XRAY - Model racing cars

hello I m so happy yesterday I bought my (used) new real r/c car, a t1 and, to say im in need of help wuth a question on the gears. well right now, im low in mula ,but i want to drive the car,so i install some old stuff in the car,but my main concern is the pinion gear. im lost. it have a spur 48 pich/87 t. the motor is akyosho lemans 240sb and i think is a 19 t . I now is old but for now. I want to play and save some mula. I need to know what pinion gear i need . Im going to Practice at a ashphalt track . any help will be apreciated ty.. I will get some good stuff for my car I promise. LOL

well wellcome here is or world hope you find ,some new friends lol

Hi Mustang
I would suggest you aim to start at around 6.0 fdr (final drive ratio) for your gearing with a 19T. It is quite possible you will get down to an FDR in the low 5’s but better safe than sorry. Lower FDR = higher gearing which if too high = engine strain and overheating. If your track is big and open you will end up with a lower FDR number, if tight and twisty a higher FDR number

Drive the car for 6 laps or so then check the engine temperature. 140 deg F is a good target to start with. Then just repeat until you run out of battery or have done 20-25 laps. If your temperatures are coming in under 140 replace the pinion with one with 1 more tooth and then repeat.

Alternatively and better, ask some of the people at the track what FDR they are running for a similar motor. If they say around 5.5 than I would suggest you start at around 6.0 and stay there for a while – but check that temperature. If you are a beginner you will put more strain on the engine (more heat) so are better starting with a lower gear ratio = higher FDR.

BTW a 19T is awfully fast for a beginner . If you have a transmitter where you can adjust the power I would turn it down a bit. The way to have fun and improve is to stay on the black stuff!

The T1 family of cars has an internal gearing ratio(IR) of 2.125; with an 87T spur I would start with a 30T pinion which will give you an FDR of 6.16. or a 31T pinion will give you an FDR of 5.96

I would suggest you ask some of the people at the track what FDR they are running for a similar motor. If they say around 5.5 then I would suggest you start at around 6.0; ie add a half to what they say

If you have the documentation with the car there will be a section in there on gearing and there might be a gear chart. If you do not ,then if you PM me with your email I will send you an Excel spreadsheet that I built for my T1R. Or you will find a .pdf with gearing chart on the XRAY site somewhere for the T1 family


HTH


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T1's had an optional low ratio kit available at the time which alters the car's internal gear ratio. this will have an effect on how you gear the car if it is fitted.
To confirm which ratio set is fitted to the car, count the number of teeth on the front axle or rear diff gear, and then count the teeth on the layshaft gears - if you have the car in pieces some of the gears have the number of teeth stamped on them so no need to count.
Hope it helps.