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Scouser

Mad Bull Diff Question

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Evening all, hope you are all keeping well.

During these strange days I have found myself running multiple battery packs through the Mad Bull and enjoying every second. I have been running trail trucks pretty much exclusively over the last few years and didn’t realise how much I had missed a good old blast around at full throttle, kicking up rooster tails and basically hooning around.

The one thing I do miss about the trail trucks is their locked diffs. The Mad Bull will just spin its unweighted tyre and leave itself beached, requiring a helping hand to get going again.

Now I don’t want to lock the diff on the MB but I would like to get a ‘limited slip’ set up. Has anyone successfully achieved a lsd on Tamiya diffs or am I chasing rainbows?

Any help gratefully received.

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1 hour ago, Scouser said:

Evening all, hope you are all keeping well.

During these strange days I have found myself running multiple battery packs through the Mad Bull and enjoying every second. I have been running trail trucks pretty much exclusively over the last few years and didn’t realise how much I had missed a good old blast around at full throttle, kicking up rooster tails and basically hooning around.

The one thing I do miss about the trail trucks is their locked diffs. The Mad Bull will just spin its unweighted tyre and leave itself beached, requiring a helping hand to get going again.

Now I don’t want to lock the diff on the MB but I would like to get a ‘limited slip’ set up. Has anyone successfully achieved a lsd on Tamiya diffs or am I chasing rainbows?

Any help gratefully received.

The Mad Bull has an enclosed, but not sealed diff. You can't put any old oil in there to tune it, but thicker grease or oil will stat in there and stiffen it up. Look for tamiya AW grease, or something i found worked well was three blobs of the super stiff 2 million diff oil i use in the front of my touring car. Don't fill the diff, but a couple of blobs between the gears seems to stay put and slow the diff action down. 

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I used the Tamiya putty in all of mine. Gave enough slip to turn well but plenty of grip.

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Another vote here for diff putty. Holds well and won't leak out. 

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Our Mad Bull (Fighter Buggy) is pretty difficult to handle.

 

It only has oilshocks and a super Stock BZ Motor in it.

It Doughnuts quite easily.

 

Is it a good thing to lock the Diff a little bit or should we just put a Gyro inside it?

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Before looking at diffs or gyros, I would consider tyre choice. What are you running at the back?

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11 minutes ago, whahooo said:

Same as front.

I use Lunchbox tires on all 4 Wheels.

Hmm. Shocks and springs?

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On 3/31/2020 at 12:14 AM, TurnipJF said:

Another vote here for diff putty. Holds well and won't leak out. 

Tamiya diff putty is brill, another vote her for it

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9 hours ago, TurnipJF said:

Hmm. Shocks and springs?

 

Tamiya CVAs with a Stiff Setup (So you can jump a little bit).

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I found the stiff springs made the car too wild and difficult to control, bouncing off the ground rather than riding over it. I started on soft springs, then went to stiff rear springs to control the understeer and it was awful, almost undriveable. Immediately went back to the soft springs and that's where it now sits, and it's a lot of fun. I'd recommend going to soft springs all round. Jumps just fine (I've sent it off some pretty ridiculous jumps and drops!). 

The other thing I noticed is that the stock tyres are pretty awful, no grip at all. They just spin up everywhere. On @TurnipJF's recommendation, I've fitted DT03 buggy wheels and tyres now and it's amazing! Night and day in comparison. Definitely worth trying some tyres with more grip, perhaps the monster spikes if you want to stick with the big tyres.

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14 hours ago, whahooo said:

Same as front.

I use Lunchbox tires on all 4 Wheels.

Back in the Dark Ages (1990!), we started an odd form of "Monster Truck" Racing - with King Cabs exclusively, on Lunchbox Tires.... 

The Races were on Carpet... And that was the ONLY place where Lunchie Tires had ANY decent grip.

If you want to keep the Fat Tire look of the Mad Bull (I would!), I'd look for the widest Pro Crawler Tires you can find. Pro-Line, RC4WD, Duratrax or anything in that Class...

You'll end up with SO much grip - you'll have to start worrying about ROLLING OVER!! 😜

..... I would forget about locked Diff. Too much strain on the stock Drivetrain. One more vote for Diff Putty. 😉

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5 hours ago, whahooo said:

 

Tamiya CVAs with a Stiff Setup (So you can jump a little bit).

Therein lies the issue I believe. Due to its motor pod design giving it a large amount of unsprung mass, you need the suspension to be set up quite soft in order to get any sort of decent handling. I use 3 hole pistons and soft yellow oil at the back and front on mine along with the stock springs and that seems to do the trick nicely.

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