Rebuilding the TRF419XR

Over the last couple of weeks I have (very) slowly rebuilt my TRF419XR. This car of course started out as the TRF419X in May 2016, and was then refreshed with the TRF419XR Conversion Kit in December 2017.

While we wait for something new from TRF, my car needed to be refreshed and prepared to be ready to run on carpet again. During this rebuild, I added a few parts which I will detail here.

First off is the Donath alu chassis for the TRF419XR. These were made in limited numbers by Christian Donath, who up until this season run TRF cars and made many ETS stock A-finals. Since no alu chassis for the XR version has been made available by Tamiya, this is the only option I’m aware of. Except of course the 419X WS chassis from Tamiya, which lacks some of the center line holes of the XR.

Last winter I run the stock carbon chassis, well aware that an alu chassis would most probably be an improvement. But since I was lucky enough to get my hands on one of the Donath chassis’, I decided to build my car using this now.

The overall shape of the chassis is similar to the standard carbon XR chassis, although it obviously has more flex cutouts. As most alu versions, it’s 2.0mm thick, and the same width as std at 85mm, and weighs 15g more.

The second major update was that I decided to use the new 42325 TRF419 37T Aluminum Gear Differential Case when I rebuilt my diff. I had already used the alu pulley part until now, and wanted to test the alu case as well.

The case is beautifully made with great precision, as you would expect. Finally I could thread gear diff screws into an aluminium part! How I have waited for this! 🙂 Once built the diff really feels amazing, so I really look forward to testing this.

The major difference apart from the material is that the alu case hold quite a bit more oil compared to the standard case (15-20% more). This bigger volume together with the alu material should mean it works better over a 5 minute run.

Of course it comes with a penalty of higher weight, but it will be interesting to test.

Here are the weight difference of the cases:
– 419 std plastic case: 5.8g
– 419 alu diff case: 8.4g

(I would have taken pictures of the diff, but somehow my camera battery mysteriously vanished during the build and is nowhere to be found) (had to buy a new battery…) 😀

I also upated the driveshafts front and rear with some of the latest TRF parts. The parts I used were these:

42321 Lightweight Cross Joints for Assembly Universal Shafts (2pcs.)
42320 Lightweight Joint Casings for Double Cardan Joint Shafts (2pcs.)
42319 Lightweight Cross Joints for Double Cardan Joint Shafts (4pcs.)

Small changes obviously but I really like the joint casings for the front DCJ’s. Together with the cross joints, the front driveshafts are around 1.6g lighter each.

I did not have the new 42322 44mm Swing Shafts (Hard) for the rear driveshafts, as I must have missed to order those.

Rebuilt 419XR (almost) ready for the carpet.