Converting geared bike to single speed

[predki]

One of my bikes is going to be single speed (F.W. Evans) I don't have any experience with converting. Will it be enough to remove spacers from the rear hub, redish the wheel, fit the single speed freewheel, change the bottom bracket and crankset? May it works without redishing? Am I right?
I want to keep my wheels if it's possible.

 

[benjy]

if its a screw on free wheel its a pain, need to redish ect but there is a screw on part that pushes the freewheel to the right place, seen them on ebay but never tryed one, if its cassete hub just need spacer/ gear kit

 

[lewisfoto]

A really good single speed is all about simplicity and efficiency, so the proper chain line is critical. All of what you mentioned above are the correct steps: shorter bottom bracket spindle, respacing and redishing the rear wheel. The other benefit of redishing is the wheel is a stronger shape and in my opinion looks better.

 

[torqueless]

Re:

This probably works best with a 120mm between dropouts.

I don't know how this works with cassette-hubs, but for threaded hubs, Basically, there's two options, (or a little bit of both options) - You either mess around with/replace the bits around the bottom bracket to get the chainring in line with the freewheel, or you mess around with/replace bits of the back wheel to get the freewheel in line with the chainring.

Personally I prefer the latter- I haven't had to change from a BB axle or cranks that accepted double chainrings in order to get a perfect chainline, but I usually end up with a slightly reverse-dished wheel with most of the spacers on the non-drive side, and if you are reverse-dishing the wheel you should, for safety's sake, really move the slightly shorter erstwhile drive-side spokes over to the non-drive-side and vice-versa, which means taking the whole wheel apart and rebuilding it.

 

[predki]

Re:

Thanks for all the responses. Redishing the wheel is not a big problem as I built it so more or less I know how to do it. Still don't have proper bottom bracket, I have Baylis Wiley No 15 that according to classiclightweights http://www.classiclightweights.co.uk/bblengths.html should be ok for single speed, but unforunately both left and right crank arm are too close to chainstays. I ordered this thingy: http://www.sjscycles.co.uk/cottered-sea ... -prod6861/ so will see maybe this will work, it's longer, until I'll find something more correct.

Frame rear dropout spacing is 120mm (it was 126mm before painting, but I 'squeezed' it to 120) the wheel is 126.
I think that redishing is better option than the freewheel spacers, maybe for chainline tuning at the end? Now it look really odd with all the empty space.

Few photos:

 

[torqueless]

Re:

When you say the crank arms are too close to the chainstays with the Baylis Wiley bracket, do you mean that the ends of the cranks actually contact the chainstays? Is there no clearance at all?

FWIW I have two bikes set up like this at the moment- One with Stronglight crank and cobbled together bracket, one with SR Royal cranks and 7400 Dura-Ace bracket. Both sets of cranks are for double chainring, and both have the single chainring on the 'outside', where the big ring usually goes. Both have a chainline about 47mm from centre. Crank and 48t chainring clearance to the chainstays is about 10mm or a bit less.
Here's a picture of my spacer/dishing situation- (and yes, the bolt-hole for the rear brake on this frame really is that far off-centre)

 

[predki]

Re:

Thanks for the photos, clever idea.. never thought it could be done this way and you can reuse all the spokes. Firstly I need to find proper bottom bracket and cotter pins as the ones I have are not good (it will be clear on the photos) or I would need to put 15mm of washers.

 

[grumpycommuter]

What are the dimensions of your Bayliss Wiley spindle? I have one but need to compare the dimesions to yours.

 

[chipper]

Check your L/H crank looks bent to be

 

[predki]

Re:

more or less like this: