Home Forum Bike Forum Correct Chainlength For 1×9 Setup?

Viewing 40 posts - 1 through 40 (of 83 total)
• Correct Chainlength For 1×9 Setup?
• P20
Subscriber

How do you work out how long your chain should be on a 1×9 set up? I’ve always used big ring/small sprocket and jockey wheels vertically inline for 3×9 set up, does this still apply?

A quick search on here found Park Tools answer:

SIMPLE EQUATION: L = 2 (C) + (F/4 + R/4 + 1)

L = Chain length in inches. Round the final result to closest whole inch figure.
C = Chain stay length in inches, measure to closest 1/8”. Use chart below to find decimal measurement.
F= Number of teeth on largest front chainring.
R= Number of teeth on largest rear cog.

mboy
Subscriber

Simple answer is as short as possible.

Remove as many links as you can, get that chain nice and tight. If you remove too many, add one back in.

No magic formula or anything, just as short as you can get it.

greeble
Member

Best and most trusted 1×9 chain length calculator I’ve used is –

Shift the bike into 1st.
Remove shock spring/air from shock.
Compress the suspension.
Fit the chain, add or remove links until the mech is almost at full stretch.

If its 1×9 on a hardtail then

Shift the bike into 1st.
Fit the chain, add or remove links until the mech is almost at full stretch.

job done.

been using this method for 10 years

you will find if you “guess” the chian length the chain maybe too short this will have a massive effect on suspension action. the chain may stop the bike getting full travel. leading to snapped chains or at worse ripped off mech hangers from frames. too slack and the chain will flap around all over the place

TandemJeremy
Member

large to large, not thru the mech and 2 links. If its a full susser compress the suspension to the point chaingrowth is greatest

simple and just works

greeble
Member

P20
Subscriber

Cheers i had a feeling it may be done by the big/big combination. Its on a hardtail so no suspension gubbins to worry about 😉

fatboyjon
Member

14 foot 6.

passtherizla
Member

I use the following method…

Wrap the chain round your chain ring cog (without going through rear mech. Then around the largest cog on the cassette, note where they meet add +3 for shimano chains without quick link and +2 + quick link for KMC/SRAM chains.

always worked for me.

passtherizla
Member

just out of interest why is it balls? what ‘should’ I be doing?

greeble
Member

just out of interest why is it balls? what ‘should’ I be doing?

doesn’t take into account mech length.

Dickyboy
Member

Nothing wrong with the add 2 links rule & no reason it shouldn’t work on a 1 x 9 set up just as well. Been building & fettling bikes for nearly 40 years & always worked for me.

TandemJeremy
Member

add two links is how I have done all my bikes for many years, it ensures the chain is as short as possible

Dickyboy
Member

Should be using a short cage mech on a 1 x 9 set up anyway

greeble
Member

Should be using a short cage mech on a 1 x 9 set up anyway

not all people do

TandemJeremy
Member

why does the mech length make a difference?

greeble
Member

why does the mech length make a difference?

more or less chain passing through the mech depending on the mech length. adding two links maybe too much for a short cage mech – leading to incorrect chain length
and maybe too short for a long cage mech leading to incorrect chain length

passtherizla
Member

@ Greeble, thanks for the explanation. But i thought adding in the 2 extra links accomodates the rear mech? I actually add 3 as this is what it said to do in a book I had. 3 for shimano and 2+ quick link for chains with quick link.

Cheers Dicky… I’ll stick to what i know then.

TandemJeremy
Member

don’t agree greeble – the mech length makes no odds at all – + two links works fine for a long cage and if you go short cage you would not want the chain any shorter

Dickyboy
Member

+ 2 links we know works for a long cage mech on a 3 x 9 or whatever setup, with a 1 x 9 setup the overall tooth capacity is smaller so a mtb short cage mech can be used & because of the length of the mech a shorter chain might be able to be used – I would go with +2 links, try it & if too long take another link out (easier to remove 1 than add 1 afterall)

mboy
Subscriber

TJ, you’re talking tripe again

Mech length of course makes a difference. Shorter cage mech is going to have less chain running through it…

Trying to use a formula to work out chain length isnt perfect. Just shorten it to as short as it can go, whilst still being able to get every gear. If you shorten it too much, add a link back in…

TandemJeremy
Member

Mboy – sorry I don’t see it – when in big / big the chain is almost straight along its bottom run – the short road mech and the long mtb mech I have are both the same and taking another link out would make the chain too short on the road mech despite it being much shorter mech – its still big / big + two links is the shortest chain possible

Dickyboy
Member

Edit – the plus 2 links is not a good start for 1 x 9, the formula for 3 x 9 is big to big plus 2 links is only okay because you should never actually ride big to big. Setting up a 1 x 9 in the same manner will prob result in too short a chain when riding on the largest sprocket.

greeble
Member

Edit – the plus 2 links is not a good start for 1 x 9, the formula for 3 x 9 is big to big plus 2 links is only okay because you should never actually ride big to big. Setting up a 1 x 9 in the same manner will prob result in too short a chain when riding on the largest sprocket.

Hense why this…

Best and most trusted 1×9 chain length calculator I’ve used is –

Shift the bike into 1st.
Remove shock spring/air from shock.
Compress the suspension.
Fit the chain, add or remove links until the mech is almost at full stretch.

If its 1×9 on a hardtail then

Shift the bike into 1st.
Fit the chain, add or remove links until the mech is almost at full stretch.

works best

TandemJeremy
Member

Plus 2 links does not produce too short a chain on a 1×9 – it makes one exactly the right length – 2 bikes I have set up like that

greeble
Member

Plus 2 links does not produce too short a chain on a 1×9 – it makes one exactly the right length – 2 bikes I have set up like that

keep kidding yourself

TandemJeremy
Member

greeble – I have had two bikes running 1×9 with chain setup to big / big plus two links using long cage mechs and it is perfect

Dickyboy
Member

TJ – sounds like your mech is near horizontal when in biggest sprocket which aint right in my book

TandemJeremy
Member

Yup – thats right – as short a chain as possible is best in my book. Less chain slap / less chance of the chain coming of.

soobalias
Member

i thought you were a big fan of a granny ring TJ, or is that on other bikes?

TandemJeremy
Member

The 1x9s are / were commuters. (one got nicked)

chrismac
Member

I agree with the general consensus but be careful when setting up a full suspension bike as the longest effective chain length on many bikes, including mine as I found out to my cost, is not at either end of the travel but about 1/3rd of the way through. My bike has a VPP link system so the path of the rear wheel is backwards and then up in a sort of C shape. As a result there needs to be enough slack in the chain to allow for the suspension to follow its path.

rootes1
Member

Plus 2 links does not produce too short a chain on a 1×9 – it makes one exactly the right length – 2 bikes I have set up like that

tried that on my 29er with a short cage mech and it was way to short..

P20
Subscriber

What have i started?? 😆 😆
Its an old school M952 long cage mech

mboy
Subscriber

Its an old school M952 long cage mech

Oooh, if you want a tatty, but functional, short cage version of the same, I still have one kicking about somewhere I think from when I ditched 9spd to go to 10spd. Short cage definitely helps reduce chain slap and aids keeping the chain on in a single ring setup.

Dickyboy
Member

Just checked mine & with the rear mech as taught as I’d be prepared to go (ie still making a S shape in the chain) mine is just about big to big plus 3.25 links with a short MTB mech – on a hardtail frame.

passtherizla
Member

this is pretty much how I did mine.

yunki
Member

holy mother of erroneous thread resurrection batmen..

this method of largest chainring and largest cassette cog +2 is for a 3×9 set-up yeah..? Where you’ll never be in largest/largest..?

so..
how do we find the correct chain length for a 1×9 set-up..?

or a 2×9 set-up for that matter..?

I took Mrs Yunki’s bike to an LBS that I haven’t used before recently, and they gave me her bike back with a ridiculously short chain.. brought about by using the 3×9 method on a 2×9 set-up..

I’m about to fit a chain on a 1×9 set-up and would like some sound advice please.. 🙂

steve_b77
Member

On my HT with a 32t front & a 36t rear with a normal (probably long) XT mech I’m on “big/big +3” and it works just fine for me

GW
Member

Yunki – listen to greeble.

TJ was talking pish yet again