XPRO - Crazy spinning Doughnut Machine

[Schawa]

Hi Guys,

New to this forum. I am from South Africa. Stumbled upon this forum in my search to get the best out of my son's TC02T (Same as XPRo truck). OK, OK, it is my son's although I spend most of the time with the car.

Bought lots of spares recently from TCModels after losing a diff. Ordered on Sunday evening, in my PO Box on Thursday!! Amazing service and speed, wow!!

Anyways, here is my question. The car's diff was rebuilt following all the instructions found on this great forum. Diff does not slip, feels reasonably smooth. Considerable effort to turn gear if both wheels are held. Slipper is a bit tight, but does slip when it should. When running on grass it seems like the car has a tendency to run towards the right, not as a result of front wheels turned that way, but as if the left back wheel has more power on it. No sharp turn, just a slide every now and then. I think it runs OK on grass even with the occasional tendency to the right - all in all very manageable to drive at speed.

When the car gets onto gravel/loose sand it is a completely different matter. Running in straight line once at speed no probs - BUT when pulling away from standstill causes and immediate doughnut, spins in circles. I think always clockwise. Only when you pull away slowly does it stay straight. Making turns at speed on gravel is near impossible without spinning out.

What's wrong - diff, steering, weight distribution/shocks (or just poor driving) ?

NB: It runs with 17T Brushed motor (also bought from TC a 3000KV brushless + 100A ESC but do not want to covert before fixing the spinning)

[minke]

Not sure about the spec of the esc but sounds like too much punch when you launch. Try dialing down the initial acceleration if you can. It musta come with either a programming card or instructions to turn it down. To be honest any rear wheel drive will spin out on loose/wet surfaces if you floor it from a standstill.

Also check your left/right weight distribution, serious weight imbalance can make it pull to one side. Check there is no binding from the wheels being on too tight as well.

[Schawa]

The ESC is a very simple one that came with the RTR car. No programming card.

Binding? Sorry, noob still. I am assuming it has something to do with a too "tight" diff?

[minke]

if you cant adjust the esc then you will have to have a looser slipper. Take off the slipper spring and compress it with some pliers a few times to get it a bit shorter then reassemble and try it with a slacker setting.

The binding i'm refering to is simply the wheels being on too tight. Even 1/8 of a turn too much will cause problems.

[Schawa]

Got it Minke, thanks a million.

Will check that wheels are not to tight - and will get slipper to slip (I do think it is a bit tight)

[minke]

Its worth having a play around with adding weight too. Set up a wooden ramp, say 4ft longish propped up about 12 inches high. Watch what the car does in the air, add weight to left or right if necessary.

A piece of lead strip stuck onto the top or underside of the servo will help keep the front down too.

[Schawa]

Going airbourne tomorrow!

Thanks again. I bought car about 12 months ago. Just by chance, did no research at all. Only after the diff packed up (well, spur gear stripped) did I start to research. Looks like I by chance bought a pretty decent kit!

Do not us it for racing, we just play around..