# Conversion to single speed - some newbie questions



## oxford_guy (26 Jan 2009)

Hi - I own a 3-year old Ridgeback Neutron hybrid, which currently has an 8-speed Nexus internal hub, unfortunately the hub is completely knackered and needs replacing. I'm thinking of getting a new decent tourer bike (Hewitt or Thorn probably) for long distance rides and holidays, but would like to keep the Ridgeback as a winter commuting hack / "pub bike", so would like to get it on the road again on the cheap 

It'll cost over £120 to get a new Shimano hub gear unit (plus the cost of a wheel build), so I was thinking of replacing it with a single speed or flip flop hub, which should be cheaper and more reliable, and should be fine for my commute to work, which is pretty flat. What would be a a decent, but good value flip flop hub to get (needs to be 36 hole for my current rims)? 

Do I need one of a specific axle size for my frame? I note that some say "122mm or 120mm rear axle", some say "100mm". I'm guessing would need the larger size, but am not certain. Also, what would be a good sprocket size to start out with? 

Apart from sprockets, is there anything else I would need (spacers?)? Am only just getting my head around all this stuff, so apologies if these are stoopid questions... Thanks! :-)


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## Joe24 (26 Jan 2009)

120mm is the size of the hubs for single/fixed.
You need horiztonal dropout if you do it fixed(can do verticle but you have to find the magic gear, or a special hub)
If its single then you can have verticle dop outs with a chain tensioner(cant put a tensioner on fixed)
Its not just the sprocket at the back that makes the difference, its the front chainring aswell. So the gear size is talked about in inches.
I run 44/18 on my fixed, which is about 67/68GI.
To find out the gear inches for a gear you do number of teeth on chainring divided by the number of teeth on the sprocket. You then times that by your wheel size in inches.
So for mine it would be 44/18=2.44444
2.4444444*27(ish for 700c wheels) = 67.
About 65-68" is good to start with if you live somewhere hilly. In the low 70's if your somewhere flat.
Its all pretty simple, not got gears to worry about setting up or not working properly.
System x hubs are pretty cheap, i have one in fixed/fixed, but they do some as flip flop hubs. They arene about £25 and they are pretty good.
If your bikes dropouts are 130mm, then its abit harder. My fixed(now in peices as im getting a new frame) has dropouts at 130mm. The system x axle was too narrow. I got the fixed/fixed hubs from SJS cycles and used that rear hub(well the axle in the fixed wheel with the system x hub, just the same) and it fitted, just had to put 2 5mm spacers on.
Have a play around. If that rear hub can be put in one gear, then just put it in one gear and leave it, be just the same as a single speed


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## bonj2 (26 Jan 2009)

well you'll presumably need the wheel building up on the new hub, and therefore new spokes as they'll need to be diffrent length. i'd encourage having a go yourself, truing stands aren't dear. but if you really can't take it to a LBS.


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## oxford_guy (26 Jan 2009)

Joe24 said:


> 120mm is the size of the hubs for single/fixed.
> You need horiztonal dropout if you do it fixed(can do verticle but you have to find the magic gear, or a special hub)
> If its single then you can have verticle dop outs with a chain tensioner(cant put a tensioner on fixed)



The dropouts are horizontal, which sounds like it should make things easier



> Its not just the sprocket at the back that makes the difference, its the front chainring aswell. So the gear size is talked about in inches.
> I run 44/18 on my fixed, which is about 67/68GI.
> To find out the gear inches for a gear you do number of teeth on chainring divided by the number of teeth on the sprocket. You then times that by your wheel size in inches.
> So for mine it would be 44/18=2.44444
> ...



Okay, sounds like I need to count the teeth on the chain ring first before I can work out what size I need on the back...



> Its all pretty simple, not got gears to worry about setting up or not working properly.
> System x hubs are pretty cheap, i have one in fixed/fixed, but they do some as flip flop hubs. They arene about £25 and they are pretty good.
> If your bikes dropouts are 130mm, then its abit harder.



The Nexus 8 speed hub is 132mm OLN, so am assuming the dropouts are 135mm?



> My fixed(now in peices as im getting a new frame) has dropouts at 130mm. The system x axle was too narrow. I got the fixed/fixed hubs from SJS cycles and used that rear hub(well the axle in the fixed wheel with the system x hub, just the same) and it fitted, just had to put 2 5mm spacers on.
> Have a play around. If that rear hub can be put in one gear, then just put it in one gear and leave it, be just the same as a single speed



Unfortunately it grinds badly in *every* gear and is really hard to cycle :-(


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## skwerl (27 Jan 2009)

you can get hubs in 130 and 135mm, they're just not that common


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## oxford_guy (27 Jan 2009)

skwerl said:


> you can get hubs in 130 and 135mm, they're just not that common



"not common" often translates to "expensive"... Or is this not the case for hubs?


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## Joe24 (27 Jan 2009)

oxford_guy said:


> "not common" often translates to "expensive"... Or is this not the case for hubs?



I found they werent as cheap as what you could get a decent 120mm one for. Like i say, i got the SJS fixed/fixed one, and just put two 5mm spacers on the axle and it fitted my 130mm spaced frame fine.
There is a company(think its london fixed or something or other) that do moutainbike hubs converted to fixed, that fit the wider sizes of dropouts. Cant remember if they are expensive or not though.


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## e-rider (28 Jan 2009)

132.5 OLN hubs are designed to fit either 130mm (road) or 135mm (mtb) steel frames as you can just bend them a little to fit - first you need to find out whether yours is 130 or 135mm and get the correct size. It will probably be cheaper to buy a suitable new 'pre-built' wheel - as the cost of hub and spokes without the rim will be almost the same; without considering the wheel jig and knowledge required to build your own - although building your own wheels is great; just not the thing to do if you're looking for a cheap fix and you don't already have the equipment!

Chainline could be an issue if you intend to use your old triple chainset.

If you have a rear derailleur fixing on the frame - I'd go for the cheapest cassette type rear wheel 'off-the-peg' and a single speed conversion kit with chain tensioner - much easier to adjust chainline and cheaper to set up.


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## e-rider (28 Jan 2009)

oh yeah - if you want mtb fixed hubs - www.hubjub.co.uk sell them, but they're not cheap!


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## oxford_guy (28 Jan 2009)

tundragumski said:


> 132.5 OLN hubs are designed to fit either 130mm (road) or 135mm (mtb) steel frames



Mine's a hybrid frame, it takes a 700c wheel, so is this likely to be 130mm (road)? Where on the bike do I need to measure this?



> as you can just bend them a little to fit - first you need to find out whether yours is 130 or 135mm and get the correct size. It will probably be cheaper to buy a suitable new 'pre-built' wheel - as the cost of hub and spokes without the rim will be almost the same; without considering the wheel jig and knowledge required to build your own - although building your own wheels is great; just not the thing to do if you're looking for a cheap fix and you don't already have the equipment!
> 
> Chainline could be an issue if you intend to use your old triple chainset.
> If you have a rear derailleur fixing on the frame - I'd go for the cheapest cassette type rear wheel 'off-the-peg' and a single speed conversion kit with chain tensioner - much easier to adjust chainline and cheaper to set up.



My bike doesn't have a triple chainset or cassette, its currently a hub-geared bike (with horizontal dropouts)...


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## oxford_guy (28 Jan 2009)

Hmmm... my LBS have offered me Surly 1 x 1hub with 135mm spacings for £25 - worth it? They said its normally about £50. Think its this one:
http://www.sheldonbrown.com/harris/surly1x1.html


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## e-rider (28 Jan 2009)

If you have a single chainring and horizontal dropouts you bike is crying out to be converted to a proper single/fixed gear.

So they have offered a hub from a Surly 1x1? I thought the Surly 1x1 was sold as a frame only. Anyway, is it fixed or freewheel or both, or double fixed or double free (flipflop). Sounds good for 25 quid but it'll not be cheap to get the complete build - what's their quote for the complete build?

135mm will not be much good if your frame is 130mm - it's the distance between the rear dropouts. Most hydrids are 135mm but not all.


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## e-rider (28 Jan 2009)

How many teeth are on the chainring?


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## oxford_guy (28 Jan 2009)

tundragumski said:


> If you have a single chainring and horizontal dropouts you bike is crying out to be converted to a proper single/fixed gear.
> 
> So they have offered a hub from a Surly 1x1? I thought the Surly 1x1 was sold as a frame only.



I believe the hub is sold separately too, as have seen it on the interweb...



> Anyway, is it fixed or freewheel or both, or double fixed or double free (flipflop).



They can certainly set it up as flipflop single/fixed - which would be my preferred option



> Sounds good for 25 quid but it'll not be cheap to get the complete build - what's their quote for the complete build?



Think the labour charge would be about £25 or so, plus cost of spokes and maybe a new rim, depending on how shagged my existing one is





> 135mm will not be much good if your frame is 130mm - it's the distance between the rear dropouts. Most hydrids are 135mm but not all.



Okay, will check, but I think its likely to be 135mm, as the Nexus hub gear unit it currently has is 132mm...


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## oxford_guy (28 Jan 2009)

tundragumski said:


> How many teeth are on the chainring?



Haven't counted yet...


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## mickle (27 Feb 2009)

Just found this thread through a web search! Kewl.

I'm in the process of refurbishing our ZEM 4 seater quadricycle and in the process want to convert the front two riding positions to single speed and I need a pair of *130mm* flip flop hubs. Any ideas people?

I've found some US ones and the utterly lovely (but too dear for this application @ £70) Goldtech.


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