1/8" vs. 3/32"
 

So, i realized that i'm pretty much stuck with my 3/32" chainring... i have a 1/8 chain and rear cog- i am about to gear down and i'm going to have to get a bigger cog rather than a smaller chainring. Should i just stick with 1/8, or should i go down to 3/32 while i have the chance?

go with 3/32" and get a 3/32 chain too.

Sheldon Brown says that 3/32" is actually better, something about bushings...

Most people are stuck with 3/32" chainrings. It just so happens it doesn't really matter much if you're using 3/32" rings and cogs with a 1/8" chain. Shimano BMX freewheels actually come in 3/32" and say they can be used with either chain, right on the box.

running a 1/8" chain on 3/32" drivetrain give can also give you a little more flub space with chainline. definitely ghetto, but a reasonable way to avoid issues when your chainline is only off by a few mm.

i did this for a long time with zero worries.

I'm definitely a proponent.

It depends on your cranks. If you have cranks are 130BCD, finding good, inexpensive chainrings in 3/32" will be a lot easier. If you have 144bcd, the opposite is true. Mixing widths isn't bad as long as you are using a 1/8" chain.

I am building a bike and will have a 1/8" chain ring and a 3/32" drive train. what chain size should I use?
Thanks!

1/8th it won't work otherwise

If you don't have it yet, get 3/32 chainring and run 3/32 complete.

I guess I could get a 1/8" freewheel if I want to use my matching sugino chainrings, huh?

http://sheldonbrown.com/harris/singl...tml#freewheels

I'm not sure if Shimano makes a 1/8" specific freewheel, they don't even show them on their own site.

I'm confused. Why would you recomend a 3/32 drivetrain? Does an all 3/32 drivetrain have an advantage/advantages over an all 1/8 drivetrain for a singlespeed/fixed setup?

Aren't 1/8 chain's more durable/the "proper" choice for a bike with no derailer? Maybe I was just under the impression that beefier = better for a fixed gear/singlespeed drivetrain. Am I misinformed?

I think he's suggesting that while having 1/8" all around may be betting than having 3/32 all around, 3/32 all around is probably better than the mixed bag that i would wind up with (unless i want to buy new cranks... which i don't.)

has anyone actually switched over? will i notice a difference, or will there just be a difference that i can over analyze and discuss?

either way, i would -really- like to have a quieter bike. this seems like a good step, especially considering my current 1/8 vs. 3/32 miss-match.

http://www.surlybikes.com/spew3.html

"4. 1/2x1/8" chains vs. 1/2x3/32" chains. 1/2x1/8" 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 are 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 of chains showcase their innovations and developments in quality. The rollers are better, the plates are better, the pins are stronger, and the construction method (riveting procedure) 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."

^ interesting - i suppose the bit about manufacturers choosing to invest in 3/32" chains makes sense - although there are some sweeping, citation-less statements in that post - "The rollers are better, the plates are better, the pins are stronger, and the construction method (riveting procedure) is better on all multi-speed 3/32" chains"

also, why are so many of the higher end track chainrings/cogs (campagnolo, sugino, miche, eai) often only available in 1/8" if 3/32" if superior? is it merely tradition/convention?

Thats how I run it and it works perfectly. Seems a bit quieter too but that may be psychological

I have a feeling in my chainring that it doesn't matter which size you use, since most of us are buying the cheap $6 chains anyways.

A $100 1/8" chain has to be better than a $6 3/32".

Besides, how much innovation is being done on 3/32"? It's as antiquated in terms of technology as 1/8". Have you seen how small 10 speed chains are?

The very best 1/8" chain is equivalent to the very best 3/32" chains. I am aware of only one "very best" 1/8" chain -- the Izumi V gold -- while the top 3/32" chains from the major manufacturers are all about equivalent, as far as I can tell.

A big difference is that as you step down in price in 1/8" chains, quality drops rapidly and severely, while similar price drops in 3/32" stuff result in what are still very good chains.

1/8" chains can be run on 3/32" cogs and rings without any problems whatsoever. I know this from extensive personal experience.

1/8" chains are much more sensitive to the quality of components and to chainline. Top quality 1/8" stuff set up properly can be whisper quiet. Anything less is likely to make more noise than 3/32" stuff. IOW, it's a lot easier to get a quiet 3/32" setup than 1/8".

I do not have any actual failure figures to refer to, but the top road sprinters in the world use 3/32" without apparent problem. If one is capable of sprints of more than 45 MPH then one may be justified in being concerned about the tensile strength of the chain. FWIW, 3/32" has largely supplanted 1/8" even on the track. Match sprinters still use 1/8" though I'm not completely sure why.

As for longevity, IMO cleanliness is the key with any chain. Quality 1/8" chains used on the track last for years if not decades, because the track is a very clean environment. Their lives will be much shorter on the road, especially if left wet/dirty. Same goes for 3/32" though, too. I would plan on replacing my chain every six months to a year, on a bike used on the road. This may be a good argument for not using expensive 1/8" chains.

One area where 1/8" is markedly superior is for bikes with crummy chainlines and/or flexible chainstays. 3/32" chains are designed to derail. If conditions on your bike encourage derailling, you may find yourself coasting on your 3/32" equiped bike, where a 1/8" would stay put. Albeit noisily. The solution, IMO, is to fix your damn chainline.

Condensed version: for a bike used on the road, I think 3/32" is less expensive, quieter, and much more available than 1/8", with essentially no drawbacks.

The difference is top road sprinters start from 40mph while match sprinters can start from zero. Low speed mashing means substantially more force on the chain. In all likelihood a decent 3/32" chain will hold up to either but the same cannot be said for chain rings.

A lot of the kilo riders have gone to 3/32". I've never personally seen a chainring of any width fold. Have you?

Nope but I've seen them get notched fast. Perhaps dura-ace or the like are better but mid range 3/32 don't deal with large forces well.

Ah. Good to know, thanks.

To save money on chainrings (and, apparently, chains): my 1/8" chainring is about to outlast 4 3/32" chainrings! I am happy, and pissed at the same time. Happy with my 1/8" drivetrain, and pissed with the 3/32" chainrings.