The Single Speed Thread

[Volatile]

Stupid noob enters room....

I'm having trouble understanding how to convert my 7 speed freehub to single speed.

Can I remove the cogs from the freehub to install my 16t cog, if so (and I'm quite sure it is so) how do I remove the old cogs? Pictures please, I'm a picture kind of guy

 

[RichJS]

Stupid noob enters room....

I'm having trouble understanding how to convert my 7 speed freehub to single speed.

Can I remove the cogs from the freehub to install my 16t cog, if so (and I'm quite sure it is so) how do I remove the old cogs? Pictures please, I'm a picture kind of guy

The cogs form a cassette (or "cluster".) On newer bikes the cassette slides onto a splined freehub, and going SS is a matter of replacing the cassette with a single splined cog and spacers either side of it. Like these: http://www.fireeye-bike.com/odds_fe_ssk.htm

You could just pull apart the cassette and use a single cog, but unramped cogs (and chainrings) work better - and are safer!

However, given that you're on 7-speed perhaps yours is old enough that the cassette screws on to the hub. Which do you have? Read this (has pictures): http://www.sheldonbrown.com/k7.html

 

[Volatile]

Been reading up, and yes, have visited Sheldon's site, subject is the one pictured left (I have already converted another bike with the one on right)

I'm guessing the cogs cannot be removed and I will need to replace the cluster with a BMX type sprocket?

 

[nexusfish]

Hi, i have a full ridgid xc single speed that i want to put some forks on for a 24hr race.the frame is designed for the low steel forks it came with, these are not height adjsted to allow for suspension to be put on later. the problem is when i put a set of regular 100mm (rock shox) 80mm (manitou) the bike becomes way too slack and i find it hard to corner comfortably and it feels like i am riding a chopper

as i am used to ridgid forks i dont need a lot of plush travel just a bit to take the sting out of the ride.
is there a way of lowering any common forks so they only have around 60mm travel or 80-100mm forks with an unusually low axel to bearing race height?

thanks

 

[Yeti575]

you need a set of rigid carbon forks, they will soften the ride...

 

[Stevob]

Been reading up, and yes, have visited Sheldon's site, subject is the one pictured left (I have already converted another bike with the one on right)

I'm guessing the cogs cannot be removed and I will need to replace the cluster with a BMX type sprocket?

No-one seems to have given you a response on what to do next.

You could replace the seven speed freewheel with a bmx freewheel, providing that the thread matches, and it should, however doing this would move the chainline too far towards the centre of the bike for a single speed. It would probably offline by 1-1.5cm compared to the front middle chainring, which could lead to problems with dropping chains.

Your best bet is to try and find a cheap second hand rear wheel which has a removable cassette. Then purchase a single speed conversion kit which includes a single speed cog, spacers for the cassette to adjust the chainline, and a tensioner of some sort.

 

[Stevob]

Hi, i have a full ridgid xc single speed that i want to put some forks on for a 24hr race.the frame is designed for the low steel forks it came with, these are not height adjsted to allow for suspension to be put on later. the problem is when i put a set of regular 100mm (rock shox) 80mm (manitou) the bike becomes way too slack and i find it hard to corner comfortably and it feels like i am riding a chopper

as i am used to ridgid forks i dont need a lot of plush travel just a bit to take the sting out of the ride.
is there a way of lowering any common forks so they only have around 60mm travel or 80-100mm forks with an unusually low axel to bearing race height?

thanks

The cheapest way to soften the ride on a rigid is to get a larger volume tyre, say 2.4 and run it at a lower pressure. What size tyre are you running with now?

But if you have the cash, get some carbon forks like Yeti575 said. You'd want some with an A to C measurement similar to what you currently have.

 

[jean5614]

I'm not sure about the front end, but running a larger tyre at the back takes some of the sting out. When I went from riding a Trance to SS full time several years ago i looked into this, especially for 24hr races. I have found a 2.3 Larsen TT has been fine and I will be switching to x mark 2.25's. I don't run low pressures because I am a fat bastard, but it still takes a bit out of the bumps.

 

[konasaurus]

post some bikes bikes bikes

 

[alchemist]

post some bikes bikes bikes

Check out some of the bikes that will be at the World Champs here

 

[EzyLee]

Here you go, wasn't going to post until complete, but this will be my first SS MTB. It is an on one inbred frame that I blasted and coloured, the rest are bits that I got pretty cheap or from my parts box.

Will post a spec list once it is complete, just waiting on some rim strips!

 

[Stevob]

Have you tried to see if that chain fits with one less link? It may be a little prone to slipping on the rear cog, as there's not much wrap happening there.

 

[CP]

Parts advice

Hey guys, just started on the road to SS-ness. I've got a Hardrock frame with vertical dropouts to use, wanting to build something sub-11kg for hoiking around some local footpaths and some mild XC riding.

I've read the last third of this thread and gained some good insights. But one thing I've noticed is that people are still using a vast array of tensioning methods. If you were starting from scratch, what's the best tensioning method (assuming I don't get a magic gear)? I want to keep a clean look and like the idea of a BB-mounted tensioner, and also love the look of the Fire Eye derailleur tensioner (and their caged cog kit). I would have thought that if you ran a caged cog on the wheel, and a bashplate up front, you could get away with a looser setup without worrying about the chain coming off. Is that a bit naive?

I plan to run my spare set of wheels but would be willing to use an eccentric hub or BB if that was a preferred method.

Last question, keeping in mind I want to keep it light, any advice on my chain/sprocket size (width)? Should I start on an 8sp chain and appropriate chainring/cog, or is a 9sp just as easy to work with? Thanks for the advice guys. This will be a slow build over a couple of months but will be sure to keep you posted.

 

[EzyLee]

Have you tried to see if that chain fits with one less link? It may be a little prone to slipping on the rear cog, as there's not much wrap happening there.

I haven't actually. Thanks for the heads up, once it has the tyres on I will make any adjustments needed.

 

[leftieant]

Hey guys, just started on the road to SS-ness. I've got a Hardrock frame with vertical dropouts to use, wanting to build something sub-11kg for hoiking around some local footpaths and some mild XC riding.

I've read the last third of this thread and gained some good insights. But one thing I've noticed is that people are still using a vast array of tensioning methods. If you were starting from scratch, what's the best tensioning method (assuming I don't get a magic gear)? I want to keep a clean look and like the idea of a BB-mounted tensioner, and also love the look of the Fire Eye derailleur tensioner (and their caged cog kit). I would have thought that if you ran a caged cog on the wheel, and a bashplate up front, you could get away with a looser setup without worrying about the chain coming off. Is that a bit naive?

I plan to run my spare set of wheels but would be willing to use an eccentric hub or BB if that was a preferred method.

Last question, keeping in mind I want to keep it light, any advice on my chain/sprocket size (width)? Should I start on an 8sp chain and appropriate chainring/cog, or is a 9sp just as easy to work with? Thanks for the advice guys. This will be a slow build over a couple of months but will be sure to keep you posted.

Pretty much it all comes down to cost. A chain tensioner is going to be a cheaper option than an EBB setup - while you can get EBBs that will thread into a normal BB shell, expect to pay $$$.

Eccentric hub might be an option, but again, $$, and it effectively precludes disc brakes as well.

Chain-wise, I think it is worth sacrificing a little weight for strength here, as you will be loading it up pretty hard. Value for money, SRAM PC-1, or a couple of other options that are probably discussed earlier in this thread.

Caged sprocket - haven't heard about them. Might give you a *tiny* bit of leeway on tension (but not much) - the risk with a loose chain is it slipping sideways and derailling, or not getting enough purchase on the gears, and slipping.

 

[CP]

Cheers for that. This is what I mean by the caged rear cog.

I think I may just go with a cheap tensioner to start with and see how I go. They're cheap enough to take the punt I guess, and then may look into eccentric things if all else fails.

 

[Stevob]

You can run an eccentric rear hub with discs. White Industries has a matching eccentric disc mount to go with their eccentric hub and would be my preferred method for converting a standard frame once you've decided single speed is for you.

A friend had a Forward Components Eccentric bottom bracket which is designed to fit a standard shell. Had very few problems with it also from memory. The amount of tension adjustment is smaller than what you'd get with the White Industries setup, but it's also much cheaper.

 

[Carlin]

Cheers for that. This is what I mean by the caged rear cog.

I once made something like that with some large cogs and an angle grinder. It worked pretty well, but if one of those is needed to keep the chain on then there is something wrong with the set-up.

A tensioner is neat and solid when properly set up. It is your best bet. (And run the chain a bit shorter than EzyLee )

 

[CP]

Chain

So from advice here, I sussed out the PC-1 Sram chain. Thing is I couldn't find any info on it really, other than the fact it weighs about 20g more than a PC-991 which I currently use on my mtb.

Can anyone shed some light? Is the pitch of it equiv to a 7 or 8 speed chain? Is there any design difference that makes it more suitable for single speed? The price is right which is good.

Oh and lastly what sprocket width do I need to use if I go for the PC-1, 2.3mm?

Cheer guys. Just ran a brief inventory and if I run some rigid forks, should be around 9.3kg build, or 10.3 with suspension forks. Not sure which way I'll go yet. Can't wait to get it built though!

 

[alchemist]

So from advice here, I sussed out the PC-1 Sram chain. Thing is I couldn't find any info on it really, other than the fact it weighs about 20g more than a PC-991 which I currently use on my mtb.

I'm a fan of just using 9 speed chains. Just means less parts to keep around at home (spare links, quick links) and if you do break a chain on a ride it's more likely some one will be carrying a spare quick-link and vice-versa. Strength-wise I doubt any here is actually breaking 9 speed chains on their single, however they may last a little longer.