flip flop hub .. there was the Quick beam idea.. you had a double crank and so as you took the wheel out,

& flipped the hub over, the gear could be a tooth more or less on both ends, +1-1, to keep the chain length the same.



....

79pmooney

I have also always been under the impression that it was not designed for use by trained athletes and that they would probably kill it. Granted this was from conversations I heard 40 years ago when a buddy of my shop's mechanic used to come over after hours and talk bikes. The hubs may well have changed since then. (You might have heard of my mechanic's buddy, local guru/eccemtric Sheldon Brown.) Oh, and this conjecture that the Sturmey-Archer was not up to serious use by athletes was made years before anyone dreamed of skidding as a routine stopping practice. (With sewps? $$!!)

Ben

79pmooney

I think there is a new product or bike that has a switchable free to fix setup. The OP might try googling for it. I donno if it is anyway applicable to existing bikes.

Ben

TimothyH

The Affix hub.
The article is from 2010 and I don't know if the company is still in business or if the hubs are still produced.


-Tim-

wipekitty

I've had similar thoughts myself.

I seriously considered the IGH variable fixed gear setup, but concluded that if I was going to change gears anyway, it was already defeating the purpose of the fixed gear exercise.

The idea of a setup that can be changed from fixed to free while on the bike is intriguing. That said, I can see two problems:

(1) Logistically, it's unclear that a mechanical setup would work. My understanding of an IGH and planetary gearing is that it must be either fixed or free - not both. I can't imagine a derailleur working well with a fixed cog, even if one could conceivably create a gear cluster that combines a fixed cog with a freewheel and (an) additional gear(s). [Perhaps an actual bike mechanic can correct me on this.]

(2) This setup would appeal to an extremely small market. The purists presumably want to keep a pure fixed gear (along with actual or perceived training benefits). The people who ride fixed because it's cool are generally not riding large enough hills to have problems finding a gear that simultaneously allows climbing but prevents spinning out. That leaves yahoos (like me) who really enjoy fixed gear road cycling, but sometimes, would rather coast a long descent.

BobbyG

Okay, so from a technical side, it's too complicated and expensive for such a small potential customer base. I guess I need to go try a fixie to see if it's even something I'd enjoy...

But am I correct in thinking that a fixie carries more "momentum" than a free-wheel bike and would make things like long gradual rises seem like less work? (even though from a strict physics standpoint I assume it isn't)

wipekitty

Oh boy - there was a very long thread about the "momentum" issue a while back, and I don't remember what the consensus was. In my experience, fixed seems to provide more momentum on rollers because one is always pedaling, but makes no real difference on a longer climb.

I highly recommend trying fixed - it's fun! I've come to the conclusion that fixed is the most fun on rolling hills and flats, whereas a single speed freewheel is more fun for long descents (and equal to fixed for climbing). I also enjoyed fixed gear riding when I used to play in downtown Denver traffic. Regardless of actual benefits, fixed will definitely keep you honest on any kind of terrain.

Trakhak

The consensus at the bottom of that long thread/rabbit hole was that there is no advantage related to momentum with fixed-gear bikes: if you're not expending energy propelling the bike forward, either you're expending energy keeping up with the pedals or you're slowing the bike by letting the pedals drag your feet through the pedaling circle (exactly like a freewheeling bike, except for the last part).

I sincerely hope there's no revival of that discussion. It became extremely tedious to rebut the same arguments after the first 40 posts or so.

On the other hand, someone recently posted a brilliant summary:

Fixed gear:

Pro: no coasting
Con: no coasting

Freewheel:

Pro: coasting
Con: coasting

79pmooney

There's no magic to fix gears. No hidden benefits (at least from a physics standpoint). But they are 1) a blast for some of us, 2) a way of life for some of us, 3) very efficient for staying in riding shape on limited miles or time and 4) do a really good job of smoothing out pedaling, especially if you regularly go down hills that push your comfortable RPMs.

I ride fix gears for more than half my miles. I often change gears, both at home before I leave and on the road. I insist on having near velodrome/competition level reliability, so all my riding is on 1/8" gear. All my gear changing is done with stops; loosening the hub nuts and changing cogs (and on one bike, chainrings). Not very different from what was done 100 years ago. (At 64 yo, and 100k fix gear miles, neither I nor my knees have to prove I can still get up 10+% grades on the 42-17. And going down very long descents is much more fun in gears like 42-12 or 42-13.)

Part of the challenge of riding real hills on fix gears can be the decision to stop and change gears or not. A cost/benefit analysis. Stopping is lost time that may well pay off in spades hours later on a long ride. (It also allows me to do rides I simply could not do without the gear options. The hillier Cycle Oregon rides for example.)

Now, if more of us rode fix gear and more of us changed gears, maybe, just maybe, we could become mainstream enough that a creative mind would figure some of these options out (fix-free while riding, really good fixed hubs, etc.) We'd all win.

Ben

fietsbob

the Sram Torpedo one was linked to via that wired magazine thing..

guess hipsters writing computer code is a big sales sector for fixies..

BobbyG

(With tongue in cheek) I'm not trained, and not much of an athlete, I'm a cyclist mostly by virtue of saddle time. I do consider myself a serious commuter though...

Thank you for the synopsis and the brief pros and cons.

I didn't think to look it up as it was a spur of the moment thought. I had looked up my original question and found no discussions, and only a few things on the interwebs.

My curiosity has been satisfied.

Thanks for your responses.

MikeyMK

The last time i rode a fixie, i was about seven years old. So i have little experience of them. But i do have a lot of experience cycling, and i would not consider one for a moment - the inability to hold the inside pedal up in hard cornering renders it unthinkable for me.

elmore leonard

Fixies are really exercise bikes for people wanting a good 30 minute work out. Popular with younger people looking for good exercise going back and forth to work. I don't think they are a substitute for hours of road riding in hilly cities or country roads unless you are in tip top physical shape. I live in a river delta, which is flat land, and at 77 I still enjoy my fixie ride. Nice work out for the legs even when you are braking. I bought a new critical fixie for Xmas. I also have a mountain bike for longer rides.

TimothyH

I ride a 48-16 (79 inch) fixed gear on the road in hilly North Georgia all the time and have done group rides up to 60 miles with 3000 ft climbing.


No. It neither seems like less work nor is it actually less work. You just pedal harder. That's all.


Pedal strike is the least of your worries.

Taking a smooth line, learning to read the crown on the road and knowing when to slow down are skills which become ingrained. In group rides it sometimes means hanging back a little so you are not bunched up in a pack but it really becomes second nature and isn't a concern. You will become a smoother, more predictable and safer rider for it.

Smaller pedals such as Speedplay or Shimano SPD help. I struck a pedal once in my life and it was a slight scrape while riding extremely aggressively. The large platform pedals came off that day and SPD's went on.

It really isn't a problem. Lean your bike over and see what it takes to scrape a pedal. It is an insane angle.


-Tim-

BobbyG

Yeah, that could be a deal breaker for me as well.

MikeyMK

I don't ride on roads. I ride on a combined pedestrian/cycleway system in a town built from scratch to be this way. Our roads are isolated. We're talking the kind of turns you could do in your garage. Junctions around underpasses, around posts, off kerbs, around pedestrians and dogs on/off their lead - you often have one line to take and so it's the pedal that needs adapting.

Striking a pedal is common, it's enough of a skill developing intuitive pedal positioning at a fraction notice, and often i won't bother if i think it'll clear. This has backfired occasionally, and i have pedals with the resulting scars. This happens more on the e-bikes because the pedals communicate to the computer, and pausing even for a second can cut the motor.

So i'm experienced in trying to pedal freely and corner, and in my case it's a very problematic exercise.

ThermionicScott 

This idea comes up every so often, and it's certainly mechanically possible, but I think liability keeps anyone from actually putting it out there.

Like you said, a system that could suddenly switch from freewheel to fixed would be jarring, and you'd need a way to make sure it could never switch modes by accident. In a recent thread, a member suggested a clutched system where the fixed-gear mode came in gradually while you held a lever for a certain amount of time, and I could see that working.

79pmooney

That does depend a lot on the bike and cranks as well as the pedals. My Peugeot UO-8 with sewups, 168 cranks and Leotard platform pedals hit all the time. My left pedal spent about half its life w/o a dustcap because scrapes spun it off (and tightened the right dustcap). A later Peugeot with 170s wasn't much better. I won't even consider going fixed on my Raleigh Competition.

Ben

Retro Grouch 

BMX free-coaster maybe? The freestyle flatland guys used to take the brake shoes out of a coaster brake hub so they could coast backward.

The guys using flip flop hubs tend to like an easier hill climb gear on the freewheel side because they can coast down the hills. Too easy of a fixed gear means you have to spin a gazillion RPM downhill.

TimothyH

You are free to think whatever you want but it is very arrogant for those with no experience to tell those who have significant experience how it works and how it should be done.

If you lean enough to strike a pedal on the turn pictured then you are riding way too fast, out of control. Riding fast and leaning enough to strike a pedal in the turn pictured is reckless. High speed, off camber turns is where pedal strike becomes a greater risk.

I say this as someone with significant experience riding fixed gear bikes on the road and not for your benefit but for the benefit of others who might be reading. Pedal strike is not a reason to shy away from fixed gear.



-Tim-

Dan Burkhart 

Or just get your feet as far away from the pedals as you can.