TB02 spur gear mod?

[tim.sanderson]

I picked myself up a TB02 today, and I'm looking to run it in our GT2 class at our local track.

(the silver can and ESC will be getting yanked out)
GT2 is basically very similar to VTA... our rules are 21.5 motor, any 2 cell lipo, 4.0 FDR, rubber tires and bodies such as the Mazda Speed 6.
The only problem is this car is very limited to what gearing you can run in it. It uses 48 pitch metric pinion/spur, and has only certain pinion gears I can use due to the motor mount.

My question is, does anyone know of any off the shelf 48DP or 64DP spur gears I can buy for this chassis? If not, is there some type of mod to use another car's spur gears? I'm less worried about my pinion selection, because I have a modified motor mount that will allow me to use pretty much any pinion.

I'm running a belt drive car right now, but have had a hankerin' to get a shaft drive TC up and running for this class. There's just something so nice about the simplicity of a shaft drive car over a belt drive. And the 21.5 motor isn't fast enough to cause me too much grief with torque steering. If I can't get the gearing right, I may have to sell it, and buy another metric shaft drive TC.

[SMOKE-DOG]

I have a TB02 and have been wanting to use standard 48p gears also. My guess is that you would have to rig up some sort of mount for the spur to fit onto the shaft. I've never seen one on the market anywhere. Tamiya always makes gearing difficult with their .04 and .06 gears with mounts that are specific to that vehicle.

[jwscab]

what do the parts look like? would a standard spur fit with an adapter? I could probably spin up an adapter if it's not too complex.

[tim.sanderson]

I don't know if that would work... it's pretty tight for space in there. But that would be awesome! I've got some spare spurs and stuff at home. I'll take a gander at them after work, and take some pics and stuff.
Thanks!

[tim.sanderson]

Here are a few more pics of the chassis. Not shown, is a box full of spare parts, 3 bodies (2 used, one brand new) and some old rally tires/wheels. Also not shown is the carbon fiber strip along the bottom of the chassis.

It's too bad about the gearing. If I can't modify it to run 48 or 64dp spurs/pinions, I may have to off load it to buy something else.

Anyone know if the TB03 can reach an FDR of 4.0 to 4.25?

[jwscab]

looks like tamiya gave you a spur adapter if you had the kit. plastic parts tree M item 8.
http://www.tamiya.com/english/rc/rcmanual/tb02.pdf

tb-02 thread on rctech.net that has some further info. sounds like you would be OK if you had another motor mount made, or trimmed the fixed locations out of the stock one.
http://www.rctech.net/forum/electric-road/24245-tamiya-tb-02-a-37.html

slotted motor mount:
http://www.rcmart.com/catalog/rc-tb02-hopup-part-yeah-racing-alloy-motor-mount-tb02r-tb02013v2bu-p-25487.html?cPath=595_744_1232

another useful post:
http://www.rcuniverse.com/forum/m_4232234/anchors_8542335/mpage_32/key_/anchor/tm.htm#8542335

[tim.sanderson]

The adjustable motor mount isn't a problem... the holeson one of my mounts have been cut out to make a crescent shaped screw hole by the previous owner. The only problem is with the current 52t spur, I'd need a metric pinion in the mid 30s range to get the correct gearing. I don't think they make them that big. (at least, that is what I am told from a few different sources) If I can get a 35t metric pinion, I might be able to use this car after all. I shall look for one now.

[tim.sanderson]

It's weird about the adapter-thing. I've read conflicting reports on whether you can or can not run different pitched gears with it. I'll have to buy the tree and see for myself. There's a good Tamiya place 2 minutes from my work. (Galaxy Hobby in Mississauga) Maybe I'll see if he's got it on my way home tonight.

Good links, jwscab!

[jwscab]

yeah, I dunno what the speculation in those threads is about, unless it has to do with the fixed motor mount locations severely limiting pinion/spur combos.

in any case, the fact that there is an adapter included tells me something is workable. even if the adapter doesn't work, AN adapter can be fitted that CAN work.

coincidentally, after tracking that info for you, it gives me a good solution for a decently priced metal motor mount that bolts to a flat chassis if my mid motor project needs something instead of the plastic mount that's built in.(ie, I melt it from motor heat)

[tim.sanderson]

I found a local store that has the 'M' parts tree. Gonna pick it up on my way home. Hopefully I can buy the rest of the stuff I need tonight, too.

I also found this on the 3racing site:

picture.jpg (33.53 KiB) Viewed 2139 times

picture.jpg (33.53 KiB) Viewed 2139 times

http://os.3racing.hk/products.php?products_key=2907
It's an aluminum gear adapter.

[tim.sanderson]

Well, I bought all the parts, and after getting it put back together, it seems like it may work. If my math was correct, I should be at a 4.0 FDR. I put in a 64 pitch spur using the adapter on the M tree. (thanks, jwscab!)
I'll post pics and stuff later.

[tim.sanderson]

I think I was successful converting over to 64 pitch gears last night. (I won't actually know until I get it onto the track tomorrow) Right now as it stands, I'm at a 4.3 FDR. A little lower than the 4.0 maximum, but I thought I'd start here, to make sure I don't run too hot.

Here are all the details/pics from the conversion:

http://www.tsanrc.com/2011/06/tamiya-tb-02-gear-mod.html

[tim.sanderson]

Here's a look at the TB, ready to run tonight:
Not the tidiest of wiring jobs, but when I have a bit more time (i.e. sometime this weekend) I'll sass it up, and hide all the wires. I didn't have time, as I wanted to get it up and running for tonight's impromptu open practice at the Depot track.

Although I have a new un painted Mazda Speed 6 body at home, I just drilled some new holes in last year's super-well-used body. Hopefully this weekend I'll have a chance to get the new body ready for next Sunday's racing.

[tim.sanderson]

Here's me running the TB-02 during the first day of test-runs on Friday:
[youtube]c4rv0pxpCRY[/youtube]
I'm very happy with this chassis! I managed to get my fastest lap down a little over half a second. My Average lap time was much faster too, and much more consistent than last Sunday. The track was the identical layout to last Sunday, seeing as there has been no rain to wash away the sugar-water that was sprayed. Made it easier to gauge the difference between this chassis, and the Sprint 2.

[bearrickster]

Looks like you have it sorted out nicely. it moves around the track very well.