Hi Guys i am fairly new to on roads electric and i have herd all this talk about roll out and internal ratio setups. This completely baffles me. I have a Corally RDX PHI with a spur 68 and a pinion 40. I also have a 17.5 Novak motor.

When i spoke to some guys at the track i go to they said that ratio is alright but i have been looking at all these different charts and still have no idea whats going on really.

I wouldnt mind putting in a bigger spur gear cause compared to alot of the other guys they are running one which are a lot bigger.

Any help would be greatly appreciated

cheers
JAJ

HI mate it totally depends on what speedie you are using if it has all the Boost settings ,turbo timming we need to know that before we can help
Cheers

Hi i have the Novak package which comes with the GTB speedie. I dont believe it has any boost settings, or turbo timming.

if you run a meakin at logan, your best bet would b to run the 21.5 turn class as the motor and speedie you can get from Heavy for $165 that is the prefect class to start with. you can contact Heavy on the Actionrc web site.

a rollout of around 56 could b a start. go on gearchart.com , wheel diam 63

Okay, yea i have been at meakin a couple of times. But i was thinking i need a bigger spur but i read all this stuff about blowing up motors and frying speedies and i dont wanna just change it without fully understanding.

get on that web site gearchart.com and you willl be able to have a choice of spur and pinions . go a larger spur and smaller pinion but the 56 rollout is a good starter. then you can work of motor temp dont go over 70deg if u want to b safe.

Okay thanks mate much appreciated. I am thinking of having a go at a 72 spur and 36 pinion which works out to be 3.42.

Also i noticed you have a schumacher, im getting one this sunday.

cheers
JAJ

That gear ratio should be fine for 17.5 Josh. Just run with the stock guys with the gear that you have and you will learn pretty quickly (save your money mate). The other suggestion I would make is to download the HUDY/XRAY setup book and the quick reference table and have a read through it to help you understand what changes effect your car.

My advice would be talk to the guys at the track as they can SHOW you all you need to know. Gearing depends alot of different motors, speedies, and settings so it can be radically different if you change just one of these things.

Err if you put on a larger spur, then to maintain the same gearing (ie speed) you will need an even bigger pinion.

a 40t Pinion is already starting to get pretty big. Some cars start to get issues with physically fitting big pinions and spurs, but if you start getting spurs much larger you will have more trouble finding pinions bigger than 41 if i recall correctly.



The thing you need to remember is that because different cars have different amounts of teeth on belts and pulleys you often cannot look at the spur/pinion of another car and put the same spur/pinion in your car for the same speed.
This is why different cars have different internal ratios . Some cars even have options for different pulleys and belts which change the internal ratio for the car.

And just to make things even more confusing, the speed of your car is determined by the tyre size. Most on-road rubber tyres are the same diameter but if you are running foams the tyre size will shrink as the meet progresses.

People who talk in FDR (Final drive ratio) essentially do not take into account the tyre size. Rollout does take into account the tyre size.

So yeah a rollout calculator like www.gearchart.com is your friend.


Now ontop of this just to make things more complicated. Different motors and speedie combinations have different rollout preferences for optimal performance.
The best thing to do is find someone running the same motor and speedie as you and chat with them about A) what settings they are running on their speedie and copy them and B) then ask the rollout/FDR that they use.


When playing with gearing you should also run short tests for a couple of minutes to see how the motor is performing (heat wise), or you run the risk of blowing your motor if you take it straight out for a full 5 minute run during a race.


I hope that helps you, but i suspect you may need to read it all a few times.

Hang in there, once you get used to it, its not too bad....

Actually looking back there arent going to be many people runnning a GTB. For people in general to make a comment they could give general indications but would also need to know about the track. Which is also one of the reasons why dragonfire would have said to ask around the local track.

I dont know what things are like in QLD but where i race there is always someone willing to help out newbies. Unless people are rushing around trying to fix things i'd be surprised if there wasnt someone at your track who could help you. Just let race control know you are new to on-road when you register and ask if there might be anyone who could help you out with gearing. The guys in race control should know the people at the track pretty well.