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B.RAD

My first Tamiya build - Mad Bull

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2 hours ago, B.RAD said:

Heat shrink is a great idea! Kicking myself I didn't think of that ๐Ÿ˜† I haven't got any so will need to buy some, do you have a recommendation for sources?

You can get heatshrink from modelsport too. ๐Ÿ‘

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1 hour ago, Silver-Can said:

You can get heatshrink from modelsport too. ๐Ÿ‘

Doh! Me and my over-enthusiasm! I've already placed the order for the pinion. I've emailed to see if they can add some heat shrink in, fingers crossed.

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On 2/4/2021 at 7:44 AM, Baddon said:

Great fun go anywhere kit, Go custom, its your buggy there are no RULES!

As mention above the steering mod is the only one left you will want to do.

One oddity, the front wheels go a bit wobbly in reverse.

And welcome to the slippery slope...

I'm HOPING to find a Mad Bull in the U.S. - most Tamiya Kits are sold out here, and international Shipping has made Shipping from anywhere else but Canada impractical. ๐Ÿ˜–ย 

These Chassis ALL suffer from awful Front End Geometry!!! Grasshopper, Hornet, Rising Fighter, Mad Bull and all the other types that shared that type of Front End.ย 

The Rising Fighter and Mad Bull share nearly identical parts....ย 

What I've added to mine, that vastly improves stability and Cornering is this:ย 

ย @Pintopowerย makes several COOL upgrades for "marginal" Tamiya Suspensions!! Basically makes the simple Swingarms into a true Double Wishbone Suspension!!ย 

No, it won't beat a RC10! But the improvement is DRAMATIC, especially in reverse.

If I can get a Mad Bull, I'm getting it!! ๐Ÿ˜

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Small update today as not much time amongst family duties...

Got the rear diff and gearbox built. I should have taken more pictures along the way as this was a very satisfying task, but it was so enjoyable I completely forgot and just got carried away with the construction! ๐Ÿ˜†ย 

Finished article, doesn't look like much but now I know what lurks underneath I can fullyย  appreciate this work of art.

PXL_20210207_144453850_copy_403x302.jpg.cb624b869c565e3d154881bff854e661.jpg

Checked in with my old man earlier and he's already up to the same point as I am in his Hornet build. No doubt by the time I post this he'll have overtaken me! No probs, it's not a competition... ๐Ÿ˜

Motor installation is next so I'm now kicking myself that I didn't order that steel pinion earlier, as now @Silver-Canย has mentioned it, I realise I'd read about that mod before and it should have been on my pre-build purchase list. Never mind, just an excuse to slow things down again and enjoy the process even more!ย 

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๐Ÿ˜ yeah it still gets me how all these relatively little bits fit together and generally work so well.

Re pinionย  - my personal view is that you'd be fine running it for a short while before any noticeable wearย occurred. I would suggest it might be worth fitting the kit supplied one to complete the build and check everything is working as it should and then swap it out when the new steel one arrives. You'd be fine running it for a week or so as is - but entirely your choice, of course ๐Ÿ˜‰ ๐Ÿ‘

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8 hours ago, Carmine A said:

I'm HOPING to find a Mad Bull in the U.S. - most Tamiya Kits are sold out here, and international Shipping has made Shipping from anywhere else but Canada impractical. ๐Ÿ˜–ย 

These Chassis ALL suffer from awful Front End Geometry!!! Grasshopper, Hornet, Rising Fighter, Mad Bull and all the other types that shared that type of Front End.ย 

The Rising Fighter and Mad Bull share nearly identical parts....ย 

What I've added to mine, that vastly improves stability and Cornering is this:ย 

ย @Pintopowerย makes several COOL upgrades for "marginal" Tamiya Suspensions!! Basically makes the simple Swingarms into a true Double Wishbone Suspension!!ย 

No, it won't beat a RC10! But the improvement is DRAMATIC, especially in reverse.

If I can get a Mad Bull, I'm getting it!! ๐Ÿ˜

I hope you can find one! I'm sooooo excited to get mine built and running ๐Ÿ˜Š

I love all the 3D printed parts that are now available, it's an awesome developmental technology and is expanding this field fantastically. I'm not sure I'm at the point of engaging with that level of mods yet, but as has been previously said, it's a very slippery slope...!

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@Frog Jumperย The red o-ring idea was genius!! Thank you so much for sharing. One at each end worked perfectly to take up the slack and get the shock nicely lined up. Brilliant! So satisfying to use spare bits to improve the fit ๐Ÿ˜Š

PXL_20210208_092842655_copy_302x403.jpg.e452bddd4986d76132965743b6e64d8f.jpg

Looks super cool to my eye too ๐Ÿ˜

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Some small progress to report. Rear end is built up and attached, and suddenly a kit of parts is starting to look much more like a car!

PXL_20210208_094246266_copy_403x302.jpg.6cf10a77fbaab0e142796815eaebd120.jpg

PXL_20210208_094303292_copy_403x302.jpg.3355e2c040195f2d23fa0fa51568c3ac.jpg

A question for the collective about the rear shock install. I can see that I will have the same issue as the front shocks with the large tolerance gap on the mounting points. I have these balljoints spare from the CVA shock kit so could fit four, one at each end. Would this work? I think it'll fit fine, but will I have problems with them popping off?ย 

PXL_20210208_094408639_copy_135x96.jpg.02c702ba8de12272a083e5bb56072b91.jpg

Unfortunately I don't have any of the red o-rings left as that would be the ideal solution!

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5 hours ago, B.RAD said:

...... I have these balljoints spare from the CVA shock kit so could fit four, one at each end. Would this work? I think it'll fit fine, but will I have problems with them popping off?ย 

PXL_20210208_094408639_copy_135x96.jpg.02c702ba8de12272a083e5bb56072b91.jpg

Unfortunately I don't have any of the red o-rings left as that would be the ideal solution!

We've used those Balls, and similar, on everything from Monster Trucks to Racing Buggies to Touring Cars!! ๐Ÿ˜‰ย  Not only ISN'T that a problem, it's actually BETTER! Less end play at the Shock Ends.ย 

You just don't want to remove and reinstall CVA Shocks too many times. The Ends eventually get a little stretched and could POSSIBLY become loose.ย 

{NOTE - I'm talking about the Guys who remove their Shocks after EVERY 3-5 Runs, for constant, OCD adjustments and Shock Oil Weight changes!!!๐Ÿ˜œ}ย 

...... and, I also would have recommended using the Tamiya Red O-Rings to take up the slack on the Step Screws!ย  @Frog Jumperย just beat me to it! ๐Ÿ˜ย  Not only LOOKS good, but positively sets the Shock Ends firm.ย 

(Last Note: I always have several spares of the Tamiya Red O-Rings... NEVER use them!! Almost guaranteed to LEAK with thinner than 50W - or 600w CST - Shock Oil. I only use Team Associated - and almost never had leaky Shocks!!! ๐Ÿ‘๐Ÿ‘๐Ÿ˜‰)

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That's great advice, thanks @Carmine A!

Presumably the balljoint ends will be ok screwing in to the plastic? It's supposed to be a self tapping screw that goes in and these are threaded for a nut, but I guess if I'm careful they should be ok?

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Just snug them flush against the Plastic, don't over torque, and you'll be just fine! ๐Ÿ˜‰

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An interesting evenings' tinkering. Having spent much of the day pondering how I was going to install these rear shocks without causing the same slack issue as the front end, and also feeling very perturbed by the offset in the mounting points, I remembered that my aforementioned grandad (from that Christmas when I was so carefully ejected from the build!), who was an absolutely phenomenal model aeroplane builder, had a super box of small nuts, bolts, washers and spacers that I inherited when he sadly passed away.ย  I dashed into the garage after work and lo and behold, a box of 4mm spacers provided the perfect solution!ย 

PXL_20210208_184706336_copy_884x566.jpg.bbc8f802d18d14c20eca73cd3c019531.jpg

I fitted these to one of the rear shocks and while much improving the fit, I was still really unhappy at the forced 'bend' that was being applied to the piston. It made the action of the damper stiff, and with the radius being forced into the piston rod, I could see it leaking oil in no time. The twist is actually visible in this photo, and a good representation of the fab spacers!

PXL_20210208_190336554_copy_604x453.jpg.a56f3fc8d4a06faab86eecc882cc1fb0.jpg

So out of interest, I installed the other side without the spacers. This fit just fine, as the slack allows the shock to twist at the mountings rather than in the piston. So for now, I've installed both this way. I'm not at all happy with this, but it's better than the solid mounting approach. Looking back at the photos, maybe using the spacer on the top but not the bottom might be a better approach? I think the balljoints are the ultimate answer, I'm just worried about that narrow thread...

PXL_20210208_190542306_copy_604x453.jpg.d11cd98417ff129e3e6f2764dcd266ee.jpg

The other thing I've noticed is that the physical design of the rear mounting means the back end hits the chassis tub waaaaaay before the shocks get anywhere near their full travel! Is this right?? I can only assume this will be very noisy in operation! Have I done something wrong?

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I found the best solution for shock mounting on this and several other similar chassis is to use Tamiya's 50591 5mm ball collars, which clip into the top and bottom eyelets of the shocks, and allow you to pass a 3mm self-tapping or machine screw through the middle. This gives you the slop-free connection of a ball joint along with the security of being able to use a suitably long screw of the right thread type for the material. They also allow you to remove and refit the shocks as many times as you like without stretching the eyelets.

s-l640.jpg

ย 

In use on my Thundershot:

2019-09-02_11-34-43

ย 

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As for the back end hitting the tub before the shocks run out of travel, this is normal and correct. You typically don't want the shocks to reach the full extent of their travel and be the limiting factor in your suspension's compression. A fully compressed shock has no more damping to give, so passes any further forces straight to the shock mounts, potentially breaking them. Far better to have the chassis bottom out or the suspension hit its stops while the shocks still have some travel left.

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15 minutes ago, TurnipJF said:

I found the best solution for shock mounting on this and several other similar chassis is to use Tamiya's 50591 5mm ball collars, which clip into the top and bottom eyelets of the shocks, and allow you to pass a 3mm self-tapping or machine screw through the middle. This gives you the slop-free connection of a ball joint along with the security of being able to use a suitably long screw of the right thread type for the material.

ย 

Wonderful! These look like a perfect solution!ย 

I'm going to have to start making a list before I buy things, doing way too many orders at the moment!!

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2 minutes ago, TurnipJF said:

As for the back end hitting the tub before the shocks run out of travel, this is normal and correct. You typically don't want the shocks to reach the full extent of their travel and be the limiting factor in your suspension's compression. A fully compressed shock has no more damping to give, so passes any further forces straight to the shock mounts, potentially breaking them. Far better to have the chassis bottom out or the suspension hit its stops while the shocks still have some travel left.

Ok great, that's a relief then, thank you. Thought I'd done something wrong!

The CVA shocks are shorter than the friction shocks supplied in the kit, I think I added a spacer in but need to check. There is very little travel at the moment before contact occurs, once the weight of the electrics and battery are in I'd be very surprised if it wasn't sitting in full contact all the time. I will check the shocks tomorrow and see if I can remove the spacer to give a bit more travel. All good fun!

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2 minutes ago, B.RAD said:

Wonderful! These look like a perfect solution!ย 

I'm going to have to start making a list before I buy things, doing way too many orders at the moment!!

I usually order such things from Tony's Tamiya Parts on eBay. With free postage, it doesn't matter if I order everything at once, or individual bits as I need them - there is no extra shipping to pay if I place multiple orders. Here is a link to the ball collars:

https://www.ebay.co.uk/i/383658769500

ย 

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1 minute ago, TurnipJF said:

I usually order such things from Tony's Tamiya Parts on eBay. With free postage, it doesn't matter if I order everything at once, or individual bits as I need them - there is no extra shipping to pay if I place multiple orders. Here is a link to the ball collars:

https://www.ebay.co.uk/i/383658769500

ย 

Absolute legend!! Thanks so much. Ordered! ๐Ÿ˜ Will save as a favourite seller too.

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7 minutes ago, B.RAD said:

Ok great, that's a relief then, thank you. Thought I'd done something wrong!

The CVA shocks are shorter than the friction shocks supplied in the kit, I think I added a spacer in but need to check. There is very little travel at the moment before contact occurs, once the weight of the electrics and battery are in I'd be very surprised if it wasn't sitting in full contact all the time. I will check the shocks tomorrow and see if I can remove the spacer to give a bit more travel. All good fun!

Hmm. That sounds a bit sub-optimal. Ideally you would build the CVA shocks to be as close as possible to the length of the stock pogo sticks, which IIRC means no internal spacers.ย Also, are you using the springs that came with the kit? They suit the car well - far better than the ones that come with the CVA shocks.

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Just a thought: if you are going to be running it with your dad and his Hornet, you might find that it makes a better running companion if fitted with standard size buggy wheels and tyres. It looks pretty good in this guise I think. Here is mine, set up as a running companion for my wife's Rising Fighter:

2019-09-26_03-00-11

ย 

Something else you might want to consider is the heatshrink mod to the steering push rod. It serves much the same purpose as replacing the thing with a set of ball links and threaded rod, however it is a lot easier, and fully reversible. One applies the heatshrink like so:

2021-02-08_11-17-01

ย 

Installed it looks like this:

2021-02-08_11-17-33

The heatshrink stops the pushrod from moving up and down in the holes, which reducesย slopย significantly, and also stops the front of it from getting caught on the chassis if the steering is over extended a collision.

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That looks absolutely awesome @TurnipJF!! I love it in white with the decals, and with the buggy wheels on! I imagine the smaller rolling radius makes it quicker to accelerate too. What wheels are they please?

I've just bought some heat shrink so will copy this steering pushrod mod, thank you. Very neat.

Ref the springs - I'm using the soft springs supplied with the CVA kit. As I'm taking them apart to remove the spacer anyway, I'd be happy to change the spring if you think it's worth it? All advice is very much appreciated!

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4 hours ago, B.RAD said:

What wheels are they please?

ย 

The wheels are Tamiya Star Dish items, 53086 on the rear, 0445167 on the front. To fit the narrower front wheels, you will need the shorter front axles, part number 0555059.

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