CVT Drive Belt Info
CVT Drivebelts
What's the best belt?
There is no hard and fast answer for this one. It’s more about choosing the belt that will best suit your application. We can supply a range of belts from different manufacturers depending on what best suits your application. We’re more than happy for you to CONTACT US to discuss your needs so we can make a recommendation for you. If you are destroying belts in a short amount of time then changing to a “stronger” belt is almost certain to NOT solve your problem. You most likely have an underlying issue such as bad setup or worn components that will need to be fixed first. “Stronger” belts also come with different drive characteristics too, usually less comfort unless the CVT is re-tuned. You can find more info on clutching in our CVT Blog HERE
What causes belts to fail:
Whilst belts are a wear item that need replacing, they should last a long time if there are no underlying issues. Normal applications (not racing conditions) should see over 300 hours of service life.
Typically heat is the number one cause of belt failure and that is mainly caused by bad setup or improper use such as getting on the throttle when stuck in mud or using high gear on a slow hill climb. Another cause that is often overlooked is towing heavy loads in high gear.
When we talk about excessive heat being a belts number one enemy, we are referring to the heat inside the structure of the belt at any given second. Belts appear to have a threshold where if they stay fractionally under a critical point, they could sustain high demands for hundreds of hours. If the belt temp tips a fraction over that threshold, temperatures can run away fast and the belt can literally explode within seconds. It is important to understand those extremes in circumstance; one belt could work hard for a very long life at up to 99.9% loading. Another brand new belt that for whatever abuse, damage or bad environment could literally explode in less than 30 seconds. These extremes do happen.
There are examples of turbo charged quad bikes in the U.S. drag racing with 200hp on standard belts... and then there a racers with no more than 80hp who can blow multiple belts in one race. Clearly there are combinations of factors that are ok and others that are not.
Other causes of belt failure can be;
Overlooking damage from previous belt failures or excess wear grooves on the pulley faces.
Not preparing the pulley faces properly by cleaning them with a scotchbrite pad and rubbing alcohol to remove any scuffing or rubber residue.
Water and mud ingress.
New belt info:
Before you install your new belt it is critical to make sure that the clutch pulley surface is 100% clean from residue or previously damaged belt marks. You also need to ensure that the surface is smooth and free of physical damage.
Any damage, marks or residue will damage or cause new belt slip which could drastically shorten its life.
If you have had a previous belt “fail”, whether it has come apart completely or partially you should disassemble your clutches to clean them out, you will be surprised where belt fragments can end up and cause issues. Also be sure to clean out all the inlet and outlet air ducts to the CVT case. If you reassemble and test ride and the machine takes off at low rpm, or too high rpm, or can’t reach top speed as normal... your clutches are not moving properly because of old belt debris in the wrong places. Don’t continue riding, and definitely don’t hammer it, you could very quickly damage the new belt you have just fitted.
Running in a new belt;
There are many theories and opinions on “running in” your new belt. Some are more questionable than others. By all means, go with a manufacturers recommendations or whatever procedure you feel comfortable with. The best advice is just be sensible and keep operating conditions in the normal ranges to start the belts life. If you prepare/maintain your clutches, and the pulley faces are in good condition, you only need to make sure that the belt is clean before fitting. If you have any doubt, wash the belt in warm soapy water and leave to dry (never clean a belt with a chemical).
To be on the safe side, we recommend a gentle first drive of 10-15min, varying the rpms and load to give it a heat cycle without creating excess heat, and then allowing to cool.
General CVT use advice;
In any driving situation you should make sure your driveline is warmed up before riding/driving hard. You can bring your engine to operating temp by idling on the spot but it’s not ideal and you really need to actually move the machine around to warm the rest of the driveline up effectively. Not that super cold starts are a big problem in most of Australia, the simple logic applies, if it is super cold minus zero temps, a more gentle 5 minute start before normal driving is a good idea. If it’s a hot Aussie summer 40+ degree day, a 20 second warm up will do the trick and you can just about go straight to full pace... but then how hard do you want to go in extreme heat anyway?
Remember that excessive belt temperatures will drastically influence belt life. A belt temp gauge is the best way to monitor your belt temp in a SxS(we have them HERE), it’s a little harder to monitor temps on an ATV and generally not as required because they are much lighter machines. The main exceptions are any continuous high speed or sustained high load uses that will accumulate excess heat.
In high load environments, use low gear wherever possible- e.g hillclimbs, mudbogging, towing, rock crawling and even loading on the trailer and moving around the yard. Using low gear reduces the load on the clutches and belt sometimes up to 50% (it depends on the gear ratio difference between High and Low).
If doing water crossings, there is a chance you will get some water into the belt case and on the clutches, if you feel any slip at all, once you get across the water to a point where you know the CVT intake is back above the water line and breathing dry air, you can select neutral and hold the engine rpm up around 4000rpm to blow dry out the belt case. Everything can be dried out within 30 seconds. Allow the rpm to return to idle, select the desired driving range, and make sure the belt grip and engagement feels normal as you try to drive off. If it still feels slippery, you need more blow dry time, or you have a water leak into the CVT case.
If you don’t have a sealed CVT case and there is water leaking in, you can only reasonably apply about 5% load to the CVT to get out of the river, which in most circumstances won’t be enough, but it may assist slightly when you have to tow it out.
If you try to accelerate hard with a wet belt you can destroy it in seconds.
In any situation where you think you may have overheated the belt, where possible don’t stop instantly. Instead, completely reduce the load by using the lightest throttle and gradually slow down. Don’t go in to full deceleration where the belt experiences high back shifting forces either. The best is to hold about 5% throttle as the machine slows down. Then leave it idling in park or neutral to allow airflow and time to cool down. Don’t just turn off the engine to let it cool. If you do, the belt will stop on one section of the pulleys and heatsoak will begin and the belt could try to rubber weld itself to the pulleys. (Drying out a wet belt using high engine rpm in neutral of park works very quickly, but cooling an excessively hot belt down takes a lot longer). When trying to preserve a belt that you think might be getting too hot, knock the rpms and load back. Make sure you favour mid range rpm for good airflow and generally ‘baby it’ by decreasing speeds. A short cruise in low range is a good idea if you are in boggy sand or on a long up hill.
You should regularly inspect your belt for damage or wear, if you notice either you should replace the belt and look for potential causes of the wear or damage. Dont forget to check out the CVT Blog HERE for more info on clutch setup and how it will help with belt life and performance.
As usual, if you have any questions we’re here to help. Feel free to get in touch on our contact form HERE
You can also browse our belt listings here:
