Put a new chain and chain ring on me SS swift. How tight should the chain be? I’ve got it so there is about 10mm of movement when i push on the top run of the chain. Is this ok? I’ve never put a chain on a bike before let alone a single speed with an EBB. All good fun n games 😀

Typically no more than 5mm at the slackest point is my rule. Check by rotating the cranks because the chainring won’t be perfectly centred.

10mm ro so sounds fine, as long as it’s not tight, and doesn’t fall off either.

Is this measurement to be taken when the chain is under load or no weight on the cranks?

Does the chain need some slack in it? Are there any downsides to it being too tight ? Also, is there a more accurate way of setting the alignment? It’s a kmc 610 chain, Renthal 36t chainring and a cheapo 16t sprocket. It looks straight by eye but I just wondered if there was a way of measuring it.

Feeling slightly nervous about riding it again if I’m honest. When it snapped its chain (tbf it was an old chain and buckled shimano 36t paper thin chain ring) it made me realise just how nasty it could have been and I’m not keen to repeat it.

Steve

are they still swollen?

Having the chain too tight will increase chain and chainring wear. You will also notice that the cranks will not spin freely. Between 5 and 10mm sounds good to me. Do you have a chain tug to help you tension it?

are they still swollen?

😀 I was almost considering changing my name the Stephanie.

Ahhhh I think the fact my cranks stop after a couple of spins by hand might indicate I’ve set it up a bit too tight. I have an ebb on the swift and find it a bit tricky to set up the tension. Just a few mm in either direction means the difference between slack or super tight.

At a track training session we once had a quick talk about chain tension. It shouldn’t be tight as it actually causes friction and wear.
The guide for slackness was certainly less accute. He picked up the bike and shook it up and down violently. “If it comes off then it’s too loose.”
And that was it.
So some degree of slack and certainly not too tight.
Being able to pinch top and bottom whilst under no pressure by 5-10mm in total should be a good amount I would concur.

On a single speed bike I wouldn’t run it too loose because of the amount of chatter you’ll get from bumps and stuff.

So with no load on the cranks, if I pinch the top run and the bottom run together there should be no more than 10mm of movement?

Yes at the slackest point in the revolution. Always set when unloaded. I hang mine from the front wheel, slacken the nuts and the wheel drops under gravity. As I said, rings aren’t round. You don’t want to set it so tight that when you spin the cranks there is obvious friction. I think you know why you don’t want it too loose. This experience from setting chain tension on tandems, track bikes, fixed and single speed MTB. My MTB has a slightly slacker chain than my fixed – about 10mm, but that’s down to wear and laziness.

Double post

I always used to just adjust it until my cranks felt a little binding and then back off. Since then all my SS bikes have had chain tensioners so I’ve not worried about it.

Thanks for all the replies and advice. I quite like the idea of a tensioner but I don’t like the look of them as I feel it ruins the look of a single speed. I see E-13 do one that fits under the front chain ring, at least I assume it’s a chain tensioner, are they fit for purpose or not needed coz I have an EBB?

I think it’s more of a chain guide than a tensioner