Whats the smallest 64p spur anyone has run? I want to make my R into a USVTA for fun (I know its not going to be that competitive) and trying to get an idea where I can start. From thercracer 70/53 is possible for a 3.43, has anyone made it lower? I'm thinking about being future proof for the Gravity 25.5 assuming its going need to be lower than that and the possibly the spec USVTA motor.

Once you grind away the cover to clear a largwr
pinion, any combo is possible. You can go lower than 3.43.

TT02 is a good choice for VTA.

My son ran the type S in VTA and did awesome until I upgraded him to TA08.

To add onto that, you need the speed gear set in order to mount normal RC spur gears (the kit has a very specific mounting system that requires special spur gears). And to be able to freely combine any pinion/spur variation, you'd also need the Yeah Racing motor mount.

Right, the R already has the gear set and I already have the mount. Im looking for the specific answer on the smallest spur that anyone has used successfully. There is no sense in buying a few different spurs if someone may already have the solution, but it looks like that may be my only option to get the right answer.

I have seen a speed runner put a 49T (48dp) spur in a TT-02, but you need a very large pinion for that, which does not fit under the kit's normal motor cover without cutting it.

I would ditch the pinion/spur cover and get one of the aftermarket carbon fiber hold downs. Then get an adjustable motor mount and set your gear mesh like any other car.

Thats the plan! This is a carpet car so not worried about boulders getting in my gears.

I currently have a Robinson Racing 60t 48p spur gear in my TT-02 VTA car. I think 48 pitch gears are a bit more forgiving when setting mesh than 64p gear. Unfortunately I think Robinson is out of business.

I ran some fairly small 64p gears in my TC3/TC4 (2.5 internal gear ratio) when I was running in it VTA. I will dig through my stuff and see how small I went with those spurs. I'm pretty sure I ran some 64p spurs in the 70's range.

There are issues when running small diameter spurs (regardless of pitch) in shaft drive touring cars.
1) The motor/wires can come close/interfere with the drive shaft - especially if running a snap on heat sink
2) May not be enough motor mount adjustability to get desired gearing/gear mesh
3) Large pinions may interfere with the chassis or gear cover

It can be challenging to set perfect gear mesh on small spur gears. I've stripped many spurs when I've not had good mesh, the motor shifted during an accident, or I didn't properly secure the motor. With small spur gears I always erred on the side of tight mesh. Better to finish the race with less than ideal mesh than strip the spur the first time you use the brakes.

A trick I've used in the past with 64p gears is to choose a pinion size 1 tooth larger than what I am going to run. With the larger pinion installed, set the mesh VERY tight. Remove the larger pinion then install the 1 tooth smaller pinion instead. Usually the mesh will be pretty good when doing this. However this isn't foolproof. While I like the Yeah Racing adjustable motor mount, I still prefer using 48 pitch gears in my TT-02 as I've had less issues with stripping spur gears.

Wait, what about Robinson going out of business? They're my go to whenever I need pinion gears in Tamiyas screwy 0.6 mod.

I gotta admit, the TJRparts.com gear cover replacement is dialed!! He even has a channel milled for the bearing. https://tjrparts.com/products/tt-02-gear-cover-delete

I may be mistaken about the status of Robinson Racing Products based on the fact their website shows that it was last updated in 2015 (Robinson Racing Products - THE LEADER IN RC GEARS !!!!). However it looks like their Facebook is more updated (https://www.facebook.com/RobinsonRacingProducts/)

I might contact them directly as I'm down to my last 48p 60t spur.

I am currently running 64p gears and have a 74T spur with a 52T pinion. That gets you a 3.7 FDR and ha been good for 76mph for me...

Just ordered 56T and 60T pinions to try and help me get to my 100mph goal. The 60T should get me to a 3.21 FDR and a theoretical top speed of just over 100mph. Fingers crossed!

Question, sorry if I am beating a dead horse. Our local track is starting a tto2 box stock class. Box stock so far. Our issue is the stock dog bones are popping out with a slight hit. What can we do to fix this issue . This will be a 100% beginner low budget class.

Quit hitting things while turning.