chaihot5

iTrader: (8)

To all Racers

im still bit confuse about this gear ratio thing, how do you know which gear ratio to use on which track and whats the difference between the 48 and 64 pitch. Some advice please for a newbie like me

cheers

Alvin

48pitch gears have bigger teeth, and can take quite a bit of damage from rocks etc. without losing teeth. 64 pitch on the other hand has much finer teeth, but they're more difficult to mesh, and is more damage prone, I know, as a newbie I was chewing up 64p gears! Swapped over to 48 for a while and eased my pocket.

The plus side of 64pitch is it gives a finer array of gear ratios to choose from. The gearing choices with a 48 pitch are lesser.

Alvin

The gear ratio should be chosen based on both the motor and the track.

For example at RC Speedway with a 23x2, I use a final drive of about 6.4:1 FDR. With a Dyna run (13x2) I run about 8.26:1

Smaller numbers equals a higher gear ratio, giving better top end and less acceleration.

Conversely, a larger number indicates a low gear ratio, giving better acceleration at the expense of top end.

Some people arrange the gearing suchg that the battery pack dumps in 5 minutes. Others gear for the car to hit maximum speed at 1/2 to 3/4 of the length of the longest straight. Gearing can also be decided by the lap time done by the car.

Finally, if you run foam tires, Rollout becomes an issue - as the tire wears down the slower the car becomes - due to reduced tire diameter, so you will need to gear up accordingly.

Rollout can be calculated as (Tire Diameter x PI) / Final Drive Ratio

So for example I run a foam tire which has a Diameter of 64mm, I will get a roll out of (64x3.142) / 8.26 = 23.6mm appox 24mm rollout.

When the tire diameter reduces to 60mm, I will need to adjust the roll out by changing the final drive to ensure it is also 24 mm.

So:

Final Drive = (60x3.14)/24 = 7.85:1

Hope this helps.

~Alvin

chaihot5

iTrader: (8)

Thanks Alvin

That helps alot, r u racing this sunday, hope to c u there

Cheers

Alvin

Hiya,
Yes I will be racing this sunday. Have we met?

~Alvin

chaihot5

iTrader: (8)

No cos this is only my second race, the last one was a diasaster cos did not tune up my car But this time i hope history will not repeat. Spend a lot of $$$.

Cheers
see u this sunday

Alvin

Well then good luck! What car are you running?

chaihot5

iTrader: (8)

Im driving Evo T1, got it from Eric cheng. Very nice car, hopefully i wont tarnish its reputation from my inxperience driving

The last race i was using Xpress, did not do my homework and anyhow did the electronics so the car fail on me.

Hopefully can get some advice from you during race day

Cheers Alvin

Alvin

T1 huh? Won't be too difficult to track down ;-) I drive a 414m, red & white bodyshell with tamiya stickers all over ;-) See you at the race soon.

dtm

Look at your brushes after a run.....what you are aiming for is just a slight "darkening" at the tip....discolouration and you have over geared...use a smaller pinnion.....no colour change you can try 1 more teeth on the pinnion...this is takes into account track, grip and most importantly driving style!

chaihot5

iTrader: (8)

Alvin,

sunday race was not a happy occasion for obviously my gear ration was wrong, i was using a 12x2 motor with my pinion at 23 and my spur at 93. Grave problem as my car look like it was on a sunday car drive. I know it created lots of inconvenience to the other drivers as they were ramming behind me. Sorry guys.

Anyway wat gear ratio should i b using for a 12x2 motor and a 11x3 motor for the nxt race, thanx for the advice.

Cheers
Andrew

ART2

iTrader: (2)

Hmm...I don't find anything wrong with your gear ratio, seems fine to me. I'm using 96/24 for my 11x3 on a 414M. But if your car feels slow with the 12T motor, maybe you can try 93/25 or retain your gear ratio if you intend to use a 11T motor. Hope you can find the correct gear ratio and see you at the next CCK race on the 13th Oct.

Alvin

First question, what's the transmission ratio of a Xray? Also, is the comm cut? What brushes/springs are you using? What about the timing?

Art2: Guess what, I was running 8.26:1 FDR on my dynarun 13x2 ;-) I figured out why my car has been so loose lately, I have been running the wrong toe in blocks! ARRRRGH!!!

Tzer

Saw your car during the race. Think your problem is in your setup and not the gear ratio. Your car drift too much. Your motor need to be solder properly, came off during the race right. For setup ask those running the same car as you. There's quite a number of guys running Xray that day. Just make friends with them. Most racers are more than willing to help you.

ART2

iTrader: (2)

Hey that's about the same gear ration I'm running for my 11x3...am I overgearing my motor? Wrong toe in block....yeah it's hard to identify the correct toe in block for the 414M, it should have the small dot on both sides of the block, like that it will be easier to see. I also install the wrong toe in block the fisrt time I rebuild the car.