Donnyten

Hello. I would like to convert a vintage bicycle from multispeed to single speed. Due to the frame having vertical drop out, i've been advised to keep the derailleur on the bicycle. Honestly I would rather do away with that component as well. I've already taken off the gear switch as well as the Cable leading to it. Where I get confused is what do I do with the multi sprocket and the plastic thing behind it? Here is a photo of it. My motivation behind this is that less parts to fail and overall simplicity of cycling.

View image: IMG 0869

cb400bill

Replace the rear wheel with a single speed wheel.

cny-bikeman

With a vertical dropout you cannot adjust the chain properly, which is critical with a single speed. It is possible to put a one speed freewheel on the existing hub, but you need to adjust the "chainline" and the vertical dropout is still a problem. As for simplicity, you can just leave in one gear or just use the rear derailleur. bikes can go for many hundreds of miles without significant adjustment or problems.

Donnyten

Couldn't I just do the one speed free wheel hub and cut the chain to the appropriate length? Am I missing something? Last resort is replacing the entire wheel

dsbrantjr

You will only be able to change the chain length in 1 inch increments (1/2 inch with a "half link") which is probably not a fine enough adjustment.

Donnyten

So it would be better to just to replace the wheel then huh?

JanMM

You could replace the derailleur with a chain tension device like a Surly Singleator. Drivetrain | Parts and Accessories | Surly Bikes

And then just put the chain on a cog of your choice.

dabac

The wheel is NOT the problem.
The DROPOUT is the problem.
With a vertical dropout, you can't slide the wheel back & forth to adjust chain tension.
And you need the correct chain tension (and a decent chainline) to keep the chain from derailing.
If you don't want to use a chain tensioner, you're down to faffing about with "magic gear", ghost sprockets, half links, filed dropouts, asymmetric BB adapters and whatnot.
Sure, you can MAKE the wheel the problem, and solve it by buying an expensive hub with an asymmetric axle.

Bike Gremlin

An offset hub could do the trick. Especially if you want to go fixed gear, not just single speed. In case of fixed gear, no derailleur (or any other chain tensioner) is advised.

caloso

Single speed wheel and chain tensioner, like the Surly one mentioned above. People do this all the time.

Hypno Toad

I made my winter MTB into a SS with an Origin8 converter kit. It has worked great for a 3 years of winter riding.

Donnyten

Thanks for the replies. Might go with the amazon kit

spdracr39

Am I hallucinating or is there a chain on both side of the back wheel **********?

Donnyten

It's a motorized bicycle by the way. Was actually trying to hide that because in some parts of the community the motorization of bicycles is not respected

IthaDan 

Don't shift. BOOM! single speed.

Real answer: either pick up a chain tensioner or set the RD with the limits or a spoke or something to hold it so it can work as a chain tensioner.

Donnyten

I just got back from the bicycle shop and one of the mechanics there says it is possible with a freewheel and some spacers if the chain doesn't lineup so I will give that a go

corrado33

You're missing the point. A vertical dropout doesn't allow you to adjust the chain tension. Therefore your chain will likely be too loose and may fall off when you're trying to pedal. Sure, you can change the length of the chain, but you can only change it in 1 inch increments.

Drew Eckhardt 

You could use a Trickstuff eccentric bottom bracket made for 24mm crank spindles in BSA shells; price 180 Euros which is about $200 plus the crank.

Retro Grouch 

The cheapest and simplest solution of to keep your current wheel, multi-speed freewheel and derailleur. Put your chain onto a single cog, preferably one near the middle of your freewheel cluster. Now find the high and low limit screws on your derailleur. Screw thos in until the derailleur arm is fixed directly below your chosen cog.

Donnyten

200 bucks is way too expensive . Might as well get another bike for that much. I'll keep posted on how a simple free wheel conversion might go.

fietsbob

On the Cheap ?
Wally*World's Thruster Fixie is only $99, put a freewheel on it's hub.

LesterOfPuppets

I think they come with a freewheel and fixed cog.

CafeVelo

Please stop killing classic bikes in the name of singlespeeds.

If if you absolutely must, then ​at least use a frame that can be set up that way.

LesterOfPuppets

That's to adjust chainline. You want the chain to follow a path parallel to the centerline of the bike, or at least close to it.



You also need to adjust chain tension. See the pulley on the engine drive side chainstay? That's a chain tensioner. You'll need one on the pedal drive chain also. The derailleur currently solves that purpose, so if you remove it you'll need another chain tensioning device, an eccentric hub or bottom bracket OR to try finding the magic ratio (trying out different tooth count freewheels and chainrings 'til you find the combo that's just right for the length of chainstays on your bike, and also one that you like for pedalling.)

LesterOfPuppets

I think the bolt-on Chinese motor kit's gonna hurt it more than SS. SS won't hurt the bike at all 'til he takes anglegrinder to those cable stops.