Gear System Issue

We have a problem which is restricting us from setting up our multi-gear system. Our problem is that the heavy duty chain that passes through the Greenpower 14 t motor sprocket is not compatible with our bike sprockets. Due to this issue we unaware of how to effectively set up the multispeed gear system and were wondering if you could advise us on how to solve the issue. We were initially thinking of using just a motor to axle arrangement but now we are considering a layshaft. However, we do not know which method would be most beneficial and taking into consideration this is our first year with a multi speed system.


  • Not wishing to state the obvious but you need to make (or have made )an adapter so that you can mount suitable sprockets for a cycle chain onto the motor shaft. Perhaps an easy method would be to weld a steel cycle sprocket directly onto the GP sprocket (Sturmey Archer type for instance) or an adapter plate to which you can bolt the sprockets, allowing you to change the drive ratios should you need to. Two of our cars use cycle sprockets & chains directly driven off the motor......we acquired these at a time when the Trug chassis were available but that was some years ago. They are aluminium, split in two threaded halves so that the gear size can be changed (single speed cars). They use aluminium track cycle sprockets with the small lugs which engage in machined indents.
  • Try Lakehurst PT - they did us a few sprockets, reamed out to 20mm with two grub screws at a very reasonable price.
  • When you say 'not compatible' - are you using the correct pitch roller chain and sprockets? The original kit car chain is not bicycle sprocket pitch. The distance between rollers and the roller diameter need to be matched to the sprocket dimensions.
    Standard bicycle chain is 1/2" (12.7mm) pitch (distance between roller centres). If your 14t motor sprocket doesn't match this then you'll need a new motor sprocket as Peter suggests.
    We use 8mm pitch chain on both RLR2 and the kit car, and had a range of motor sprockets made from HPC Gears to allow changes in ratio. 8mm pitch chain is rated at 2kW, which is well beyond what a Greenpower motor will put through it. On the rear axle of RLR2 we had split sprockets laser-cut that are mounted to a common carrier to allow further fine tuning of ratio.
  • We have had more of the sprocket holders that formarke speak of, manufactured locally. We can have more made if you like, but at a price!!
  • Hi, we are currently trying out a new design of floating bike cassette on a lay shaft with old chain driving wheel and bike chain from motor. Got the idea from a velotilt drive on YouTube, amazing machines, and it seems to be working ok at the moment. Yet to sort the changer but will be putting latest video on YouTube showing how's it going on bench. Hope it works well under load. Whether the extra weight is worth it not sure but we now have a ammeter to show us the best time to change gear so here's hoping. Look for Chris Burkett, greenpower racing at Wolstanton.
  • Chris, why don't you try a central locking motor for gear shifting? It will allow you to cheaply have a linear actuation system for your gears, or so I'd assume.
  • Sam, had thoughts about solenoid for shifting but wanted to keep it fairly simple/recognisable for the kids so looking at a lever with locating comb as the shifter. Would allow for extra push to change gear but then correct final position for straightest chain. Having a steel shaft made at mo, thanks KMF, due to concerns of the lay shaft going banana under load. Hope this can be properly tested before we break for half term.
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