How can I improve monster beetle's handling?

[LMF5000]

This is my first RWD Tamiya and my first big-wheel truck (my other models are 4WD touring cars on TA-02 and TT-01, a buggy on TT-02BR, and a cross-country on CC-02).

The monster beetle (ORV chassis) is ridiculously bouncy on rough ground - to the point where the front wheels spend half their time in the air. I tried to remove the spacers of the front dampers (that clip on above the spring), but no difference. It doesn't seem to absorb bumps, rather it crashes and bounces over them.

On dirt it easily spins out, while on tarmac it has a tendency to lift a front wheel then flip over. When braking hard it tends to spin 180° when it's close to stopping and ends up facing the direction it came from.

I have the front tie rods within 0.1mm of the instruction's recommended dimensions (verified with vernier callipers) which gives the front wheels a slight toe-in. I also noticed the servo saver seems very soft and the front wheels can have a bit of a mind of their own.

Has anyone found good ways to solve one or more of these quirks?

[MadAnt]

That's the way 80's monster trucks handled. Softer springs may help, but you still have limited suspension travel and a high center of gravity. The ORV platform started life as an offroad car with small wheels, then someone at Tamiya decided it could be a monster truck too with big tires and a high mounted body. 

[TurnipJF]

I find mine runs a fair bit better with a lighter body. 

I have also added 3mm internal spacers to the shocks to reduce their maximum extension a little. 

[Saito2]

The Monster Beetle body seems a good bit lighter than the Blackfoot body it shares a chassis with. As such, I find the stock front shock set-up to be over-damped. With heavy dampening and a light front end, it does seem to hop and bounce over obstacles rather than absorb them. Unfortunately, Tamiya uses the cheaper, non-adjustable "nailhead" fixed pistons which mean your only recourse is to run lighter oil. On my Monster Beetle, I run different piston rods with swap-able piston heads and use a piston with large holes. Grinding a slot in the side of the stock nailhead pistons can reduce dampening as well, but its permanent.

The Monster Beetle's tires are also on the firm side. Not only does this add to the bounce but on loose dirt and tarmac, results in spin outs. A softer wider tire like the Lunch Box's helps to some degree. They are smaller, but they can be stretched over the stock rims. Here's a video about the swap using the Monster Beetle's brother, the Blackfoot:

  

 

[CMshooter]

Oil shocks with travel limited to lower it a bit.  Aim fir dog bones to be level at static sag.  Lower profile 2.2 stadium tires.  

Don't go too deep modding it beyond basic setup.  Lower tires may mean a pinion change to keep speed up.  There is a limit, and it will never match the Stadium Blitzer for overall performance.

 

[OoALEJOoO]

I'm afraid the Monster Beetle was created to be a thing of beauty and less as a performance machine

You can still make it a bit better as others suggested. I did that to mine initially but fast came to regret it. Suspension was lowered and a bit of weight added at the bottom. Now that the car handled a bit better, I pushed harder, resulting in nasty crashes & flips. The body is now permanently scarred as well as myself: every time I see the body I get some PTSD .

For me the greatness in the handling is not to try to improve or tame it, but to learn to drive around it. Makes an interesting and fun drive once you modify your driving strategy for that. You will surely not be too fast or win any records though.

[LMF5000]

31 minutes ago, OoALEJOoO said:

I'm afraid the Monster Beetle was created to be thing of beauty and less as a performance machine

You can still make it a bit better as others suggested. I did that to mine initially but fast came to regret it. Suspension was lowered and a bit of weight added at the bottom. Now that the car handled a bit better, I pushed harder, resulting in nasty crashes & flips. The body is now permanently scarred as well as myself: every time I see the body I get some PTSD .

For me the greatness in the handling is not to try to improve or tame it, but to learn to drive around it. Makes an interesting and fun drive once you modify your driving strategy for that. You will surely not be too fast or win any records though.

I've actually been driving it without the body (as I haven't painted it yet) and I'm trying to learn its quirks. I suppose it's enjoyable if you see it as mastering a piece of history, but compared to the modern tamiya's I'm more used to building and driving it's quite a huge difference.

[Saito2]

2 hours ago, OoALEJOoO said:

I'm afraid the Monster Beetle was created to be a thing of beauty and less as a performance machine

Hey, that single piece of box art there is what got me hooked on Tamiya for many decades now.

[markbt73]

You know what's funny? I've had like six Blackfoots and one Mud Blaster over the years, but never a Monster Beetle. Maybe that should change...

Anyway, to the OP, just slow down, let the car tell you what its limits are, and practice staying within them. It's a forty-year-old design that was somehwat of a compromise even back then. Show it a little sympathy. You don't always have to be going balls-out to enjoy things. If you can get to the point where you can carefully balance throttle and steering inputs to slide the tail around a turn, then watch the rear end squat as it accelerates down the next straight, you'll be closer to understanding it.

Or stick the body on top of a Traxxas Stampede chassis. But then it won't be a Monster Beetle anymore.

[El Gecko]

16 hours ago, LMF5000 said:

This is my first RWD Tamiya and my first big-wheel truck (my other models are 4WD touring cars on TA-02 and TT-01, a buggy on TT-02BR, and a cross-country on CC-02).

The monster beetle (ORV chassis) is ridiculously bouncy on rough ground - to the point where the front wheels spend half their time in the air. I tried to remove the spacers of the front dampers (that clip on above the spring), but no difference. It doesn't seem to absorb bumps, rather it crashes and bounces over them.

On dirt it easily spins out, while on tarmac it has a tendency to lift a front wheel then flip over. When braking hard it tends to spin 180° when it's close to stopping and ends up facing the direction it came from.

I have the front tie rods within 0.1mm of the instruction's recommended dimensions (verified with vernier callipers) which gives the front wheels a slight toe-in. I also noticed the servo saver seems very soft and the front wheels can have a bit of a mind of their own.

Has anyone found good ways to solve one or more of these quirks?

A stronger servo saver helps. I'm using a Kimbrough on mine. There is a lot of slop in the front end that can't really be tuned out unless you spend a lot on hopups.

Reduce your braking force using EPA on the controller, that will reduce the tendency to 180 on braking.

Check that your shock ends are moving freely and not binding. If necessary, add shims to the mounting screws. Reduce the damping and/or spring rate in the front as much as possible.

Lastly, if this is your first 2WD, you'll have to adjust your driving style. Basically all of this:

1 hour ago, markbt73 said:

just slow down, let the car tell you what its limits are, and practice staying within them. It's a forty-year-old design that was somehwat of a compromise even back then. Show it a little sympathy. You don't always have to be going balls-out to enjoy things. If you can get to the point where you can carefully balance throttle and steering inputs to slide the tail around a turn, then watch the rear end squat as it accelerates down the next straight, you'll be closer to understanding it.

The ORV is a "finesse" chassis and needs a delicate but precise touch on the controls.

[OoALEJOoO]

4 hours ago, Saito2 said:

Hey, that single piece of box art there is what got me hooked on Tamiya for many decades now.

The original Monster Beetle and also the Monster Beetle Jr. are also among my favorite Tamiya box arts.

How sad Tamiya didn't release proper box art with the Monster Beetle Trail

[Juggular]

Back in the days, instructions for every Tamiya kit showed toe-in.  Recently, almost everything is toed out.  So maybe it's worth trying toeing-out?  

When you are turning, the wheels line up better with the circles they are making, if they are toed out.  

Ackerman did this by angling the steering horns inward.  When you turn, the wheels toe out.  Since Blackfoot doesn't have this, you might try toeing out and see if that helps.  

[Saito2]

38 minutes ago, OoALEJOoO said:

The original Monster Beetle and also the Monster Beetle Jr. are also among my favorite Tamiya box arts.

The Monster Beetle Jr. was the first Tamiya product I ever owned. I remember the hobby shop owner repeatedly telling me this was a small, battery operated "toy" and not a radio controlled model, about which, I did not care very much. It was the Monster Beetle I could afford at the time. I also recall taking it out of the bag and staring at that box art the whole way home, lol.

[LMF5000]

5 hours ago, Juggular said:

Back in the days, instructions for every Tamiya kit showed toe-in.  Recently, almost everything is toed out.  So maybe it's worth trying toeing-out?  

When you are turning, the wheels line up better with the circles they are making, if they are toed out.  

Ackerman did this by angling the steering horns inward.  When you turn, the wheels toe out.  Since Blackfoot doesn't have this, you might try toeing out and see if that helps.  

I tried that - it makes it uncomfortably skittish in the straights. Basically on a straight smooth tarmac road I was having to make constant micro-adjustments to keep it going straight because it went whichever way the slop in the steering was allowing it to go. Very tiring to drive like that. I kept progressively toeing-in the wheels until I hit the sweet spot by trial and error then a few days later measured the tie rods with a Vernier caliper and to my surprise I actually ended up at within 0.1mm of the lengths written in the manual, totally by feel! This setting is very obviously toed-in, but becomes less toed-in when the shocks are compressed and even less when it's moving forwards and the friction is pushing the wheels backwards.

[ruebiracer]

20 hours ago, Saito2 said:

The Monster Beetle body seems a good bit lighter than the Blackfoot body it shares a chassis with. As such, I find the stock front shock set-up to be over-damped. With heavy dampening and a light front end, it does seem to hop and bounce over obstacles rather than absorb them. Unfortunately, Tamiya uses the cheaper, non-adjustable "nailhead" fixed pistons which mean your only recourse is to run lighter oil. On my Monster Beetle, I run different piston rods with swap-able piston heads and use a piston with large holes. Grinding a slot in the side of the stock nailhead pistons can reduce dampening as well, but its permanent.

The Monster Beetle's tires are also on the firm side. Not only does this add to the bounce but on loose dirt and tarmac, results in spin outs. A softer wider tire like the Lunch Box's helps to some degree. They are smaller, but they can be stretched over the stock rims. Here's a video about the swap using the Monster Beetle's brother, the Blackfoot:

  

 

Thanks @Saito2 for mentioning this video, was total fun and informative. Never had thought of this tire swap before. Seems like a cheap and stylish alternative, especially for the Blackfoot.

[ruebiracer]

I came very late to the Monster ORV platform in 2012. I had a Subaru Brat as kid, the rests are still left of it. With cheap wrecks on ebay and local markets, I restored 2012 my first Monster beetle 3 years before it´s return as a RERE. The RERE´s were supercool, but a bit lazy done by Tamiya. Gearboxes are weaker than the originals regarding sideplate flex and quality of the pot metal gears for the diff. But Handlingwise, I was impressed, what an ORV even sitting higher as a Monster can do. It´s in no way comparable to the Blitzer series or more modern trucks, but they developed in Race trucks with much lower stance. But as many said, handling can be improved, and all other flaws. I recommend:

- Top Force rear springs for the rear, very absorbing and you get a bit of sag called droop. Front Rere Springs are not that bad, But I think I cut of 1 coil on one of my Monster beetles. 

- get better piston rods with changeable pistons for adjusting damping. More soft is your go, too.

- One of the biggest help I noticed late on mine is / was: heavier wheels. I bought back in the day some nice aluminum rims, which are of course heavier and expensive, but help like on a crawler to shift the point of flipover. Sounds stupid, but my nephew with the same base setup as mine without alu wheels rolled over during hard street driving, mine was not as prone to roll. That was the AHA effect for me. Also going on bigger speeds the heavy wheels seem to act a little like 4 Gyros, once turning they roll their way, it seems. 

You could modify your kit wheels with tire balancing weights glued to the inner wheel inside the tire to test this effect. Never got round to it yet.

- High torque servo saver setup with centralized mount and 3mm bump steer spacers on the knuckles is my favorite steering setup, togehther with a modern Brushless servo which is not self locking. you can turn it easily with your hand, when current is off. This saves knuckles and has much less play in the steering.

Offset the battery to the opposite side of the engine to counterbalance the motor, helps a tad, too.

Need to list more, you can also check my MB beginning in my showroom and click the MB parts:

58060: Monster Beetle from ruebiracer showroom, My Monster Beetle Runner - Tamiya RC & Radio Control Cars 

Don´t forget to enjoy this vehicles, because of their great scale appearance, history and fun. Try not to bash it, but prevent the car from damage and avois stupid stunts. Or get a basher body for those.

Kind regards,

Matthias

[Kowalski86]

Adding some weight to the chassis near the back may help, most of the early/re-re Tamiyas were designed for the extra weight of a second servo, heavy humpback NiMH batteries and a 4-AA receiver pack. Without all of that weight, you get less traction and more bounce.

Another factor is the mid-motor/short wheelbase setup, the ORV will always be easy to spinout and it'll lack the traction that rear-motor designs have off-road.

[MadAnt]

I just remembered, Parma makes a lexan baja bug body that will fit the Monster Beetle. I've bought multiple of them over the years and are great for a basher. 

My Grasshopper has that body on it and I have a spare somewhere.

The prices have gone up, I remember buying these for 25 bucks each years ago.

https://www.amainhobbies.com/parma-pse-1-10-rock-crawler-monster-truck-old-school-bug-body-clear-180mm-par10340/p1588170

 

[Kowalski86]

15 minutes ago, MadAnt said:

I just remembered, Parma makes a lexan baja bug body that will fit the Monster Beetle. I've bought multiple of them over the years and are great for a basher. 

https://store.sabulatech.com/BL2398-Baja-Bug-Body_p_55.html

Sabula makes one likely from a similar mold for $25, I used one on a Frog and it was pretty durable, and they comevwith window/light masks.

[Guest]

Upgrade the badword out of it with Aluminium parts and a Kingfly aluminium chassis. Also get MIP ball diff as that puny Tamiya diff will disintegrate after a few runs.  New shocks are advisable, limit the shock travel, cable tie around the rear body mount posts will help with the CVD popping out. Get some decent tyres as well, those Tamiya ones are too hard and far too tall, lunch box tyres work well and are cheap. 

[Wooders28]

I had the original, and had more issues with the usual ORV gearbox woes tbh..

Damping and springs are the only really tuning options for bounciness (if you want to keep the ORV Beetle look, start lowering to its belly and fitting different wheels, you may aswell get the Blitzer Beetle..🤔)

As I've fitted faster (brushless 🙄) motors to most tamiya chassis, I've needed lighter oil in the shocks and/or swap the piston to the more hole option and/or drill the holes larger (kind of a one way ticket with that option though..), until I get the desired damping, although in some cases I've ended up fitting different shocks (Schumacher big bores usually) to get the desired effect.

You kind of want it to sag a bit under its own weight.

[ruebiracer]

For me, no aluminum Kingly chassis is needed. Original ORV frame is not bad at all. Also the CVA 2 gen. shocks are excellent with other piston rods and interchangeable pistons. You can modify them with Tamiya stuff to an excellent point.

In case of diff problems and clicking noise, go cheap with an screw through the outdrives old frogshot mod. Forget about braces or stiffer sideplates. They do not cure the problem, only the symptoms. The sideload pressure only goes in the bearings and kills them.

If money is not an issue, go get the MIP ball diff and have a lifetime solution. 

[Guest]

7 minutes ago, ruebiracer said:

For me, no aluminum Kingly chassis is needed. Original ORV frame is not bad at all. Also the CVA 2 gen. shocks are excellent with other piston rods and interchangeable pistons. You can modify them with Tamiya stuff to an excellent point.

In case of diff problems and clicking noise, go cheap with an screw through the outdrives old frogshot mod. Forget about braces or stiffer sideplates. They do not cure the problem, only the symptoms. The sideload pressure only goes in the bearings and kills them.

If money is not an issue, go get the MIP ball diff and have a lifetime solution. 

It is cheap plastic crap, that is my opinion and that is why I upgraded mine to aluminium    Are we not allowed our own opinions on here? . 

[MadAnt]

39 minutes ago, Dangerous_Beard said:

Are we not allowed our own opinions on here? . 

Nobody is stopping you, everyone who has replied to the thread has given their opinions on the subject and topic.

[Guest]

1 minute ago, MadAnt said:

Nobody is stopping you, everyone who has replied to the thread has given their opinions on the subject.

Well that's alright then.