M-04M Gearing and diff questions please
#16
Tech Initiate
Good damping on the rear will still help putting the power down. The standard springs and friction dampers aren't up to much. Maybe something to try. Also see if your speed controller allows some current limiting to control the power delivery.
#17
Set your rear suspension a little softer than the front. Also set your rear end to a lower ride height than the front. Try to have about 5-6mm front and 1mm less in the rear. Some nice shocks are probably a good idea otherwise your setup is going to be fiddly. You should be able to tune your suspension a lot better because your arms don't flex as bad as mine (mine is a M02).
But first you need to make sure you've got good tires. Without these you're going to have only headaches. You didn't tell us what surface you run on, so I will guess asphalt. I found that the best tires were 60D Type A slicks. These probably have a tad less grip than the S-grips but that keeps the front from turning in too fast.
I think this is where you have to work. Try to get as much weight as possible on the rear and grippier rear tires. I have also loaded the car with weight to compensate for the lipo I'm using, and put most of the weight on the rear wheels.
#18
Tech Adept
iTrader: (5)
You may also want to add the toe-in rear uprights (tamiya no. 53345) - I got a set on order now!
I have a similar problem - the rear end comes loose only on the straight (front has plenty of grip, no off power slips either). As niznai said, try a heavier battery - it helps.
Finally, take apart and clean the gear diff and rebuild it with the regular (thinner, not thicker) grease.
I have to say that I didn't have this instability problem until I made the following two changes - lowered the car by changing from standard cva dampers to mini cva dampers, and moving the s-grips to the rear (leaving the kit standards on the front.)
Alot of things to consider then ... Next time, I am going to change only ONE thing at a time!
Farzad
I have a similar problem - the rear end comes loose only on the straight (front has plenty of grip, no off power slips either). As niznai said, try a heavier battery - it helps.
Finally, take apart and clean the gear diff and rebuild it with the regular (thinner, not thicker) grease.
I have to say that I didn't have this instability problem until I made the following two changes - lowered the car by changing from standard cva dampers to mini cva dampers, and moving the s-grips to the rear (leaving the kit standards on the front.)
Alot of things to consider then ... Next time, I am going to change only ONE thing at a time!
Farzad
#19
Sorry guys i've not been updating the thread
So things are moving on, i ordered a 3racing diff.
This helped a little bit but the car was still pretty much undrivable for my poor driving skills.
While i was at it i also ordered the M05 fast gear set from 3racing.
I refitted the stock Esc and 540 motor and installed the 33/21 spur gear.
I don't have any Tamiya pitch gears so i went through my standard 48P pinion gears and found that a 28T pinion in the 21T mounting hole fitted perfectly.
I did some calculations and found that on the standard 21/37 with my brushless motor spinning at 21600rpm i would see a max speed of 26.13mph.
With the new 28/33 i should see 39.06mph.
So in theory the new gearing should dramatically improve slow speed acceleration control.
I took it out for a spin and it was the best it's been.
It still has a tendency to snap rather than slide if the rear steps out, but when it does step out it gives you a lot more time to do something about it.
Everything was going great but i kept seeing the car kick up dust.
To be honest as it's Greek roads i didn't think to much about it at first.
I then realised it's not stopped raining in 3 days so there should not be any dust
I bent down to have a look at the car and found smoke coming out from under the shell
I removed the shell, disconnected and removed the battery and let the car stand for 15 mins.
15 mins later i saw the smoke had beeen coming from the motor, so i did the old "i wonder if it's still hot" test of touching it
Yep it was still hot.
I've since refitted the 9T brushless motor, so fingers crossed this'll be able to pull the gearing better than the old 540 (without over heating).
Weird thing is though when the motor was smoking the Esc was only warm to the touch
So i'll test it with the 9T and we'll see.
I know that standard 48P are not exactly the same as Tamiya 48P, but i figured i'd test it this way till the gear wears and if it's ok i'll then invest in some new spurs and pinions.
The wheels and tyres i ordered arrived as well, so i'll glue those tomorrow and i'm sure they'll help a hell of a lot, as the slicks are really soft and sticky.
I'll let you know how i get on with the 9T motor and new tyres.
Better take a fire extinguisher just in case
Cheers
Mark
So things are moving on, i ordered a 3racing diff.
This helped a little bit but the car was still pretty much undrivable for my poor driving skills.
While i was at it i also ordered the M05 fast gear set from 3racing.
I refitted the stock Esc and 540 motor and installed the 33/21 spur gear.
I don't have any Tamiya pitch gears so i went through my standard 48P pinion gears and found that a 28T pinion in the 21T mounting hole fitted perfectly.
I did some calculations and found that on the standard 21/37 with my brushless motor spinning at 21600rpm i would see a max speed of 26.13mph.
With the new 28/33 i should see 39.06mph.
So in theory the new gearing should dramatically improve slow speed acceleration control.
I took it out for a spin and it was the best it's been.
It still has a tendency to snap rather than slide if the rear steps out, but when it does step out it gives you a lot more time to do something about it.
Everything was going great but i kept seeing the car kick up dust.
To be honest as it's Greek roads i didn't think to much about it at first.
I then realised it's not stopped raining in 3 days so there should not be any dust
I bent down to have a look at the car and found smoke coming out from under the shell
I removed the shell, disconnected and removed the battery and let the car stand for 15 mins.
15 mins later i saw the smoke had beeen coming from the motor, so i did the old "i wonder if it's still hot" test of touching it
Yep it was still hot.
I've since refitted the 9T brushless motor, so fingers crossed this'll be able to pull the gearing better than the old 540 (without over heating).
Weird thing is though when the motor was smoking the Esc was only warm to the touch
So i'll test it with the 9T and we'll see.
I know that standard 48P are not exactly the same as Tamiya 48P, but i figured i'd test it this way till the gear wears and if it's ok i'll then invest in some new spurs and pinions.
The wheels and tyres i ordered arrived as well, so i'll glue those tomorrow and i'm sure they'll help a hell of a lot, as the slicks are really soft and sticky.
I'll let you know how i get on with the 9T motor and new tyres.
Better take a fire extinguisher just in case
Cheers
Mark