The TRF420X was great from the start though, and the improvement from the TRF420 really surprised me. Throughout the comparison testing I did on two very different tracks, the TRF420X was consistently 0.15-0.2s faster both on fastest and average times. It’s clear that the car carries more corner speed, but is at the same more forgiving and easier to drive. This is a great combination, and the reports I have heard from TRF420X users around the world are along the same lines; i.e. the car might look old to some, but is very user friendly AND competitive.

You can find the setup I ended up with after June/July/August testing at the end of this blog post. This is for low grip asphalt in 15-25 deg C weather.

You’ll find some hints of the setups I run on the TRF420, and also on the TRF419X and XR, but there are clear differences as well.

Perhaps what stands out most in the setup is how narrow pin width I run at the front (C-C), but this is something I have been running for many years and always preferred, as it has given me the most consistent car and best results over 5 minutes on the low grip tracks I run on. The more standard wider front as recommended in the manual (F-F) did work much better for me on this car compared to previous cars, but for now I still stayed with the narrower setup. I also went one step down on the roll centers both front and rear – i.e. using the 4.4mm pin height.

For a while I also run the rear diff and front spool in the high position, and at least in some conditions I tested in I actually liked that. However, the low position is still what I prefer most of the time.

My standard setup for the past few years has been to run progressive springs both front and rear, as it has always produced the best 5 min run results. This is something that changed this summer, as I found that a linear 2.8 rear spring (Axon – ST-SL-014 WORLD SPEC SPRING SLS C2.8:Brown) worked best on the TRF420X for me.

The best thing when it comes to setting up the TRF420X is how adjustable the flex of the chassis is. I found that with the available options (which are all included in the kit), you can really fine tune the car to your driving and to the track conditions. With the possibilities offered by the motor mount, the upper deck, and the rear flex plate, you can really change the feel of the car. I ended up running a very soft car, by removing the front belt tensioner (softening the front part of the upper deck), the top deck screw in front of the spur, as well as the removing the rear flex plate completely. This is what produced the fastest car for me in the conditions I run.

These are still a lot of things I want to try with the setup of the car, but I just run out of time for now. I have for example still not tested the Toe Control rear suspension on the car, so there are lots of things left for next summer.

One thing I had really wanted to try was the latest dampers from Axon – the HIGH BIG BORE SHOCK III / TC10 SUPER SHORT.

I got these dampers last winter before the TRF420X was announced, as I thought I would be running the TRF420 for another summer and wanted something new to test.

To just get a a chance to try these super short dampers on the TRF420X, I run TRF420 towers with the lower bulkhead mounting holes cut away, using the upper holes but mounting them in the lower holes of the bulkhead. If you look closely at the pictures you will see how low the towers and dampers are. Obviously this was just a quick way to try them, and while it worked surprisingly well, of course they would need some custom made new towers to get all the holes (bulkhead and damper mounting) in the correct positions. Let’s hope Axon would actually make some of these for the TRF420/TRF420X!

The dampers worked really well though, and it was clearly noticeable that the car was more stable and stayed more flat on track. I imagine they might be good on carpet. But to say something more definite you really need proper towers and more testing, so let’s see what the future brings.

Time to summarize the first summer with the TRF420X then – I might have been sceptical at first, but I am by now a big TRF420X fan. I think that says everything 🙂