Grasshopper suspention

[Timr100 1]

Hi all I am a complete newbie, after many many years I have bought my first tamiya the grasshopper, so I am asking for a little advice, I have fitted it with a 540 motor and a Robinson 18 tooth gear as well as bearings does fitting oil filled shocks make a big difference to its handling I noticed on ebay you can also get an anti roll bar link and shock mounts any advice would be much appreciated many thanks Tim. Oh and any tips would be much appreciated too

[nowinaminute 2815]

It doesn't make much difference at the back because the suspension locks up when accelerating, a design flaw/characteristic of all Tamiya models using that solid transaxle design. It will be possibly make it better when you're coasting along but even then, the rear suspension doesn't work great because all the weight is in the axle.

It will make a bigger difference at the front end.

One thing you can do at the rear is upgrade to hornet style pivots, it doesn't fix the lock up issue and introduces problems of its own but it will at least give you some axle articulation so the wheels can go up and over bumps and spend more time in contact with the ground although again, it becomes largely ineffective when you're under power.

I would say it's worthwhile at the front though and if you get them at the front it won't look right if you don't get then at the back. That's what I always tell myself anyway

[Timr100 1]

Many thanks for the advice. 

[Timr100 1]

So whilst messing around with the front suspension I came up with an idea (ALOT of free time on my hands at the moment) to stiffen the front shocks up I inserted some springs from a biro pen inside the original springs on the front and the difference is unbelievable. Quick and simple. Bit of bodge job but as test really pleased. 

[WillyChang 1814]

Grasshopper suspension ain't much to write home about.  

Think when we tried to get it working on a track, rear Hornet style shocks on the back worked best. I preferred the Grasshopper's fixed pivot vs Hornet floating hinge though. 

At the front we weren't allowed to hack in oil shocks so the springs were it. Best way was to stop it flapping like chicken wings by setting the car to arms horizontal then slipping lengths of fuel tube (silicone rubber tube) so the suspension stopped there. Gave much better steering stability.

Best performance improvement was tyres, get some good rubber. We ran WildOne larger wheels in front & rear, get some good grippy rubber especially at the rear that's suited to your local surface. Fronts don't do much work but higher clearance with bigger wheel was advantage.

Weight inside tub is good for stability too. Lipos can be 100-150g lighter than a nicad pack, most of the original cars also had the receiver pack of 4xAAs onboard too. Try adding 200-250g weight inside the chassis & Hornet suspension starts working halfway decent  

[nowinaminute 2815]

1 hour ago, WillyChang said:

Weight inside tub is good for stability too. Lipos can be 100-150g lighter than a nicad pack, most of the original cars also had the receiver pack of 4xAAs onboard too

Very good point, don't forget the additional servo too! I rebuilt a nikko dandy dash a while back and the suspension didn't want to really move without all those old parts so I ended up putting the throttle servo, MSC and massive old Acoms receiver back in as well as some extra weight to simulate the AA pack and compensate form the light battery. After all that it worked 100x better. I just hid the new ESC and reciever out of view.

Really most Tamiya models right up into the 2000s were still designed around having a heavy nicad, second servo and AA battery pack etc. Stuff like the TL01 was being pushed for use with an ESC but still had the provision for using an MSC so it can really pay to have some extra weight low down in the chassis to compensate.

You can buy little self adhesive wheel weights online for cheap, they are very handy for this purpose.

[Juggular 4964]

Welcome! 

Personally, I like the Hornet suspension.  

The Grasshopper is the #1 when it comes to pogo-stick action. That's not a good thing. I wanted them dampened.  As WillyChang said, it's already lighter than Tamiya intended back in the 80s.  So I even cut off 6mm from front springs to make room for the o-ring dampers of the Hornet.  Those little o-rings work fairly well.  If I were given a choice between taking only the Hornet front or the rear pivot, I'd take the front. (But both front and rear parts are in the same D tree, so you'd get both anyway)

Stiffening the front suspension could reduce the pogo-stick-ness. But the suspension gets hard on already light chassis, and make steering less responsive. (then again, pogo-sticks are the worst when it comes to steering, so stiffer springs are still an improvement)  

The rear doesn't really need any damping.  The Hornet gearbox slamming into the chassis is a bit annoying, though. (like many other members, I had to get a 3rd shock)