Last details on the TB-03 chassis TB-03: the wheels

These elements are in charge of transmitting power to the ground, so they directly influence the overall chassis handling on the track. This is also a good opportunity to seriously talk about tires. Since my model came without wheels, I planned to give it the rims matching the bodyshell. These rims are actually the same as on the kit 58394 Eclipse Advan SC430 based on the TA-05 IFS chassis.

The touch of originality with these rims is they need 6 stickers from one of the bodyshell sticker sheets to be decorated. Two more properties can be observed:

• these rims have a +2mm offset, as mentioned on the bag and as per the engraving on each rim. This is an offset that is often used by Tamiya, but not necessarily by other manufacturers (see the article about my TA-04 TRF for more information about offsets).
• their width is 24mm whereas the most common rim width used by Tamiya models is 26mm. However, most of their high-end models come with "narrow" 24mm rims.

Here, the offset is used to clear the rims from the suspension arms and to adjust the wheels into the bodyshell wheel arches. On the other hand, the rims width as a direct influence on all other elements since the 26mm tires and foam inserts can not be used with these rims. In addition, 26mm rims do not fit the TB-03 chassis, apart from a few exceptions.

But why 2 different standards for rim width?

Good question . Actually, there is even a third standard for rear rims: 31mm. For example on Tamiya's TA-02SW chassis (the very much looked after kit 58172 Taisan Porsche 911 GT2).

For years, the standard was 26mm rims, including for official races. This is still a de facto standard for almost every manufacturer's leisure-oriented models. But there it is: in the world of official races, some people write rules. These people probably do smoke too much of the carpet they race on: this is how they came one day with the idea that rims should be 24mm wide from now on and made this rule mandatory to enter official races.

The true reason?

Only guesses: in the Touring category, the maximum track width is 190mm. Using offset 0 rims, manufacturer can benefit from all this track length. Reducing the wheels width by 2mm represents a benefit for the overal chassis stability since the arms can be longer (which improves the suspension efficiency).

Moreover, this new rule seems to have appeared more or less at the time brushless motors appeared with their tremendous power increase torturing the gearings. Reducing the wheel width meant reducing the grip, so efforts to be handled by the gearings were reduced. On the other hand, we can also guess that tire and tire treatment evolutions to increase the grip were canceling the effects of the new rule.

In the end, it is difficult to know why some "smart" people decreed a new standard for wheels. Motivation may have been more on tire manufacturers side since everyone had to entirely renew their stock...

Whatever. Even if the situation is silly, we have to deal with it.

So, with the TB-03 chassis only accepting 24mm wheels, you need 24mm rims with a +2 offset (reference 51299), 24mm foam inserts (reference 84202) and 24mm tires. On tires side, Tamiya offers several sets.

• Stock tires:

Supplied (with inserts) in "high-end" leisure-oriented kits, that is TA-05/TA-06 and TB-02/TB-03 chassis. 

These tires are correct to handle the box-supplied Mabuchi 540 motor. They come either in radial or slick flavor. From what I know, they seem better than "lower end" kit box-supplied tire sets like in the TT-01.

• "Option" tires:

For a better grip, especially with the Sport Tuned motor or better, you should pick one of these sets.

Type A tires are my best choice since they work great on the tracks I usually run. Type B3 tires are recommended when the weather is hot. In fact, Type A tires are the best choice for temperatures below 25°C: above, the Type B3 will provide the best grip. As for the Type C tires, I never tested them: Tamiya recommends them to run on carpet or on oily tracks (typically the track where Gas-Powered models run too).

First run with the TB-03

We decided to meet at our usual track with my friend David from RC 4 Old Nuts. First of all, the photo shooting session:

In the sunlight, the ORC Amemiya SGC-7 bodyshell is gorgeous: sorry, I was not able to make the photos depict it at its best. Anyway, the model is ready, time to switch it on. And then... silence.

This is the very first thing I noticed: silence. I am used to shaft driven models (my TA-01, TB-01, TL-01 and TT-01 chassis), but I immediately thought I was driving a belt driven car like my TA-04 TRF. By this, I mean the same feeling that everything runs sooo smooth, and silently.

My choice of the 0.4 pitch gears probably helps, but the running quietness undoubtedly comes first from the optimized chassis drive. The TB-03 chassis is part of Tamiya's "high-end" offering: drive parts adjust even more precisely and ball differentials are known to be quieter than the bevel gear differentials from my other more entry-level chassis. From the very first spins of wheels, I knew I had achieved my goal with the TB-03: I have a perfect counterpart to my TA-04 TRF, but with a better protected drive.

The drive optimization is not only a matter of sound: the motor also runs better. On my TL-01, the motor is about the same: of course, comparing two different motors in two different chassis is not the best comparison ever, but the fact is I can handle the 9T Brushless power with my TL-01. However, with a similar setup on a chassis featuring an optimised drive, the motor feels it has tons of extra power, so much more power that I will need to set limits on the radio until my driving skills get better to handle it.

On the track, the TB-03 is easy to control: very much like with my TA-04 TRF, the chassis feels stable whatever you do, always running very smoothly and you soon feel like a professional racer at the wheel . However, neither David or I could feel any difference between the IFS system compared to a classic suspension system: we didn't try to push the chassis (or the drivers) to the limit though, but we both doubt our driving skills are good enough to notice it.

I am very pleased with the TB-03 chassis since it is the perfect counterpart to my TA-04 TRF for running on dirty tracks. The pleasure to drive properly and delicately is very similar to my belt-driven racer's: this was my goal and the TB-03 achieves it. Moreover, the bodyshell looks amazing (even if the front end is fragile).

Related article

• 49278 TA-04 TRF