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hopping up a vintage grasshopper 12 years 5 months ago #3254

hi, i have a problem with my grasshopper. it is almost impossible to keep it in a straight line, i dont mean tracking off,the steering arms are set up as per manual and the trim is set to centre.
at slow speeds the car goes in a dead straight line.
what i mean is the slightest movement on the steering sends it in to a wild spin/donut and it is very difficult to get it straight again.
is it a front end grip problem, do i need less toe in on the front wheels or, would a weight bias added help, bearing in mind it has the esc fitted now so the batteries have been removed from the rear that fed the receiver, so much less weight in the rear now.
any ideas welcome

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Last edit: by agemax. Reason: new title

hopping up a vintage grasshopper 12 years 5 months ago #3255

The stability of the Grassshopper is a common problem. Especially when replacing the original motor. :S
But looking at your pics in the "ready to rock" topic I conclude the car really has a lot of toe in...
Making the tie rods shorter and creating some toe out should definitely be an improvement already.

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Last edit: by Edou.

hopping up a vintage grasshopper 12 years 5 months ago #3256

hi, i have a problem with my grasshopper. it is almost impossible to keep it in a straight line, i dont mean tracking off,the steering arms are set up as per manual and the trim is set to centre.
at slow speeds the car goes in a dead straight line.
what i mean is the slightest movement on the steering sends it in to a wild spin/donut and it is very difficult to get it straight again.
is it a front end grip problem, do i need less toe in on the front wheels or, would a weight bias added help, bearing in mind it has the esc fitted now so the batteries have been removed from the rear that fed the receiver, so much less weight in the rear now.
any ideas welcome


A couple more suggestions...

Check the front uprights - there are two holes where the ball joints for the steering rods can be fitted, the innermost holes will give more steering angle & less stability, the outermost holes give slightly less steering angle but more stability ... either have advantages, depending on how you drive - the inner setting will give you more steering lock & faster response, which with practice will let you keep the power on & drift it, the outer setting is less likely to get it sliding with steering input in the first place.

Secondly - throttle control - from looking at your videos, you seen to be using the throttle as an on/off switch - try slowing down a little for cornerning ;)

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hopping up a vintage grasshopper 12 years 5 months ago #3257

ok i will try it, but they are set up as to the spec/dimensions in the manual.
i guess to adjust is to try.......cant do any harm

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hopping up a vintage grasshopper 12 years 5 months ago #3258

hi, i have a problem with my grasshopper. it is almost impossible to keep it in a straight line, i dont mean tracking off,the steering arms are set up as per manual and the trim is set to centre.
at slow speeds the car goes in a dead straight line.
what i mean is the slightest movement on the steering sends it in to a wild spin/donut and it is very difficult to get it straight again.
is it a front end grip problem, do i need less toe in on the front wheels or, would a weight bias added help, bearing in mind it has the esc fitted now so the batteries have been removed from the rear that fed the receiver, so much less weight in the rear now.
any ideas welcome


A couple more suggestions...

Check the front uprights - there are two holes where the ball joints for the steering rods can be fitted, the innermost holes will give more steering angle & less stability, the outermost holes give slightly less steering angle but more stability ... either have advantages, depending on how you drive - the inner setting will give you more steering lock & faster response, which with practice will let you keep the power on & drift it, the outer setting is less likely to get it sliding with steering input in the first place.

Secondly - throttle control - from looking at your videos, you seen to be using the throttle as an on/off switch - try slowing down a little for cornerning ;)

cheers, the ball joints are in the outer position, as for the throttle control the new ESC does not give as much thrittle control as i was expecting. it seems very tricky to drive "slowly". maybe the transmitter is a bit old and tired? the batteries are good

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hopping up a vintage grasshopper 12 years 5 months ago #3262

i wonder if wider front wheels/tyres would help? what other front wheels fit a grasshopper?

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hopping up a vintage grasshopper 12 years 5 months ago #3263

i wonder if wider front wheels/tyres would help? what other front wheels fit a grasshopper?


Vintage Sand Rover/Holiday Buggy, Subaru Brat, vintage Pajero wheelie ... Midnight Pumpkin/Lunchbox too, if you swap the uprights...

There are some things you can do to improve the Grasshopper's handling, but ultimately I think you'll have to accept that it's arguably the worst handling Tamiya buggy ever, and learn to accept it, unless you are willing to expend some money, time & effort on it:

The front end, thanks to the single wishbones suffers badly with bump steer, and lack of damping, Hornet "damper" parts really don't do much to improve things, the Team CRP FX10 front end upgrade & proper dampers are the only way to go if you're serious about improving things;

The back end acting as a hinge (and having no damping) means that a bump on either wheel lifts both rear wheels, the Hornet pivot points and dampers are the only real upgrade, but you do need to do something about partially locking the middle of the gearbox pivot (look around for the "third shock" mod for the Pumpkin/Lunchbox to see what I mean - but bear it mind there's almost no room to do the same on a Grasshopper, and no-one has yet come up with a satisfactory answer as far as I know);

Increase weight over the back end so the unsprung/sprung weight balance is more favourable;

Sort out the odd throttle response - it's either the ESC, motor or transmitter at fault, so test each one by substitution, I'd suggest a standard "silvercan" 27 turn 540S motor rather than the motor you already have in there, you'll also need an 18 tooth 0.8 module pinion.

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hopping up a vintage grasshopper 12 years 5 months ago #3265

a bit of R&D discovered the rear wheels will fit on the front. with a little spacer,(washer) it clears the steering ball joints, wonder if this will help?
sure looks cool

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hopping up a vintage grasshopper 12 years 5 months ago #3266

For the wheels you could also do what I went for... Tamiya 12mm hex adapters and a set of DT-02 wheels.
The adapters are parts number 53913 and with it you will be able to fit rims with a more universal (12mm hex) wheel hub.



I find the tyres I'm using have a real improvement on grip :




These were only 15 euro for the complete (preglued) set... :)
Notice the front wheels having toe out - using a 23 turns 540 motor. ;)

Edit : with the rear wheels in front I think it would be missing some ball bearings.
Looks a bit like a Monster Hopper though. :lol:

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Last edit: by Edou.

hopping up a vintage grasshopper 12 years 5 months ago #3269

but its the front wheels i want to change, not the rear. so i shouldnt need the hex adaptors i would think cuz they arent driven?

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