[Closed] Quick noob Single Speed chain tension question, Oval chain ring...

An oval chainring does not change the chain length, but like round rings, invariably they are not perfect and if you set the chain really tight you may be able to detect a tight spot on most setups.

I set my singlespeed up with maybe a cm of chain deflection i.e fairly snug but equally it still seems to work fine when it's all baggy 🙂

An oval chainring does not change the chain length

Yes it does. Enough for me to go back to a round ring when I tried one (Absolute Black) a few years back when I had a single speed. I am rather picky about even chain tension and chainline though so others may not notice or care.

actually an oval ring does change the tension, you're right about chain length - it's trigonometry that causes it. However in practice the difference between the large and small diameters of the oval ring compared to the length of the chainstay means the effect is small and so single speeds work just fine.

Set it up so it has a bit of deflection when at it's tightest and go with it. First time SS'er? Have fun!!

I also have an oval ring on an SS and as above it does change the tension.
Never been a problem though.
Just set it so it's tight on the high spots and make sure the chainline is straight.

As above I'm on oval rings on a singlespeed. The effect is small enough that you're in an acceptable range of tightness all round the pedal stroke.

What's your method for setting chain length? Mine's an eccentric hub. Whatever you have a bit of trial and error should get you to a point where it's not too tight at the tightest point and you should then be right.

Another Absolute Black user, chain tension on mine is no different to using a round ring.

Or you could just use a round ring as ovals are placebo?

I don't think they are placebo. I've used an oval on a regular bike and couldn't really feel any difference so was a bit meh about it. Since then I've stuck a same size pair on my Pinion gearboxed hardtail. When they are in sync they make no difference, just look weird (only reason I did it), but if I put them 90 degrees out of sync they are horrible giving a pulsing feeling like the rear tyre keeps slipping. So I'm saying the effect is there you just don't feel it when using the oval properly

Thanks for replies guys.

I have sliding drop outs and the ring is an AB as it happens.

So, at the tightest point, how much deflection should there be on the chain do you reckon?

Thanks again.

So, at the tightest point, how much deflection should there be on the chain do you reckon?

'a bit'. This is singlespeeding, there's supposed to be an element of shonkiness to it!  Maybe a cm? But then we'll need to calibrate how hard to push the chain to get that deflection?

Seriously, set it up, put in in a workstand and pedal it slowly backwards and FEEL it (man!) - if you can feel it is dragging through the tight spot then it's too tight. You'll recognise the feeling far more accurately than you can measure it.

[i]So, at the tightest point, how much deflection should there be on the chain do you reckon?[/i]

It really isn't that fussy, as above I go for about 1cm but if moves for some reason and I end the ride with it hanging like a washing line it still doesn't slip. If you go too tight you will feel it, but even with steel bolts in my sliding dropouts they will move enough to remove the tight spot during a ride.

ON a singlespeed, so long as you have good chain alignment and proper single speed cogs and chainring, tension isn't important to keep the chain on. Take a look at the dangly chains on 3rd world bikes which are usually SS, and they're often hauling big loads.

Usually it's only when you are using cogs etc designed for derailleurs that there is a problem because a slack chain allows the cogs and chainring to do what they are designed to do, let the chain slide off easily.

However a reasonable amount of chain tension feels much better on a single speed because you're not taking up slack.

So chain tension does not have to be precise, or bow string taut, just adequate to prevent binding.

correct.... but be aware on the one in 1000 day it does slip you will be out of the saddle, hauling up some hill, and you will smash your nuts (or ladyparts, singlespeeding isn't sexist) on the toptube. That's also part of being a sser. And the swearing.

It really depends on how particular you are and how much a sloppy chain annoys you. Admittedly I do ride brakeless fixed so my chain needs to be closer to perfect than on SS as skid stopping with a loose chain is horrible but even when I used to ride SS I was very particular as I just hate the rattling over rough ground and the general slackness, take up of slack etc,.

I realise most people won't be bothered by it...

I set mine up with as little slack as possible but not so tight that when you spin the cranks backwards you can feel binding at any point.
But it’s not that critical anyway - I don’t see how any chain in reasonable condition is ever going to “slip” on proper (non derailleur type, in other words) sprockets or chainrings, even if it was running more slack than ideal.
I’ve never, to date, had this happen anyway. Chainline is more important, imho.

As above, I adjusted it to the point where i could feel a resistance at the tightest point, then backed it off enough so I couldn't. Nowadays I just set it to a shade off its tightest point before tightening the axle and a bit of inherent play makes up the difference.

You want a smidge of slack anyway, because no ring and sprocket is perfectly round. I bunged a super cheap 'snial' ebay wobbly ring on a while back, and never had an uneven chain tension issue. The teeth were too thick for a 10sp chain, mind, something I only found out after I switched to gears. Main thing to note is that once you've set it up, chains wear, so keep an eye on it. Once you've been through a couple of adjustments, you should be able to work out how much deflection is 'about right'.
If anyone wants to get all nerdy about it, they can measure the circumference of an oval ring and then take 180 degree measurements at different points. I quite like oval rings, and have run them for years on geared and singlespeed bikes. But when I realised I had to buy a new chainring after the snial one proved to be too wide, I had to buy a round ring as it was one of the new pattern Shimano cranks and all my other rings didn't fit. I ended up getting a bog standard SLX narrow wide 30t round, and I can't say I've noticed a massive difference. I'll still buy oval anyway, as it's usually cheaper than a stock ring.

Thanks guys, as ever, a massive help!

Think I'm pretty much up to speed to get the chain and tension all sorted.👍😊