What's the *simplest* way to do this?

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RichardB

Slightly retro
Location
West Wales
I'm currently building up an old frame to have as a fixed wheel/singlespeed. The frame has an OLD of 130mm, so I bought a 27" wheel with a threaded hub and 130mm OLD (capacity up to 7 speeds), assuming I could fit a fixed sprocket or single freewheel on the hub directly. Now I have read a bit and watched a few YouTube videos I realise that I may have a significant problem with the chainline. I'm still painting the frame and acquiring the components, so I haven't been able to measure anything in situ yet. However, measuring the parts 'unassembled' leads to me to think I will have a sprocket about 8-9 mm out of line with the chainring. I'm using 3/32 chain, which should tolerate a bit of misalignment, but I am wondering what to do if the chainline is not acceptable. As I see it, I have a couple of options:

1. Spacers on the hub to throw the sprocket outwards (limited by depth of hub thread)
2. New BB with shorter spindle to bring the chainring inwards (it will be fairly close to the chainstay as it is, I think, so not much room for manoeuvre here either)
3. Adjust cones and spacers on hub to bring thread into line with chainring, then re-dish wheel
4. Buy new wheel with flip-flop hub and keep the existing one for the next project.

I'm thinking that (1) and (2) will be of limited success unless the discrepancy is small. (3) seems to be the standard solution, but I am not keen to go down this road. I don't have a trueing jig and although I have successfully built motorcycle wheels to within 1mm of true, using a home-made jig, I doubt I would find a light bicycle wheel as easy. This option would also preclude the use of the wheel later on with a sprocket set and derailleur, which I would like to keep as an option as my locality is quite hilly and it's 40 years since I rode a fixed gear for a couple of seasons. Not sure how the knees/lungs/heart will cope: I intend to give it a try, but I won't feel any shame in going back to gears if I need to. I have got a few sprocket clusters and an old derailleur that I can throw on if needed.

I'm happy to buy a new wheel with the correct hub (4) - for the modest cost it would give me the best of all worlds, but so far I have not been able to track down a proper track hub with 130mm OLD and a 27" rim at reasonable cost.

Any thoughts from someone who had been through all of this before would be welcome! The whole point of the build is to keep it light and simple, so a straightforward solution would be ideal.

Just thought - perhaps option 3a would be an answer - move the cones and axle spacers, and pay an LBS to redish the wheel. I had hoped to do all of the work myself, but perhaps that might be a sensible way out. Thoughts?
 

midlife

Guru
Lost track a bit but does your wheel have a proper track hub with a left and threaded bit for a lock ring
 

ColinJ

Puzzle game procrastinator!
I put together a DIY singlespeed bike and wasn't too fussed about the chainline at first but I soon discovered that the chain dropped frequently (say once every 5-10 km). After that I moved the sprocket over by a spacer or two so that my chainline is near enough perfect. Now the bike drops the chain less than once per 2,000 km!

The chainline after adjustment...

555127
 
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RichardB

RichardB

Slightly retro
Location
West Wales
I don't think that would work on mine. The wheel seems less dished that yours (it was sold as suitable for 5-7 speed threaded freewheels) but the threaded portion is only about 10mm deep, so anything more than a thin spacer is going to reduce the amount of thread that the freewheel has to drive the hub. There certainly isn't room for a stack of spacers like that. Are you using a multi-speed block with all but one of the sprockets removed? I have got a single speed freewheel at the moment, a fifth of the width of that.

Having said that, your chainline is nigh perfect now. ^_^
 

ColinJ

Puzzle game procrastinator!
There certainly isn't room for a stack of spacers like that. Are you using a multi-speed block with all but one of the sprockets removed? I have got a single speed freewheel at the moment, a fifth of the width of that.

Having said that, your chainline is nigh perfect now. ^_^
Yes - I didn't have much spare cash so when a friend donated the frame/fork, I put the bike together the cheapest way that I could using old wheels and parts that I had lying around. I spent about £80 all-in.

I thought that I would just use the bike for quick trips to the shops, or nipping 7 km down the A646 to visit friends in Hebden Bridge. It turned out that I really enjoy riding it and have done lots of 100 km and 100 mile rides on it (mainly away from significant climbs!) and a few 200 km rides in the past 4 years.
 

midlife

Guru
Ah, fixed not a sensible option, maybe buy the cheapest freewheel and run the chain on the cog that lines up with the chainring?
 
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RichardB

RichardB

Slightly retro
Location
West Wales
Ah, fixed not a sensible option, maybe buy the cheapest freewheel and run the chain on the cog that lines up with the chainring?

Hmm, I thought someone might say that! Looks like I have bought the wrong wheel configuration. I have a few spare 5-speed freewheels which I might try your suggestion with if I can't get the single freewheel in line. If not, I can always fit a short derailleur and run it as a 1x6 or whatever.

I have asked SJS if they can supply a proper track or flip-flop hub with 27" rim and 130 mm axle, which would solve the issue. Just waiting for their reply.

[Reasons why Richard thought a standard wheel would be OK: in the 80s I ran my Carlton Corsair on fixed for a couple of winters. I was much less technically aware in those days, but I know the hub had a simple thread on the left side. I just turned the wheel over (I think I even left the 5-speed block in place, I was so lazy) and fitted a single track sprocket with a lockring (RH thread but on Very Tight Indeed) to secure it. I was aware of the safety issue and retained the rear brake. I used the inner of the two chainwheels and never had a problem with the chain coming off in probably 1-2000 miles. I think I must have been lucky, but that's why I thought a plain threaded hub would be OK for me.]
 

12boy

Guru
Location
Casper WY USA
I can't get next to fixed anymore because of the long downhill stretches requiring RPMs that would be too fast for me. Getting a used freehub wheel is the easiest and possibly cheapest way to go...
You can switch sprockets easily to change gearing for different terrain.
You can get a perfect chainline without dishing or getting a different BB.
Going back to geared is no harder than restoring the shifters and derailleurs.
You now have 2 rear wheels. In my case swapping identical wheels with different tires makes going from studded snows (heavy and slow) to road tires easily makes things better in the winter when road conditions around here change quickly.
 
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RichardB

RichardB

Slightly retro
Location
West Wales
Why not get hold of a 36 hole freehub and swap it over for the threaded one .
Then you can run single speed as per @ColinJ .
Getting a used freehub wheel is the easiest and possibly cheapest way to go...

Good suggestions which I may well follow up, although neither any good for a fixed gear, unfortunately. I've had a reply back from SJS Cycles, hub is unsuitable, can't offer any suggestions. I'll have a think, but I may well stick with gears and just run the bike as a 1x7 or whatever and keep looking for a 130OLD x 27" wheel with a track hub. The whole idea was to be light, simple and robust, but maybe running a single or fixed in a hilly area with 66-year-old knees was not the best idea to start with.

Thanks for the input.
 
https://www.ebay.co.uk/itm/Fixed-wh...244680?hash=item2649a40ac8:g:9BUAAOSw4Plfheug
I used one of these when I first started riding fixed gear on an old Raleigh,I was dubious about it unscrewing with back pressure but it never did,It's much easier to use a proper track frame if you want to ride fixed as they have the correct spacing at 120mm,ordinary road bikes are easy enough to convert with a tensioner and a singlespeed kit,in fact I use one as my commuter bike
 
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RichardB

RichardB

Slightly retro
Location
West Wales
https://www.ebay.co.uk/itm/Fixed-wh...244680?hash=item2649a40ac8:g:9BUAAOSw4Plfheug
I used one of these when I first started riding fixed gear on an old Raleigh,I was dubious about it unscrewing with back pressure but it never did,It's much easier to use a proper track frame if you want to ride fixed as they have the correct spacing at 120mm,ordinary road bikes are easy enough to convert with a tensioner and a singlespeed kit,in fact I use one as my commuter bike

This looks like it might be the answer to my prayers. Uses existing hub. Choice of fixed or single freewheel. Looks like chainline will be at least OK if not perfect. Cheaper than any of the alternatives. I'd worry about it unscrewing as well, but we will cross that bridge when we come to it, if at all.

Have ordered one.

Thank you!
 
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