Goodwood Gearing

As you may know from most of the posts I have added this season not only here but also on the GDS Racing page, gearing and therefore pace on the track has been bothering me at pretty much every race! When I thought I was onto a good ratio the batteries wouldn't last and when they would last the car was just too slow. But thanks to some help from the team at RLR I have been able to see where I am going wrong.

The issue was simply having the gears set too high to allow the motor to rev at around 2000rpm. Over the course of 1 set of batteries at Merryfield the average rpm was under 1000 at a ratio of 3.2:1. Then with the wise words of RLR ringing in my ears, that the planned ratio of 3.7:1 for Castle Combe was still to high so a quick drop to 4:1 (the max we could drop it with the gears available) seen over the same 1 battery set the rpm rise to over 1300.

So its seems a bit counter intuitive that putting a slower gear on makes the car faster (obviously to a limit) but it works. M6 increased by about 1.5m/s even with my extra weight compared to when the team at Camborne drove it, and the batteries lasted much better. Not only that but the increased rpm also considerably lowers the amps drawn. Where I always aimed for a high speed running amps of about 20A, with this gearing its now virtually nothing, which for the hilly sectors of the tracks makes all the difference by saving energy and putting less heat into the motor. A win win situation!

Now with the final round just over a week away I have been madly working through data from the last few races and looking at countless ratios to see for myself why RLR suggest a 60 tooth and I can now see why. With the increase we should be pulling 2000rpm comfortably with no worries of high amps. For an Autumn race at Goodwood this is just what you need. As well, unlike Castle Combe, I wont have to throttle back when I hit some wind or a hill as the high speed amps will be low enough that the low speed amps wont be massive. But the main point from this I will be able to race flat out the entire lap without having to worry about what the amps are doing, how hot the motor is, if I need to throttle back etc etc, I can just go out, and if all goes to plan, just race and hopefully get that step closer to the middle of the pack where M6 just didn't quite have the pace last weekend.

Thanks again RLR and good luck at the Final!