TT-02 Rally Inner Foam/Inserts?

[Pylon80 2628]

Hi all,

Could not find any answers after some research on various forums (at which I am not too good...).

Just picked up my dream RC car ('99 Subaru Monte Carlo Rally... back when they were racing the coupe :)), I had to buy the TT-02 kit to get it (58631) and was planning to sell that chassis and then source an XV-01 chassis... but anyways, here is my question:

The kit came with the rally block tires, harder rubber than the ones available as a spare (54861), I am fine with that. However it did NOT come with any inner foams. I know the TT-02 is a very simple and lightweight chassis and I am wondering if Tamiya did not purposely skip the foams as they might not be needed especially on the harder rubber compound. Thoughts and experience anyone? Anybody else has this kit? Do I absolutely need foams?

Thanks!

[TurnipJF 9192]

You do need foams, not to support the tyres, but rather to stop them filling with sand and debris via the vent holes in the rims. 

[Pylon80 2628]

Thanks JF, very good point about the sand and debris, glad you pointed it out before I start running the car. I actually want the car to be able to run in any conditions.

If it is only for the tire/debris concern though, I will try something I have been thinking about for a while on some of my other cars: to glue a small block of foam in front of the vent hole, kind of like an air filter. Then probably a bit of electrical tape on the other side for weight balancing. I will check that the tires is bonded all around on both sides.

[Big Jon 684]

I vent the tires with a 1/8" hole to let the debris out. Works just so.

As for foams, if you're running primarily off-road, the hard rally blocks seem to work best without foam. As traction comes up, they work better with foam or closed cell inserts.

[Pylon80 2628]

Thanks Big Jon, do you mind explaining what closed cell inserts are? 

[Big Jon 684]

On 3/22/2021 at 10:50 AM, Pylon80 said:

Thanks Big Jon, do you mind explaining what closed cell inserts are? 

Closed cell inserts are much firmer than open cell, and come in a contoured ring shape. They allow an air gap in the tire to let the carcass "work" while proving plenty of support to keep the tire from folding up. The come in a variety of densities for tuning.

The newer soft rally blocks work even better than the old hard ones. I've only tried them with the included foam.