Tamiya TRF421 track testing - Cut arms
Last night I thought I would try to cut the arms on the TRF421. My local track is very tight and twisty so there is a possibility that the c...
We change the layout every month at my local track, and it was a new, very tight track to contend with. At first I just ran my standard set-up and the car was instantly on the pace. However I'm still trying to understand the range of tuning options for this car, so I decided to cut the upper arms to see what effect it would have.
The car felt good, it was a little more 'lively than I initially anticipated. With the cut upper arms I found that it was a little more keen to enter the corner when on power. At the Apex it certainly rotated but it might have been too keen and a couple of times I did find myself almost over rotating.
I made a tiny tweak to the rear droop and the motor mount screws to make the car a little less aggressive and the TRF421 was more predictable, but still very reactive when I wanted it to be. It seems very much to me that the cut arms do give more grip, but at points maybe they flex a little too much under certain loads.
Looking at the lap times I was faster and still maintained the same consistency variance between the cut and not cut arms.
From a performance point of view, the cut arms had shaved 5.1% of my average 10 lap time to the uncut arms. Obviously there are other factors that need to be considered, including the fact that it was a new layout and I was learning it on every run. However it was still notable how much quicker it did feel at times.
In conclusion, I would say at the moment it seems like a good option. I will make another set of arms that are un-cut so I can swap between the two as I seem fit. I personally wouldn't want to only run the cut arms at this point.
I am also keen to try the cut arms, but with the one piece top deck, it might just stop the occasional over-rotation of the car when coming in too hot. I'll try that next week.
