Mad Bull tyre change

[Jozza(2)]

If I change the tyres on a Mad Bull for those which come with the Fighter Buggy, will I need to change the motor pinion and/or other gears, or is the gearing ratio unaffected by the tyres (are the Fighter Buggy rear tyres the same diameter as the Mad Bull balloons?)

[retro]

The Mad Bull tyres are bigger than the Fighter Buggy, but both cars use the same counter gear and 17 tooth pinion. As far as I know there aren't any other gearing options for this chassis (anybody know for sure?). So you don't have to change anything (apart from the wheels, tyres and front uprights), but the top speed of the car will be a little lower. Acceleration should be better though.

[mud4fun]

Aren't the front axles longer on the mad bull? I checked out my daughters car and the axles are long like a 2WD monster truck, normal 2WD front wheels won't fit unless you add lots of washers etc??

[Jozza(2)]

I hadn't thought about the axles - they may well be longer, as the tyres are monster ones, but I think that the front tyres have a fairly small mounting on them, so they might be the same. Think I will take it apart to investigate, so I might need to get some smaller axles.

I was thinking of changing the motor for a non-rebuildable stock which would have a higher RPM than the kit one, so that should sort out the speed decrease hopefully.

I'm just kicking some ideas around at the moment, the one thing I don't want to do is end up spending 40+ quid "upgrading" the Mad Bull, when the Fighter Buggy kit is only about that much anyway!

[retro]

The front axles are longer, thats why I said you need to change the front uprights as well as the wheels/tyres. Although, as mud4fun said, you could just add spacers on the front axles to save money.

[Twmaster]

Since I have both the Mad Bull and a Fighter Buggy I thought I would toss this out there.

Tire diameter.

Mad Bull tires: 110MM

Fighter Buggy Rear tires: 80MM

And yes the upright length is different.

Mad Bull: 20MM

Fighter Buggy: 12MM

The Mad Bull uses the same upright as the Blitzer family of buggies. I would bet that the upright from a Grasshopper/Hornet etc would work fine.

As for the gears the MB and FB are both DT-01 chassis buggies with the same gear ratio of 9.33 to 1 and is not changable. However, there are *two* sets of motor mounting holes. According to the manual I have for the Mad Bull there are no other pinion options available. Also the motor cover only goes on one way.

The part number for the uprights (two required) is 0555059.

Hope this helps you some.

Cheers,

[SJoerD]

Doesn't the Mad Bull have a adaptor plate to run a 10t Blackfoot pinion? Tamiya did something similar with the Grasshopper 2 gearbox on the Lunchbox / Midnight Pumpkin, to make up for the change in ratio due to ****** tires. []

Just for statistics, the Lunchbox came before the Grasshopper 2 so technically a GH2 uses a Lunchbox gearbox in stead of the other way round. []

A GH2's tire diameter is pretty close to that of a Fighter Buggy, and the Mad Bull uses Lunchbox tires. So I would expect the Mad Bull to come with a smaller pinion or adaptor plate... [?]

[Twmaster]

quote:Originally posted by Sjoerd

Doesn't the Mad Bull have a adaptor plate to run a 10t Blackfoot pinion? Tamiya did something similar with the Grasshopper 2 gearbox on the Lunchbox / Midnight Pumpkin, to make up for the change in ratio due to ****** tires. []

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id="quote">id="quote">

No it does not have any adapter. As stated before it is a 17 tooth pinion on the MB. Just like the other DT-01 based buggies.

quote:Just for statistics, the Lunchbox came before the Grasshopper 2 so technically a GH2 uses a Lunchbox gearbox in stead of the other way round. []

id="quote">id="quote">

Well I would say you are wrong here too as the LB and GH2 *both* use the same gearbox as the original Grasshopper.

quote:A GH2's tire diameter is pretty close to that of a Fighter Buggy, and the Mad Bull uses Lunchbox tires. So I would expect the Mad Bull to come with a smaller pinion or adaptor plate... [?]

id="quote">id="quote">

While you might expect that to be so it is not per the comments above. Also note the MB and the rest of the DT-01's use a cpmpletely different gearbox than the GH, LB etal.

[yzfJim]

Hi there you can get a genuine Tamiya 19t pinion from the fighter buggy that is what the second lot of mounting holes are for....

[theshopkeeper]

Yes, the 19t is the following part:

3515007 19t Pinion Gear 58184 - Fighter Buggy £2.50

You can't over gear this gearbox, even with a 19T a modified will run cool since there's very little power loss from motor to wheels due to the solid axles. The box is NOT THE SAME as the Lunchbox/Hornet one, which needs an 18T Hornet pinion to give the same speed as the Mad Bull.

Other than the wheels/body/uprights the only difference between the two kits is the colour of the plastics, which are interchangeable anyway.