I normally ride with a 3/32 chain, and I like 3/32 for the light weight of the whole drive train, and because I don't have any reason to not like it.

Next spring I intend/hope to build a new fixed gear bike, possibly my last build, and the option of building a 1/8 drive train interests me.

However, as a weight weenie, the heavier 1/8 drive train would need to need to have some benefit, such as smoothness or reliability, in order to justify it.

I wouldn't go to 1/8 solely because of its traditional use on the track, but only if it offered some other benefit.

Input, please, from someone who has ridden both 3/32 and 1/8.

Thanks.

Sheldon Brown wrote that 1/8" does not offer any strength advantage over 3/32" chains. I wonder how much merit that has seeing the ubiquitous use of 1/8" chains at the tracks. On the other hand, how much of what we see at the track is just a cultural relic from the past?

it seems like a 1/8 chain would be more resistant to "stretch" (which is actually wear), due to the greater surface area of the bushings.

but my SS has always been 1/8, so i've not got anything to compare it to, sorry.

Ken,

I use both types of chains on different bikes. Personally, I would be less preoccupied about the miniscule weight differences, focus more on the other drive train parts, and just use whatever chain those parts require. The extra width of the chain has no direct benefit; however, the nicest roundest chainrings are high end 1/8" track chainrings, so for that reason alone its worth considering a 1/8" chain. My Sugino Zen chainring is more perfect than any other ring I've ever used...the chain is the exact same tension at all points during the rotation of the cranks. For that reason, its just unbelievably pleasant to ride in comparison to my 3/32" rings which have always had at least minor (sometimes major) tight and loose spots. If perfection is what you want, then you should look into good 1/8" track chainrings.

As far as chains are concerned...I've tried lots of chains, including expensive NJS chains and I always come back to the the KMC Z510HX for 1/8" and the Z610HX for 3/32".

Having read many of your past posts, Ken, I'm certain you will put way more thought into this than anyone else would ever bother, so I'm very curious to see what you come up with in the end.

Good luck!

All of my 3/32 chainrings, and cogs, have tight and loose spots.

It drives me crazy.

I keep my chain much looser than I would if I had a really circular chainring and cog.

Sometimes when I park my bike, I have the chain in a loose portion of its cycle, and the amount of slack depresses me.

Can mihlbach please comment on the significance of bushings/rollers in 1/8 chains?

Do they have a function?

Some of my reading suggests, or I infer, that 1/8 chain with bushing and rollers has greater efficiency and causes less wear and tear on the chain ring and sprocket.

An aside from Wikipedia:

"A larger sprocket will give a more efficient drive (reduces the movement angle of the links). Surprisingly, higher chain tension was found to be more efficient;..."

I have always intuited that larger chainrings and sprockets provided more efficiency than the same gear ratio in a smaller gear set, but I had not seen that confirmed in print, before now.

Also, given the above from Wikipedia, if I had truer circles at both ends, and a tighter chain, this would give me greater efficiency; perhaps enough to offset the additional weight.

Ken - The more round things are (at both ends) the better the drive will be in regard to efficiency and using he largest possible chain ring and cog combination to get your desired gearing will also maximize efficiency.

On my newest build I used an old Sugino VP crank and Sugino chain ring and was very pleased at how true the chain ring was but then again...it was a Sugino.

Chain tension, as always should be set so that the chain does not bind at any point in the crank's rotation.

That is a good point, I never really thought about the energy transfer effiencency of rounder/truer chain drive components. It's obvious you would have a smoother ride, but higher chain tension definately seems possible without binding as easy. This is something to think about....

This is a great thread. I've not followed the bike world much the last 10 years, just biked the same bike and left it at that. Now the kids are gone and I'm into this SS thing I've wanted to try since the 80's. My MTB is set up with a 16t freewheel and 42t single crankset (68 inches). The crank was from eBay, a new Shimano tandem Captian's side. It was modified by re-taping the pedal threads so it could be flipped and used as a standard single crank. I've not read up Sheldon Brown on this yet but what's the basics on 1/8" components, differences from 3/32 other than the obvious chain size? Now I'm not sure if all my parts are 1/8 or 3/32. And can someone clarify the rounder thing? I assume the larger the cog & chainring, the rounder they are, am I correct? Would my 42 and 16 be considered a good biggest round combo?

Maybe this should be a seperate thread, but you all know your stuff here! I've built and messed with bikes since the 70's, just need to come up to speed on the current stuff.!

3/32 chains don't come in white.

1/8 ftw

My bike setup produces two tight spots and two loose spots in the chain in each cycle of crank rotation.

In addition, one of the tight spots gets tighter, and its corresponding loose spot gets looser, about every three cycles of crank rotation.

This happens because of an out-of-round condition, or lack of circular perfection in the sprocket, the chainring, and the crank star.

Any thing less than a perfectly aligned frame will exaggerate the effects of all these imperfect circles, and the sum of the imperfections will add up periodically, usually in relation to the ratio between the chain ring and the sprocket.

Further, some very light chain rings will actually flex under load, thus losing even more of their roundness.

One pays premium prices for premium cranks, chain rings and sprockets for their relative roundness compared to cheaper components.

Additionally, the Sugino Zen series of chain rings have extra stiffness built into them, with little weight penalty.

https://www.businesscycles.com/tring-sug.htm

1/8" SRAM chains are $10 at performance, and that's good enough for me.

Bushings give the chain less lateral flexibility and therefore work best with a straight chainline, but, given a good chainline, I don't know what role they play in efficiency and wear rate compared to a narrower bushingless configuration. However, 1/8" inch chainrings and cogs are thicker and for that reason they will obviously wear more slowly. However, as far as I can tell, 1/8" chains wear at basically the same rate as a 3/32" chain.

There is also debate about whether or not 1/8" chains are stronger. Strength is determined by the material and thickness of the chainparts, not chain width. At any rate, this argument is mute. Even the daintiest 10-speed chains are plenty strong.

Given two identical drivetrains that differ only in width (1/8" vs. 3/32") I can't imagine that there would be a measurable difference in efficiency that is attributable solely to the width of the chain and cogs. Because track bikes lack deraileurs, ultra-round chainrings (and cogs) are critical at the highest level of competition because of the finer level of feedback and control that constant chain tension provides. The fact that the most highly refined FG drive train components happen to be 1/8" is simply an artifact of the eccentric tendency of track cyclists to stick with the traditional 1/8" drivetrain. Most 3/32" chainrings are less perfect, either because they are not intended for professional track cyclists or because they are made for geared bikes, where roundness doesn't really matter because the deraileur compensates for imperfections in chainring roundness.

You cant ride a 3/32 super toughness amirite. ; ]

I like you.

Also: Miche chain is the best. I love that chain.

There is NO benefit and EVERY advantage to go 3/32. The only vaguely possible reason you would not want to go 3/32 is the availability of 3/32 chainrings in 144bcd. Which is either shyte, or dura ace track which is $. Which is moot if you aren't planning on running 144bcd cranks.

1/8 is slower, noisier, heavier and above all completely unecessary on the road. I won't even bother debunking any of milbachs posts. I mean formulas are the same as phil woods besides the bearings right?

Even though Operator is a friend of mine....

I'd still say 1/8" for any SS bike.

Is that wiki correct? I always found it easier with it being a little more slack then tight. That’s also why I thought people who ride on the track have slack chains too.

I have ridden both 1/8 and 3/32 and I liked the 1/8 significantly more but then again the 1/8 setup was all high end parts and I guess that’s where I am going with this. There are tons of great 1/8 components. As for the chain in particular? The only thing I have heard is possibly less likely to throw a chain from flex but I have no idea if that’s true.

I don’t know if they have them in 3/32 but the 1/8 chains like the super toughness and I think a couple others have a pretty cool master link that allows to take off the chain without a chain tool but doesn’t jeopardize the integrity like some masterlinks

phil woods and formulas are not at all the same hub shell. made in different factories, with different standards, with different materials. i haven't heard of any phil hub threads stripping, have you?

operator was being sarcastic...

Operator doesn't actually ride a bike.
https://www.bikeforums.net/memberlist...rt=posts&pp=30
He's proven himself time and time again to be an annoying angst filled know-it-all who mostly sits in front of his computer holding grudges and typing out angry posts, but never providing any real substance to his arguments, which are usually misguided anyway. The only member of BF whose more worthless than operator is Pcad, but at least Pcad is entertaining

Run far away from KMC colored chains. Anyone that actually rides will tell you they are garbage.

I would really like to see some scientific proof that two chains of the same quality and materials but sized 1/8th and 3/32. From any math or science Ive ever learned 1/8th would be stronger. Im not disagreeing, I just would like to see some proof to all these "3/32 IS STRONGER AND FASTER BRO" comments.

All else being equal, chain width is irrelevant to strength. Check with the chain manufacturers. For example, KMC rates both their Z510HX (1/8") and Z610HX (3/32") chains to 1,200 kg. These two chains are identical in every way except width. Other KMC chains are rated differently because of their different materials and design, not their width. I'm no engineer, but I suspect that sideplate x-sectional area would probably be the most important factor, and these can be the same for 1/8 and 3/32.

from the KMC website..."Z510HX & Z610HX: This is a perfect chain for racing and Heavy Duty BMX use, the tensile strength is a good 1,200 Kg. It
can be used on almost every front sprocket and rear freewheel/Cog. Light but strong, this chain is a
bestseller in the BMX Freestyle world, but it is also becoming very popular in the mid-high end range
internal gear hub equipped bikes, because of it's long life and high reliability."

https://www.kmcchain.com/index.php?ln=en&fn=bu_bicycle#c

What a fascinating discussion.

Putting everything together, the issue has not to do with the dimensions of the chain, whether 3/32 or 1/8, but rather whether the chain has bushings in addition to the rollers.

The high-end 1/8 chains have bushings and rollers.

Low-end 1/8 chains and most, if not all, 3/32 chains, have rollers but not bushings.

Check out the pictures and the discussions on these following sites provided by a major industrial roller chain manufacturer:

https://chain-guide.com/basics/1-1-1-...ion-chain.html

https://chain-guide.com/basics/1-1-4-...ain-parts.html

The 1/8 chains with bushings have the advantageous qualities of greater lateral stiffness, less internal friction, greater flexibility, greater resistance to shock and external wear, and greater resistance (when properly cleaned and lubricated) to internal wear.

However, 1/8 chains with bushings pay for their advantages with significantly greater weight, complexity and cost.

The question: how do the advantages of bushings compare to the light weight and low cost of bushingless chains; and, in terms of incremental improvements in quality associated with high-end track components added on to the advantages of bushings, will a perceptive rider notice a difference in performance, smoothness, control and confidence?

A Sugino 75 crank with a 43t Zen Messenger 1/8 chain ring and a 19t Phil 1/8 cog (I like prime numbers) will give me the same gear inches (about 60) I presently ride with a 3/32 drive system.

I can't imagine a quieter nor smoother drive system than the one I presently ride, but, I'd sure like to get rid of the slack in my present system.

I feel the slack, now, and it annoys me.

In the end, how much would I pay in weight and money to get rid of the 1/2" slack in my chain?