Singlespeed & Fixed Gear - Two-Speed

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View Full Version : Two-Speed


smurfy
11-24-03, 11:17 AM
I'm not sure if this is the correct forum for this topic but I wasn't sure where else to put it, so here goes! I'm not sure if anybody ever posted about this before.

A new "twist" on the single speed craze is the two-speed transmission, where a conventional double crank and front derailler is used, but the rear gear is a single cog.

This setup is a little more flexible than a SS for commuting in a hilly area and for club rides and light touring. It would also probably be ideal for MTBing. You would still have the advantage of a dishless rear wheel (and SS simplicity) with maybe one more, perhaps low, gear to get over a tough hill. This would be an ideal setup for a frame with vertical dropouts so a Surly Singlator (or equivelent) could be used. I've done this to my early '80s Peugeot road bike and it works great!

My local shop specializes in single-speed and fixed gear and they are doing these conversions.

www.gaansari.com


OneTinSloth
11-24-03, 12:09 PM
i asked surly about this type of conversion a while ago, and they said the singlator didn't have enough range to take up the slack for more than a 4 tooth difference in chainrings, and even then it would be a lot for it to handle. they suggested that i modify an old derailuer or something...

i never got around to it...

the other way to do it would be to get an old three speed hub and cancel out the lowest gear i think, and you get a two speed fixed hub. i'm not exactly sure how it's done, but i've heard it works...i think sheldon brown mentioned it or something...

legalize_it
11-24-03, 12:17 PM
call me crazy, but i prefer riding my SINGLEspeed MTB, bc its a SINGLEspeed, not a 2 speed. it wouldnt be as rewarding to make it up a hill bc i switched to my wussy granny gear. plus having a singleator or any other chain tensioning bolt on device sucks, once youve experienced horiz dropouts. ive done both.

BUT, on the other hand-- that is precisely the reason the Paul Components Melvin chain tensionser has 2 pulleys. so you can run 2 chainrings. having 2 chainrings on only one tension pulley will lead to chain derailling over rough terrain. the melvin is more like a rear derailluer, it has one pulley closer to the rear freewheel to keep the chain always lined up w/ the freewheel, and the second pulley to allow the chain to be slightly angled for the offset chainrings. it also allows a longer chain, so you can have a wide range for your chainrings.

SO, theres lots of other people doing the same thing...dont feel bad riding a 2spd singlespeed :D ;) :D


slopvehicle
11-24-03, 12:19 PM
I've seen a couple of people do the two speed thing around town. Doesn't this sorta defeat the purpose? It'd be easier to just have two bikes: a SS/fixed road frame for commuting and a MTB frame for off road.

schwinnbikelove
11-24-03, 12:25 PM
Aw man, I thought I had a unique idea! But seriously though, it's good to know that that is being done and that it works that great. Do you please please have any pics of that Peugeot?

That would be just for single speed, right?

smurfy
11-24-03, 02:44 PM
I don't have any pics of my Peugeot two-speed (yet)...sorry! It's a road bike so I don't really know how a two-speed mtn bike does off road.

Anyway, I'm actually not using a Singlator but a late '80s Campy C-Record rear derailler somebody gave me and an old Dura-Ace ft. changer and a Shimano stem shifter with the right shifter taken off. They're much lighter than the low-end Simplex stuff that was on it. I wasn't aware that the Singlator only had a four-tooth spread.

I already have a fixed -gear and I'm building a SS bike so having a two-speed is just more variety for me!

shecky
11-24-03, 03:29 PM
Eventually, this train of thought evolves back to full front and rear derailers.

However, the point is well taken. I personally would rather have five well selected gears than 24+ mostly redundant gears.

For a two speed, there are several routes to go. Dual (or triple) chainrings should suffice. But a tensioner is necessary. The cheapest and easiest tensioner solution may be a old derailer. Which means that it might be more sensible to implement the gearing at the rear hub rather than the chainrings (fewer parts). Two or three speeds could probably be hacked together easily with a freehub. Probably a bit more difficult with a freewheel. I think i saw a two cog freewheel in a pic from this years Interbike. And I think Suntour used to make a two cog freewheel/derailer marketed to BMX racers.

Then there are internal gear hubs. Sturmey Archer 3 speeds are pretty common. And fairly durable if you're acquainted with the quirks. Sheldon Brown has a speculative article about converting the AW model to a two speed fixed gear. I think I recall finding a web site of someone who did it successfully. And there's one or two people who convert old Bendix kickback hubs to two speed fixed gear.

auk
11-24-03, 05:53 PM
Then there is the rare and coveted Sturmey fixed three speed hubs. About $350+ on ebay. Saw a real old SA two-speed fixed hub a couple of weeks ago on ebay. Same price.

Damn cool stuff, but also extremely heavy.

Dave



Then there are internal gear hubs. Sturmey Archer 3 speeds are pretty common. And fairly durable if you're acquainted with the quirks. Sheldon Brown has a speculative article about converting the AW model to a two speed fixed gear. I think I recall finding a web site of someone who did it successfully. And there's one or two people who convert old Bendix kickback hubs to two speed fixed gear.

shecky
11-24-03, 06:33 PM
I'd forgotten about those S/A fixed hubs. I've never actually seen one. And at those prices, I've lost all interest.

I think I kinda misspoke about the modded fixed Bendix kickback hub. After reading about it here: http://www.thebikesmith.com/special.htm I think it may be the two-speed non kickback hub.

Here's some info on the S/A conversion:
http://www.users.globalnet.co.uk/~hadland/fairbrothersa.htm

dirty tiger
11-24-03, 08:55 PM
My Dad and I used to talk about building a bike like that but never got around to it.

I reckon 70% of the people who own MTB's never change out of the rear cog simply changing from the first and seconf chainrings.

I always chuckle when I see people riding 24speed full-sup' MTB in the bike lane.

They are buying into the whole "extreme sports" crapola.

A simple three-speed would suit them better, but they are too dorky.

slopvehicle
11-25-03, 12:31 AM
I always chuckle when I see people riding 24speed full-sup' MTB in the bike lane.

They are buying into the whole "extreme sports" crapola.

A simple three-speed would suit them better, but they are too dorky.

Worse still are the folks riding cheapo freeride style bikes around. I figure the went shopping for a "mountain bike" for getting around campus, and found these overbuilt Treks, a year old and going for $300.

That said, it's nice having suspension in town. I'm usually going over enough curbs to get some use out of it...

exchef
11-25-03, 09:24 AM
Eventually, this train of thought evolves back to full front and rear derailers.

However, the point is well taken. I personally would rather have five well selected gears than 24+ mostly redundant gears.

Indeed. Not evryone's as tough as us. ;) Much as I love my fixie, I can see its limits, like I imagine if I ever move back to Oregon I'll want another gear or two, not to mention touring.



For a two speed, there are several routes to go. Dual (or triple) chainrings should suffice. But a tensioner is necessary. The cheapest and easiest tensioner solution may be a old derailer. Which means that it might be more sensible to implement the gearing at the rear hub rather than the chainrings (fewer parts). Two or three speeds could probably be hacked together easily with a freehub. Probably a bit more difficult with a freewheel. I think i saw a two cog freewheel in a pic from this years Interbike. And I think Suntour used to make a two cog freewheel/derailer marketed to BMX racers.


Keith Bontrager has a pretty good and typically cynical/funny screed on this.

bontrager.com/keith/rants.asp?id=8

There are an awful lot of ways to hack this. There must be three different hacked two speeds outside the physics building here.

Keep pedlin'

alexs
11-25-03, 10:35 AM
Keith Bontrager has a pretty good and typically cynical/funny screed on this.

bontrager.com/keith/rants.asp?id=8


Long live the Jihad!

VC-161803
11-25-03, 11:03 AM
Before I converted to fixed, my friend wanted to try my road bike. She normally rides a front suspension mountain bike. She would only ride about 50 feet before getting off and saying that she was afraid of going over a bump with no suspension. This was on a smooth Chicago street, mind you.

Some people believe that they need suspension for cracks in the street. Sad.