Fishtailing

[travis.smith17]

Hey everyone I've been trying to figure this out for some time. I get my 1/10 onroad all wheel drive RC car up to about 30 mph and and the back wheels start fishtailing and it's only at half throttle. I working towards speed runs. I have the camber and toe at 0 degrees. There is no play in the wheels. My diff oil is 10k in the front and 30k in the rear. I've tried contact foams. Nothing I have done get the car past 30mph. Is it because I need more space and slower on the throttle? I would not image 30mph being hard to over come

 

[tntpoof]

have you weighed the car?. what's the rear weight?. I have put lead and brass on my rear end b4.

 

[travis.smith17]

have you weighed the car?. what's the rear weight?. I have put lead and brass on my rear end b4.

Never crossed my mind. I have a kitchen scale. I will let you know over the weekend. Thanks

 

[tntpoof]

kitchen scale will give you some # but it wont be accurate, I picked up 4 digital scales years ago for under 40$ and move them around a board I have setup and do some quick centering to get a idea..and if your doing speed runs id switch gear oil weights around..dont lose any rpms to oils put it to the ground . when I read you 30mph wipeout I was bumming I have a sct that I play with on 3 cells that will do 85 mph-losi sct v1 ..do you know what aircraft safety wire is? its a handy way to attach thing semi permanent...its learning how to twist it just tight enough that added thing wont move. and using the right ga wire..

 

[AClegg]

have you weighed the car?. what's the rear weight?. I have put lead and brass on my rear end b4.

But have you tried putting the lead and brass on the car? ?

Immature joke, I know, but I couldn't resist.

 

[travis.smith17]

kitchen scale will give you some # but it wont be accurate, I picked up 4 digital scales years ago for under 40$ and move them around a board I have setup and do some quick centering to get a idea..and if your doing speed runs id switch gear oil weights around..dont lose any rpms to oils put it to the ground . when I read you 30mph wipeout I was bumming I have a sct that I play with on 3 cells that will do 85 mph-losi sct v1 ..do you know what aircraft safety wire is? its a handy way to attach thing semi permanent...its learning how to twist it just tight enough that added thing wont move. and using the right ga wire..

Okay I'll try switching the oil around. The diffs are the same so I'll just swap them around. Do I want the rear to be equal to the front or heavier. I haven't had a chance yet to weigh anything. I have not hear of that wire before. What exactly do I use that for? The extra weight? Thanks for ur help.

 

[tntpoof]

not a good ide to just switch the oil you have Id start with new (nib)...also wire is in this link you can buy small amounts... you can use a pair of vise grips to spin wire drill small hole thru added weight then wire then spin at top of weight cut thru last twist in wire roll with hemostats to get sharp edge away from all..
Stainless Steel Safety Wire - Chief Aircraft Inc.

 

[tntpoof]

they make a set of safety wire pliers that can be switched from counter clockwise to clock wise with turn of knob(to costly for most)
PROTO Automatic Safety Wire Twist Pliers, Wire Size: 0.020 in to 0.041 in, CW/CCW Rotation - 4JV75|J196 - Grainger

 

[travis.smith17]

I know what ur talking about. I used a wire similar to that before when I was in the army the pliers too. Thanks.

 

[tntpoof]

ok..

 

[StephMir]

I had something similar happen to my Kyosho Fazer On-Road. Check out my thread here: https://www.rctalk.com/forum/thread...e-side-when-accelerating.132022/#post-1305687
Long story short, I replaced both differentials, gaskets and gears. Also, I put 3k in the REAR and 30k in the front, based on a Kyosho video I saw by some professionals here:

Great info. Hope this helps.

 

[Greywolf74]

I had something similar happen to my Kyosho Fazer On-Road. Check out my thread here: https://www.rctalk.com/forum/thread...e-side-when-accelerating.132022/#post-1305687
Long story short, I replaced both differentials, gaskets and gears. Also, I put 3k in the REAR and 30k in the front, based on a Kyosho video I saw by some professionals here:

Great info. Hope this helps.

30K is too thick imo for speed runs which is what the OP was trying to do.

 

[Edough13]

30K is too thick imo for speed runs which is what the OP was trying to do.

I'd disagree as in my experience with speed running and I've done 145mph so far you need almost locked diffs. I run 20mil diff oil in my Limitless with a locked center spool. Some of the best in the world will lock the front diff and run 20mil in rear. I'd try to thicken up the diff fluids and play with your front toe. When the diff has light fluids you can have it diff out and cause the spin out as one side is being allowed to spin faster than the other. With locked or almost locked diffs the wheels stay spinning the same speed all the time not allowing the diff out and spin out.
Also I'm sure the lower weight makes it difficult as I tried to run my Tamiya TT01 1/10 and it was a pain and all over. Managed 50mph with it but it's just so light that any little steering correction would cause it to spin and go flipping down the road. That's another suggestion is turn your steering down to almost nothing so when you make an adjustment it hardly makes the car move at all but just a slight turn back to straight. I run my Limitless at 140+mph with my steering at like 7% so adjustments don't send me across or off the road. Here's some attempts I made with the TT01 think I managed 46 or 48mph here but as you'll see it was not easy as I had light diff fluids and steering not turned down enuogh.

And 144 with my Limitless

 

[Greywolf74]

I'd disagree as in my experience with speed running and I've done 145mph so far you need almost locked diffs. I run 20mil diff oil in my Limitless with a locked center spool. Some of the best in the world will lock the front diff and run 20mil in rear. I'd try to thicken up the diff fluids and play with your front toe. When the diff has light fluids you can have it diff out and cause the spin out as one side is being allowed to spin faster than the other. With locked or almost locked diffs the wheels stay spinning the same speed all the time not allowing the diff out and spin out.
Also I'm sure the lower weight makes it difficult as I tried to run my Tamiya TT01 1/10 and it was a pain and all over. Managed 50mph with it but it's just so light that any little steering correction would cause it to spin and go flipping down the road. That's another suggestion is turn your steering down to almost nothing so when you make an adjustment it hardly makes the car move at all but just a slight turn back to straight. I run my Limitless at 140+mph with my steering at like 7% so adjustments don't send me across or off the road. Here's some attempts I made with the TT01 think I managed 46 or 48mph here but as you'll see it was not easy as I had light diff fluids and steering not turned down enuogh.

And 144 with my Limitless

Definitely in agreement with ya on the steering and I agree with what you're saying about wheels spinning at the same speed but the thicker the diff fluid the more you're going to limit you max CVD RPMs which can end up costing you top speed. I guess it all a balancing act and part of tuning your exact rig. The rig I used for speed runs is vastly different then yours so I guess we can't make apples to apples comparisons there.