Tamiya TRF415 restoration.. Updated daily

I acquired a bag of bits which seemed to contain most of a TRF415. So I thought it would be good to see if I can cobble together a runner for a club night. It will be interesting to see how it fairs against the latest and greatest, and it will be a good trip down memory lane for me to race one of my favourite chassis of all time.

I intend to keep this all cheap, I will raid all of my old spares (Yes I am a hoarder), and try to get this TRF415 racing at the track for as little cost as possible.

Day 1 - Sunday

The chassis was in a very poor state when I got it. The previous owner had used thread lock on the bulkheads.. I do not like using it on a race car, and use it sparingly if I ever do. This chassis was caked in it, the screws were already threaded in the lower bulkheads so they were attached.

I tried several different things to remove the screws, there are some good screw remover drill bits that I had been pointed to, however as this chassis was already quite worn on the underside and had a few scars I decided to Dremel a small slot into each of the screws to use a large flat head driver. As you can see the chassis has a few deep marks etc anyway, so a couple of additional scars will not trouble the chassis. The fact that it is 3mm thick ensures that it able to easily cope.

Even with this, some of the screws were wedged in the chassis. I heated up the screws with a solder tip to 500 degC in the hope this might help and it just loosened it enough to make the final two screws be removed :)
A Tamiya original TRF415 ball differential with a 35t pulley
Whilst the plastics and bulkheads were soaking in the ultrasonic cleaner I started to make a ball diff from the parts in the box. The balls are ceramic. I cleaned the thrust bearing and re-oiled it. I then tightened it up so it felt quite stiff. It has been a long time since I have built a diff. I find them more satisfying to build, but the maintenance is a pain.

Luckily in the box there was a front spool along with the one way. I would have locked the one way up if i didn't have a spool (A drop of shoe glu did the trick). The spool cups were destroyed so I used a spare set of steel spool cups from the TRF419.

The original 415 and 415ms had one piece bulkheads. The design theory is all about providing great alignment. Whilst that might be great on paper, the reality is that maintenance is a massive pain. The MSX addressed this with two piece bulkheads and a revised upper deck.

The centre shaft also has the direct 16t pulley. It has got a little worn but it still perfectly usable. This is another bonus as the original 415's came equipped with a centre one way pulley.


I mounted the diffs and bulkheads. The belts are in ok shape, although I did give them a good clean and clear the belts. Again I would normally just replace them but I am trying to spend as little as possible to get this ready for the Club race.  The bearings were cleaned and re-oiled with the 1UP bearing oil and the whole drive train feels nice and free.. Probably because of all of the wear :)

Time to fit the suspension blocks. These are the old type so slightly wider than the later versions (For Detailed info on the Tamiya suspension blocks settings etc see this link). At the front of the chassis you need to run a suspension bridge or add 4mm of shims under each screw to clear the belt. I did consider drilling a set of holes so I can fit split blocks, however the front cut-outs on the chassis are narrow so they would not fit.

The chassis comes with the TBEvo III suspension arms. These were used on a range of Tamiya chassis up until the TA05. I always enjoyed racing indoors with this set-up as it was rock solid, hitting a board was never an issue thanks to the thick plastic and hardy 1150 bearings.

I was going to use the plastic parts, but delving around I noticed that optional Tamiya 53687 TB Evolution 3 Aluminium Rear Uprights were included. These provide much more tuning possibilities than the kit part. You can change the height more easily, as well as the length of the turnbuckle.  The stock plastic hub has its upper attachment point 29mm above the axle, these are lower (23mm) so you need to factor that in when moving set-ups across from a standard 415.  As these have 1deg of toe in, I used a 1A and 1D block to give me a total of 2.5 deg rear toe in.

The front arms and those chunky C-Hubs are mounted on a set of 1B blocks. The front arms are 2mm longer than the current 419 suspension arms. So I will try this, but might swap it to 1A blocks if I do not get enough bite at the technical track I will be racing it at this week.


I rebuilt the driveshafts. They had very little wear and are totally fine for running. They are 46mm long, whereas the original 415 would have come with 42mm long driveshafts. This might cause an issue with the suspension movement. So I will need to check the movement once assembled

Looking in the box there are a set of aluminium TRF415 kingpins.. These will be lighter than the kit standard versions, but they will need to soak up the occasional hard hit on the boards at my local club, so I have decided to fit the original steel version.

The front and rear hubs are held on with e-clips and not retained with grub screws like the more modern suspension system. The C-Hubs are really solid, I never remember breaking one when I used to race with this suspension. If only Tamiya would fix the C-hubs on the newer TRF cars... maybe I should try it on the TRF419XR :)

Moving around to the rear, I found that the 46mm swing shafts were on the cusp of binding with the diff bolt. It was usable but I thought I would look around in my other old spares to see what I had.

I found a lightly used set of aluminium differential outdrives. So I rebuilt the differential with these because they have a deeper recess for the thrust bearings and bolt providing more movement. run

Time to add the stiffener posts, the rear ones are 25mm front are 27mm

Front steering arms..ARGHHH!! there is a snapped aluminium screw in the arm. No doubt snapped when the previous owner tried to remove it. There was no way to grab it as it was recessed, this is going to be a problem.

Result! After asking around I decided to drill out the screw. It was only aluminium so I got the trusty Dremel and first used a 1mm drill, then kept increasing the size until I got to 2.6mm. At this stage the remaining parts of the screw just started to fall out. I used a steel screw and gently cleaned out the thread. So after a stressful 30 mins I had fixed the arm.

Steering now assembled, there is no ackermann adjustments available. So when you move the front arms you also adjust the ackermann..

The arms have a 2mm spacer underneath, and should have 4mm on top to stop them moving up the steering posts. I didn't have any so improvised with a 3D printed spacer.

As if one 3mm deck is not stiff enough, why not add another one for the rear :) I do remember that 0 or 1mm under the rear bulkhead mount was a good starting point, so I went with 0mm

Nothing to see other than the subtle change of design of the Tamiya turnbuckles. That is probably why they do not bend as easily :)

The front deck is installed along with the spacers

2mm top deck installed. There is no flex on this chassis.

Font and rear towers

On to the final stages. I installed the rear stabilizer bars, however the front bars require a special nut which I cannot find. So I improvised and used a short ball nut and reamed out the 2.6mm hole to 3mm so I could use a screw to hold it in place.

Success :)

I mounted the old style fluorine dampers. The original chassis would have come with silver versions, however this chassis has the blue ones.

Nearly there now. I just need to add electrics
I am happy with the progress so far

The chassis is 28mm wider than the TRF419XR chassis


I mounted the electrics. Look how far that motor hangs out of the side.

The chassis is designed for nimhs, and there is an issue with weight balance, so I will need to add some weight or hang the lipo out a bit to ensure the left and right balance is spot on.

Thursday - Race night.

I managed to make it down to my local club, but it was late thanks to being busy at work. I missed the first two runs, but got the car out for the third run.

The car felt great straight out of the gate. It looks like I had still remembered a decent set-up for the chassis and the car was incredibly planted and easy to drive. I had moved into the first position quite quickily however after a couple of minutes I had no drive. I thought the pinion had come loose. On closer inspection it was the direct centre pulley. It had come loose on the shaft as I hadn't tightened the grub screws enough. Most probably when I was moving it to ensure it span as freely as possible. Doh!

For the final race I hoped it would all work. And again for the first few minutes it did. I had tweaked the front shocks to make it quicker into the corner and the TRF415 responded superbly. I was flying ahead.. then suddenly the steering started to play up.. So I had to pull out of the race.  I wondered if it was the old servo that I had mounted.. however when I looked closer, it was the steering rack, again a screw had come loose.

I tightened it up and gave the TRF415 a 10 min shakedown at the end of the night.. nothing else came loose (ahem), so its all ready for next Thursday for a proper race night, not a shakedown.. And yest I will check the screws are all fine :)

Trf415 8286187272981692662

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