Single Speed Help...

[Escape Goat]

On bumpy ground, with good/correct chain tension, the chain pulls off the rear cog under pressure . It's from a cassette actually, so not proper SS. Chain line is perfect.

Nothing is worn.

Anyone shed any light on this?

Thanks!

[Bearbonesnorm]

It's from a cassette actually,

Could be that the 'cog' is actually turning slightly on the splines. I'd get a proper SS cog and try that (not a crap pressed one but something with a nice wide base such as Surly)

[belugabob]

It's from a cassette actually,

Could be that the 'cog' is actually turning slightly on the splines. I'd get a proper SS cog and try that (not a crap pressed one but something with a nice wide base such as Surly)

^this

[sean_iow]

As they've both said, it's probably the cog twisting. I see you were asking for spacers in the classifieds as you are using plastic ones? Which wont be helping. Have you got a ss lockring or are you using one off a cassette? The ss one has a wider flange to seat on the spacers. The best solution is just to buy a kit, something like this

https://www.bikemonger.co.uk/bikemonger ... -219-p.asp

And use a proper wide base cog, I use the Surly ones.

https://www.bikemonger.co.uk/surly-cass ... -191-p.asp

Pricey but top quality and don't damage your freewheel. I've got a brand new Halo 15t one but it needs an 1/8 chain, but if you are running a chain that wide and want a cog that small let me know and I'll do you a good deal

[mfezela]

Are you using a chain tensioner? Do you have 'full' chain wrap on the cog/sprocket? Ideally the chain should engage with at least half the teeth on the sprocket.
This pic (which I grabbed at random) shows the wrong way. Less than 30% of teeth engaged!

Screenshot_20200525-124225_1.jpg

(48.05 KiB) Downloaded 914 times

[Bearbonesnorm]

These are worth a punt Allen, just as long as you want 21t

https://www.planetx.co.uk/i/q/SKOOSSGA/ ... d-sprocket

[voodoo_simon]

I’ve never Correctly tensioned a SS, I’ve always put it on tight and never had a chain jump like that.

I’ve tried using a cassette once to find the right SS gear for my fat bike but gave up on that idea after a day or so (the cassette) as it jumped off frequently.

As Stu says, stick with a proper SS cog

[Escape Goat]

Brilliant. I know the ins and out when there's more than one gear. But single is new to me.


I've managed to get a wide one sorted out from my post in classifieds, really happy now.

Thanks chaps, when this is installed with non plastic bb spacers I'll let you know how I get on.

Thanks all

[GregMay]

Having had it happen when cranking up a hill many years ago - you don't want it slipping when it's under a lot of power.

Crotch + stem interface is not ideal.

Wide SS cog, preferably steel, metal spacers - perfect chainline.

Welcome to the SS club, it's simple and painful at the same time.

[Alpinum]

Interesting.
I would've guessed the obvious (slack chain, bad chainline) as I've been there myself. Especially with the chainline, when I thought it was okay but needing a second adjustment.

Also frame flex, not so obvious and rather unlikely.

But I learned something new regarding running ssp on a regular cassette. For me the only reason for a wide cog up 'till now was only down to it not chewing into the freehub body. Well, now I know better. So thanks also from my side.

As Greg wrote; welcome to the party. A lovely way to engange the riding a little bit more.
I learned quite a bit when I started ssp'ing. Stuff I can also put to good use when riding geared.

[fatbikephil]

What frame you using for that EG?
Velosolo are a good source of sproks - same as Surly but a bit cheaper.
Next question - what gear ratio?!

[Pirahna]

Just to add, cassette sprockets are designed to let the chain fall off, if they weren't then you wouldn't be able to shift. A single cog from a cassette is narrow where it fits on the hub, the Surly ones recommended above are more than twice the width at the hub, this reduces the damage a narrow cog does to the hub splines and also stops the cog distorting. Lastly, Surly cogs aren't cheap so be sure you know what size you need, they also like 9 speed chains.

[jay91]

I've being using the halo fat foot ss cogs for about 4 years never had issue with them cheaper than the surly ones


https://www.sjscycles.co.uk/cassettes/1 ... -sprocket/

[Escape Goat]

What frame you using for that EG?
Velosolo are a good source of sproks - same as Surly but a bit cheaper.
Next question - what gear ratio?!

So as its flat around here I used 40 x 17.great for 90% local. May change to 36 as I've got hold of a 16 wide ...

[fatbikephil]

Thats a big gear - I use 36/18 on the g***** bike and 32/21 on the two 29+'s

[FLV]

Its not a big gear, its a MASSIVE gear

32:20 for me.

[ScotRoutes]

Currently 32:18 here. It's my first ever attempt at SS so I was wanting to play it safe. I reckon 32:16 would be fine as long as I select my routes carefully, and only once I've restored some level of fitness.

(this is all on 26" wheels)

[Scud]

It's not that bigger gear if you're somewhere flat-ish, i live in Breckland, so the part of Norfolk where it is actually rolling not flat, and run 42/15 on gravel bike with 45c tyres and 46 (oval)/15 on road bike with 28c tyres.

I find it's actually more difficult singlespeeding somewhere flattish as you're constantly pedalling and as it's flat-ish you need a gear you can get up the off road slopes on but that you don't just simply spin like a loon on the flat tarmac sections.

[Escape Goat]

Its not a big gear, its a MASSIVE gear

32:20 for me.

If it's flat no reason why not :) I would never dare take this to the lakes though.

I will have to change to 36 soon to fit an oval on there, so 36 x 16 it will be. For now.

[Bearbonesnorm]

find it's actually more difficult singlespeeding somewhere flattish as you're constantly pedalling and as it's flat-ish you need a gear you can get up the off road slopes on but that you don't just simply spin like a loon on the flat tarmac sections.

Very true, you never get a break.