TRF415 big pulley and gear diff conversion.

So you have a 415 and you want to get back to racing against the big boys. The 415 is still perfectly able to get you into the A finals, how...

So you have a 415 and you want to get back to racing against the big boys. The 415 is still perfectly able to get you into the A finals, however there are a few things you can do to help the 415 be easier to maintain and cope with a brushless system.

As I needed to service my 415 I decided to see if I could cheaply sort out two main upgrades

417 pulleys - I would like the internal ratio to match the 417 so I can swap gear settings (Also according to Tamiya the 417's I.R. is much more suited to brushless, and larger pulleys are always a win to avoid slipping belts)

Rear gear diff pulley - I like ball Diffs, but the gear Diffs do seem to have more bite, and they also last for ages before needing servicing.

So after a bit of shopping around I found the following list of parts

1 x SAK-65 v2 Gear Differential 37&38t version 2 for Sakura Zero £9 (eBay)
1 x SAK-07A Center pulley set 19t for Sakura Zero £3 (eBay)
1 x Tamiya 54023 DB01 Front One way pulley £5 (eBay)
1 x XRay 305444 183mm x 3mm 61t rear belt £5 (forum price)
1 x Hot bodies HB70738 169t front belt. (eBay win)
1 x Tamiya 53588 10mm Shim set

Right so let's start, the car has the top deck undone and the rear ball diff, centre pulleys, front spool and belts removed.

The Gear Diff

First up I made the 3 racing gear diff. The packet comes with two main pulleys, 37 or 38 teeth. I went for the 37t pulley as that matches the later TRF cars. The diff was really easy to assemble, and I was really impressed with the build quality.

I used 2000 weight oil as I find it is loose enough to allow the car to rotate and still is assured on acceleration.

When fitting the diff in the car you will need to shim it to fit with 10x0.3mm shims a pack of 10 will be sufficient, make sure it's not too tight. Also make sure you fit the new 61t X-Ray belt over the rear spindle before fitting it... Which I didn't at first.. Doh!

Shaft protectors
It must be noted the Sakura Has a slightly wider diff cup so you will need thicker shaft protectors, however 3racing includes them with the diff so swap them out with the old Tamiya ones on your rear shafts.

Centre Pulleys

The later TRF415's from the MSX Marc Rheinard versions all have plastic centre pulleys so you can fit any TA05 or Sakura Zero pulleys as replacements. To match the 417 I went for the 19t Sakura Zero pulleys.

It's a nice easy job,I stripped down the main pulley and removed the 16t pulleys. Then after cleaning up the direct pulley holder, I mounted the new 19t pulleys.

I then fitted the two belts over the pulleys and fitted it back into the car.

Front spool

Really easy, just replaced the 36t pulley with the Tamiya 37t one.

Now everything was fitted to the car. Just rolled it on the table top to check that everything was free and nothing was rubbing etc

So here are the fitted pictures of the rear of the car

Notice the shims fitted on the diff and then the bearing before placing in the bulkheads

And the centre pulleys

I gave it a quick run and it was fine, gear Diffs do seem do give more bite on acceleration. The rest is just to help on gearing changes. So let's go racing and see if the old girls still got some life in her..

Trf415 1080598653253335319

Post a Comment

  1. hi there my friend, i wonder if you could help me with some measurements. i need the Gear diff dimensions so that i can check if they will fit into my car. I need the distance between, outer diff bearing to center of pulley, short side and long side, then the distance between outer cup to cup. Please help me. Thanks.

  2. What car do you have? i will try to get the measurements sorted by the weekend.



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