All current HPI Off Road Nitro cars are fitted with a slipper clutch mechanism as standard. It is important that the slipper clutch is correctly adjusted for optimum performance and to prevent damage to the car. The slipper adjustment should be checked with every use because as the slipper pad wears the slipper adjustment point may shift.
If the slipper is set too tight the user risks damaging the car’s transmission. If the slipper is set too loose then the car will have a lack of performance and the user risks damaging the slipper clutch components.
This procedure is to show how to correctly adjust the Rush evo slipper clutch, although the same general procedure could be applied to any HPI Nitro car fitted with a slipper clutch.
You can also hop up your Rush Evo Slipper Clutch with the HPI #72207 Heavy Duty Disk Hub (Aluminium/Hard Anodised)
to enhance the performance and reliability of the slipper clutch mechanism. Click here for the tutorial
If the car has already been used, remove the spur gear and inspect the slipper pad.
If the pad is glazed as shown then roughen it up slightly with some fine sand paper.
Replace the gear but at this point only tighten the slipper nut so that it is flush with the shaft as shown.
Start by tightening the nut by two and a half complete turns, this should show just less than two millimetres of the thread after the nut as shown below.
Test the car to see if the slipper is set correctly by following the below procedure.
Can you hear the slipper slipping as shown in the below video? Notice how the sound of the engine revs (revolutions) does not match the speed of the car. The engine is revving far too high for the speed that the car is going. Most of the power is being lost because the slipper clutch is set too loose.
If you can hear the slipper clutch slipping as in the video then do not continue to run the car. Tighten the slipper clutch by half a turn at a time. Re-test until the slipper clutch is set correctly.
If the car is run with a loose slipper clutch then the likely outcome is damage to the slipper.
When the slipper is set correctly the car should pull away without hesitation as shown in the video clip. Notice how the car accelerates straight away and that the sound of the engine revs match the speed of the car.
If the slipper is set too tight then the user risks damaging the transmission.
To test this hold the car as shown.
Try to rotate the spur gear whilst holding both rear wheels down. The slipper should slip just a little bit and you should be able to rotate the spur gear very slowly. If you cannot turn the spur gear then the slipper is set too tight. Loosen the slipper by half a turn and re-try.
With both tests for too loose and too tight you will be able to find the correct setting which will ensure protection of the car’s transmission, quick acceleration and long slipper clutch life span.