ZX5 spinning problem

[CougarRob]

Hey guys, I was hoping that someone can help me with my ZX5-S which has developed the ability to spin in its own length when you accelerate on lowish grip tracks (Worksop for example). I run a fairly standard set-up:

Front Springs - Lime Green
Front oil - 40wt
Rear Springs - Standard Silver
Rear Oil - 25wt
7 deg front hubs
All susp pick up points as per RogerM's set up
X12 7.5T motor
21tooth pinion
Stock Spur
Trackpower 3200 lipos with extra weight on battery strap to bring up to min weight.

The rear diff is nice as free. The front diff is slightly tighter. I have tried standard anti-squat and also zero with the same results.

The car has gone from being great to drive (so much so that I have resisted the urge to get an FS) - to a right handful!

Any ideas please would be much appreciated.

[RogerM]

Is everything free in the driveline? If one wheel / diff out drive bearing has given up that will make it want to pivot around that corner.

Was it ok then suddenly went bad?

Also check that your shocks are equal lengths and that droop is even.

[CougarRob]

Thanks for quick reply Roger, I will do a complete strip down and rebuild. Everything 'feels' ok and free but you never know..... some of the parts are now quite old (obviously) and it could probably do with new bearings.

I was partly hoping you would say that it was a good idea - even vital - that I buy an FS!!!!!!! Just need the incentive as changing from sticks to saddles is going to be pricey....

Thanks again.

[RogerM]

Well the FS is certainly a damn fine car

[Robbiejuk]

Could this be anything to do with that standard dogbone your still running in it? Could be binding up.

[CougarRob]

Hiya Rob, I think that it might be the transmission bearings. The dogbone assembly is actually ok (i thought that might be the problem at first). You'd think that the bearings would be perfect considering my profession!!

[RogerM]

Also check for broken drive pins behind the wheel hexes! I've seen pins break so that there is enough friction they feel fine when spun by hand but not enough to transfer drive! Never on a K' car though but worth a check if all else looks ok before stripping the whole car down.

Good luck and please report back.

[Robbiejuk]

Originally Posted by CougarRob

Hiya Rob, I think that it might be the transmission bearings. The dogbone assembly is actually ok (i thought that might be the problem at first). You'd think that the bearings would be perfect considering my profession!!

I would still consider changing it to a cvd or uj, I can't remember the last car i brought that came with standard driveshafts that wasn't a tamiya mini

[RogerM]

Actually, if you have a CVD on one side and a dogbone on the other the transmision will feel different side to side, even more so on a slipper surface!
Driveshaft joint positions can have much more of an effect on the handling than most people realise or even consider possible (due to the way they influence the suspension on wind up / torque loading). The Losi boys have played with different driveshaft positions till the cows came home and I believe used different ones depending on track conditions at some points in history!

That might be you issue! I read it as you running dogbones both sides at the rear.

[CougarRob]

I have stripped everything down and its definately the rear hub bearings on the CVD side.

I know that its less than ideal to run dogs ones side and CVD the other but its been like that for a while with no real noticable problems (My driving is the most noticable problem!).

The rear CVD hub bearings are shot and the front hub on the same side is going too...... obvious really but when you are at a race meeting you tend to overlook things.

Will get a new bearing set and try again......thanks.

[Robbiejuk]

I would change the driveshaft to mate, it is possible that it might have caused your bearing problems...

[RogerM]

Originally Posted by CougarRob

Will get a new bearing set and try again......thanks.

RcBearings.co.uk ... great quality and brilliant price

[CougarRob]

Thanks Roger but your signature already worked - used your hyper link to RC Bearings. I have ordered a set for my ZX5 and my RB5 - already posted apparently!!