3/32" or 1/8" ??

[Christophe]

Morning All

I'm just about to replace my drivetrain and just pondering chain widths.

Is there any disinct advantage between 3/32" and 1/8" chains? Currently running 3/32" which runs well but is there any advantage to running 1/8"?

Any thoughts / advice greatly appreciated.

Cheers

Chris

[Chris N]

I like 3/32", but have never used 1/8" to compare it against.  I decided when I built my first fix 7 or 8 years ago to go with 3/32" because of price, availability of parts and perceived durability - and have stuck with it ever since to ensure interchangeability of parts between bikes.  Some more pro-3/32" opinions here:

1/8" chains vs. 3/32" chains

1/8" chains suck. Run whatever you want, but bigger isn't better here. Yeah, they're wider, but according to manufacturer-supplied data, they're not stronger and they're definitely not of better quality. Multi-speed drivetrains is where the bucks are at, and chains that work on such drivetrains are where the manufacturers showcase their innovations and developments in quality. The rollers are better, the plates are better, the pins are better, and the construction method is better on all multi-speed 3/32" chains. I guess if you grind your chainring and chain down the handrail every night at the local pub, a bigger 1/2x1/8 " chain will last longer, but most of us don't and it won't.

http://www.63xc.com/wakem/wakedriv.htm

Chain

Chains are pretty well undertood these days. See the sidebar for excellent chain primers from Sheldon Brown and Greg Goode. But I do want to shed some light on a long-running discussion. 1/8" or 3/32": which is better?

My preference is for 3/32", for the following reasons.

Wide choice of components
It was once the case that track cogs were 1/8", but these days 3/32" cogs are available in all sizes. Build a 3/32" drivetrain and you have access to the widest possible range of chainring sizes and drillings, not just the 144mm BCD stuff favoured in the track world. And, in an emergency, you can always put a 1/8" chain onto your 3/32" chainring and cog. The reverse definitely isn't true.

Better lateral flex
Since it was developed for gearies, 3/32" chain deflects better than 1/8". That might not sound important in one-gear applications but -- believe me -- it can be important if you're riding a lightweight, flexible frame at high RPM on rough terrain.

Stronger
Over the last 30 years, manufacturers have concentrated their development efforts on making the narrow chains required for geared bikes. Features like bushingless assembly, beveled sideplates, and high pin pressure are all pretty much 3/32" specific.

I run a SRAM PC-48, the most basic Sachs 8spd offering, without any problems. I reckon to replace it maybe two or three times a year. To get the most out of the chain, I clean it regularly (a Powerlink comes in handy here) but I don't spend money on it. It seems silly to spend lots of money on a part that, by design, is supposed to be replaced regularly. Keep it simple and somewhat on the cheap!

http://www.63xc.com/mattc/setup2.htm

SRAM list the 'push power' of their PC 850 chains (comparable to the PC-48 mentioned above) as 2000N (the same as all their 10 speed road chains and most of their 9 speed chanis) and the PC 1 is listed as only 800N.  However, the tensile strength of of the PC 850 and PC 1 is the same so I can only assume that the rivet/side plate assembly of the PC 1 is of a lower quality.  Proper track chain may be better, but I don't have the data to hand.

[Christophe]

Chris - Interesting stuff. Thanks very much for that. I had read about Sheldon's opininon about 3/32" but have also read elsewhere that some people think 1/8" kit wears more slowly and therefore lasts longer.

[Manotea]

I started with 3/32 and switched to 1/8 after I *broke* 3 chains in a high mileage year. This may say more about my approach to maintenance than the difference between the two standards, and it may be purely psychological but, leaving aside reduced wear rates I find 1/8 has a more positive/robust/heavy duty feel. I'm a bit heftier than Chris, sometimes considerably so. When wrangling up hills, putting every bit of torque through the transmission you can muster, you gotta trust it. Similarly, when descending I feel more secure with a 1/8 chain on board. YMMV.

[Tewdric]

I went 3/32 purely because that's what the chainset I already had was.  I'll probably go to 1/8 NJS stamped when I replace it like this:  http://www.hubjub.co.uk/njs/didzm.htm

I don't think vanilla 1/8 is worth the bother having read the above specs.

><(((('> might be along in a minute to tell us the right answer!

[Tail End Charlie]

My first fixed was 3/32 and I changed chains regularly, perhaps every 2500 miles, or twice a year.

My current one is 1/8 and I haven't changed the chain in over a year and it's still within limits. I would much rather use the 1/8.

I'm surprised one of the links talks about using a chain designed for gears as I think chains designed for gears must be less strong as they need to be able to allow deflections in them. Apart from very early on, I always used the 3/32 designed for hub gears (so no deflection needed).

[zigzag]

i used the 3/32 some time ago and 1/8 now. there is a difference - 1/8 feels "nice and right". maybe due to solid, thick and stiff chainring. 3/32 is fine as well, but for fixed/ss i'd use 1/8, based on my own experience (i haven't broken any chains yet (jinx)).

[giropaul]

The reason why trackies (except maybe the odd pursuiter) almost always use 1/8 is that most 3/32 chains are made to derail easily (for gear changing) whereas 1/8 chains are made to stay in a straight line.

Therefore, the received wisdom is that it's much less likely that a 1/8 chain will come off at speed.

[Chris N]

In over 30,000 miles of riding fixed I've never derailed or snapped a 3/32" chain.

[Pickled Onion]

The theory is that 3/32" chains last longer, something to do with the bushings or whatnot, but I've kept records for a few years and can say that on average my 1/8" wippermans @ £9 a pop last over twice as far as the PC 48s @ £7 ea I was using before.

Anyway, whether or not the chain lasts longer is debatable, the simple fact is that the sprocket and chainring have more metal on and will last longer in 1/8 than 3/32, and they both cost more than chains. The only downside is the extra weight.

[Crumbling Nick]

In over 30,000 miles of riding fixed I've never derailed or snapped a 3/32" chain.

I derailed one, benignly, about 40 000 miles ago. Improved chainline & a paranoid approach to chain tension have avoided a recurrence thus far...

[rogerzilla]

I use 1/8" .

Pros: can buy full-bushing chains which are less likely to jump even when slack.  Can use 1/8" ring and sprocket which are much longer-lasting.  Can use traditional 3-piece master link, although some 3/32" chains have Powerlink-type connectors now (I've yet to find a reusable one for a real 3/32" chain, as opposed to an 8-speed chain).

Cons: heavier, bushingless 3/32" chains *may* allow lubricant to penetrate more easily.

There is no consistent advantage of one or the other width of chain in tensile strength.  The SRAM PC-1 does have an iffy reputation for breaking and I don't use it anymore - I use cheap KMC singlespeed chains or the Wippermann "antirust" BMX chain, which is dull-galvanised and looks a bit better than other chains after a winter's commuting.

I smell a bit of BS in the 63xc snippet, since "bevelled side plates" are like tits on a fish in a fixie application.

[border-rider]

I use both, but the winter bike gets 1/8 for durability of sprockets so by osmosis the rest of the fleet usually ends up with mostly 1/8.

There is a certain charm to a nice nickel-plated 1/8 chain though

[bobb]

1/8" looks cooler. That's all you need to know. All information above is irrelevant

[Ian H]

1/8" looks cooler. That's all you need to know. All information above is irrelevant

Despite that I use 1/8th.

[rogerzilla]

1/8" looks cooler. That's all you need to know. All information above is irrelevant

Despite that I use 1/8th.

ITYM "because of that I use 1/8th".

[Ian H]

1/8" looks cooler. That's all you need to know. All information above is irrelevant

Despite that I use 1/8th.

ITYM "because of that I use 1/8th".

Oh no I don't.

If you saw my fixed, with its ancient powder-coated frame, random accessories, mudguards, proper brakes (plural), you'd realise it ain't cool.

[itsbruce]

On bikes that I've converted to fixed, I ride 3/32.  Seems more appropriate, somehow.

[steveh]

I'm pondering how to set the length of the new chain on my now double singlespeed bike.
18t one side, 17 the other.
According to the oracle that is the Sheldon Brown site you should START with the axle in the middle of the track ends, split and add the joining link, and when tensioned end up in the same place.
Pardon?
That makes no sense to me, especially with two different sprocket sizes.
As the frame (Revolution Track) has rear-facing track ends my plan was to start with the axle at the front end, set with the 17t sprocket that side (42t ring), measure, split, join, then get tension right.
That then means if I do move to 18t there's enough chain there to cope.
Am I mad, or does this make some sense?
Cheers
Steve

[LittleWheelsandBig]

If you are at the front of the dropouts with a 17t, how will it fit with an 18t? Fit an 18t cog near the front of the dropouts and end up where it will for a 17t (about 1/4" further back).

[Rev Will]

The other way round, as LittleWheelsandBig said. You might want to get hold of a half link to make sure you can get the 18t as far forward as possible.

[steveh]

Knew I wasn't thinking straight 
Thanks
Steve