Singlespeed Advice

[Dan_K]

This may be a STW question rather than here but I was hoping to avoid the usual arguments that any post on there results in....
Since converting to singlespeed, i've noticed that if I try to power up a short hill, I sometimes get a bit of slippage and a clunky noise from the front ring.
I think that there might be a slight amount of slack in the chain. Does this sound normal or is this common with all singlespeeds?
I've tried removing another link but the chain is too short and i've adjusted the chain tensioner as much as I can but it occasionally happens still. Was thinking that a half link might be the answer but I don't want to waste any more time on it if occasional slippage is normal.
If a half link is the answer, has anyone got one spare laying around? The only ones I could find online were in the states.
Long term i'll get a new frame and dedicated single speed chainset but I haven't got the cash right now so am looking for an easy fix.

[Bearbonesnorm]

It's certainly not normal Dan. Have yu got a picture of your drivetrain?

Under heavy load he top chain run will be pulled tight, in effect pulling the chain down onto the front ring. There'd need to be an awful amount of slack to counter the effect, are you running a SS specific ring?

[paul78]

Sounds more like a chainline issue than chain tension.

Try this as a reference as how to set it up ...

http://sheldonbrown.com/chainline.html

To be honest though I usually just 'eye in' my chainline as its usually very obvious if its not running straight.

If it is off then every time you are out the saddle shifting the bike and increasing load on chain then its going to want to straighten itself as best as possible hence clunky noise.

To make matters more complicated if you are not using the correct parts then that can cause issue ... a 1/8th singlespeed chain on a 3/32nd chainring has some horizontal play in it... I prefer to use 3/32nd parts throughout ... also a cnc chainring is a good idea as it will generally run truer than soemthing cheaper and pressed .. that helps getting a more uniform chain tension as it will be both rounder and flatter than a pressed ring ( sounds painful :) )

[Dan_K]

Helpfully, all the recent pics are of the non-drivetrain side so i'll take one later on and post it.
I got the kit from Charlie the Bikemonger so it came with replacement front ring, chain and rear sprocket which I bolted onto the old 3 ring chainset. Got the chain as tight as possible along with the adjuster.
It's still got the original Truvativ Power Spline BB on and Truvativ Isoflow cranks. What other possibilities are there?
It's almost like a clunk when the power goes on but it's not as if the cranks rotate out of position or anything. New BB time perhaps?

[Zippy]

My freehub is sometimes clunking on the singlespeed and I slipped about twice at strathpuffer at the weekend (although the wheel slipped more on the ice ). I'm running 1/8 throughout with a chain tensioner which is pretty solid I've found.

Chains tend to have tight and loose spots, and if you've not got either a tensioner or a way of tensioning the chain with an eccentric BB, eccentric Hub or Sliding dropouts, it might work for a while but not forever as you the chain will stretch and then be too loose whatever the case, but too tight for a half link. I learnt this the hardway and mangled a set of cranks and produced a lot of heat attempting to stretch a chain I'd forced on too tight

[johnnystorm]

Half-links at £2 each seemed a bit steep to me. I bought one of these:

http://www.amazon.co.uk/DiamondBack-Hal ... 642&sr=8-1

[Dan_K]

Here's a pic of the drivetrain. Like I said, it's as tight as I can get it:


IMAG0506 by DKNWHY, on Flickr

[Bearbonesnorm]

Any chance you can reverse the spring in the tensioner, so the chain gets pushed up rather than down* ?

*I don't actually think that's your problem though, I'd say that either your chain's too tight (maybe only in one spot) or the BB is on it's way out.

[Dan_K]

I'm not sure if the spring can be reversed.

After riding today, I think it could be the BB. I've never replaced it (2006 bike) and there is a bit of sideways play and a slight clicking noise on closer inspection.
Maybe changing to singlespeed has made the problem more pronounced. I was hoping that it would just be an easy case of ordering and fitting a new one but I have no idea what size it is or the tools to do it as my road bikes run hollowtech/SRAM bbs......

Edit: I think I've got the BB removal tool but not the crank puller. Do I need one?

[Bearbonesnorm]

These

BB ... 68mm x 113mm
http://www.chainreactioncycles.com/Mode ... elID=21496

Tool.
http://www.chainreactioncycles.com/Mode ... elID=10181

[Dan_K]

Ordered. Thanks Stu.

[Dan_K]

Put the new BB on tonight.

The old one was knackered so needed changing anyway but I still get a slip/clunk from the chain under load so it must be something else. I think I may use it as an excuse to buy a new frame

The BB I took out was 118 and the new one is 113. Fits ok and doesn't seem to have made any difference but will I die?

[Bearbonesnorm]

The BB I took out was 118 and the new one is 113. Fits ok and doesn't seem to have made any difference but will I die?

One day but it won't be caused by the new BB ... you might well find it improves your chain line. Have you tried slackening your chain off a touch?

[Dan_K]

The BB I took out was 118 and the new one is 113. Fits ok and doesn't seem to have made any difference but will I die?

One day but it won't be caused by the new BB ... you might well find it improves your chain line. Have you tried slackening your chain off a touch?

I'll try that next Stu, cheers for the advice.

[paul78]

Still sounds like a chainline issue ... if you look down the line of the chain does it travel over front ring and rear cog perfectly inline ???

I usually mount my chainring in the middle ring position to try and centre everything and it looks though yours is mounted in outer ring position.

Would be difficult to over tension the chain with a sprung tensioner... I could never get tensioners to tension the chain properly at all :(

[Bearbonesnorm]

As Paul says Dan, might be worth remounting your chainring in the middle ring position. A 113mm BB and mid mounted ring should give you a decent chain line ... does it do anything odd/make a noise when you back pedal?

[Ray Young]

I had a similar problem on a geared bike, turned out to be a knackered free hub. Of course I didn't find this out until I'd replaced the whole drive train with new stuff.

[Dan_K]

I'm off on Thurs so I'll have a proper look at the chain line in daylight and then take off the free hub if that looks ok. Thanks.