gearing for a mod motor

[DC Racing]

I ran a 10x1 last time we ran mod at a 7.40 final drive. That is 78/27x2.56. Then i ran a slipper clutch, now i run a slipper eliminator. I had to go down to a 72 to make it fit. So to run the same ratio, i would have to run a 72/25x2.56=7.37 final. The only prob is my motor plate wont let my motor slide up high enough to get a good mesh. What should i do, should i go up a tooth since its mod and make it fit or should i dremel some out of the plate? thanks

[travymoto]

Chad, is it the screw holes that you would have to dremmel...or the hole that the com axle goes through? It might me a bit tricky do the screw holes by hand. You can always just put the slipper clutch back on while you decide. Since it's mod I don't think the slipper assembly is going to hurt your speed. If it were stock, I'd be more worried about rotating mass.

[DC Racing]

well it would be the screw holes, but i talked to mike martin and he said that to go up a tooth if the gear mesh would work, since i needed to go faster ne way, and if it gets to hot to just turn down the timing. ? for everyone though, making a final drive ratio lower makes the car faster, but does it make the car faster in acceleration to or both? thanks

[travymoto]

If you make the final drive lower, you increase top speed and reduce accelleration.

[DC Racing]

Well, when you ran 19t last week, you had a wayyy lower final than all of us and u had your timing high i think, u killed us all in acceleration and top speed, so that dont make since. ha

[travymoto]

I ran a 6.24 final drive and had the motor @ 35* of timing. I think you guys ran a lower ratio that that no?

[DC Racing]

HAHA no way, thats why i asked u bc kip was really shocked to, i was running the lowest at a 6.6999 at 24 degree. So u were freakin fast. lol My motor was at 170 i can only imagine what yours was at. u coming tom?

[David Butts]

You guys are only running that much gear? A 6.69? I ran the ministock at 6.0 with an ultrabird at 36 degrees and almost won the main a few weeks ago. Those 24 degree motors should pull at least a few more teeth than that. The first time I was there I ran an ultrabird at 24 degrees with a 3.78 gear. Now that was too much gear. Turned the brushes a pretty shade of purple though.:confused: See y'all tomorrow

[DC Racing]

I have it geared as high as possible, the lowest spur, the highest pin, thats all i could pull. i qualified 3rd so that wasnt to bad. CONSISTENCY!!!!!!!!!!!! I have a ?, what effects would a smaller gear mesh ( less teeth) have than a larger gear mesh?

[David Butts]

I have it geared as high as possible, the lowest spur, the highest pin, thats all i could pull. i qualified 3rd so that wasnt to bad. CONSISTENCY!!!!!!!!!!!! I have a ?, what effects would a smaller gear mesh ( less teeth) have than a larger gear mesh?

There are two ways to look at that. Some r/c racers feel as if the best combo is the smallest possible resulting in the lowest rotating mass. The problem with that is that the smaller the spur and pinion the greater the ratio change with only one tooth pinion difference. according to the S.A.E.(society of automotive engineers) and large gear manufacturers the more efficent setup will always be the largest gears that can be fitted and still achieve the same overall ratio. It's reffered to as the angle of attack and departure of the teeth or gear profile itself.

It's really hard to comprehend without a diagram but try this. Take two pinion gears and mesh them together and look at how much rubbing takes place on the tooth contact event itself and then do the same with two larger spur gears. You'll then see why some people always run the largest combo they can get on the car. Will it make a lap time difference on everyones car? No. Can it help anyones car? absolutely. Will it gain tenths per lap? Probably not. can it be one more piece of the puzzle to going faster? Hmmmmmm? Trial and error is what it's all about.

[DC Racing]

Alright thanks david ill test it tom and see what happens. Ur running edm mod tom right?

[travymoto]

HAHA no way, thats why i asked u bc kip was really shocked to, i was running the lowest at a 6.6999 at 24 degree. So u were freakin fast. lol My motor was at 170 i can only imagine what yours was at. u coming tom?

I think I read that Kip runs a 5.9 with the reedy, so I was right in between you guys. Yeah my motor was hot, but you could cook a steak dinner on Butt's motors..lol

I will hopefully be there and I'm bringing a new Enforcer as well.

[travymoto]

Alright thanks david ill test it tom and see what happens. Ur running edm mod tom right?

He's running latemodel....and he is going to run a pack or two in his dominator...that should be cool.

[DC Racing]

So your going to run mod sprint and edm. That should be cool. I need to get new tires tom. What gearing are you going to start at tom for mod as a final drive?

[travymoto]

I'm not sure yet. I have a few mods ordered but they aren't in yet. I am going to borrow a few motors tommorow so I will have to figure out gears when I get the motors. WHat 10x1 do you have?

[DC Racing]

im running a revolution 10x1 its pretty nice.

[travymoto]

Chad,

nice run tonight !!!

[DC Racing]

Thanks man i had a blast, its nice to win over such good and experienced drivers with a buggy haha, i know i will have a hard time next week bc i know many people will be at the track practicing all week and i know when you come back youll be faster bc of your gearing mistake i the main. Oh well, thanks for the tip on the suspension, i think i might try a softer rr spring next time i go also and see if it helps. I got so lucky though, after the race i looked at my motor and my positive lead wire was not connected. HAHA shweeeeeeeeeeeeuuuuu!!!;)

[travymoto]

Chad,

After thinking about it last night, the softer rr spring may not be the ticket. Is the rear of the car really stuck to the track out of the corner(making you push) or does it seem like the car sort of slides out to the wall when exiting the corner? The softer rr spring will help if it's sliding out. If it's really stuck, you could try a harder rr spring or a sway bar for the rear to get more exit steering.

[DC Racing]

ok heres what happens to my car through corners, i enter well rides bottom good(i got all my off power pushing away) then when i get on the throttle it hooks up well, even better than what it was before the shock move, but it does slide a lil coming out, i have to keep the tires turned left hard exiting. So next time i go thier im going to try one rate softer in rr and jsut try it, but im not shur if i could tell a diff or not. Ill try and see what happens. I have on film all the races and thats how i know, ill watch again jsut to make shur im right. I might go a few softer so i can learn the diff, also i might stay the same way bc i need to work on gearing and it was good. Ok few quick ?'s and im done, charging at 4.0 amps will give me longer run time than 5 correct. I need to try that. Also if i went down a tooth, to a 26 from a 27, and changed my timing from 10-to like 15 or so will it be just a lil slower or will it be a big diff, cus i keep dumping and my motors hotttt. thanks want same performance but less heat, so i figured go down one and turn up timing to make chang?

[travymoto]

Ok, it sounds like the softer rr spring might make it worse. You might want to try one of the other changes I posted above instead. Is they rr blue spring you have on a buggy front? I think Losi makes a black spring that is ever harder and you may want to try that. As far as the gearing thing goes. Try the lower amp charge to see if it helps. Going down a tooth might make your wheel spin worse a make the car loose (what happened to me in the main), but you could try the timeing/gear combo you posted above and see if it works.

[DC Racing]

alright ill try that, its actually a buggy rear blue that i have on it. I know they make that black one thats harder. Also im running a medium swaybar,(soft med hard) so i might put on the harder one for fun. And as far as gearing, im jsut going to keep the same gear only turn down the timing some more. Thanks