42285 Tamiya TRF419 Build and Review

Earlier this year the TRF419 announcement took a lot of people by surprise. The TRF418 was only a few months old and was a great car being well received by many club level racers. Tamiya had other plans and with feedback from the Team drivers, a new car was developed with the goal of reclaiming the top spot at race meetings around the globe.

The TRF419 has got lots of totally new parts. As is common with Tamiya the name has changed due to the bulkheads changing, but there are a lot of other new components including a totally new gear diff. So lets take a closer look.

Chassis plates

The new chassis is made of a softer weave than the 418 but it is still 2.25mm thick. 

Softer carbon weave is used on the TRF419 chassis

As you can see there are a lot of holes to change the motor mount flex, and also holes to maybe fit an ARS set-up at the rear. The upper deck is very similar looking to the TRF418 version, but with the slightly width for the wider bulkheads.

Screws

Lightweight and strong. Titanium screws are always a great hop-up for a racer.

For the build I am using the excellent Titanium screws from 'Moody Fools'. These are top quality and they help lighten the car. I also used some Tamiya blue aluminium screws for a little bit of bling. Check out their shop here

Stages 1-3 bulkheads / Motor mounts

With the Carbon chassis parts drying (I used CA glue on a cotton bud to do the edges, I sealed all of the carbon parts apart from the upper deck).

Let us take a look at the new motor mount.

The number is because it is a German kit, and these are stamped to ensure they can run in official Tamiya German races

This is a totally new part and the mount is now a 1 piece design with several mounting positions to change the flex characteristics. The mount allows the motor to be further towards the back of the car (3.5mm) and it is also a little further out (approx 1mm).

The centre post is also separate. I will attach it with a little threadlock as it is a pain if it comes loose. You can remove the centre post if you wish but I will leave it there even if I remove the top deck screw to give me more tuning options at hand. (Note-Do not use threadlock on most parts, it is not needed and it makes maintenance much more difficult, I will make note on the other couple of places where I use it)

The new split blocks are not compatible with the older cars

Whilst we are here we can see the new split suspension blocks, these are very similar to the Yokomo style now. I never had an issue with the previous design but these are not keyed into the chassis and they should be able to handle a very large whack without moving (I do not intend to try this out)

The rear end is now assembled, notice the new 0.5mm spacers under the split blocks

The lower bulkheads are made to the same fantastic quality as the TRF418 parts, they are also keyed to fit into the chassis (to help avoid tweak) and they also have a guiding pin on the top to ensure that the upper bulkheads are aligned perfectly. The difference is that as the bulkheads are wider on the chassis, they are now inline with the suspension mount holes. The eccentric diff holders are now not flush with the outer edge. This inset allows you to use the same size diffs as before (And makes the new diff backwards compatible with the other cars).

Here you can see how to change the flex characteristics of the motor mount by using more or less screws.

The kit set-up shows you to fit 4 screws on the underside for a Medium flex characteristic. As you can see with the 6 holes there are range of configurations that you can adopt, including just fitting screws to the middle two holes to have a lot of flex.

Now we just need to fit the front bulkheads and the lower steering posts. The steering is the same as the TRF418 parts, however it would have been nice if Tamiya had used the TbEvo6 style posts as they are much easier to fit and remove. I did use a small amount of threadlock on the screws that hold in the steering posts.

Stage 4 Assembling the rear gear diff

The TRF419 comes with a newly designed gear diff. This is a big deal as the TRF team drivers were reporting impressive improvements on their lap times when they just fitted the diff into their existing cars.  The parts are really well built, and these are one of the areas that you really need to take time to build the diff well.

One of the new parts for the TRF419 is a re-designed gear diff. The previous one was fine but some did have issues with it leaking and feeling notchy.

The new version however is a big step up in both smoothness and build quality, some of the TRF guys were saying that the diff alone improved lap times in their cars when they tested it.

Here you can see the main new components.

The new internal bevels are moulded from a new plastic, the teeth are larger and there are less of them, making the diff even more reliable under heavy load, and mod motors.

The casing has also been changed, there is room for much more oil in the cylinder now. This ensures that the oil temperature can remain more stable as it will not overheat as easily, making the diff more consistent through the race. 

The two halves are really nice, and you can see the ridges on the edge that ensure the diff halves slide together smoothly and precisely. 

Here are the rest of the components. Other new parts are the diff outdrives, these are now the same length for both the left and right sides. The rest of the parts are familiar to anyone who has built the previous diffs, the cross shafts are the same and you also get shims for both the large bevel gears and the smaller spider ones. 

The kit also comes with both the black and hop-up orange O-Rings. I have used the orange ones for some time now on the previous gear diff and they stopped any issues with the diff leaking.

Tip - The Xray O-Rings (Part no XR972050) are better and will reduce the chance of the diff leaking through the outdrives. If  you use them you will have to use 0.2mm of shims instead of 0.3mm as it is slightly larger. I use the Tamiya 54589 Gear differential shim set for these shims. 

Building the diff.

First up I trimmed any excess plastic of the gears

This is easy and it's worth doing this to ensure that you do not get any snags when the gears mesh.

Now just slap in some Associated Green Slime on the inside of the diff case where you will place the O-Ring. 

Then slap a load of the green slime on the o-ring and insert it into it's housing in the diff case. You want to ensure that the whole ring has slime on the inner and outer edges for the best possible seal.

The diff half then has to be inserted along with the 5x8mm bronze bushing. I actually replaced the bushing with a bearing, I have done this for other similar diff designs (Like the TBEvo 6) I'm not certain if it helps but in my mind it's got to be better than just a bushing.

Now its time to fit the large shim over the O-ring, I also coat the back of this shim with a smear of Green slime, this helps keep the diff sealed and it also helps ensure that the O-ring stops swelling due to unwanted friction.

It's the finicky tweezer moment trying to get the small shaft through the hole.

Then click the large gear on top of the shaft (It fits with a nice reassuring click), the result is that it spins smoothly and there is very little lateral movement on the shaft.

The other half is the same basic constriction, however this side also has the gasket.

Splurge green slime around the inside edge of the diff cylinder and over the screw holes.

Push the gasket down gently with the edge of your hex driver until it's perfectly seated in the diff

Now we assemble the inner gears. These now have shims and the fit when you place them in the diff is really very precise, a much better step up from the previous gear diff.

Now it's time to fill the diff up with the oil. I use 2000 oil in my base set-up. When filling the diff just ensure that the oil is up to the top of the small bevel gears.

You want to leave the oil to settle for a while if possible to get any air out, if you have a large shock pump you can use this to help speed up the process. I like to twist the diff half whilst pushing down on the cross shafts to get rid of trapped air quickly.

Fitting the two diff halves you now have to ensure that the bottom and top halves are perfectly matched. 

Its a little difficult as once the diff is full of oil you have to look underneath to find the spot. So I just marked it with a paint pen on the side to ensure I didn't have any issues locating it. The two halves slide together very smoothly to make a perfect fit.

Now it's time to finish it off.

Before I fit the screws I drop a dollop of green slime into each of the 4 screw holes. Then it is time to just screw the diff together.

Do this in a cross pattern to avoid any warping. I get to around 1mm from having the screws being perfectly seated and then just take my time gently screwing them until they are all firmly seated and tight in their holes.

Stage 5 Attaching Rear diff

The top quality 1510 TRF bearings are fitted over the diff outdrives and then we need to fit the eccentric to be mounted in the eccentric belt adjusters over them.

I like to mark the circle with paint pen, it just makes it easier to adjust when at the track when in low light etc. Also you should look to ensure that the upper bulkheads fit well when mounted. If they do not sit flush you should either lightly sand the edges of the adjusters, or just fit some small 0.1mm shims) between the lower and upper bulkheads to ensure you are not crushing the bearing. However on both the TRF418 and with this 419 I have personally not had to do this.

The kit comes with the H5 ball connectors, these have a 1mm shim added so remember that when checking set-up sheets

The rear diff is now assembled and spins freely. The rear belt is 6mm shorter to reflect the more rearward motor position in the TRF419. The front belt is 6mm longer to compensate (2 teeth more).

Stage 6 Spur gear

If you stare hard enough at this picture, it seems to blink at you!

The rear pulley is redesigned, it is still made of metal and has 20 teeth, but the centre shaft fits into a pair of 840 flanged bearings.

You need thin spur gears such as Panaracer or Kawada Super EX ones.

The pulley takes most spur gears although if you want to assemble it as per the manual you will need to use Panaracer or Kawada Super EX ones (Or the Tamiya 116t included). NOTE: You can use other spurs but instead of using the E-Clip you will need to use the 4x1.0mm spacer included in the kit see page 20 in the manual.

Stage 7 Front Direct Pulley

This is the same lightweight pulley from the TRF418.

Now the pulley is black, it is still the same with 37 Teeth. I also used a drop of threadlock on the screws, (That's it for threadlock and the build) The Spool outdrives are now the TRF417v5 Type so you do not fit any drive blades anymore. I like to run them dry and just replace the outdrives as soon as I notice any wear. (NOTE The outdrives have two sets of holes that are offset by approx 0.4mm, fit the pins in the holes that are shown in the instructions)

Stages 8-9 Steering assembly

The steering arms are still the same as the TRF418 pieces.

The whole assembly fits together well, and it feels really free.

Tip - 3Racing (Part No 3RAC-SW03) do some great shims that have even more fine values (1.0mm, 1.5mm etc) and can work brilliantly in the steering assembly when eliminating any slop. I found that a 3x5x1.5mm shim instead of the kit included 3x5x1.0mm shim on both arms just took out any spare movement.

Stage 10 Upper deck

The upper deck is 2.0mm thick, it is thicker at the rear than the previous 418 upper deck.

The belt tensioner is the same TRF418 part, a very lightweight and elegant part, and the two 630 bearings feel free when mounted onto it.

Stage 11 Rear Arms

The TRF419 suspension arms were first found on the TRF418. They are very well made, and they are also very strong. I raced for over a year with my TRF418 and the arms did not need to be replaced at all, and they are still slop free.

The suspension shafts are also now ti-nitride coated again after the disappointment of just standard steel ones being included in the TRF418. These shafts are firm when fitting them in the suspension arms but that is normal, you want them to be firm and should never ream them out, as the suspension is built to rotate in the suspension blocks not the arms.

The manual now also tells you to shim the suspension arms to ensure they do not bind. This is something that many have already been doing (Never shave the arms), and it is good to see Tamiya recommending this.

Use shims to ensure the arms fit perfectly with not lateral movement but fall freely under their own weight.

There are some shims included in the box, but it is good to have the Tamiya 53585 shim set, for spares and more shimming options.

Arms fitted and the rear has 3 degrees of Toe in.

The rear suspension set-up is 1X 1F this is wider than the 418's 1XA 1E set-up

Stages 12-13 Front Arms

The front arms are also the same as the TRF418. Very solid with just one lower suspension setting.

The downstop screws are wider than most cars, this reduces the damage that can happen to the lower deck on contact.

They fit well, and they did not need any additional shims to feel good.

The front is the std 1C,1C layout, I have a 1B split block to try some extra arm sweep if I need it.

Stages 14-15 Rear Axles

The rear axles are made of aluminium, and they use an axle ring to hold in the pins.

This design has been really reliable, and the only thing you need to ensure is that you note the direction of them when fitted into the hubs.

The ball connectors are the old ones on the rear hubs, not the H5 parts. I used Roche axle blades instead of the kit white ones.

You have to ensure that the leading end of the Axle ring when the wheels moves forward is the part that fits in the hole. The picture above shows this for the right hand side of the car.

Stages 16-17 Front axles

To drive the front of the car Tamiya includes a pair of steel double cardan drive shafts. These stop a lot of jitter when cornering with a spool. It is excellent that Tamiya includes them in the kit as many similar priced kits do not include them.

The shafts use the axle rings to hold in the retaining pins and I use a little AW grease on the pins.

Before fitting the front axle, knuckle and C-Hub together I assemble the screws in the knuckle. This allows me to ensure that it is all true and straight.

I shim the inside of the wheel axles until there is no play. I found it only needed 0.3m on each axle.

The TRF419 also comes with the new type C-hubs. These eliminate the chance of the driveshafts rubbing against them, but I am not that happy with them as they have some movement both up and down and also the kingpin hole seems a little too large so there is some movement there.

I did shim out the vertical movement with a 0.2mm shim between the front knuckle and the upper flange. The kingpin movement however is still there, it's acceptable I have run these on the 418 for some time, but the older C-hubs never had this issue so I find it puzzling that these do not feel as good.

I used the Tamiya turnbuckle tool as it makes everyone's least favourite job (making turnbuckles) a painless task. The turnbuckles are still aluminium but the new design has made them even stronger, I never needed to replace them for titanium parts since this new design, although if you are running a faster class then Titanium ones will obviously be more resistant to the impacts that can happen in those faster classes.

At this stage I like to check the arms are still free, there is no tweak and the drive train is smooth.

The chassis is taking shape now.

Stages 18- 19 Stabilizers

The kit comes with Medium front and rear roll bars. (Black).

They are easy to assemble and when attaching them to the bulkheads I ensured that the grub screw in the mount allowed the bars to rotate freely but did not have any other movement.

Stages 20-22 Dampers

Tamiya's range of dampers have been well regarded for a long time, it is still common to see a flash of Tamiya blue amongst other anodised chassis parts in the pits.

World class engineering is synonymous with the TRF brand

Tamiya is not resting on it's laurels though, and the TRF419 shocks now are big bore. This leads to a range of new parts. First up the cylinder now has a larger internal tank. (External dimensions are the same).

The larger internal cylinder ensures that pistons are also new, and they have a distinctive groove around the piston holes which will change potential oil flow. The Piston rods are the same Ti-Coated parts but the rod guide is now 1 piece (First Seen on the TBevo 6) and this ensures that the piston's movement is really smooth.

Muchmore 450 oil is added and the shocks are set with 3mm rebound.

The kit also comes with the TRF blue O-Rings. These ensure you have a very smooth movement, although the Blue O-Rings can be prone to leaking more if you do not service them regularly. If you want an easier to maintain shock then just fit the clear O-rings.

The kit comes with the new larger diameter TC springs. The red ones (Soft) are included in the kit which may be ok for outdoors racing, but I will be running the car on carpet so will fit the Yokomo Pink (Front) and Blur (Rear) springs once it hits the track.

Stages 23-24 Attaching Dampers

The damper mounts are slightly wider to accommodate the wider bulkheads, the geometry looks to be the same.

To fit the shocks I like to use the Tamiya 42231 Ball nuts for TRF Dampers.

I only need one packet as the new arms only have one lower mount so I rarely need to remove the lower ball cup. (Once I am happy with oil and springs). However I do like to change the upper hole setting much more often so I just use them on the damper stays for that reason.

Stages 25-28 Electrics and fitting

The new motor mount is a similar style to that seen on the TRF418.

The big change is that it now has an extra little nub that allows you to mount the antenna holder on with it's own screw. This makes it a fraction heavier (0.5g approx) but it makes it much more convenient to install. The mount also acts as a battery spacer.  NOTE: The instructions say add 5mm of shims but you should fit 4mm otherwise the battery will not be straight.

I fitted a Sanwa BLSv2 along with an Xray extra strong servo saver. I use this instead of the kit one as the Xray servo saver is 18mm high, the Tamiya kit one is shorter and it makes full lock quite difficult to achieve.

Other electrics were the Fleta Pro ESC, Fleta ZX motor and the Sanwa RX-471 reciever. There is ample room to fit all of these parts on the car.

Excellent power and Price ensure these Lipo's are very popular at the track.

I used the BRCA / ROAR approved Nano-Tech Ultimate cells for the car. The TRF is really light so I didn't have to worry about the weight of the larger capacity cells. However weighing in at 311g these are only 5g heavier that my previous 6200 lipos. You can get them from here (7500 UK US INT EU AUS) (6600 UK US INT EU AUS) (6000 UK US INT EU AUS)

With the Electrics installed I used the SKYRC Corner weighing system to balance the car.

The circuit board is a local club transponder (it weighs approx 5g like my RC4  PT)

It was already looking quite balanced, I only had to add 25g to help balance it out. I also like to put a chassis on 2 pins to check it is balanced without any spring anomalies, and the car was also levitating like a Guru :)

Final fitting

I used the TRF adjustable body mounts (Part no 42245) mainly because I like shiny blue bling.

You need two packs for a car.

So here is the finished chassis with electrics.

T

I had fitted Sorex 28 Black Pre-glued tyres. These are excellent on carpet.

The Fleta ESC and motor combo has been really reliable and fast for me.

Hopefully most of my racing rivals will see the back end of the car once it's on the track!

Track test

I had a Mazda GX shell ready to fit (The holes are the same as the TRF418) and also fitted a Racing Dutch Prototype 190mm wing on the car (Separate report on that later).

I took the car for it's first outing at a small local club. I ran the kit settings and it was quick just from the get go. The thing I noticed instantly was the corner speed of the car was much improved from the TRF418. This could be the slightly softer carbon chassis and other refined flex characteristics of the car.

I started to play with a few settings, including changing the front wheel spacers to 1mm to calm down the steering a little.

I managed to scrape a first place against a field of 13.5 runners with my 17.5 car. This was down to the straight being quite short and the lack of speed there was easy to make up on the infield as the car just stuck to the track.

The Second event was at a much larger carpet track set-up for the Crewe 1/12 national. I was running a 17.5 blinky against a mixed field. The straight was really long so I suffered on that part of the track but the car was hooked up on the infield.

I wanted to make the car really easy to drive, as I knew that being able to hit the right apex every time would really help me eek the most out of the power difference.

I started 4th on the grid in the A final and set about chasing the front runners. I chased the guys and gently worked my way up by attempting to exploit the corner speed and consistent handling that the TRF419 was providing.

On the 4th lap I was able to hook on the inside of the third place runner. It was a sharp 180 degree turn and the car held on to the inside line and I was able to get over a car length in front before being able to put on the power. I held onto third and by the end of the large infield I had built enough of a lead to hold of the 13.5 boosted car's charge on the main straight.

I managed to keep in the groove with the TRF419 responding perfectly to my input. I found a couple of different racing lines on the infield as I became more confident with the car's level of grip. These lines allowed me to gain on the second place driver and as they came up to a back marker I was able to swoop and pass them both.

Despite a charge from the second place runner when we got onto the straight I held my nerve and kept my line and again the cars pace on the infield helped me extend the gap.

I finished second with a great big smile on my face. I was only a few seconds behind first place and if I had the pace on the straight I would have troubled them.

Set-up

Here is the set-up I used.

Editable sheet from http://www.petitrc.com/

Overall

I'm really excited with the TRF419. I was not expecting a huge leap from the TRF418 but the car is quick and even easier to drive.

There are a few things that could be better, the C-Hubs are not as refined as the parts they replace and they are also not as strong. The Servo Saver should also be taller (18mm).  These are small complaints though as the rest of the car is superb.

The smoothness of the diff is great and it feels much more refined as you enter a corner. Overall cornering speed is increased, and the motor mount has a lot of tuning variables allowing you to hunt for that extra tenth at the track.

The quality of the parts is typical Tamiya quality, and also the kit specification is also better than most of it's established competitors. I cannot wait to get it back onto the track, and see where this car can take me.