1:12 F1 wheels question

Modeling Subjects Autos
1

For anybody who built any of the three models in this series: the Ferrari 641/2, MP4/6 or the FW14B, just a quick question.

I just took my 641/2’s tyres out of their little holders and mounted them on the wheels. I was amazed to see it being very soft wheels, though, esp for the size of the car. Did anyone do something to them to firm them up a bit? Or are they fine as is (once you seat them properly)?

2

SeaBee,
I have the Matra, Honda, Renault,Tyrell and Ferrari T312, all have soft tires and look just fine. I am not sure if the newer kits are any heavier, but it might help the kits “sit” right if they are.

Don

3

SeaBee,
In truth, F-1 cars run with tires set at a fairly high psi, so there is no “flat spot” like a normal passenver car tire set at 30-32 psi…but those big Tamiya kits with the soft tires really don’t look bad at all when they’re installed…I’ve built several, and they look just fine. Don’t worry yourself about it. Enjoy the build - I love those big models.

4

Hi,

I agree with LeeTree that there should not be “flat spot” on F1 tyres. Because a flat spot would degrade tyre performance.

However, I am afraid that the pressure of F1 tyres should be 18 psi when the machine starts its warm lap. I don’t know why it is smaller than that of our passenger cars which is about 30 psi. It is interesting.

Hope SeaBee happy with his 1:12 Ferrari 641/2. Below is Alain Prost and his 641/2 (in 1:24 scale).

5

Very happy thusfar, thanks!

I might in the end go for the option of using the mount-points for display cases (thoughtfull of Tamiya!) to take some weight off the wheels, maybe adding a washer between the supplied mount-pieces…

6

Concerning the lower psi of racing tires: Because racing tires generate much more heat in the course of the race, then any street tire could possible generate. As such, the gas in the tire expands from the heat, and 18 psi, actually increases.

7

When I did my 642, I cut washers from sheet plastic and inserted them inside the tires and around the rims. These plastic donuts bear the weight of the model and prevent the tires from looking under-inflated. My McLaren’s tires actually flat spotted after a few years, having sat on the same spot in the case for some time.

A piece of sheet stryene and a compass are all you need, and the entire fix took no more than 30 minutes or so to accomplish.

Jeff

8

Thanks Jeff, good idea! My only problem is that I don’t have any place I can find sheet styrene (yet). But trust me, I’m looking - I need some for another project as well.

9

I have built most of the 1/12th Tamiya the first in about 1972 and the 641about 8 years ago. All are sitting on their tyres and none show any sign of “flat spotting”. However if you have any doubt then Jeff’s idea is certainly one to follow.

10

Actually in F1 they have been using Nitrogen gas in the tire to prevent such drastic change in air pressure due to heat.

They started doing this from the late 80’s.

11

There was a tip on using foam inserted in the tires for the same reason, i.e. preventing flat spots.
This can lead to another in the great debate circle. There must be a “flat” spot on the tire, where it contacts the road surface. however it must remain on the bottom of the tire. This is the contact patch, without it, there is no movement.
In an effort to get the most tire to the ground, increase the contact patch, slick tires were made and thus banned by F1 to slow the cars down. That is the reason for the "grooved tires, less contact patch, less stability, less speed.
When our brothers in the aircraft world first received “bulged tires” for models, the cry went up that modern aircraft, due to the tire pressures did not “bulge”. Horse Hockey!
Where there is contact, there will be a “flat” spot. You DO NOT want the spot to rotate with the tire, Flat Spotting. caused by braking. But a “flat” spot on the bottom is acceptable.

Don