Monster Grasshopper Conversion

[rc_ox 323]

Hi folks, 

I've been talking to my son about doing a Monster Beetle conversion on his re-re Grasshopper for a while now. Just checking if there are any 'gotchas'? Do the larger wheels put too much load on the steering and gearbox? 

We put a 540 in it which has given it good boost in power and speed. However it doesn't have enough ground clearance on the lawn and often gets hung up in thick grass. I thought the balloon tyres would help lift it and improve the springy suspension slightly too. So far the Grasshopper has been a great first car for my 6 year old - very durable and looks great!

I am considering the following two options... 

 

Option 1 - Lunchbox 

Get the Frog Hex adapters

Install Lunchbox front axles as they are longer

Lunchbox wheels and tyres 

 

Option 2 - Monster Beetle

Monster Beetle wheels and tyres. 

I guess I'll still need the longer Lunchbox axles on the front for this option too. As far as I know the rear Monster Beetle wheels have the same adapter as the Grasshopper.

 

Has anyone done one of these conversions and had good/bad results?

[Running Fox 70]

I think by upgrading your grasshopper that way, you get a kind of Mad Bull:

http://www.blackholesun.fr/en/35-en/my-models/off-road/buggy-truck/108-tamiya-58205-madbull-dt-01

 

Found this on Youtube: 

 

[Running Fox 70]

You probably also might need to mount a ampro engneering transmission brace to get rid of the hopping behaviour of the car.

[73robb 132]

Have a read here, there was a Hornet with Mad Bull Wheels a while back 

 

 

[rc_ox 323]

Thanks for the fast replies @Running Fox and @73robb!

I looked up the front axle adapters in that youtube clip and they are way too expensive to get shipped to Australia. I think the part is about US$7 and shipping is US$14...by the time you add the tyres and wheels...he's run out of pocket money! The Lunchbox axles on the front should work just as well - I borrowed a friend's to check that they fit. One of the LHS's here has a pair for AUS$12. The bumper will have to be trimmed or removed for the wheels to get enough clearance though. 

I guess I should have done a better search of TC - Vrooom666's post already covered my question 

Well the conversion seems like a fun project so I think we will go ahead! I'll be sure to post the results here when it's done. 

[rc_ox 323]

2 hours ago, Running Fox said:

You probably also might need to mount a ampro engneering transmission brace to get rid of the hopping behaviour of the car.

Oh, I think that's only needed on the Hornet and Lunchbox (maybe the Grasshopper 2 as well?) The standard Grasshopper doesn't have that twisting action in the rear, it's pivot points are secured so it doesn't jolt when accelerating....if that's what you mean? 

 

[ThunderDragonCy 8116]

Fairly sure you don't need the hex conversion either. Lunchbox uses the Grasshopper gearbox and Lunchbox wheels aren't hex, they're the older Tamiya style. I think they will bolt straight on. As you say, just get the Lunchbox uprights and trim the bumper and you're golden.

[Running Fox 70]

2 hours ago, rc_ox said:

Oh, I think that's only needed on the Hornet and Lunchbox (maybe the Grasshopper 2 as well?) The standard Grasshopper doesn't have that twisting action in the rear, it's pivot points are secured so it doesn't jolt when accelerating....if that's what you mean? 

 

Correct. You only need it iff you have that moving axle. Looks like a fun project to me! Be sure to send us some pictures!

[rc_ox 323]

12 hours ago, ThunderDragonCy said:

Fairly sure you don't need the hex conversion either. Lunchbox uses the Grasshopper gearbox and Lunchbox wheels aren't hex, they're the older Tamiya style. I think they will bolt straight on. As you say, just get the Lunchbox uprights and trim the bumper and you're golden.

Good point, thank you! I'll see which way my "client" wants to go Lunchbox tyres or Monster Beetle spiked. Either way, it should be fun.

Stay tuned... 

[Juggular 5079]

@Running Fox I like how everything is non-standard.  That's more fun.  I could buy AMPRO parts and know from the start that everything would fit.  Since you had to wrestle with mechanics of it all, that deserves more respect. My hats off to you.  

Bigger tires going slower is interesting. I suppose a stock 380 motor doesn't have enough torque to turn big wheels as fast as smaller wheels.  Traxxas 18 turn 380 is a good choice.  

I'm following this thread @rc_ox  I am curious what your client wants also.  

 

[rc_ox 323]

I may have to change tack a little. I have been tallying up the cost of the front lunchbox axles + Monster Beetle wheels + Monster Beetle tyres and it adds up to nearly half the cost of the kit (inc. shipping because our LHS's don't stock many Tamiya spares).  

I just found the hex adapters for the Frog (#53913) - this allows you to run regular hex wheels on the rear rather than be locked into the MB/LB/GH wheel adapter type. I can test out the Monster Grasshopper conversion with my Wild Willy 2 wheels - he can buy a set or WW2 wheels/tyres if he likes it or he can try other buggy wheels too. 

 

[ThunderDragonCy 8116]

49 minutes ago, rc_ox said:

I may have to change tack a little. I have been tallying up the cost of the front lunchbox axles + Monster Beetle wheels + Monster Beetle tyres and it adds up to nearly half the cost of the kit (inc. shipping because our LHS's don't stock many Tamiya spares).  

I just found the hex adapters for the Frog (#53913) - this allows you to run regular hex wheels on the rear rather than be locked into the MB/LB/GH wheel adapter type. I can test out the Monster Grasshopper conversion with my Wild Willy 2 wheels - he can buy a set or WW2 wheels/tyres if he likes it or he can try other buggy wheels too. 

 

I have some brand new lunchbox uprights for sale if you want them? I am in the uk. PM me for details if you want.

[rc_ox 323]

Well I finally came around and finished this project - I can't beleive it has been 2 years since I posted this thread! As I recently replied to another thread about the same conversion idea, I thought I should include the details here as a conclusion to this thread. 

As mentioned above, the cost of a full set of wheels and front axles - it just wasn't worth the $$$ to buy them individually. But unfortuantely my favourite LHS closed up earlier this year so I grabbed a few kits at great prices. One was a Midnight Pumpkin - Black Edition. I missed a Red Lunchbox by a few hours  No matter, the Pumpkin kit has all the necessary parts to convert this Grasshopper into a MONSTER.

Parts borrowed: 

• Wheels & tyres
• Front axle
• Front bumper 

We had already upgraded the motor to the 540 with 18t pinion. I also noticed the ball ends on the grasshopper are smaller than the ones in the Pumpkin but I didn't change the steering rods so I moved the Grasshopper's ball ends over to the new ones from the Pumpkin. So far so good. I can confirm it is a hoot to drive and clears thicker grass and sand with easy and there is less "diff'ing out" with those big rear tyres. The front wheels are a bit gangly but lots of fun. 

 

[Ziddan 983]

So, another post to this thread two years later

Thats an excellent combo!

Would you happen to still have the Monstered Grasshopper?

If so, could you measure the width of the clearance between the front and back tires for me?

 

Ive put a beetle shell on a grasshopper chassi and was wondering if lunchbox/midnight pumpkin wheels would leave enough space for said body.

Looks like it might barely fit but as you might still have the combo i figured id ask

[rc_ox 323]

6 hours ago, Ziddan said:

So, another post to this thread two years later

Thats an excellent combo!

Would you happen to still have the Monstered Grasshopper?

If so, could you measure the width of the clearance between the front and back tires for me?

 Thanks for your reply! 

I put the Grasshopper back to it's stock form and returned the Midnight Pumpkin parts to the box with the rest of the kit. 

HOWEVER! I would be more than happy to dig it all out for a fellow TC member 

I'll try and get it done this weekend and post the measurements here....stay tuned....

 

[Ziddan 983]

Back in the box? At least put that kit together on its own

Thank you, i appreciate it 

[rc_ox 323]

On 4/28/2022 at 2:14 PM, Ziddan said:

Back in the box? At least put that kit together on its own

@ZiddanHaha!  You have a good point there - yes, it should be built! Actually, I'm hoping my 'better half' will have a crack at building the Pumpkin - she has watched me put enough of these things together, I think she should share the enjoyment too. 

 

I dug out the parts and re-assembled the Mosnter Grasshopper as promised. The distance between the tyres is....

FRONT: 135mm 

REAR: 145mm

I also noticed the gap between the nerf bar and the front tyre at full lock is a little tight. You might want to take that into consideration.

[Ziddan 983]

Thanks dude, much appreciated 

Saving the kit for your better half is definitely a valid reason for it to wait around 

[rc_ox 323]

You are more than welcome! 

Good luck with the Beetle-Hopper - sounds very cool 

[Sogogi 3333]

Out of curiosity, what are ways to fit regular grasshopper front wheel on lunchbox front axle? (I want to put truck tires on but also don’t want to swap axles everytime i want to put grasshopper wheels)

[El Gecko 1428]

5 hours ago, Sogogi said:

Out of curiosity, what are ways to fit regular grasshopper front wheel on lunchbox front axle? (I want to put truck tires on but also don’t want to swap axles everytime i want to put grasshopper wheels)

Slide a few of those white plastic bushings on the axle before the wheels. It'll make for more wheel scrub because it changes the offset, which might help with turn-in, and it'll widen the track without having to resort to the wider GH2 front suspension arms.

However, I should recommend the GH2 front suspension arms anyway, to help stability with the monster wheel/tire setup. The tendency of a Grasshopper to roll over is only magnified with larger tires. I tried it once, broke a steering upright, and went right back to normal buggy wheels. And I still manage to roll it at least once nearly every time out (haven't broken anymore uprights since it's been back on buggy wheels either)