TT-02b gearbox upgrades for brushless

[DavidJH]

I'm considering going brushless on my tt-02b. I have the upgrade bug for sure but it's all great fun and not too expensive if you buy from PJ.  I was looking at the 10.5 tamiya brushless but have heard the Tt-02b diffs need an upgrade to take the extra power. So far I've got the aluminium drive shaft and cups (the ones that connect the gearboxes front and back) and ball bearings throughout.

I'm planning on buying the universal shafts front and back too.

I've read that replacing the diffs with the metal ones from the df-02 is a good shout but I'd like something that just slots in if possible. So don't want to do any filing of parts if possible. Also is it necessary to do front and back or just the back box?

are these the right parts?

https://www.modelsport.co.uk/product/tamiya-parts-bag-a-df-02-26642

Do I need a couple of these too?

https://tamico.de/?a=2372&lang=eng

or do I just take the gears out of the first link?

I've also read that just shimming the tt-02b diffs is enough...I have 2 packs of 5mm shims but I'm not entirely sure how to use them in the gearboxes.

Also is the ball diff from the TT-01 any good? (it's the only one they have at PJ/price wise that I'm happy to run to)

car so far in pic

Thanks.

Dave

 

 

[Jonathon Gillham]

I have the DF02 diffs and you need both parts you've linked to. The DF02 uses 3 gears, the TT02 4 gears, so the cases are different. The filing thing is very straightforward, its just to take a few mm off the back of the pinion. A cheap file and flat surface is all you need, and you have the plastic part to compare to as well.

GPM also make metal gears for the TT02. I'm pretty sure its just the ring gear (and probably the pinion) that will be necessary as the internals in mine have always been fine. Its also common for race kits designed for mod motors to have plastic internal gears.

https://www.rcjaz.co.nz/tamiya-tt02-steel-ring-gear-bevel-8pcs-set-for-tt02b-gpm-tt2100-p-90070804.html

https://www.rcjaz.co.nz/tamiya-tt02b-steel-ring-gear-1pc-for-tt02-gpm-tt2100g1-p-90071611.html

https://www.rcjaz.co.nz/tamiya-tt02b-steel-propeller-shaft-gear-1pc-for-tt02-gpm-tt2100g2-p-90071612.html

You can try the standard diffs to see how they last. I find mine wear out even on the kit motor after enough use though. Standard diffs are very cheap so you can just keep replacing them. The reason I went back to standard diffs is the DF02 diffs sap a lot of power so the car is noticably slower with the kit motor and df02 diffs. A 10.5T motor won't have the same issue though as brushless have a lot more torque.

Shimming is just using shims to get a better gear mesh, ie put a shim in behind the pinion to get it closer to the ring gear and reduce the slop. I think if you get it right it will delay the inevitable but isn't a proper fix for a 10.5T motor.

Gearing is key here too, to make the most of the new motor. The DF02 gear bag includes a 19T pinion which will make a big difference. The 10.5T can probably handle the biggest pinion you can fit quite happily.

[DavidJH]

Thanks for this Jonathon. All those metal gears you linked to are quite pricey aren't they?

to be honest I probably don't need it to go 10.5t fast it's just the next fastest one if the much maligned 15.5t!!! But all this talk of stripping diffs make me think I should go for one of them and buy a nice big pinion at least then I could have a go at using the stock Speed Controller...oh and shim the badword out of them.

 

[Jonathon Gillham]

6 hours ago, DavidJH said:

Thanks for this Jonathon. All those metal gears you linked to are quite pricey aren't they?

to be honest I probably don't need it to go 10.5t fast it's just the next fastest one if the much maligned 15.5t!!! But all this talk of stripping diffs make me think I should go for one of them and buy a nice big pinion at least then I could have a go at using the stock Speed Controller...oh and shim the badword out of them.

 

Yep, they are pricey. The DF02 diffs are definitely better bang for buck.

You also need to be careful not to go crazy on the TT02 cars. You can spend a fortune and still have something that isn't great. If you want to go fast a secondhand race kit is the way to go - you'd probably find a used Ae B64 for about the same as those GPM gears!

[DavidJH]

I'm looking to get the 8x0.3mm shim as described here - scroll down to just below where he talks about the Tamiya 22047 - Front Direct coupling

https://www.thercracer.com/2014/08/tamiya-tt02-guide-mods-tuning-and-tips.html

Would you put one of these on both sides of the diff?  Or just the side to force the bevel gear into the diff ring gear?

Is this the shim he's talking about?

https://www.rcbearings.co.uk/index.php?route=product/product&path=179&product_id=2236

Or these?

https://www.plazajapan.com/4950344535880/

Or these?

https://www.plazajapan.com/4950344545896/

Dave

[DavidJH]

Reading some of the old threads it seemed some people just used the metal bevel pinion...

https://www.timetunnelmodels.com/live/catalog/advanced_search_result.php?search_in_description=0&osCsid=bvol79ba3ru6ktjv40ov1um0t7&keywords=5455040
 

now that's much more reasonable. Hopefully that and some shimming will do the trick