Singlespeed chain tensions

[nickosdialled]

Hi,

Sorry if this topic has been raised before, but I was wondering what general experiences are making this work without a chain tensioner. I'm building a singlespeed bike from a 93 Hahanna/FireMountain frame but according to the calculator at:

http://eehouse.org/fixin/tutorial2.php

I can't find an exact match for any practical gear combination. Was thinking of getting a half link chain and just seeing how I get on. Is there much variance between what is considered perfect chain tension and acceptable?

Interested to hear experiences...

Thanks

 

[JamesM]

Half link chains stretch. Conventional chains wear and get longer which is known as stretch when really it isnt. Half link chains do this too but they also actually stretch because the link plates which are bent get flatened out. If you achieve perfect chain tension with a new chain it won't be long (100 miles maybe) before you chain starts to become slack (less with a half link chain). If you can achieve perfect chain tension with a slightly worn chain you may get a few hundred miles before it starts to become slack, but whatever you do it will eventually become slack. A slack chain in my opinion looks worse than a tensioner and may result in the chain coming off, especially of road. I like the bolt up (not sprung loaded) cotton wheel type tensioners myself.

 

[suburbanreuben]

Instead of using a half link chain, get a half link for use with a normal chain.
I assume your chainstay length is 16.75" ? If so, then 32;16 will work with a slightly worn chain and a half link, or 33;17 will work without a half link. WEar a chain in on a geared bike for a while, or find a mate who likes to change chains regularly.

 

[foz]

I'm always on the look out for 8 speed (3/32") chain halflinks - any idea where I can get some? I don't need a whole chain, just a few links would do!

thanks, Andy

 

[suburbanreuben]

here: http://www.tandems.co.uk/products.php?mode=search

I wouldn't worry about the chain "looking" a bit slack. If the chain line is Ok, it will stay on pretty well even when quite baggy.

 

[unkleGsif]

I'm always on the look out for 8 speed (3/32") chain halflinks - any idea where I can get some? I don't need a whole chain, just a few links would do!

thanks, Andy

http://www.ebay.co.uk/itm/3-32nd-Ha...=WDVW&rd=1&ih=008&category=56193&cmd=ViewItem

This is what I run on my '90 Cindercone.... it allows me to run a new chain, with gearing I wouldnt otherwise be able to without a tensioner (which I dont like, and cant because of a bent hanger)

G

 

[foz]

great, thanks for the link!

 

[Woz]

It depends how much you are "off" really. If it's just a fraction, say 1mm:
- Try with a slightly worn chain
- File a bit off the rear axle
- There are some variations on sprocket diameter from Gusset vs Shimano; small but noticeable.

 

[kingoffootball]

Half link chains stretch. Conventional chains wear and get longer which is known as stretch when really it isnt. Half link chains do this too but they also actually stretch because the link plates which are bent get flatened out. If you achieve perfect chain tension with a new chain it won't be long (100 miles maybe) before you chain starts to become slack (less with a half link chain). If you can achieve perfect chain tension with a slightly worn chain you may get a few hundred miles before it starts to become slack, but whatever you do it will eventually become slack. A slack chain in my opinion looks worse than a tensioner and may result in the chain coming off, especially of road. I like the bolt up (not sprung loaded) cotton wheel type tensioners myself.

I have to disagree with that slightly.

I'd agree that if you have vertical drop-outs then a chain tensioner is the easiest option, even if you do find a perfect ratio.

But I built a single-speed for my brother-in-law with a decent half-link chain (KMC) on a bike with horizontal drop-outs and he must easily have done over a thousand miles on it now (admittedly not off-road) and I check the chain every week or two and it hasn't stretched or required any adjustment yet.