42316 Tamiya TRF419XR Build Review and set-up

The Tamiya TRF419X is a superb chassis and has claimed victories at a range of events such as the Reedy Race, ETS, Nationals and local clubs. Despite it's success it seemed that this might be the last TRF chassis as Tamiya changed its commitment for the TRF program. The loss of the factory drivers signalled what many thought would be the end of our favourite blue brands commitment to 1/10 onroad. Well those fears are unfounded and we now have the Tamiya TRF419XR. Obviously I was keen to try it out and see if it could improve on my TRF419X.

Unlike many of the earlier TRF chassis, there are two different kits available.

Tamiya 42316 The fully blown kit, This is only available in Japan, and also includes bonus parts high shock towers (For separately available std TRF shocks) and heavy battery retainers for life batteries.

Tamiya 42317 is a conversion kit. This is available worldwide and contains the important new parts to upgrade your TRF419X or TRF419X WS to the latest specification.

I purchased the upgrade kit, as I do not live in Japan and it saves me a great deal of cash. Let's hope the Tamiya Racing Factory keeps offering this option to all racers where possible.

In the box

The conversion set includes the following new and redesigned components
  • 2.25mm Carbon fibre lower deck
  • 2mm Carbon fibre top deck
  • Carbon Centre pitch stiffener
  • New Aluminium motor mount 
  • Revised front & rear aluminium lower bulkheads
  • Aluminium inner servo mount
  • Front & Rear stabiliser holders
  • Centre pitch turnbuckle
  • Fan mount (30mm or 40mm)
So that is all of the parts needed to convert the TRF419X (Or WS) to the XR specification. 

The build

As I had the conversion kit, It will not be a full detailed build like the TRF419X kit (Click the link for that review) , I will just look at the new parts and cover the differences and give it a track test.

The new lower deck made from 2.25mm carbon fibre. This makes it 0.1mm thicker than the TRF419X original. The big noticeable difference is that the cut-outs are now symmetrical. It has been a bug bear for me that the original chassis didn't have these cut outs, as I couldn't see how it would help with symmetrical flex. The chassis is also wider at the front wider (0.5mm on each side), making it a little stiffer. There are now also more holes along the centre-line for adjustments and the holes for the pinion fitting have been removed.

The weight for the two chassis lower decks are:
  • TRF419X    (69.6)
  • TRF419XR (71.1)

The new 2.0mm top deck is the same thickness as the TRF419X part. The main difference is that the front 'V' is deeper and the pinion adjustment holes are now cut out of the top deck. The TRF419XR top deck is 0.5g heavier at 7.8g.

The new lower bulkheads still have the three mounting points for the chassis, providing us with lots of interesting options to tune the flex of the chassis. The big addition is that they now have mounting points for the bearing mounted stabiliser set. Thanks to the additional holes in the side of the new bulkheads they just weigh in at 6.2g each, a negligible 0.1g heavier than the older bulkheads, despite the increased size.

The front and rear stabilisers now are mounted in a pair of 740 bearings.

Once mounted they feel very smooth, It makes the whole setting up business a little easier as you do not have to worry about them binding anymore.

The new motor mount has a longer centre section that provide more flex options. It is also longer to accommodate the centre brace that is also included. 

The centre shaft now uses 3mm screws (at last), providing a stronger attachment and also easier maintenance.  Here you can see the additional screw mounting holes.

The revised inner servo mount has been tweaked to provide an extra mounting hole for a range of centre links. Centre links are something that I have experimented with over the last couple of years and I found them to be a useful tuning aid. With drivers such as Atsushi Hara also running these mods when he raced the Tamiya TRF419X,  it is good to see that the design team have embraced it for this new chassis iteration.

Included in the Kit is a carbon centre stiffener. It is reversible and can be attached in several ways to change the flex characteristics. The default kit setting is the stiffest, and the chassis is very stiff with this attached. It is not quite as stiff as the aluminium chassis, but it is very close and I have driven it on high grip carpet and it feels good.

Flip the deck over (Where the holes have no bevel), and you have the next stiffest setting.

Softer still, you can attach the screws from the bottom and just bolt them in.

The Turnbuckle is a good option if you want the car to feel more lively going into and accelerating out of a corner. Obviously you can remove it for even more flex. It is a great tuning aid, and you can experiment with other options such as a pitch centre damper or even a centre shock.

The kit also comes with a new 45g centre weight, a massive 15g heavier than the TRF419X part. As you can see it fits easily under the centre stiffener.

The final new part is the elegant fan mount. It is held in place from the underside of the chassis via a grub screw access hole in the bottom of the motor mount. The fan mount can hold 30 or 40 mm fans. I would advise you checking that the screw is always attached, as it can come loose. Myself I prefer to use my own motor fan booster as it is much more efficient.

The rest of the kit is as the TRF419X build. I am using the optional alloy diff halves (With the internal large Diff shims) and have a smooth leak free differential.

The front I am also using the alloy 37T pulley. This really helps the feel of the car when entering high speed corners. I also run the lightweight spool mod for the outdrives as I race stock class, and it also saves the drive shafts from excessive wear.

The kit instructions suggest fitting the differentials back to the lower position (they were high on the TRF419X). Lower will not roll as much but have a larger angle on the driveshaft. An angled drive shaft will always try to flatten out when rotating. So a low diff will make the car feel more stuck at the apex, a higher diff will make the car more responsive with the chassis being more free at the apex.

Its just a tuning option. On high grip carpet I like them both high. Its harder to drive but faster. outdoor I have the front high and the rear low as a starting point. There are more noticeable things to tune than the diff  height however.

The new parts all fit well, the top deck is a better fit than the original part with more space around the centre pulleys (although it is still tight).

Here are some shots of the final assembled chassis.

At the Track

I was keen to see how the car would handle on the hardest kit setting as a starting point and would go from there. The track is low to medium grip carpet (grey) and quite technical. As is normal for me at a club night, I was not their in time for practice so I just had to line up for the first round with only a couple of shakedown laps under my belt. It felt good, but I was not expecting much from my first nights racing as I expected to make a lot of changes to my set-up.

At the sound of the tone I raced off towards the first corner, a fast double apex sweeper. The TRF419XR was very responsive on the way into the corner, although as it was the first round I was being a little light on the throttle. I was able to position the car easily on the exit apex and the car gave me no hassle as I approached the slow 180. Hitting the brakes the car felt settled as I tried to hook around the apex and launch myself off. The car was a little too settled for me as I like to rotate a bit quicker when so slow.

I was keen to loosen the car up a little, however a look at the timings did show that in the last 3 minutes that I was really consistent after getting to grips with the chassis. For the second race I thought I would move the shocks out at the rear a little and change the screws under the motor mount to help it rotate a little more.

In the second heat the car was still very stable but I had gained even more turn in and the car was noticeably faster around the slow 180. The car was just great and I managed to secure the fastest time of the day by three seconds.

The final qualifier was next. I decided to make the centre link a little softer so I swapped the centre deck over and installed the button screws. The grip had come up now and it was a gamble, but I was very keen to see how the car would respond. I need not have worried, the car felt fantastic. The extra flex was enough to give me more corner speed but it was still stiff enough to feel really consistent and demand that I keep my lines. The result was FTQ by nearly 6 seconds and more excitingly to myself I had managed 5 laps within 0.1 sec of my overall fastest lap time. That just shows how easy I was finding the car on the track.

I was feeling good ready for the final, the car was great. So I instead of making a few minor tweaks I decided to swap out the centre deck and run the turnbuckle. It was a gamble but I really liked the turnbuckle on the TRF419X and it made the car better on mid or lower grip surfaces. Whist at it I made a few minor tweaks to the droop just as I wanted the car to feel even more lively at times. I also went down a tooth on the pinion to give me even more speed out from the slow 180 corners.

I lined up onto pole position and waited for the beeps. Launching away the TRF419XR just felt great. Under braking the car was a little easier to free up when I wanted it. I used this to my advantage to brake later and throw the rear out at the slow corner. After a minute I had already passed one of the back markers, and was approaching another.  Unfortunately as I passed them they then weaved into the inside on the fast double apex sweeper and knocked my Tamiya into the air, throwing me off the track into the pit area.

After a heroic scramble from the drivers in the pit to retrieve my car, it was placed back on the track, however I was now down in fourth. I drove away, not sure if the car was in one piece (Tamiya C-Hubs... you gotta love em!). Luckily and car felt tight and exact as I charged onward to try to make something of the race.

I quickly caught up to the third place driver, I could see that he was going a little wide at the S section, so on the next lap I took a slightly different line to squeeze inside. The TRF419XR responded precisely and I got alongside them as we raced to the next corner. I now had the best line and could outbrake him and claim the corner to take third.

The Second place driver was close ahead, and thanks to the zippy response of the Fleta ZX v2 motor I was gaining quickly. I could see that his corner speed was not as fast as mine so I used this to my advantage. I ran close and then took a slightly wider line in one of the mid speed corners. At the Apex I was already nudging ahead and then as I throttled away I claimed second place.

The minute warning had been called and I had around a third of a lap to make up to even challenge the first place driver. However it is always easier to chase so I decided to just put in some fast laps as the grip was the best it had been all night (Temporary Carpet track). I put in two fast laps and (One was 2 tenth faster than my previous best of the night). I was approaching the leader.

For the next two laps I kept trying to stick the front the car in any gap that was being left open, but the driver was keeping it very clean and sticking on the best line on the narrow track. As they were concentrating on keeping be behind the pace was quite slow and I was all over the rear. So I decided to take a gamble and really lean on the car. As we approached a mid speed 90 degree turn I went a little wide changing the apex so I would exit alongside the barrier on the inside. This was not the best line to approach the slow 180 but that was my plan. I raced hard to the apex of the corner, going very deep as the leader approached from the left taking the smoother line. I was on the inside, but could I make it stick. I hit the brakes as late and as hard as I could and threw the steering to full lock. The rear of the car responded and broke grip, allowing the car to rotate around the tight apex. I then caught the rear and powered away just edging ahead.  I managed to hold on with only three corners to go to claim the win. I was literally shaking with the adrenaline, that's why I go racing.


Here is the final set-up for the Mid carpet.

You can download the editable set-up sheet from our friends at Petitrc.com (Click here)


The TRF419X is a great chassis and the new XR version improves on it in many ways. The stiffer lower deck makes it feel more consistent, even at its softest setting. Impressively the car is also quicker in the corners thanks to the revised flex characteristics.

The smoother sway bar mounts are a nice addition, and the revised centre shaft is much more durable, and also easier to maintain. The quality of everything is excellent as you would expect from TRF.

Most importantly the TRF419XR is a chassis that responds well to set-up changes yet just always seems to feel really drive-able. I have raced most TRF chassis over the years starting from the 414 and this chassis is the easiest to drive. Importantly is is also quick, you are able to lean on the chassis when you need it, I have raced it several times now and it has not let me down, I am just becoming more impressed with it after every outing. 

I am looking forward to putting the TRF419XR through its paces over the next racing season, next up high grip black carpet, and then outdoors, so keep checking back.

Useful links

I purchased my Upgrade kit from TonysTamiyaParts
Manual (Click here for PDF)
Editable set-up sheet Via PetitRc (here)
TRF419XR 7218613402706334475

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