How can I tell too much chain tension with SS?

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How can I tell too much chain tension with SS?

19 posts & 13 voices | Started 4 months ago by hock | Latest reply from hock

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hock - Member

I am aware that there was a similar thread recently but my question is about too much tension rather than not enough.

I am running 36/16 SS in a geared frame with weakish down-push singulator thingy. Chain (KMC Gold 9/10 speed) kept slipping 1 tooth in peak high-torque uphill situations.

I took out 1 link today, now I am worried that the chain might be a little too tight as I can lift up the chain only 0,2 inch/5mm and even that needs some pressure. Turning the cranks backwards I can feel the tension (slight *whirr* like moving from 1 teeth to the other), but it's not a huge resistance, i.e. I can easily turn the cranks backwards with 1 finger. Giving the cranks a good push they will rotate 1 rotation backwards before stalling (some of that surly also due to resistance in (newish DT Swiss) hub). You get the picture.

A friend reckons that it's OK and that the chain will stretch that micro-bit to make it totally OK after one ride.

Do you reckon I found the magic chainring/cog combination (no need for singulator) for my bike and everything will be just fine?
Or am I about to trash my drivetrain?

Posted 4 months ago #
wwaswas - Member

if the cranks turn when you're just pushing it along then there's probably too much static load on the freehub would be one way.

personally I'd get a pushy uppy tensioner to get more chain wrap.

Posted 4 months ago #
scottfitz - Member

I did my tensioner up tight then 9 speed chain streched when i went for a ride then I did my tensioner up tight then 9 speed chain streched ETC....

it took about 5 rides to sort it self out.

am worried that the chain might be a little too tight as I can lift up the chain only 0,2 inch/5mm
Sounds fine

Take Hex key out with you if it slip nip it up tight again.

Hope this helps

Posted 4 months ago #
s - Member

have you checked the chain tension at different crank positions?

Most setups are not 100% true and there will be a slack or tight spot if you rotate your crank?

Tension it for the tightest point

Posted 4 months ago #
jambon - Member

Tension it for the tightest point

+1

Nothing is ever perfectly round. Any tight points will grind horribly.

Posted 4 months ago #
bm0p700f - Member

I would bin the tensioner and go for magic gearing. Each tooth you add to either cog adds 1/4" (maths explains this I know it not intuitive) to the total chain length needed. Also loosing one tooth remove 1/4" from chain length. So wrap your chain around the cogs and wrk out what fraction of a inch you need to take out. Then by a new chain ring or rear sprocket or both (depending on the ratio you want to run) with the right number of teeth and go from there. That is what I have done and I have no tension issues anymore. Single speeds do not need or want a tensioner. If only the bike could talk.

Also chains don't stretch they wear though.

Posted 4 months ago #
drofluf - Member

If you have it too tight you'll destroy the bearings in your bb or hub.

Don't ask me how I know this....

Posted 4 months ago #
loum - Member

Or your chain may snap as you're climbing out of the saddle

Posted 4 months ago #
scottfitz - Member

I would bin the tensioner and go for magic gearing.

Its each to there own. I like having a tensioner, easy to adjust on the trail with a multi tool.

Posted 4 months ago #
hock - Member

Take Hex key out with you if it slip nip it up tight again.

Tension it for the tightest point

I apologise, maybe I wasn't clear enough:
my (crappy) tensioner was at its max. tension. It still slipped.
I took the tensioner off today as soon as I realised that the chain minus one link is going to be very tight anyway. So it's bordering on too tight (...?!) without singulator. No need to tighten it, in the contrary. And no means to tighten it either (-> Soul frame with normal geared drop-out).

And yes, there is a tighter spot when rotating the crank, but the difference is not massive in my case. I.e. no position allows for lifting the chain by more than about 5mm/0.2 inch but there's also no position when it feels as if I am going to tear the chain apart. At least that's what I reckon/hope.

My bike store has a better, push-up tensioner on order which I could then run with plus 1 link again.
Or I have - by chance - found a chainring/cog combination that can be run without any tensioner at all despite the non-SS specific drop-outs.

So while it was suggested as a rule of thumb somewhere else in this forum that one should be able to lift the chain by an inch I can only lift it by half of that and thus the question is again:
does it - based on what I described - sound like I have too much tension on the chain and I run into severe risks of grinding away my chainring/cog in no time respectively over-stretch/split my chain
OR will it stretch in an OK way and it will be just fine after a ride or two?

Experience based advise very welcome as I desperately want to go for a (chain slip-free) ride tonight.

And sorry again, if my initial post wasn't clear.

EDIT: sorry missed a few posts while typing mine -> Thanks! Yes, I'd prefer the "magic combination", too. I was just wandering how to tell whether the tension is too tense. Because when my current 36/16 is "magic" already - BINGO! If not and the forum wisdom reckons I am rather on the too tight side of things I will try 1 tooth less, i.e. 36/15.

Posted 4 months ago #
Sam - Member

It sounds like it's over tensioned, do you have an older worn chain you could fit to see if this one will stretch a bit over time to make it workable? I'd also recommend against using a 9 or 10 speed chain, they don't mesh well with most SS chainrings and cogs - that could be part of your problem - both with the tightness you have now and with the slipping you were getting before.

Posted 4 months ago #
Mostly Balanced - Member

Push up tensioners only work if you're very close to the 'magic' gear without them. They will only take up a very small ammount of slack, far less than a link's worth.

'Magic' gears will cease to be magic after half a dozen muddy rides as the chain wears.

Best solution is to start with a good fresh chain and sprocket and as Sam says, don't use 9/10 speed, most sprockets are designed for 7/8 speed chains.

Posted 4 months ago #
hock - Member

Thanks, Sam and Mostly Balanced!
I will "steal" an old 8speed chain from one of my other bikes for tonight and try a fresh SS chain asap.

Many thanks, again!

Posted 4 months ago #
bikewhisperer - Member

I'd go one better than an 8spd chain, and get a 3/32 singlespeed chain. The plates at the side are higher so there's even less chance of it coming off.. so even less tension required.

Posted 4 months ago #
bm0p700f - Member

Well my magic gear is still magic after many very muddy rides. Chain wear will in the end cause some skipping but I like to change my chains at 0.75% wear so my cogs last longer. I also would not use a 9/10 speed chain on a SS, firstly they are expensive. I use a 8 speed chain with sucess and a 3/32" chain on magic gear bike and that works very well.

+1 on push up tensioners only working when close to magic gearing. I found the hanger mounted tensioners just did not take enough slack so I had to go with magic gears.

Yes your set up is over tensioned by a little bit. Chaning the chain will not chnage this but it will be more durable. Changing your ratio will change the tension and 36/15T will work well (1/4" is probably all you need) but this ratio is very tall for off road riding. Fine for road duties though.
Also chains do not stretch in normal use, they wear giving the illusion of stretch.

Posted 4 months ago #
Edric 64 - Member

I use an old rear mech and a longer screw to get it in the right position it works fine and gives a use to a 35 year old rear mech

Posted 4 months ago #
hock - Member

Ride went OK, didn't go for long though, as chain was still a bit too tight and it didn't feel right to give it the full mud bath.

Found this great link meanwhile: FixMeUp!
According to this and based on my 16.5" chainstay a 38x17 set-up with one chainlink more than currently will give me the right chain length to go without tensioner while providing a similar ratio to my current 36x16.

So I will get a 38T CR (have 17T cog already) and a suitable chain tomorrow.
And no tensioner no more - hooray!

Thanks a lot for your support all!
Special thanks to bm0p700f for encouraging to go the magic and still muddy route.
I will complain here when it doesn't work!

Posted 4 months ago #
epicyclo - Member

If your chainline is spot on, and you are using proper singlespeed (non-derailleur) cogs and chain, you can have a lot of slack without any problem other than it doesn't feel as good as a properly tensioned chain.

I set up with a firm chain rather than a tight one, and if it doesn't spin freely backwards, I ease it off a bit more.

When you're doing this with a geared frame you can get pretty close if you have a few spare rear cogs. Just use the one that gives the best fit. Anyway with a singlespeed you're going to be in the wrong gear for most of your ride, so the actual ratio isn't that critical so long as it is close to what you want (swings and roundabouts).

Posted 4 months ago #
hock - Member

Thanks epicyclo!

38/17 installed, has a little too much slack to run without tensioner, but even with the weak down-push tensioner it doesn't slip anymore.

And that's most important because it means I can go for a ride!

Posted 4 months ago #