ok…this is a long explaination, but I need some help.

did the obvious thing, converted to singlespeed because I had some spare singlepeed bits and I needed the shifters for another bike (first mistake).

on one kit – 16t and I kept my lx front chainrings, set up the chainline things were looking fine.

when trying bike out BANG! I assumed my freewheel had slipped – it was probably time to change the pawls (dt swiss onyx hub) – been there before – ordered the parts ~£6 worth and rebuilt.

great – it worked – commuted for a couple of days, but found that 16t was too much – ordered 13t cog. Chain a bit slacker but not slack enough to remove links to used a tensioner. BANG!!! oh dear…should have replaced both the pawls – not just the one that looked a little worn…

replaced the whole freewheel and pawls and retainer ~£35….BANG!!!!

oh dear – possibly not the freewheel then…put singlespeed kit on crossrides from other bike…BANG!!!!BANG!!!!SNAP!!!…

chain snapped.

ok…so please please tell me what I’m doing wrong and how I can fix it!!!!

Chain tensioner pushing down, decreasing contact with sprocket?

Try pushing up instead.

Edit: And you changed from a 16t to 13t and didn’t shorten the chain???

Sounds like too much chain/ not enough tension

well yeah…it wasn’t quite two links, and those fancy 1/2 link things weren’t for the narrow chain that I was using…thought that a tensioner would do the trick.

I assume then, that I’m correct in thinking it is chain slip?

If you don’t get the tension right, the chain can slip under high loads and go ‘bang’.

*sits here with slightly smug feeling and an EBB 🙂

Oh, I assume it’s a SS specific cog rather than one out of a cassette? Cassette cogs are machined to make changing easier, ie they enourage the chain to come off

I had this exact same problem on my Airborne (not a SS specific frame) I think what you’ll find is happeneing is this:

When the chain is under tension, the chain will ride along the top of the lower teeth on the rear spocket rather than settling into the grooves. It will then suddely slip back into the grooves again causing the “BANG”

Tensioner didn’t work for me in either direction. I shortened the chain to the point at which it would not fully fit into the dropouts (fits most of the way) and just tightened the QR at that point. As the chain stretches the wheel can be lowered fully into the dropouts. Once it stretches further it’s time for a new chain. 😉

Oh, same goes for ring at the front – SS specific ring is much better

How did you link the chain perks?

If you split the chain, might just be a weak link?

it was just one of the rods that popped out – the sides of the chain pulled apart.

interesting about the chain length – it isn’t ss specific bike, I literally wanted it to be hassle free for commuting while sorting the other builds….

cheers for the advice – i’ll shorten the chain, ditch the tensioner (fugly things anyway) and see how it turns out.

ta

I had the same issue and it was down to the standard front chainring. At the end of the day any mis-alignment in the chainline will in effect make the front chainring try to shift up or down. Switched to a non-pinned one (or drill out the pins) and that should help, teeth are deeper and uniform depth so it all helps over one that is basically designed to have the chain ride over it.

This used to happen to me on a 32:16 at the correct chain tension. Once I set my chain tensioner to push up it was sorted.

it wasn’t quite two links, and those fancy 1/2 link things weren’t for the narrow chain that I was using

What narrow chain is it you using? Does it fit width wise on the SS rear cog nicely? is the pitch right?

Get a £5 BMX chain and give it another go, then you can also use your half link to help tension it..

so what ratios do people use…I’m now thinking that I’m being, um, ambitious…I was using 42:16 which wasn’t quick enough, then 42:13….surely you’d never get anywhere with 32:16!!!

depends where you ride, what you ride etc.

play about with sheldon browns gear calculator
http://www.sheldonbrown.com/gears/

52:18 SS 700×28 165cranks

but you start off by saying you converted because you had some spare bits, rather than a particular riding goal – perhaps thats the problem

goal = not have to spend money on shifters/cassette for other build
solution = remove shifteres from my lovely xc turned commuter to save money, had the SS kit anyway…
result = spent more money on extra things because of what I thought was a knackered freewheel…

I now understand the complexities of singlespeeding, and there I was thinking it would be simple! I am this close (gestures thumb and forefinger) to buying shifters/cassette and going back to gears.

TENSION!!!!!
if your using a half tooth, standard LX chainring, its mad to use a sprung tensioner.
get it binned
get a fixed tensioner
a gusset bacheolor! (the dmr version of the same thing is crap)
with a fixed tensioner, it CAN’T skip.
much safer
also prevents the chain bouncing off for offroad use.

the bang is the chain skipping over a tooth.

i run 42:16 on 26″ road tyres, quick enough acclerating in traffic, and a comfortable spin on flat roads (but not super quick)

commuter?

road, offroad, mixed?
IME a vertical dropout frame will need a tensioner, possibly with a half-link as well. SS cog. SS chainring. 3/32 chain.

then you will incur further expense buying different chainrings/cogs to get it geared right for you, then you will get stronger and want to up the gearing again. then you will want to get a horizontal dropout frame or an EBB.

it wasn’t quite two links, and those fancy 1/2 link things weren’t for the narrow chain that I was using

What narrow chain is it you using? Does it fit width wise on the SS rear cog nicely? is the pitch right?

Get a £5 BMX chain and give it another go, then you can also use your half link to help tension it..

Is it a 9 speed or 8 speed chain your running?

If your chains too narrow for the SS rear cog it could be your problem.

aaahhh…head hurts…
cheers for the advice, I shall have a serious think!!!

These days I use a Rolhoff tensioner. Its a great wee little thing.

Another vote for switching to a pushing up tensioner.
I had exactly the same problem until i got a surly singleator and no problems since, even with my 16st+ pushing through the pedals.
Some frames just don’t singlespeed that well though. My current Kona Hoss is far worse than the frame it replaced (for chain length) and i’ve ended up with a 34×20 to get everything working properly and not fouling the chainstay.

Perks take heart, you really do sound like me about 2 months ago (and I did the freehub pawl thing as well….). All the advice on here is pretty much spot on, if you are lucky you can see if its skipping front or rear, i finally noticed it was front which meant the chainring for me. But as said, tension up with a fixed tensioner is the approach I ended up with (tried a few options…) It means you ensure max contact with the rear sprocket, up front what nailed it for me was, as I said before, the use of a dedicated chain ring, it took a while to get to that but if you google around on the net you see a few other people who mention the issue of chain rings with pins, im sure some people are fine with it but I wasn’t lucky. Even with the chain tight and a solid tensioner the force driving it up the chainring would still cause the slipping.

But once sorted its faff free and great fun, I think at the end of the day I went through one set of pawl replacement, a wheel swap to ensure it wasn’t anything else, two tensioners (batchellor as mentioned is good but couldn’t get it to tension my chain push up even with a half link as the travel was just too small, DMR tensioner (worked but had to fit batchellor roller due to chain width and two chain rings. But it now it runs like a dream

Are you using an On-One Doofer (the one that tensions down)?

If so then ignore anything else on this thread not related to changing your tensioner for one that tensions UP!

I had exactly your problem and tried everything to fix it, nowt worked until I tensioned UP, then problem solved…

…except after all that I decided I prefered gears.

At least I am now qualified to offer advice on the matter!

If you still have the same problem with an upwards tensioner then start listening to the wise old men with calves of steel above.

Another vote for push up tensioner.

However make sure the tensioner is not fouling the chainstay when trying to tension the chain!