Aluminium singlespeed cogs

Why wouldn't they work with a 10/11 chain? It's the external width (plate thickness) that's different isn't it?

Err.... dunno! Be handy if a steel cog would work.

(But I do know a 3/32" chain won't work with a 1/8" chainring - not sure if this principle holds true with narrower chains and chainrings?).

I think you're right the Surly ones work with up to 9 speed chains. I don't think aluminium would necessarily wear out straight away, especially if its narrow/wide so there is a decent amount of material.

I used to run singlespeed and keep the outer chain links on the same teeth which also helps with chain wear (or allows the chain to wear more before it's a problem), I think a narrow/wide cog would do similar. Probably haven't explained that well but Sheldon explains it here https://www.sheldonbrown.com/chain-life.html .

I used to run singlespeed and keep the outer chain links on the same teeth which also helps with chain wear (or allows the chain to wear more before it’s a problem)

Thanks, that does make sense. I used to pick ratios to achieve the opposite on my fixed gear to maximise the number of skid patches on the tyre.

On the same note, I was wondering if you have a NW cog frong and rear, whether you'd have to fiddle with chain length to make sure the right part of the link is meshing at each end. I guess so.

It's only the side plates that get thinner between 10/11/12 speeds, proper single speed chains and low-count cassette chains are much wider between the plates, 1/8th chain looks like something that could be used as a traction engine spare part!

Narrow wide on a single speed is completely pointless. No way the chain is jumping off unless you've got it way too slack and a terrible chain line.

I tried the Absolute Black and destroyed it in one dry 24hr race. Not recommended

Surly say they work with 9sp but I've struggled, get an 8sp chain and they're great.

Gusset ones work well, but if it's weight and longevity you are looking for, and have the £££, go for a Boone, absolutely brilliant

On the same note, I was wondering if you have a NW cog frong and rear, whether you’d have to fiddle with chain length to make sure the right part of the link is meshing at each end. I guess so.

I'm trying to visualise this and I can't quite make sense of it in my head, I know what you mean though. I think you could just rotate the freehub or chainring to get the wide tooth into the outer plates of the chain?

I used to follow Sheldon Browns advice above and ground down one tooth on the chainring and sprocket so I could identify it as where the outer plate goes, so similar to NW chainring and cog in that the chain goes in the same place each time, I never struggled to set the chain tension.

On the same note, I was wondering if you have a NW cog frong and rear, whether you’d have to fiddle with chain length to make sure the right part of the link is meshing at each end. I guess so.

No difference to non-narrow-wide.  Your chain has to go inner-outer-inner-outer in a loop or it wouldn't join up.  Once the chain is on both sprockets correctly, the teeth just take the next link coming their way, which will also be correct.  Then set chain tension as you would normally.

I tried the Absolute Black and destroyed it in one dry 24hr race. Not recommended

Surly say they work with 9sp but I’ve struggled, get an 8sp chain and they’re great.

Gusset ones work well, but if it’s weight and longevity you are looking for, and have the £££, go for a Boone, absolutely brilliant

This is the feedback I wanted, and confirms my suspicions about the alu cogs - thanks @andrewh.

I don't have Boone money (or Surly tbh) so will probably try Gusset or Halo and put up with a 9 or 8 spd chain.

why "put up"?  What's the downside if you're not trying to shift gears with it?  I use KMX X8 on my SSs

aluminium ss cogs can be fine, stuff from shanna at Endless Bike Co, have lasted 1000km's as have wolftooth cogs.  But if you use SRAM PC1 chains on you'll mangle them in no time at all.

8-10 speed chains not a problem.

Absolute black anything, are made of cheese, they may have got better, but using the early chain rings and cogs resulted in them shedding teeth like Shane McGowan, even with a decent chain line.

Probably depends on the sprocket, those thin ones that come in kits might work with 10s chains?

Or the ZTTO single speed adapters sandwich a 6-bolt steel sprocket between two HG freehub profiled adapters and work really well.  But again I'm not sure if 12s chains will fit.  If you could find a source of 6-bolt sprockets compatible with 12s chains it could be an option.  Know anyone with a lathe or mill?

Chain / sprocket widths are a bit vague.  Some 8s chains sit fine on some 3/32 sprockets, others don't and the chains snap.

Narrow wide on a single speed is completely pointless. No way the chain is jumping off unless you’ve got it way too slack and a terrible chain line.

I suppose if you're intent on using aluminum sprockets then it might slow down the wear slightly by putting more metal there.

I want something with a broad base that will work with a 10 or 11 speed chain (b/c they are lighter and better and will match my front chainring)

3/32 chains fit fine over modern chainrings, I wouldn't worry about that. There was a hypothesis back in the day that running 1/8 chain on a narrow chainring would let it twist and result in it snapping or wearing quicker.  But I would assume that N/W chainrings limit that even if it was a real problem.

Weight wise, I run a 1/8 chain and 42s steel BMX chainring on my commuter. It weighs a ton.  The bike in general is fairly heavy to minimize maintenance and maximize practicality.  I know that in theory a 12s chain and alloy sprocket is ~100g lighter, but unless it was a vanity build just to weigh and never be ridden I'd not bother.  The SSOD Facebook group for a while was full of people talking about those sprockets, followed a few weeks later with people complaining that they were already worn even in dry Arizona.

All good additional thoughts, thanks. Will post pics when it's finished.

it was a vanity build just to weigh and never be ridden I’d not bother

Half of this statement is true 😀

I don’t have Boone money (or Surly tbh) so will probably try Gusset or Halo and put up with a 9 or 8 spd chain.

I did baulk slightly at the price of the Boone (more than a 10sp XTR cassette!) but it was the only suitable option I could find in 24T, and I've been very impressed with it. My smaller ones are a mixture of Surly, Gusset and On One (the On Ones were really good, if heavy, but aren't made any more) When they eventually wear I'll cough up for Boone in other sizes, but then I race SS, my SS is my good bike, my commuter is keeping it's Gusset, I can't justify Boone prices for the day to day bike.

I've just done the Puffer with a 21T Surly, the 24T Boone was on the spare bike but wasn't needed. Both of these have done many races and are still going strong, infinitely better than than the Absolute Black

.

[EDIT] Just looked at the Boone site and it has 24T sprockets at $4,044 which is bonkers, I think I paid about £150 four or five years ago. I wonder if I'm on some sort of foreign site and that's not US$?

Same as andrewh - surly, on-one (when they were available) and gusset. Also the velosolo version of the surly, but that's not available now either. Pointless going to an alu absolute black one imo when there are decent steel ones.

From what's easily available, I would go for a surly.

@Andrewh @Yak what chains are you using please?

EDIT] Just looked at the Boone site and it has 24T sprockets at $4,044 which is bonkers, I think I paid about £150 four or five years ago. I wonder if I’m on some sort of foreign site and that’s not US$?

Yeah I don't know what's going on there. I've just been on the site and a fetching rainbow anodized cog  is coming in at £132 posted (+ tax).

As above, had one of those Absolute Black cogs about 10 or 12 years ago when they first came out. Absolutely terrible lifespan. Probably talking a handful of rides if that.

Been a long time since I singlespeeded but pretty sure I was running 10/11 speed chains on a Surly cog no problem?

Sprockets are not the place to save weight. How many track bikes use aluminium? I single speed with a spaced surly sprocket on a hope freewheel with a 3/32 sram pc1 chain. I commute on a fixed 3/32 with miche sprockets and holder (fast to swap), and I track with 1/8 with Dura Ace sprockets. No mud on the track of course, but my Road bikes have little wear on the sprocket (chain ring could pass as a weapon, mind).

For chains, only internal width matters. I have, when needed, run a 3/32 sprocket with a 1/8 chain and chainring. A bit noisy but works, you can’t run the reverse. If using your favourite cassette sprocket(s) - I used to put two on the free hub for choice before a ride, use the chain appropriate for that sprocket or an sram pc-1

3/32 chain usually. Might be a 11speed one on currently because it was to hand. (old/worn Surly cog).

Hope retainer rings of various sizes, 32T is as small as will fit a Middleburn crank but the fatbike has a Hope crank and will take a direct mount 28T. Cheeper BBB 39T on the commuter.

Chains are XTR 9sp, (XT on the commuter), but I did have a problem with a Surly sprocket and that chain, XTR 8sp was fine with it.

I swap bits a about a lot, only two full-time SS bikes but others, like the fattie for the Puffer, get made into SS for specific purposes but are usually geared.

All run with an Alfine tensioner and vertical dropouts so no chain length issues to contend with.