TT02 Gearing - Large Pinions

[87lc2 2833]

Hey Guys - Converting my SRX into a VTA car for the winter and obviously need to do some custom gearing.  Looking for ranges from 3.0-4.0 which means I'll be running some big 64p pinions (up to 62t possibly).

For you guys that have done this, how large of a pinion can you fit on the TT02 before running into issues?  Just want to make sure it will actually fit before I buy some gears.  I'll most likely use the Carbon Gear Cover from RC-Racer so will not need to fit the top plastic gearcase cover. 

Any input appreciated, thanks. 

[Pylon80 3435]

15 minutes ago, 87lc2 said:

Hey Guys - Converting my SRX into a VTA car for the winter and obviously need to do some custom gearing.  Looking for ranges from 3.0-4.0 which means I'll be running some big 64p pinions (up to 62t possibly).

For you guys that have done this, how large of a pinion can you fit on the TT02 before running into issues?  Just want to make sure it will actually fit before I buy some gears.  I'll most likely use the Carbon Gear Cover from RC-Racer so will not need to fit the top plastic gearcase cover. 

Any input appreciated, thanks. 

This has been covered in great details by one of our members, see his blog:

https://www.thercracer.com/2014/04/tamiya-tt02-175-215-and-vta-blinky.html

[87lc2 2833]

Thanks @Pylon80  I've read that and saw that he used a max 53t pinion and it looked close.  I may need to run a 60t+ pinion.  No harm in trying, I'll grab a few gears and see how it goes.  Adding a top deck to the chassis so can always trim that just a bit if I need to. 

[87lc2 2833]

Finally got the SRX ready for VTA and took it to its first race last night.  Took first place in the A by just under a second, it was awesome.  I think every other chassis running was an XRay, so pretty cool to win with a TT02.  Car handled great and had tons of grip due to the flex so I was able to take very tight lines around the small indoor track.

I ended up getting the gear hold-down, center chassis brace, and carbon top deck from RC-Racer and the parts are fantastic.  Ended up with a 3.8:1 FDR using a 76t spur and 52t pinion (64 pitch).  I can probably go up to a 56t spur before I need to grind the gearcase, but on the small track I ran last night 3.8 was perfect.  Great punch out of the corners and enough top end to not lose any time on the straight. 

 

[Pylon80 3435]

Congrats and very useful information, thank you!

Are the folks starting to hate you 😅 you have been taking first place in every class 😐

[87lc2 2833]

11 minutes ago, Pylon80 said:

Congrats and very useful information, thank you!

Are the folks starting to hate you 😅 you have been taking first place in every class 😐

No problem, hope it helps someone.  Great group of racers where we're at, its all about having fun and racing clean.  It's funny, after the race our race director asked the other guys if they knew a TT02 just beat them, it was a funny moment.  Everyone just had to take a look because nobody believed it.  A few of the really fast guys weren't there and I most likely would have lost to them, but even being close with a TT chassis would make my day.  I plan on running this one a lot more so we'll see how it goes.

I actually think the flex of the chassis with the stock soft shocks is a good combo for this car.  VTA is a bit slow with 25.5 motors so its all about taking the right line and getting as much exit speed as possible.  This car just dives into the corner and digs in, so much front grip that I was taking much tighter lines and getting better exits than the stiff chassis cars.   A flexible chassis is not ideal for high grip carpet (from what I've read), but seems to suit me.  I might try to tighten it up just a bit, but going to leave well enough alone for the most part.  Just happy that I can finally use my SRX to be competitive in a class.  Up until now I didn't have much use for it since the more basic Tamiya classes exclude the SRX due to the TRF suspension.

 

[Pylon80 3435]

40 minutes ago, 87lc2 said:

No problem, hope it helps someone.  Great group of racers where we're at, its all about having fun and racing clean.  It's funny, after the race our race director asked the other guys if they knew a TT02 just beat them, it was a funny moment.  Everyone just had to take a look because nobody believed it.  A few of the really fast guys weren't there and I most likely would have lost to them, but even being close with a TT chassis would make my day.  I plan on running this one a lot more so we'll see how it goes.

I actually think the flex of the chassis with the stock soft shocks is a good combo for this car.  VTA is a bit slow with 25.5 motors so its all about taking the right line and getting as much exit speed as possible.  This car just dives into the corner and digs in, so much front grip that I was taking much tighter lines and getting better exits than the stiff chassis cars.   A flexible chassis is not ideal for high grip carpet (from what I've read), but seems to suit me.  I might try to tighten it up just a bit, but going to leave well enough alone for the most part.  Just happy that I can finally use my SRX to be competitive in a class.  Up until now I didn't have much use for it since the more basic Tamiya classes exclude the SRX due to the TRF suspension.

 

So I have to ask the question people are always unable to answer. How would you compare the 25.5 (geared properly) to a silver can? If that similar power?

[87lc2 2833]

16 minutes ago, Pylon80 said:

So I have to ask the question people are always unable to answer. How would you compare the 25.5 (geared properly) to a silver can? If that similar power?

I can answer that perfectly.  I ran TT02 production class & Euro Truck last night as well.  Here are my numbers from last night:

 

TT02 Production (27t Brushed - Stock Gearing) / 35 Laps / Fast Lap 6.53

Euro Truck (27t Brushed - Stock Gearing) / 33 Laps / Fast Lap 6.98

VTA (25.5 Brushless - 3.8:1 / 45 degrees timing) / 37 Laps / Fast Lap 6.12

 

So yes, the 25.5 is faster.  It felt a lot faster when running, but the times are actually closer than I thought.  I'd say if a silver can could handle the heat of 3.8:1 gearing it would probably be quicker, but hard to say.  I doubt it would last an entire qualifier without getting smoked with that gearing though, they're hot enough after a heat in Production/Euro truck with stock gearing.

[Pylon80 3435]

7 minutes ago, 87lc2 said:

I can answer that perfectly.  I ran TT02 production class & Euro Truck last night as well.  Here are my numbers from last night:

 

TT02 Production (27t Brushed - Stock Gearing) / 35 Laps / Fast Lap 6.53

Euro Truck (27t Brushed - Stock Gearing) / 33 Laps / Fast Lap 6.98

VTA (25.5 Brushless - 3.8:1 / 45 degrees timing) / 37 Laps / Fast Lap 6.12

 

So yes, the 25.5 is faster.  It felt a lot faster when running, but the times are actually closer than I thought.  I'd say if a silver can could handle the heat of 3.8:1 gearing it would probably be quicker, but hard to say.  I doubt it would last an entire qualifier without getting smoked with that gearing though, they're hot enough after a heat in Production/Euro truck with stock gearing.

Thank you! Usually that question gets lost in the confusion regarding gearing 🙄

Racing these three classes is the ultimate experiment!

25.5 is probably great for racing as it removes any kind of cheating out of the equation and you are getting the same performance every time 👍

[87lc2 2833]

36 minutes ago, Pylon80 said:

Thank you! Usually that question gets lost in the confusion regarding gearing 🙄

Racing these three classes is the ultimate experiment!

25.5 is probably great for racing as it removes any kind of cheating out of the equation and you are getting the same performance every time 👍

Yea, I'm perfectly OK with the open motor/spec turns classes because they effectively eliminate cheating.  In the fixed timing/brushed motor classes there are definitely some tricks going on. 

25.5 seems slow, but that TT02 was flying around the track nearly as fast a I control it.  Same with the F1 and 25.5 motor, about as fast as I'm comfortable going at this point while still being able to hit my braking points & lines.  I keep getting pushed to get into 21.5 touring or USGT, but not only are those cars a lot faster, but the chassis require a lot more tuning and I'm just not there yet.  I bought a couple of XRay chassis a month or so ago (a 2017 & 2018), but I havent started to work on them yet.  I want to make sure I can drive as fast and consistently as possible in the "slower" classes before I make the move.  There are too many guys out there ruining other people's races because they went from Euro Truck to 21.5 in a matter of 1-2 months.  I won't be that guy. 

[alvinlwh 7063]

.

[87lc2 2833]

So you ran a silver can for an entire pack at 4-5 FDR and it lived?  Better than I would have thought to be honest and good to know.  After a 5 minute heat of all out racing in the stock motor classes those things are very hot, and that's at the stock 8+ FDR the TT01/TT02 runs. 

[alvinlwh 7063]

.

[87lc2 2833]

Well I guess it wasn't a fluke   Took the SRX out again last night for some VTA racing and it was even quicker, put nearly 2 laps on the a field of 6 cars.  This car really shouldn't be that good against higher end chassis, I guess it just really suits my driving style.  I can't believe the grip I can get out of this thing, its unreal.   So glad I don't have to retire my SRX and have a use for it!  There's a big summer series locally that runs VTA but a tub chassis is mandatory.  Most guys are running TA08s from what I gather, but I'm going to give the SRX a shot.  We'll see how it does on asphalt.

[Kowalski86 4076]

1 hour ago, 87lc2 said:

Took the SRX out again last night for some VTA racing and it was even quicker, put nearly 2 laps on the a field of 6 cars.  This car really shouldn't be that good against higher end chassis, I guess it just really suits my driving style. 

It goes to show just how much good driving comes down to skill/experience, vs hop-ups and all of the extra "high end" doodads.

[87lc2 2833]

7 minutes ago, Kowalski86 said:

It goes to show just how much good driving comes down to skill/experience, vs hop-ups and all of the extra "high end" doodads.

Very true.  I'm still new at the on road racing, but knowing a cars limits and where you can push it is something I'm getting better at every time out.  In any type of racing I always focus on driving first and then upgrade equipment as I see fit.  I will say it does feel really good to win in a class with a car that has no business competing.  Although for some reason this chassis just works with the crappy VTA spec tires and soft suspension.  I thought about trying to add sway bars to the car, but it just doesnt need it.  There's honestly not a single thing I would change about it - not for VTA at least.  Do I dare give it a shot in 25.5t touring     Probably not, but would be interesting.  I think a stiffer car is needed with the slicks they run in 25.5.

[87lc2 2833]

The SRX VTA is still working great   I think at this point its more than just for fun and the car actually works really well in this class.  Got out to race last night for the first time in a while and the TT02 placed second in VTA.  Qualified third after making a few poorly thought out setup changes, but got it back on track in the main and it was an absolute rocket.  Took over second in the first 3 laps and was chasing down the leader until I finally passed him with about a minute to go.  I put about 6 tenths on him and a marshal stepped out on the track to help a fellow racer and stepped on my car on his way back.  Bad luck, but it happens and I went down to second for the finish. 

Everyone at the local track is running the new Gravity tire and I think I need to make the switch as well.  They are belted and much more consistent throughout the run.  Picked up a set at the track last night and I'll prep them for the next race. 

Really loving this SRX for the VTA class and plan on sticking with it at this point.  Also geared down to 3.5:1 since there were a couple longer straights and it was a good decision, laid down some super fast lap times in the main with the new gearing.