Blackfoot spinning round

[Ks1975 0]

Hi

Newbie here but hope you knowledgeable folk can help out.

I have a 2016 Re Blackfoot. All seems to work ok except under braking (Tamiya ESC being used), where the truck spins round (and usually causes it to topple). Driving me slightly mad! 

I rebuilt the standard gearbox just to rule out one side sticking etc, checked all the stock suspension to see it is the same all round and working ok (even swapped shocks around etc) but it still does same, and always spins to the left. Also checked the wheels and alignment, and they seem fine, and the changes i did make to make sure the toe in was even made no difference anyway. 

Any suggestions as to what else to check/change to alleviate the problem - or do to they all do this?

 

[huasze 24]

If you let go of the throttle and it starts veering, then check the bearings and left axle. 

[Ks1975 0]

8 minutes ago, huasze said:

If you let go of the throttle and it starts veering, then check the bearings and left axle. 

Thanks. When i just let go, it stays straight, only spins when i brake to slow it down. And i should say, this only happens only on tarmac, grass etc doesn't show it up. 

I did wonder if the stock suspension was just too stiff. 

 

[huasze 24]

Ok, then it's not bearings. I'm no expert, but it could be something with traction. You can always put in thick differential grease in the rear diff to eliminate the issue as well

[jameswrx 40]

Can only be down to the diff if it’s during braking like that surely?  Sounds like it’s locking more one side.

Try the brake position and spin each wheel and see if one is notably different?

Sounds to me like the left side will be tighter

[Snappy1 966]

It could also be the ESC brakes 

[Ks1975 0]

1 hour ago, jameswrx said:

Can only be down to the diff if it’s during braking like that surely?  Sounds like it’s locking more one side.

Try the brake position and spin each wheel and see if one is notably different?

Sounds to me like the left side will be tighter

I'll go and check later. I recall that when i looked at it (wheels off the ground) the wheels span up evenly, and when braking, both sides stopped at the same time. Obviously there was no load which is why i was thinking suspension related! 

[A-Baum 352]

I just built a rere-blackfoot but used the MIP ball diff and mine does the same thing.  It doesn't topple over but if I throw the brakes on it'll spin 180-270 degrees.  Never thought much of it because it didn't flip over.

[David Zheng 17]

I had lots of Tamiya RWD offroad cars and trucks in the past, under heavy braking, they spun out easily especially with a bit of steering input.  Straight line braking would be the best without steering input but it will take more space.  Also the stock tires on my offroad cars and trucks weren't meant for pavement, which was another factor for easy spinout under braking.  Did you try driving it on dirt?  Finally, which radio do you have?  If you can tune down the brake by using exponential or even EPA, that can help as well.  When changing throttle EPA you might have to readjust the neutral a little on throttle trim.

[KEV THE REV 2307]

The same way you can get torque steer under throttle , perhaps the braking can have a reverse effect by unbalancing the truck , not had this happen to me on braking but I guess it could happen

[Ks1975 0]

1 hour ago, A-Baum said:

I just built a rere-blackfoot but used the MIP ball diff and mine does the same thing.  It doesn't topple over but if I throw the brakes on it'll spin 180-270 degrees.  Never thought much of it because it didn't flip over.

That's good to know - i was thinking about whether the MIP ball diff would make a difference. 

[Ks1975 0]

1 hour ago, David Zheng said:

I had lots of Tamiya RWD offroad cars and trucks in the past, under heavy braking, they spun out easily especially with a bit of steering input.  Straight line braking would be the best without steering input but it will take more space.  Also the stock tires on my offroad cars and trucks weren't meant for pavement, which was another factor for easy spinout under braking.  Did you try driving it on dirt?  Finally, which radio do you have?  If you can tune down the brake by using exponential or even EPA, that can help as well.  When changing throttle EPA you might have to readjust the neutral a little on throttle trim.

Thanks.

Dirt and grass are fine, just on tarmac which is much grippier. 

[Ks1975 0]

Thanks all - maybe it's something i just need to live with. Was hoping to race with my son's mad bull down the road, but i keep losing  

Maybe i need to get a smaller/faster buggy!!

[A-Baum 352]

4 hours ago, Ks1975 said:

That's good to know - i was thinking about whether the MIP ball diff would make a difference. 

The MIP ball difference does make all the difference in a Blackfoot/MB for a hundred other reasons.  I highly recommend it.