Konghead wheel rims breaking

[Superba]

I have bought myself a Konghead and race it with my nephews. great fun, superb for bashing and everyone loves the 6 wheels. Not sure the 4 wheel steering is a little sharp but that’s my poor driving. I have bearings, cv shocks and just put a 23t bz brushed into it. This weekend which was very cold I was bashing it and jumping it onto tarmac. Not big jumps but a foot or so. Two wheel rims have lost big chunks out of them. Was this the cold? Should I put foam in the tires? Is this normal? Way back I had a lunchbox with the same wheels and never had this problem

[TurnipJF]

Cold is the enemy of most plastics, making them hard and brittle. I am certain that would not have happened on a warmer day.

[Prescient]

Depends how cold. Thermo set plastics on Tamiya rims are pretty robust.

I suspect this is just because Tamiya + Jumps = Breakages

It's a feature not a flaw

[waterbok]

Foams should help

[Superba]

Can you buy foams, or do I buy it and make myself? Recommendation o;where to buy it etc?

 

[iluvmud]

1, these are not the same wheels from the LB

2, the truck is pretty *******in heavy and imo those jumps are pretty big for this chunky monkey and depending on cold it could impact the pliability of the plastics used to make the wheels.

3, foams will help it to an extent, but then the poor suspension design for this rig will really start to show. 

Finally.... the gf01 wheels/ tires are a bit sturdier than the current wheels they would/should hold up better.

 

mic drop......

[Superba]

Thanks for the advice I will stay away from foam. I personally think the BZ engine is Bout right for this monkey, anymore and it will get difficult.

 

[WillyChang]

wheels are hex so they'd be WR02 WildWilly2 rears... which were possibly begat from Lunchbox wheel modified for hex  tyres same

yeah I've stuffed opencell foam into these tyres before, cut strips of 2"x2"x12" stuff it in

lately been looking at Daiso's melamine (aka "magic") sponge and wondering if that'll be any good as tyre filler  they sell it in big strips, more of a memory foam feeling... just wonder how long before it crumbles into dust

[Nitomor]

I think for those type of jumps you will definitely be wanting to look at suspension. It a dead cat bounce as they are currently set up and as stated above, it's a heavy old rig.

The WT makes a big difference with suspension upgrades, I have yet to address this on my Kong as I haven't finished the shell yet. I'm hoping the GPM WT01 towers might fit front and rear to allow longer travel shocks circa 93mm and the mid ones might just need upgraded dampers (shorter than 93mm though as I'm not sure how easy it would be to improve on the damper fittting but any bottoming out would likely be taken up/transferred by either of the other two axles. 

 

 

[qatmix]

Cracking rims could well be because of the cold. At the weekend I smashed a front wheel on a stampede, and those things are tough. As to the Konghead wheels per-se I have used mine since I built it last spring and its done some epic jumps and the wheels themselves are fine. I also used it last weekend, but unlike the Stampede the Kong didn't break  

 

[Andyrt200]

I have been meaning to post about this very thing!

We cracked all three on one side on the second run out with the G6, we hadn't even started to try jumps then, I don't know what it hit, I didn't notice any big crashes & was watching my boy drive closely.  It was very cold, but I wonder if its the chrome plated plastic that is worse? The only other rims we cracked like that are some nice option chrome ones for the Super Blackfoot & they do have tyres with foam inserts & a bit more side wall on the tyres too. 

We run all the other trucks in the same cold weather, they all have coloured wheels & the only other one I have broken were my original Blackfoot's back in the day doing stupidly big jump & then that broke the centres out. 

[Nitomor]

I have exactly that problem running CW01 Montero wheels on my Hornet! ^

[NameUnchanged]

Does anyone know how strong the plastic actually is without being cold it could be because they are cheaply manufactured 

[TurnipJF]

Even expensive plastics become more brittle in the cold. We repair appliances at work, and even though they are packed carefully for transport, we still see an increase in transit damage to plastic parts over the winter months. All other variables remain the same, so we can only conclude that the lower temperatures are to blame.

 

That said, again based on my experience at work, plastics with a chromed or painted finish are typically harder than those with a natural finish, as the chrome or paint can crack and flake off if the plastic flexes too much. Perhaps the chrome wheels are made of a harder, more brittle plastic than the natural coloured ones?

[WillyChang]

it's THERMOplastic, goes soft when hot, harder when cold  

haven't noticed any difference in longetivity of WW2 wheels vs Lunchbox, but mine are all ancient early first batch examples... plastic raw material can change, depends what pellets T's beancounters have bought.

Kong kit wheels do feel hard. Might go retrieve a WW2 kit to compare.

 

BiTD we would boil plastic parts to make them less brittle, nylon molded parts like on HPIs and Associated. 

ABS plastic will start getting malleable in boiling water though.

[markbt73]

For some reason, chromed plastic parts are more brittle than other parts. I've noticed it with static model parts as well as RC car wheels. I don't know if the plating process does something to the plastic, or if they just use harder (and therefore more brittle) plastic for chromed parts (to avoid the flaking chrome problem that HPI wheels all seem to have). And the cold amplifies the problem. I've shattered chromed plastic wheels in the cold before.

[Superba]

How do I find out what other wheels I can fit to the Konghead which will still fit the standard three? Seems a bit of a minefield, I would be tempted with new Tyres as well but I don’t want them with a bigger circumference as they might rub o;each other or impede the rear wheel steering

[WillyChang]

9 hours ago, Superba said:

How do I find out what other wheels I can fit to the Konghead which will still fit the standard three? Seems a bit of a minefield, I would be tempted with new Tyres as well but I don’t want them with a bigger circumference as they might rub o;each other or impede the rear wheel steering

Exact wheels are Wild Willy 2 rears with hex. I think the tyre is unique sized to this.

Alternative is TLT-1 (Tamiya little truck) which is slightly smaller overall diameter but it's got a larger bead on inside vs outside. This wheel & tyre has been recycled onto the front of FarmKing & TumblingBull.

Have seen a few aftermarket alloy wheels for WW2 from far east.

 

[MadInventor]

I've encountered this on a madbull before, with both chrome and yellow wheels. In my case it was due to high speed rolls and the edge of the wheel impacting with the ground. When jumping the Konghead, I suspect that the suspension is bottoming out due to the weight, then the tire is compressing to the point where the edge of the wheel rim is hitting into the ground (especially if for example landing on one front or rear wheel), which is causing it to crack.

If you're still looking at replacement wheels and tires, the GF-01 dump truck items are a bolt on replacement and use the same size tire (as do MadBull / WW2 rears)

[TwistedxSlayer]

5 minutes ago, MadInventor said:

I've encountered this on a madbull before, with both chrome and yellow wheels. In my case it was due to high speed rolls and the edge of the wheel impacting with the ground. When jumping the Konghead, I suspect that the suspension is bottoming out due to the weight, then the tire is compressing to the point where the edge of the wheel rim is hitting into the ground (especially if for example landing on one front or rear wheel), which is causing it to crack.

If you're still looking at replacement wheels and tires, the GF-01 dump truck items are a bolt on replacement and use the same size tire (as do MadBull / WW2 rears)

Was about to say the same thing about the Madbull, taken chucks out of the chrome wheels due to kerbs and the kids poor driving.