Removing an el-cheapo one speed freewheel

[Dahondude]

Mate of mine got sold a bit of a lemon at a local bike shop yesterday.

Its a single speed, but built on a MTB frame so vertical dropouts. Duh!

There's a cheap one speed freewheel (20 tooth) which doesn't have the normal 4 cutouts to allow a Park Tool removal tool to unscrew it

The crankset is a MTB one (four arm, 100 mm BCD chain ring) so limited to maximum 48 tooth chainring, but currently fitted with a 42, so current gear ratio is 42/20, a paltry 2.1

We want to up the ratio significantly, so can probably accept 48 on the chain ring (otherwise looking down the barrel of replacing the entire crankset to a single-speed road crank) but need to replace the freewheel on the back with a decent Shimano 16 tooth one, thus getting a 48/16, or 3.0 ratio.

Problem is getting the current freewheel off. We've talked to a few bike shops both of who say they wont touch it as we will need to destroy the freewheel to get it off. No worries doing this, as a replacement is only $16 but how to do it? Anyone familiar with a screw on one speed freewheel that DOESNT have the four cut outs to aid removal?

[gclark8]

No probs, bring it round here, I get them off ok.

[sturmey archer]

I followed this guide using a large stilson and more force than expected...

http://www.parktool.com/blog/repair-help/freewheel-destructive-removal

[Dahondude]

Thanks! All fixed now and he even discovered the bike has an asymmetric bottom bracket so can tension the chain properly!

[hartleymartin]

Thanks! All fixed now and he even discovered the bike has an asymmetric bottom bracket so can tension the chain properly!

I think you mean eccentric... rather like most of the people here.

[brookts]

A little weld drop then use a chain whip. You could then also use it as a fixed cog if desired.