Single Speed Conversion

[Cedric]

I'm sure that this subject has been done to death so apologies in advance.

I have an old Raleigh "Boulder" MTB lying about. It wasn't a bad bike in its day but the gears have seized and I'd like to convert it to a single speed on the cheap because I am skint. The bike has horizontal drops. Would I be able to just leave the chain in the middle chainring, change the hub using a kit and adjust the chain tension by adjusting the back wheel in the drops, without using a tensioner?

Would I need to shorten the chain and is this easy? It's only for going to the shops on BTW.

Cheers!

 

[e-rider]

if you have horizontal dropouts you can but most mtbs have vertical dropouts so you would then need a tensioner. You will need to shorten the chain - new chains can be bought for £6. most hub convestions only work for 8 or 9 speed - do you have an old 7 speed system?

 

[Cedric]

Hi! Thanks so much for responding. Yeah it does have horizontal drop outs for some reason. My cassette has seven sprockets, if that means it has seven speeds, then that's what I've got . I'd heard that you could use an eight speed conversion kit and just leave out a spacer though? Thanks a lot for your help, amy further advice would be much appreciated.

Cheers!

 

[mickle]

Put the chain on the middle ring and on the rear sprocket which gives you the straightest chain.
Shorten the chain to fit.
Pull the wheel back in the drops to set the right chain tension.
Ride to shops.

 

[Cedric]

Why didn't I think of that? Don't answer! I'd still like to change the rear cassette though. My thinking is that if I do as you say (and I might anyway), people will say, "look, here comes Ced on his broken mountain bike" and hopefully, if I bodge a conversion (okay, semi-conversion) they will say, "look, here comes Ced on his single speed conversion"......Sooooo, if anyone has any tips on converting a seven speed I'd sure be obligated.

 

[mickle]

Because people so care what your bike looks like buy the kit of sprocket and spacers. You'd be well advised to replace the old chain though.

 

[Cedric]

Thanks! I've heard that a BMX chain is best, is that right?

 

[mickle]

No need.

 

[RedBike]

The bike might have a screw-on freewheel instead of a cassette. You should be able to just remove this and screw on a bmx / single speed sprocket. However, you'll be very lucky if everything lines up correctly.

 

[Oddjob62]

However, you'll be very lucky if everything lines up correctly.

Yeah, on my ss conversion getting a perfect chainline took a lot more work than i expected.

 

[Cedric]

I think it actually might be a screw on one Redbike. I think I'll take Mickle's original advice and line up the chain on the existing hub and shorten it. It seems that the main hazard of DIY single speeds is a misaligned chain skipping off the back cog. I'm thinking that if I leave the hub on, a skipped chain will be likely to catch in the smaller cogs, might be a bit safer. Thanks for your input.

Thanks Mickle, I get the impression that I have irritated you, but I appreciate the good advice.

 

[Oddjob62]

I'm thinking that if I leave the hub on, a skipped chain will be likely to catch in the smaller cogs, might be a bit safer.

Probably not that much "safer" as your chain will then be totally slack and probably fall off anyway.

 

[RedBike]

I think it actually might be a screw on one Redbike. I think I'll take Mickle's original advice and line up the chain on the existing hub and shorten it. It seems that the main hazard of DIY single speeds is a misaligned chain skipping off the back cog. I'm thinking that if I leave the hub on, a skipped chain will be likely to catch in the smaller cogs, might be a bit safer. Thanks for your input.

You also run the risk of the chain trying to climb up onto the next sprocket.
This will probably cause the pedals to jam on a single speed bike.

 

[RedBike]

I ran a single speed bike with a chain just looped around the cassette / chainset for months. The chain would re-rail / jam every now and then but it was fine for just going back and forth to work on (2/3 miles).

The main draw back was that I was limited to whichever gear just happened to line up correctly.

I then incorrectly fitted a fixed sprocket to the hub and spent another few months nearly killing myself everytime I forgot to pedal. As I had no lockring the force would unscrew my fixed sprocket from the freehub.

 

[mickle]

Thanks Mickle, I get the impression that I have irritated you, but I appreciate the good advice.

Not at all old chap and you are very welcome.