[Closed] Single Speed help please ..

Chainline ok?. Would be my first thought.

some BMX specific sprockets (and chains) are wider than a geared chain - is it possible you have a narrower chain than the rear sprocket and it's not sitting down on the teeth properly?

Sorry.... chain line ? This is all new to me
Is this the angle / off set between the rear sprocket - to- front ring, or the state of the chain please ?

Did think that re width of sprocket -v- chain. If so, suggestions please re narrower toothed sprockets ?

is it on a freehub wheel, or does it have a screw-on sprocket?

If the former, then a Groove Armada from PX

https://www.planetx.co.uk/i/q/SKOOSSGA/on-one-groove-armada-single-speed-sprocket

if the latter - then you'd be better off getting a new BMX 1/8" chain (about a fiver)

Whatever is cheap with a wide base.

On one are fine. However an easier solution would be get a 1/8th chain that will work on either just fine.

Chainline is whether your cogs are in line with each other.

Chain correctly tensioned should waggle about +- an inch up and down in the centre of the chainstay

You can run an 1/8th chain on 3/32 sprocket/chainring but not the other way around

Chain line can be hard to judge, the flexier the rear triangle the problematic it is

First easy fix is get an 1/8 chain as that should solve it, groove armada sprockets are good for the money I you aren't confident in the one you have

Thanks all. It's a screw on free wheel sprocket, so looking like a 1/8 bmx chain tomorrow

In addition if the chain and ring are 2nd hand but the sprocket new then the chain may have stretched meaning that it doesn't mesh and therefore slips.

OP said he'd checked chain and it measures fine.

There's no way a single speed will 'slip' from a mismatched worn chain/sprocket. It'll be horribly noisy but if it's slipping then there's a meshing problem somewhere, (chain waaaay loose or the pawls on the new sprocket skipping) or the wrong gauge chain as above. That'd be pretty obvious though I'd have thought.

If you have a 1/8 freewheel and are using a 3/32 chain it would be very obvious from just looking at it as the chain won't sit on the teeth properly and it wouldn't be possible to ride it. If you have a BMX freewheel it is likely to be 1/8. You can also easily see the difference by looking at the width of the teeth on the freewheel compared to the chainring.

If that is the case then you can either get a freewheel with 3/32 teeth or a 1/8 chain. Lots of 3/32 freewheels available from £10 up to £80

I've done omething similar before by mixing up 1/8 and 3/32, IMO it's best to go for 1/8 chains as they're so strong and cheap, best to maybe buy a couple as the postage sometimes is the same price as the chain! Have fun on your new bike, riding single speed on a rigid bike is one of the most freeing and pure forms of cycling fun you can have. Did I mention it's dirt cheap as well?

A 1/8” chain won't sit properly on a 3/32” sprocket - you would see daylight between the bottom of the tooth and the chain.
A chainlike issue would be easy to spot as you would have a constant grating noise where the chain is being pulled at at angle - a single speed should be almost silent when pedaling.
A worn chainring might be the issue - have a good look at the teeth, they should be symmetrical. It the tooth is looks steeper on the front of the tooth than the back then that could be the issue. However it should be obvious if the chain is slipping on the chainring.
My money is on a faulty freewheel. If everything else is looks ok then the pawls inside the freewheel could be slipping. Replace the freewheel/sprocket

My money is on a faulty freewheel. If everything else is looks ok then the pawls inside the freewheel could be slipping. Replace the freewheel/sprocket

And if that is the case get a better freewheel if you are planning on riding much. The cheaper freewheels feel sloppy, have slow engagement and make knocking noises.
Something like a Halo Clickster is a good middle ground option with White Industries the best if you are riding thousands of miles a years.

A 1/8” chain won’t sit properly on a 3/32” sprocket – you would see daylight between the bottom of the tooth and the chain.

Eh... It will.

3/32 and 1/8 refers to the gap between plates its nothing to do with that gaps between rollers (1/2 inch i seem to recall).

If you see gaps under the chain then that chain is worn or its not a bike chain.

Edit: a 3/32 won't fit on a 1/8 i agree

@woodlikesbikes

A 1/8” chain won’t sit properly on a 3/32” sprocket – you would see daylight between the bottom of the tooth and the chain.

Both chains will be 1/2" pitch so how exactly does that work?

Of course it works, like my 3/32 sprocket which I ride to work everyday with 1/8 chain. 3/32 on to 1/8 teeth won't go.

However it should be obvious if the chain is slipping on the chainring.

A single speed chain won't skip over a chainring unless it's also incredibly slack. It makes a buzzing noise as it picks off the teeth.

Some pictures would help, and feedback from the OP what he has found would also be nice.

As above, a SS chain won't skip (assuming it's track ends, sliding dropouts, EBB or similar) unless there's inadequate chain tension (Sprung tensioner or just badly adjusted). You can run horribly worn and missmatched chains and sprockets, they're noisy and draggy, but wont slip.

My money would be on the freewheel is knackered internally. Buy a halo clickster.

I’ve done omething similar before by mixing up 1/8 and 3/32, IMO it’s best to go for 1/8 chains as they’re so strong and cheap

No stronger than 3/32. They're usually made with the same plates just shorter pins and rollers. Actually more likely to fail as they'll twist on the narrower teeth. We're into hypotheticals though, you would probably be fine for years, it's just best if it all matches when you're gurning up a steep hill.

Both chains will be 1/2″ pitch so how exactly does that work?

I presume he means looking down on the sprocket, not side on, you've got a 1/64 gap each side.

No stronger than 3/32

Agree. They are just wider and therefore heavier. Pretty bad idea if starting from scratch as you will have heavier freewheel, chainring and chain for no benefit.

I presume he means looking down on the sprocket, not side on, you’ve got a 1/64 gap each side.

Yes, of course that's possible, if by 'bottom of the tooth' he actually meant the side... 🙂

If you're looking from above which side would be the bottom and would it change if you looked from underneath instead?

I thought a 1/8 sprocket might wear more slowly than a 3/32s one, having a larger surface area and all. I prefer a bushed chain for singlespeed, and again I think these can wear more slowly than a bushingless chain. These are generally easier to find in 1/8, although recently KMC released a low cost 3/32 bushed chain, the B1 narrow.

I'm curious as to exactly how much lighter a 3/32 singlespeed drivetrain (ie with basic components, not superlight super expensive ones) typically is than a 1/8 one, maybe 25-75g?

Yes, probably around 75 - 100 grams. Not a lot I agree but why add it for no benefit as 1/8 stuff is no cheaper?

I change my chain every Spring after around 3,000 miles per year and I change chain rings and rear cogs randomly based on what gearing I want (Summer versus winter) so how long it wears and if there would be any difference is a bit of an unknown.

The chains are ~70g lighter, sprockets probably less of a difference as most decent ones are wider below the teeth anyway.

I thought a 1/8 sprocket might wear more slowly than a 3/32s one, having a larger surface area and all.

But then there's more surface area and therefore more friction, therefore the same wear? I dunno, I suspect it's marginal enough that even singlspeeders don't worry about it!

No stronger than 3/32

Depends on the chain, my Gusset Badger boat anchor 1/8 chain is this best I have had. Chain stretch/failure is a big issue for those who weigh more.

Depends on the chain, my Gusset Badger boat anchor 1/8 chain is this best I have had. Chain stretch/failure is a big issue for those who weigh more.

Chains don't generally snap though, they get pried apart so it's almost always down to either poor installation or damage when they break. And they only quote one breaking load for both sizes (because longer pins don't make them stronger).

And 1300kgf is approximately 5000W at 50rpm, or three and a half tonnes on the pedal at at a standing start.

I had this. It was a mismatch between the pitch of the teeth in the sprocket and the pitch of the chain. Can't remember which way round it was, but as soon as these two matched the problem disappeared.

Sounds like chain line to me. The front larger chain ring on your cranks being too far away from the frame causing the chain to slip off the freewheel when rotated.

Photo's or video would help to be 100% but you can measure your chain line and find out if this is the case. Even eye balling it from the rear of the bike will give you a fair indication. You want the chain to be straight and inline with the front and rear cogs, parallel and equal in distance to the centre of the frame and rear wheel.

You can get your cranks closer to the frame with bb spacers, shorter square taper spindle, using cranks with a narrower chainline, mounting your chain ring on the inside of your crank tabs (if you have them) using spacers to offset your chain ring towards the frame or any combination of the above.

If it's a road frame you will most likely have a 130mm rear axel to axel, track bikes are usually 120mm, with mtb's most likely being 135 - 142mm. Chainline on a track bike is usually around 42mm. If you measure from the centre of your front chain ring's teeth at 90 degrees, to the edge of your seat tube, then add half the width of your seat tube, you'll find out what your crank's chain line currently is.

I had this. It was a mismatch between the pitch of the teeth in the sprocket and the pitch of the chain. Can’t remember which way round it was, but as soon as these two matched the problem disappeared.

Thats not pitch.

The pitch is the same on all bike chain one half inch between pins (i think there might be an obscure 10mm pitch chain system in shimanos history?, There was definitely some one inch stuff like a hundred years ago but that was still actually a half in pitch i think just with every second tooth removed)

The only thing that changes with the 1/8 to 3/32 is the space between the inner plates.

I',? Going yo try a bushed chain though. That combined with putoline for the ultimate fixed gear all weather commuter.

Its not chainline...bad chainline may cause a noisy drivetrain but it doesn't cause slipping. It will cause SKIPPING gears on a geared bike, on a singlespeed the chain would just come off. And then the OP would be asking why his chain keeps falling off.

My money is on the drivetrain is more worn than the OP realised, easiest fix is to jut put the old worn sprocket back on and let the drivetrain wear out before replacing all of it. Singlespeeds are extremely tolerant of chain wear and I only tend to replace everything when the chain gets so noisy it starts annoying me. Last time I changed my drivetrain the chain checker would not even drop into the chain, over 12" it had stretched to 12 11/16th.

The chainplates were worn down and the pins were all grooved.

Be good to actually get a response from the OP after 2 days though wouldn't it. What is the point of asking a question, getting loads of responses but then not posting again.

Folks,
1/8 chain bought and fitted & now seems to be working fine.
Thanks so much for everyone's help - and the instant education on all things s/s and drivetrain/chain line/ free wheels/etc..
J

The only thing that changes with the 1/8 to 3/32 is the space between the inner plates.

Really, that's why there are a plethora of chain designs

Also does not explain chain stretch etc etc

Not all chains are the same, snapped side plates on 3/32 never on 1/8

snapped side plates on 3/32 never on 1/8

It actually happened to me once. Had dodgy batch of Clark's/YBN 1/8 chains. Side plates were snapping like twigs.

That really pissed me off and decide to cut that crap and by-pass all half-measures.

Went straight for the Ultimate Chain, that is Wippermann IG8.

Currently in the third frame and pushing 5th years or so?

Went straight for the Ultimate Chain, that is Wippermann IG8.

Blimey. Can we get some pictures of the traction engine that attaches to that too? 😁

😀

Really, that’s why there are a plethora of chain designs

Also does not explain chain stretch etc etc

Not all chains are the same, snapped side plates on 3/32 never on 1/8

I can only salute your pedantry!

Clearly the construction of a chain could be different however my statement clearly said the only thing that CHANGED from 1/8 to 3/32 was the plate spacing.

And then you started waffling about things i didn't say... Although for a singlespeed all chains ARE functionally the same.

My current chain is made up of all the extra bits cut of previous chains...

1/8 chain bought and fitted & now seems to be working fine.

Okay, so you had 1/8 freewheel then.

My current chain is made up of all the extra bits cut of previous chains

That is asking for trouble. I have had 2 chains snap in 20 years and 60,000 miles of fixed gear riding. Both within the last year and both chains that I had lengthened and shortened a number of times due to experimenting with gearing combinations, larger chainring/cogs etc,.

The chain I put on to replace the one that snapped I am vowing never to add any links to.

depends how you add the links. I used to run a chain with 2 powerlinks in it and then I could drop in a 4 link (2 inch) or 6 link (3 inch) between them to allow me to run a larger rear cog and stay within the adjustment of my dropouts. Never an issue

That chain above though 8o

That is asking for trouble.

How so? A new chain is a bunch of unused links. A chain made out of a bunch of unused links (assuming you’re not mixing silly things) is just a new chain.

That’s not the same thing as a chain that’s been…

lengthened and shortened a number of times

People complain 1/8th chains are heavy - that Wipperman must weigh as much as a cassette, rear mech and shifter 🙂

I take it you don't get much wear / stretch? Always wondered which bit wore most - on skinny derailleur chains, the roller bore is quite big and rides on flared part of inner link. On the Wipperman, is the roller much thicker wall and riding on the pin?

How so? A new chain is a bunch of unused links

A bunch of links joined together from the factory using the bets tools/machines rather than a person in their garage using a chain tool to force pins in and out.

570g for 96 links, most chains are 270g for 112!

Interestingly, "only" 1500kg breaking load, even the normal kmc singlespeed chains are 1200kg. But the shear size of the links must make them better able to shrug off the sort of stuff that actually breaks chains in the real world.

A bunch of links joined together from the factory using the bets tools/machines rather than a person in their garage using a chain tool to force pins in and out.

I was sort of assuming joining with Powerlinks or similar, but if not then yes. Though personally I’ve re-inserted pins many times (as in many pins, not many times for one pin😀) without any problems.

I do not appreciate aspersions on my mechanical aptitude kerley 😀

They're new pins... Mostly.

Its absolutely fine. My fixed gear has a nice one piece chain with the circlip type arrangement. If it makes you feel better.