Tamiya Trf Car Outdrive Measurements

[Origineelreclamebord 45]

Hi everyone,

I am looking to convert the ball differential of my Dyna Storm to fit modern outdrives as part of a larger project. I thought the following cars may have fitting diff outdrives:

TRF415

TRF416

TRF417

TA-05

TB-03

TRF501X

DB-01

TRF511

TRF201

DN-01

For financial reasons it of course is better to ask owners of these cars if they could measure a few things for me:

1: Total length of one outdrive (for cars with asymmetrical outdrives like the TRF417: please measure the shortest outdrive).

2: Outside diameter of the outdrive/pressure plate.

3: Inside diameter of the pressure plate (the diameter of the inside part which the washer/ring on which the diff balls roll fits around).

4: Depth of the slots in which the the dogbones go.

5: Distance between beginning of the outdrive (the narrow part with the slots) to the point where the bearing is physically stopped from moving furhter onto the outdrive.

It would great if someone could help me out - I really want to update the diff to a 2006 or later spec, because the rest of the car is too

Thanks in advance,

Paul

[TenzoR 62]

You may want to look at the M05 ball diff out drives since that looks like it might fit well since both side are equal. I will double check for you when I get home about the length and measurements.

If you can get the M05 ball diff to fit that means you only have to get the nicer M05Ra re-inforced ball diff halves, the TRF201 thrust bearing parts bag, and the TRF201 diff nut and screw.

[Origineelreclamebord 45]

You may want to look at the M05 ball diff out drives since that looks like it might fit well since both side are equal. I will double check for you when I get home about the length and measurements.

If you can get the M05 ball diff to fit that means you only have to get the nicer M05Ra re-inforced ball diff halves, the TRF201 thrust bearing parts bag, and the TRF201 diff nut and screw.

Thanks for the advice I already have a TRF 620 assembly thrust bearing and a TRF416 diff nut and screw - even the spring for the diff - the TRF416 screw is 1-2mm longer than the original Dyna one, so it may well fit

PS: I didn't know there was actually a new diff released for the M05! Looks very promising now I see pictures of those outdrives!

[djmcnz 754]

Okay, here goes for the 511, the only one I was a little unsure of was #5 but check the pic, I maked in red what I measured, they're used so you can see where the bearings go, let me know if I got it wrong. All measured with calipers, +/- 0.5mm I'm afraid.

Short O/D

#1 = 22mm (raised centre) -0.5mm for diff plate seating = 21.5mm

#2 = 28mm

#3 = 13mm

#4 = 11.5mm (including curved recess) or 11mm flat

#5 = 3mm (see pic)

Long O/D

#1 = 27.5mm (excluding input shaft) -0.5mm for diff plate seating = 27mm (input shaft is 6mm additional)

#2 = 28mm

#3 = 13mm

#4 = 21.5mm (including curved recess) or 21mm flat

#5 = 9mm (see pic)

Hope that helps somewhat.... ???

NB: I was three packs short of a diff rebuild on my installed front so timing was perfect!

PS: Check out my new speedo and motor...

[TenzoR 62]

Thanks for the advice I already have a TRF 620 assembly thrust bearing and a TRF416 diff nut and screw - even the spring for the diff - the TRF416 screw is 1-2mm longer than the original Dyna one, so it may well fit

PS: I didn't know there was actually a new diff released for the M05! Looks very promising now I see pictures of those outdrives!

I can't measure the reinforced steel out drives (#54238) since they are installed on my M05 but I am positive they are the same as the alloy ones that I just recently swapped out.

If you are planning to use that reinforced out drives, you can not use the TRF620 thrust bearing and TRF416 diff nut. The TRF416 nut will not fit. You can tell because if you look at the TRF201 it does not use any plastic shaft protector, so the slots are a lot thinner. You must use the TRF201 diff screw and nut (#9804410) and the thrust bearing set (#51417). Btw, the TRF201 diff out drive looks strikingly similar to the M05Ra's reinforced ones, probably just longer.

M05 Ball Diff measurement

25.45mm

25.4mm

13mm

21mm

15.5mmm

[Origineelreclamebord 45]

Thanks for your replies I'll start comparing the measurements soon!

There's just one huge thing to overcome though. The Dyna Storm uses 1280 bearings on it's outdrives, the modern ball diffs all use 1510 bearings (or at least a 10mm diameter of the outdrive).

This means I'd have to do one of these things:

- Finding 1210 size bearings (I believe they just don't exist - which is understandable - how are you going to make the balls and the outside 'framework in which the bearings roll fit in a bearing that can only be 1mm thick!?)

- Making the slots in the gearbox halves suitable for bigger bearings. All in all it doesn't sound like too much, but playing with a gear mesh of the car is very risky. I think an aluminum plate-like insert for it could work if made VERY accurately. If that's done it means I'd have to remove the old slots and fit it in. Or making gearbox halves from aluminum (this is not really an option though due to weight).

- Making the diameter of the outdrives smaller on a lathe. It is possible and an easy solution, but could reduce it's strength. This might be solved though by adding a ring around the outdrive when the bearing is back on (if that doesn't conflict with the dogbones, that is).

- Buy two sets of outdrives and make two-piece outdrives of them like on the older cars. For each side I would use two, one on which the pressure plates are removed on a lathe and create a slotting system for the pressure plate. For the second piece the other side is removed - So everything but the pressure plate, using the same slot but then inverted so the two fit together.

Making ones from scratch sounds easier, but by modifying I am sure the measurements are as they should be, and therefor everything will fit.

I've also looked at slightly earlier cars to perhaps find suitable outdrives for 1280 bearings - but this didn't happen. The outdrives of the TA03 series diffs are outdated (not using a coil spring either), the TA04 diffs already use 1510 bearings, the TB Evo I and II use 1280 bearings, but again not suitable outdrives - and not developed for a coil spring. The TB Evo III and later use 1510 bearings. The F201 uses 1510 bearings on it's ball diffs as well. And then finally, a bit of hope, the Tamtech GB01 uses 1280 bearings on the outdrives of it's ball diff... but they are of course too small for a Dyna Storm

It's a bit like one of those "Clarkson" moments: "How hard... ...can it be?" Well, let's find out then!

PS: One more option:

- Modifying the original outdrives (which I'd prefer not to do - although they'd need the least amount of modificaiton).

[TenzoR 62]

swap in the TRF201 gear box? and modify it to fit the MDC?

[Origineelreclamebord 45]

swap in the TRF201 gear box? and modify it to fit the MDC?

I did consider that, but then it would be easier to just get a TRF201, fit carbon plate type shock towers, carbon chassis plates and a Dyna Storm shell This project is about tuning the Dyna Storm to the max without losing it's status of 'Dyna Storm' It is getting a DB01 slipper clutch too though

[TenzoR 62]

Good luck mate, please do show some of your work once you finish

[Origineelreclamebord 45]

Good luck mate, please do show some of your work once you finish

Thanks (although I'm replying a bit late sorry about that).

I've got my hands on 3 NIP sets of outdrives now. The funny thing is: I may not need to modify the outdrive after all.

I shall explain the issue with the old outdrives and the modern internals to clear it up. Normally with the modern internals (at least in the Tamiya manuals I looked into), the spring is on the end of the nut, and the thrust bearing on the side of the screw head. One of the Dyna outdrives has a thread though, so first of all, that would have to be removed and a nut and spring placed on the other end.

Placing the spring and the thrust bearing on the same end is possible without in theory changing the function of the diff. However, I thought the screw wouldn't be in the outdrive deep enough to still accept the driveshaft on one side.

I am using DB01 WO Rear Universals for the car, and with the normal diff fitted, things would fit - but only just, as it is in pretty deep. So deep that it actually reduces the articulation of the suspension. To solve this I already succesfully modified one of the driveshafts in another pair of these, shortening them by 3mm or so. I didn't thoroughly test those particular ones, but I did succesfully use the same method to shorten driveshafts on my Monster Truck - it's survived a lot of hits, and the first things on the car to give up were not the driveshafts, but lots of screws coming loose (even a frontal impact where the rods of the multi-link suspension bent dramaticly didn't damage the driveshaft).

My only concern on the driveshaft mod is the weight. It is done by using JB-Weld and sliding over a 3.3mm inside diameter (4mm outside diameter) stainless steel tube (I unfortunately couldn't find the tubes in aluminum or carbon).

I'm almost ready to rebuild the diff though - I just need to order some bearings - I've already done some work on the chassis parts, I hope to be able to post some pictures in the Dyna Storm Tuning thread from Singapore_959 soon

EDIT:

I found a pair of 1280 ABEC5 bearings with rubber shields in my spares So I built the diff!

It is very strange... It feels ultra-smooth when it comes to how 'grainy' it feels - however, it is suspiciously tight, whilst the diff is only tightened just about far enough not to slip when you rotate the gear between the pressure plates with the outdrives fixed. I just changed out the modern screw with an older one, and this seems to have an effect strangely enough.

EDIT2:

Problem solved! I added threadlock to the screw, as I thought the small blue dab of threadlock added by Tamiya wouldn't be enough. This threadlock decided to stick to stick to a part of the screw too though where it sits inside the outdrive which it goes through (aka in which it should spin freely). Now I removed it, it is smoother and just as tight feeling as the original. I'll have a look at using the Dyna's original method of a second, smaller screw from the opposite side to lock things up - on which I CAN safely add threadlock then by the way

I did notice something else as well: There is some side-to-side play in the diff in the gearcase - so another thing to look at (though that clearly is not due to the changes I made to the diff internals: Ichecked it, the length between the outdrives on a standard diff and this is the same. I think it's the bearings, or the fact that I'm using a TR-15T gear casing instead of a standard Dyna Storm one.