kommisar

I am considering modifying an existing fixed gear bike to add a triple crank, front derailleur and rear derailleur.. The idea is to be able to shift chain rings for some long steep hills to allow me to navigate as a fixed gear. Could this work? Is it reasonable? What gain ratios should I target for the gearing? The crank I have for this project is a 155mm 28/38/48 with rivited chain rings and the fixed gear bike is a 27“ wheel with a 170 mm crank 40 x 15 drive train.

Trakhak

Won't work. The first time you applied backpedaling force, the lower run of the chain would assume a straight line, stretching both the rear derailleur body and its cage fully forward (and very probably breaking it). Meanwhile, the upper run of the chain would go slack, drag on the bottom of the front derailleur cage, and likely run off the rear sprocket.

veganbikes

You cannot really have a geared fixed gear the whole idea of the fixed gear is it is one cog that is directly connected to the front chainring via chain (or belt potentially) that has no ability to freewheel and can only go in one direction. Potentially with some internal set ups you might be able to make gears work but generally most manufacturers either don't make a product or don't recommend their product for the task. Sturmey-Archer does make a 3 speed fixed gear hub (or at least did) but it didn't work well according to a lot of reports from people who have used it.

Your best bet is to use a dingle cog or chainring and manually shift or just flip the wheel.

Yes the madman inside of me really wants a Pinion to work because that would be awesome but I believe I did ask them at some point a few years ago and they said no but you could check again. However you would need a dedicated bike for that pinion is not just a bolt on system.

All this being said, the fun of a fixed gear or single speed is you are always in the wrong gear, not in a bad way really just you have to adapt to it.

kommisar

Thanks for that. This is why I reality check any crazy ideas, particularly when I can't find someone else who has done them in the past.

kommisar

Oh that sounds like it would accomplish the same thing. What didn't work well according to a lot of reports?

Kevinti

I built up a single speed many years ago with two chainrings and a FD. I added a single speed chain tensioner to the rear and thought I was clever. The bike was good fun within it's limitations, very light and simple.

79pmooney

Bull. Fix gear simply means the chainwheel and hub have no freewheel mechanism between them so they are locked together in whatever ratio it is set up or is selected if here is a choice. The fix gears I have brought to a half dozen Cycle Oregons with all the cogs between 12 and 24 teeth (and bringing as many as five at a time) is just as much a fix gear as what they race on the velodrome. So were the 3-speed Sturmey- Achers that have been around for decades. (You can argue that in heaven with the late Sheldon Brown. Good luck.)

Now, as veganbikes and others have said, you cannot use any form of chain tensioner with a fix gear (unless you swear to the gods above that you will be as dainty as Miss May all the time and never, ever coast even a millisecond. One coast and the devil will promptly fold your derailleur or tensioner into a twisted steel/aluminum sculpture. Probably toss it into your spokes and/ or tweak a stay or dropout. A deep scratch or two. Destroyed rear tire. And one massive heartrate spike.

The core concept to keep in mind with fix gears is that as long as you are rolling, that drivetrain never stops (except by skidding, massive force or something breaking). At usual road speeds and gear ratios, that force is greater than your legs can provide without real damage to you. This means the entire drivetrain should be strong and reliable. (Keeping it simple is a very sound principle.) Also keep everything away from that drivetrain. Loose bungies, rope, clothing, shoelaces, pumps ...) Again, remember, if something falls into it, that something or another something is breaking. No if here.

Says Ben, Mr. Fix Gear, who's done a few unplanned stops in his many miles of fixing.

79pmooney

And to the topic, multiple chainrings - yes it can be done.

The Peter Mooney of my username is currently set up as a "triple chainline" fix gear with three chainrings and three cogs on the rear wheel. It is traditional old school fix gear in that it runs the stiff 1/8" chain and chainrings and cogs. Two cogs on one side of the hub, one on the other. Slight dish in the wheel so the two are pushed inboard and the one outboard. Each cog lines up with its respective chainring.

But - no tensioner! I pick chainrings and cogs where the teeth add up to roughly the same total and the hub stays in the horizontal dropout slot with proper chain slack. Chain has near perfect chainlines in each of the three combos. If I wanted to, I could do skid stops. (Don't because my knees would fail.)

OP, if you can fit a Surley "Dingle" (a two-cog package that screws onto a standard fix gear hub just like a single fox gear cog) onto your IGH, you could mount that Dingle, put on two chainrings (using my keeping the chainring and cog tooth total roughly constant) and have two different gears. (You are limited to 3/32" chain. Many are OK with that. I ran 3/32" for decades but have never regretted the switch to 1/8". My version of the "Dingle" uses a 21 tooth cog as a base and a 17 tooth cog with its center cut out brazed by a pro to the 21. Very expensive but 1/8". Works beautifully.)

And to be able to play these games with a free-er hand, have a bike with a long dropout or track end slot. (I much prefer dropouts because they make flipping/removing wheels so much easier but if you are running both cogs on one side, that isn't an issue until you flat.) The perfect tool to carry - the Pedros Trixie, a combination of 15mm hub wrench and a really good lockring spanner. That spanner allows you to lift the chain off the cog or chainring and drop it onto its neighbor with clean hands. I sew a strap and velcro onto my toolbag so I can slip the Trixie under the bag and secure it quickly. Another trick - use the fender eye on your dropout if you have one or drill and tap a track end and thread a panhead screw in from the inside to act as a chain hanger. (Very useful for wheel flips! Faster and yet again, clean hands.)

I hope this leaves you with some ideas. Fix gears are a blast and shouldn't be limited to flat ground only or young men who still have knees.

79pmooney

They do work. That now famous Sheldon Brown had one and rode it the summer I was working in a Boston bike shop. He felt it probably wasn't a good fit for me as a bike racer at the time. I've never ridden one. Every report I hear is that they have the famous Sturmey-Archer reliability but fix gear shifts done poorly can be very hard on the internals and hard ridden fix gear S-As don't fare well. (That little issue I tried to stress in the previous post - no room for error in a fix gear.)

JohnDThompson 

Sturmey-Archer has made a number of internally geared fixed gear hubs, most recently the S3X. I believe that they're all out-of-production now. I've had an S3X three speed fixed gear hub on a bike for over ten years now, and haven't had any real problems with it. Apparently the early S3X production had some reliability issues, but they seem to have sorted it out by the time my hub was made. I use the bike as a "bad weather rider," but have put a lot of miles on it, including a couple century rides. My biggest gripe is the odd gear ratios: 1.0/0.75/0.65; I would have preferred two closely-spaced high gears and a big drop to the low gear for headwinds and uphills, like the older ASC hub: 1.0/0.9/0.75

veganbikes

I guess I should have worded it differently. I meant you cannot shift gears (aside from the SA hub I did mention which may have worked out the kinks and I would trust JohnDThompson because he rides it and knows it better than I) and have a fixed gear so it would be one cog unless you ran two chains maybe but that would be odd. You could have say a dingle cog or I guess a bunch of cogs together somehow and manually shift which I did elude to but I could have been clearer. I wrote it this morning after a little over an hours sleep because I had to get up and go somewhere and couldn't sleep the night before so I had a bit of time to kill before I left and bing bang boom let's go to BikeForums. Don't type on low sleep and apologies because I guess I am doing it again...lol

And no I don't want to argue with the late great Sheldon Brown well actually untrue I would love to argue with him because that would mean he was still alive and I got to talk to him and that would have been AWESOME! Seriously even if our conversation was something argumentative just to talk to him... The upmost respect to DowntownSheldon Brown

Ben did have a load of good advice. I remember as a kid getting a shoe lace caught on a single speed and falling on a fixed gear it could have been real bad and I am generally a pretty easy rider on my fixed gear I have front and rear brakes and don't skid but there have been plenty of times I have forgotten for a brief second that I was on a fixed gear and any chain tensioner or old derailleur would surely have caused a massive accident. Be safe out there but also ride your fixed gear more veganbikes ride your fixed gear more!

veganbikes

I will let this speak John is super knowledgeable as I stated in my last post and 79pmooney is also another good one. I think trying to shift with an IGH and a fixed gear can be pretty rough unless you are a smooth operator. I think probably some of the early issues did get worked out but I think there are probably some just inherent in the system because of what I said in the last sentence and I don't think that it is on S-A I think Shimano or Sachs or Rohloff or whomever probably would have similar issues. Maybe Enviolo as a CVT might fair better but they don't make a fixed gear hub but if they did I would love to try it, that would be a sick combo but I could be wrong I am not the real guru on IGHs around here there are quite a few folks who are really dedicated to that: GamblerGord, Dan Burkhart and probably others who I am not calling to get in to this one just pointing out their handles should you wish to look them up hence why they don't appear as a link I did not use the (at) symbol : @ before it.

IAmSam

Looks like all your multi-fixed-gear possibilities have already been been touched on here. But if I may editorialize a little bit - anecdotal evidence is anecdotal and outliers are outliers. But neither are typical. Many new fixed riders always try to come up with a multi-gear solution 'cos it would just be sooo great to have that extra gear or 2 for help. I chased the S3X white whale myself, hard. But history has shown us that outside of some aficionados no(neither?) multi-fixed hub was a big commercial success. Maybe someone with the conditions and needs and likes is a good proponent for the idea of physically changing cog/ring combos and all that it entails on a ride but that ain't for everybody - or even anybody - else. I think that despite a few that swim against the tide - @veganbikes point about one cog directly connected to 1 ring is what makes a sw8 phiksie. Better you should figure out if one-gear fixed biking fits you - otherwise just stick to a multi-gear coastie and don't try to reinvent the (fixed) wheel

That being said - there is a guy around here who has posted his stable of multi-fixies in the SS/FG pic thread who actually physically converts 2-3-4 speed SA hubs to fixed himself, if you can track him down around here. And 'cos I just can't completely let go of the dream...not too long ago I bumped into a 3-speed front gearbox/crankset that seemed like it could work with a fixed cog. But then I took my own advise about loving simple basic fixed gear bike riding. Good luck...

rustystrings61 

[QUOTE=IAmSam;22710243 But history has shown us that outside of some aficionados no(neither?) multi-fixed hub was a big commercial success.[/QUOTE]

Ain't it the truth! Even the simple Surly Dingle is now extinct, which is a drag - it's the heart of my favorite multi-surface fixed gear! Surly tells me there are none in their warehouse and they have no plans to ever produce them again. I am hoping White Industries will continue offering their Dos Eno 2-speed freewheels.


1973 Raleigh Competition, 531 with rapid-taper stays, running 42/44T chainrings with a Dingle fixed cog and a Dos Eno 2-speed freewheel, giving 70-in fixed pavement, 60-in fixed gravel, 60-in general freewheeling and 51-in light singletrack gearing

79pmooney

But - double sided fix gear hubs are around and no sign of them going away. Miche and at least one Japanese maker. (I hope. With COVID, nothing's a given.)

Yes, this means flipping the wheel and if you do very big changes in cog size and don't alter chain, getting the big cogged hub in and out of track ends could be tedious. By contrast, it is easy with long horizontal dropouts. Why no one make extra long horizontal dropout for the fix gear crowd is beyond me. Better still are extra long dropouts that turn down at the front like a vertical dropout. This allows running the tire very close to the seatstay with no need to deflate the tire to pull the wheel out. (The bike of my avatar photo has that dropout. Flipping the wheel is really easy, even when brain dead after long hard climbs.

Edit: I have that same Raleigh Competition. I'd kill myself if I ever tried to run it fixed! I've got 700c wheels in it and the BB is near scraping the ground. I do pedal strikes regularly.

Darth Lefty 

You could probably do something with the Problem Solvers 6-hole cogs which use the BCD for 6-bolt disc rotors

Senrab62 

Multi speed fixed is something that has expanded my love of and relative usefulness of my fixed gear bikes and experience.

Owner of a dingle and the S3X hub, they both have some usefulness and drawbacks.

Dingle: I personally use with a single chainring, though have been contemplating a double upfront. Currently have 17/20 which gives me 72 and 61 GI respectively. With 9 speed chain, chainline is not an issue. Not rubbing or jumping. Plan to play around with gearing come spring. Nice to ride out to local trail, change to lower gearing for gravel and hillier sections, then change back for ride home.

S3X: similar to JohnDThompson and his experience. I have 1200-1500+ miles on it at this point, and it has been trouble free for the most part. Ability to change gears with a shifter is fantastic. Although, it's by FAR my heaviest fixed gear I'm consistently faster because of ability to be in a less wrong gear more frequently. Currently at approx 91, 68.5, and 57 gear inches. When riding with roadies I use this bike because it helps reduce rubber banding effect. I can spin out on middle gearing but have the larger gearing to keep up on downhills or when hammering. I also gear down for winter and ride something like 69, 52, 43. This would also be my preferred off-road gearing or near about. And similar to Mr Thompson, I wish the gearing was closer to the ASC. Doesn't have the traditional fixed gear feel, but it's certainly a fixed gear. I paid $199 shipped from bike island for complete wheelset with shifters, etc. Absurdly heavy, but bulletproof. Would buy again without hesitation.

I still lust after, and look for ASC hubs for a future build. But I am satisfied with having multiple fixed gear experiences. Debating the practicality of fixed gear is interesting, because it's rarely practical. I'm almost always in the wrong gear anyway.



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base2 

Neither Efneo or Schlumpf recommend their multi-speed, planetary cranksets for fixed use. They are ok with coaster brakes, however.

IAmSam

That's it - Efneo. It does seem like they recommend against using it with a fixed wheel - wonder why? But thanks for the Schlumpf mention - I had forgotten all about them and I am pretty sure that at least one of their drives was rejiggered and will work with fixed. Normally I'd goggle it to make sure but I don't want to fall into a multi-fixed rabbit hole, again.

Good luck - ride safe...

veganbikes

Probably most of that stuff isn't designed for the forces going through it when I backpedal and it says nope probably most internal systems don't like it much. Even me a fairly careful fixed gear rider who doesn't skid to stop and has brakes there are instances where I find myself attempting to coast and well you can't do that fixed as we know.

There is possibility this stuff could work but probably not well and maybe not for a long period of time, they have to think about their product and liability as well. If they say yeah go for it and you do and it sucks and maybe it wasn't the products fault you will still say "x system sucked" and that is not good for business even if people won't look into further and realize it just wasn't meant for it.

2manybikes

I think they recommend coasting to shift. Not sure.

base2 

You shift with a kick of your heel to a button protruding from the bb spindle. It's impossibly hard to do unless you can coast for a second.

They do have crankarms with a plate that is mounted to the crankarms that push the button. But, I fail to see how it would be safe to do so while the drivetrain was in motion.

I actually own 2 Schlumpf speed-drives. One for a 68-73mm bottom bracket & another for a 73-83-ish bb. They are a fantastic invention. No way would a fixie be a good use for it, though. You gotta coast to shift/kick the button. It really is that simple.
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