42350 Tamiya TRF420 Aluminum Lower Chassis Deck Review

With the release of the TRF420, it has been great to see that Tamiya has really focused on the worldwide market with the release of several option parts so soon to the chassis release. The most important for anyone running high grip carpet is the 42350 Aluminum Lower Deck and 42349 Carbon upper deck Combo.

The aluminium lower deck is 2mm thick and is 85mm wide like the standard carbon chassis. It also comes in a nice matt black anodised finish... Would blue be too much?

The chassis has cut outs to still allow it to flex a little. The cut-outs along the spine provide it with a better roll characteristics.

The chassis still has the cutaways for the motor and all of the holes are in the same position.

The chassis weighs in at 84.12g. This is only 14.62g more than the stock carbon chassis (69.5g)

The chassis does feel stiff compared to the carbon chassis, but there is some flex

The 42349 Carbon upper deck is recommended to go with the Aluminium lower deck as its thinner design will put more load on the chassis to ensure that it will flex.

The shape is exactly the same as the standard TRF420 upper deck.

It weighs 0.7g less than the 2mm top deck.

So overall with the Aluminium Lower deck and the new upper deck you only add 14g of extra weight.

At the Track

Despite fighting a heavy dose of manflu I booked myself into round 2 of the Schumacher GP at the excellent MB Models race track. The track is one of the only permanent UK indoor venues and it always hosts great racing and high levels of grip.

The Schumacher Gp is primarily aimed at GT12 class, but as that class has dwindled there are now a lot of touring cars at the event, so much so that they outnumbered the GT12 entries. I was booked into 13.5 blinky and was keen to give the TRF420 and aluminium chassis a thorough shakedown.

As I had quickly mounted the chassis in-between eating mince pies and drinking maybe a little too much sherry I treated the practice round very much as a shakedown. I just wanted to check that the car felt good and nothing was loose. me For the practice round I just gave the car a quick run to check that nothing was loose. I could feel that the whole thing felt planted from the start (The track was already very high grip as many had been practicing the day before).

For the first qualifying I set off feeling good about the chassis. I was at a slight disadvantage as I had not attended the previous days practice so I was still learning the track but the TRF420 exhibited the traits that I have already discovered. The steering was very good, even on power entering the fast sweeper at the end of the straight. I was having a bit of hassle getting a good line at one of the infield corner sections. After a few laps I was starting to get into it but the car started to wander so I pulled over and took a look. A screw had come out of the upright.. oh well a simple fix.

For the second qualifier the car felt very good indeed. I was slowly getting used to the layout and the the TRF420 felt brilliant. The car still have a large amount of steering so I had reduced the dual rate down and had reduced front camber. I was very quick although I was curious why my number was not being called. I got to the end of the race and it seemed that the transponder was not being read on the track. I looked and it was still blinking so was a little confused as to why it was not working.

The third qualifying was also good. The car felt great and I took it steady as I wanted to actually post a good time. I managed 14th overall in the round which was good considering the quality of some of the top runners. People were coming over to look at the car, remarking on how flat it was around the track and how quick it was on the corners. It did look edgy but when racing, it never felt like it was going to lose grip so it was more like a LMP / GT12 car.

For the final round I changed the gearing as I had been running way under at 5.4 FDR. I moved to 5.2 FDR as I wanted more speed on the straight. They car didn't break grip anywhere and I managed to post a fast lap quicker than a buddy who I race against running the T4 20. The TRF420 was excellent.. The transponder however was not.. It had stopped counting my laps intermittently. So despite being faster than all of my events before I posted another bad time.

With the fact that I only had one run that was accurate it affected my final position so I ended up in the 5th in the d-Final. Not representative of my actual pace. I didn't have my spare transponder with me so I just thought I would have a bit of fun in the final as at least it would have commentary so even if my transponder stopped working, they would be watching the race so at least I could just fight for position.

As the chassis had loads of grip I went for 2 degree rear toe and added the centre post to make the rear more stiff.


From the starting buzzer I took it easy trying to avoid the classic first corner carnage. Indeed it all started to kick off and as I arrived at the first hairpin there were a few cars recovering from a collision. I gently drove around them with a few close shaves but I made up a few positions.

I was conscious that there was a lot of carnage going on on the first lap, so I didn't attack the lap. This proved a good move as their was another collision ahead, I squeezed through the gap and then found myself in second place. I quickly caught up the leader as they made a mistake, I was now starting to put a bit of pressure on. As I kept closing in the leader made anther mistake so I passed and took the lead. The second place guy tried to quickly get his place back and we had a spin. Being a proper racer they waited for me to recover and we raced ahead onto the straight. Then literally as I got ahead I could feel that the car felt a little odd at the end of the straight entering the high speed sweeper.

I tried not to let this concern me too much but the pressure was mounting as the second place driver was chasing me down because I couldn't attack as hard as I wanted to to build a lead. Despite not being able to drive as aggressively as the chassis would allow, I was able to keep ahead as the TRF420 was still able to navigate the slower infield section well. The second place driver then clipped me at the end of the straight, I instantly straightened the steering to try to avoid the car spinning, and was able to hold on, despite being pushed past the apex. The driver behind came of worse and span, giving me a bit of breathing space. The race was 6 minutes long and all of this had happened in the first minute or so. With this gap I just concentrated on extending it a little before maintaining a comfortable lead. The Manflu was kicking in hard and my eyes were streaming but I just got into a nice rhythm to take the victory.

The first thing I did after marshalling was to look at the car, it was as I had expected the two outer tyres had unglued from the rims. The rear tyre was in a terrible state as I could see the insert!  I will pit the lack of preparation down to having manflu :)


I didn't change much. Just tweaked the roll centre a little and also swapped out the centre weight to the lighter 45g version from the 419xr.


The TRF420 with the aluminium chassis was very flat in the corners, increasing the cornering speed. So despite getting the gearing so wrong I was able make time on the infield. The car felt great both on and off throttle, and I was able to stay on power as I drove through the switchback on the track. I was really impressed.

So I would say that the alloy chassis has really heightened the TRF420's driving characteristics on carpet. The low down weight and different chassis flex ensure that the car is very responsive whilst being assured and easy to drive into the corners.

TRF420 4881261252157474095

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