Chain tension

Today I'm looking at how to check your chain tension. Now, when it comes to chains, I find they're wearing out a lot faster than what they previously were. That could be down to the quality of the chains, or it could be that we're now driving faster engines.

With drivers being on the track for more practicing, a lot of these factors are wearing out chains a lot faster. If mechanics are not on top of the chain tension, we're going to find too much slack in the chain, and we might have more mechanical failures or just the performance of our kart is not the same.

Low performance categories, such as four stroke karts & cadets’ karts can have a little bit slacker in that chain because there's less power to flick that chain off. As a rule, when it comes to, Mini Rok cadet engines, once it's all fitted, you can move your fingers up and down to see how tight the chain is. We aim for it to just touch the front chain guard that goes onto the engine, not the rear chain guard.

The chain can just touch that and then basically it seems quite loose. But like I said, if your chain tension is too tight, especially in those low performance categories, it's just sucking out the horsepower of the engine. So, although you potentially might have less mechanical faults with a tighter chain, if it's too tight, it's going to drag down the engine performance. An over-tightened chain also presents it owns risks of snapping due to the strain on it when powering the engine.

You can have no acceleration and no top speed as well. When it comes to our faster karts, we need to have it slightly tighter. Probably about one and a half centimeters, two centimeters in slack. So again, it needs to have a little bit of forgiveness. If it's too tight, especially in a high-performance class, it's almost going to snap the chain. So just play it around as you're spinning the kart maybe in three spots as you're spinning the rear tyre to check the chain tension.

Faster engines can use an O-ring chain, and they're much more durable and don't need as much slack in the chain because as they heat up throughout a session, they tend to loosen up a lot more.

If you're using an O-ring chain, it will feel a little bit tighter when fitted. That's just the nature of that style of chain, but it can't be as slack as the normal chains that we use.

One way to see whether your chain is worn out, is that if you have the chain fitted onto the front and rear sprockets, if you try and put two fingers on the chain where the back sprocket is and pull it back. If it's almost coming off the sprocket, it's stretched and it's too loose. So no matter what you do, if you try and fix the tension of the chain, the chain is worn out. As you’re driving, it's going to have a lot slacker and it's going to be sucking the power from the engine as well.

If it just pulls back ever so slightly, that's okay if you're sort of finding that you can nearly remove from the sprocket it’s way too worn out. Another way is with the chain, once it's removed from the kart, if you're holding your hands at either end and you're basically trying to push it up or push it down. If it's really stretched out, you'll notice it there. So as you're pushing it up, it's moving quite a lot. If you do it to a new chain, it's going to have less movement, but nowhere near as much as a worn-out chain.

Once you've got a feel on how much slack there is, then you'll realize at what stage your chain is worn out.

It's often an area that people overlook, and then once their engine performance is going down, that's when they start to query the engine, but it's the chain. The problem is as the chain wears out, it starts to wear out your front and rear sprockets, and then you're going to see not just mechanical faults, but a few parts being damaged as well.

Aim to lube the chain after each session. It doesn't have to be too long but give it maybe two or three rotations as you're spinning the wheel.

Hopefully these tips will allow you to have fewer mechanical faults, better engine performance and more longevity with your equipment.

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