Single speed info

Hi all.

I am thinking of building the S-Works up as a single speed and have a question or two for anyone of knowledge (with these things, not in general). I have a wheel which is built on an old threaded Ringle hub (7 sp I think) but have no cassette. What is the best way for me to single speed it (by best also read cheapest...!)? I will be using quite a big ring on front (50 teeth) so what's recomended as rear sprocket size for that? Also what other ancilliary bits will I need? Have looked on Mr Brown's site and have a rough idea but wanted to check here first 'cos I know a few of you have SS experience. Ta much.

Apologies if you already know the following:

Does the frame have semi horizontal dropouts, if they are vertical you will need a chain tensioner (cheap route is to use an old rear mech and set the screws so the chain line is straight). If you are not using a chain tensioner move the rear wheel so that the chain has no more than 5mm of vertical play - you don't want it so taught that it binds or so slack that it unships when you go over a bump.

Cheapest way is to go with the casette as it is but be aware that if the sprockets have ramps etc. the chain may automatically try to shift! So you probably need a sprocket that you could get off an old cassette or you could use an unramped aftermarket one (it just so happens I have an 18t brand new and unused). You can space it on the freehub by using some bits of drainpipe cut so that the chainline is straight.

The general concensus is that offroad SS needs a 2:1 ratio (32:16 seems the standard) but of course you can vary from that. If I was using a 50t ring I'd use a big rear sprocket to avoid certain knee collapse!

Any chain is ok in my experience although the thicker el cheapo BMX ones are pretty good.

Can't help you with the hub problem but as to the ratio 2:1 is a good starting point.

I have used successfully a Hope screw on hub,which uses cassettes and then used a screw on single freewheel.I used a short BB,so as to bring the chainline in a bit.It did work,as I used a ratio that took up the chain tension well.You can buy a half link chain,which helps with the chain tension on normal drop outs,as only takes an inch out at a time,rather than two links and two inches.I now have a specific singlespeed bike,which uses a Hope Rear hub.This moves the flanges out further,so building a stronger wheel,than a cassette hub.It is worth buying,if you get the bug,as there aren't many single freewheels any good.There is one by Charlie the Bike monger AS? I think and the White industries.All Shimano ones last one ride only.
As for ratio,depends what you are doing with it.I use mine in a relative short sharp climb area and 2:1 ratio is just about doable.Live somewhere with large climbs and you'll need to be sensible with it.

If you decide you enjoy singlespeeding (as I do) then you might want to junk the tensioner and invest in a White Industries ENO Eric's eccentric rear hub and get it laced into a decent rim. Used in conjunction with a WI freewheel I've found them to be very good. Bit pricey I guess but worth it.

It also means that you can still ride your favourite bike with the vertical drop-outs as you can tension your chain by rotating the rear hub and then locking it off. No forking out for a s/s specific frame or frame with horizontal style drop-outs/track ends.

Don't bother trying any 'magic gears', before you know it your chain has stretched and just when you least want it it starts slipping when you're at your furthest point away from anywhere (sod's law states this I'm sure).

I use a 2.25:1 ratio (36:16), it's quite hilly nearby but not overly long hills.

You'll find that the longer you singlespeed the stronger you get, it always seems that you're kicking out about the same power and suffering the same but when you check your times you'll find them quicker.

If nothing else... enjoy!

Steve

My singlespped is an old P7 that I had new dropouts welded on - there was a problem with the resprayer so I got that for free and the frame conversion cost only £40.

Looks much neater than a tensioner for me but if you want to have a go at SS and see if it suits you then using an old mech (or even better, having a go on someone elses bike!) is probably the way to go.

Cheers for the responses. Will have a check and think about options then get back for more input!