Thanks 4 pointing that out on the Xpress arms on the yeah so4

Back in June my son and I started running in The Porsche Cup Cars, which uses the kit torque tune motors. Yesterday was our latest race and we were in top place for the A main. My car died right after go.

The torque tune called it quits and spit out one of the brushes which buried itself into the tub lol. Motor has a fan and the case / end bell temped at 100°.

My son finished the race in first but also told me that his car faded at the end of the race.

For gearing, we were running 64/29 the max per TT02R manual, using Tamiya mod 06 / AV gears.

For Tamiya ProSpec class it's not an issue with the 21.5. For CupCars using the Torque Tune I’m surmising that it’s too much gearing.

I took a peak at the TT02R manual and noticed Tamiya had highlighted 64/27 as popular. I’m guessing that could be the max with this motor? 🤔

If I'm not mistaken the 27T pinion is marked because it's included in the kit. Brushed motors have a limited service life. I had suspected that my battery has failed me during a club race, but it was just a bad handout motor. It doesn't hurt to lube both motor bearings multiple times a day on these things.

You maybe right. In my experience, these mabuchi motors have failed me always in the same way.. the copper arm that holds the brush shears off and the brush is imbedded in the plastic of end bell or thrown out from the vent holes. This happened on two black can sport tune in my Sand Scorcher runner, so I stopped running that motor in it. With the torque tune 2 times as well, albeit the first time was when I had it geared (FDR of 3.7 or so) to have my son 7 at that time compete in our club class for VTA.. so it was geared very high and the motor died by days end.

I didn't expect it to happen in a TT cup car class using the Tamiya gearing (FDR 5.74). But to your point, I have ran this motor now for 5 race days for a total of 18 heats. Never cleaned it and never oiled the bearing. Something to consider for sure.

For next race I plan on trying 27t (6.16) to see if it makes a difference and see how long the motor lasts. Track is super tight so it should be ok.

I've been out of racing for 10 years or so. Getting started in VTA racing again and want to use a TT02 because my intent is to move up to TCS Spec 21.5 as my.skills improve.

Question is which model to start with- TT02R or SRX? Which will be more competitive as I move up and why?

Thanks, fellas!

For a casual driver, the R is the easier option as it's hardly possible to build it wrong. The SRX has a more sophisticated suspension package that's been on one of the older TRF competition kits. If you know what you're doing, you can get more out of your car, if not, it's more likely to be hit or miss.
I've been tinkering with a TT-01 in our club series for a while, and so far haven't found adjustable upper arms as absolutely necessary. We're allowed TT-01/02 with the standard tub and basically anything else except for TRF suspension and carbon fiber parts. My car has tons of option parts whereas my son's was almost kit spec plus bearings, CVA shocks and 3 degree rear hubs. Unlike cost, performance was very similar. 😉

For VTA you will need the Type S / SRX. Don’t bother with the R. You will need a 70t / 50T 48p combo and you will need to file down the gear cover to make it fit or buy the aftermarket carbon piece brace that by passes it. Don’t have a link for that one but I’m sure someone on here can help out

https://www.thercracer.com/2020/07/t...ear-cover.html

https://www.fibre-lyte.co.uk/fl/cars/tamiya/tt02.html

I have (but have not yet installed) this one from Yeah Racing

https://www.amainhobbies.com/yeah-ra...074bu/p1570165

I've run a TT-02 type S in VTA. It was a decent car and I was competitive against the average club racers.

If I was going to buy a new TT-02 for VTA in 2025, I would choose the SRX kit. That kit out of the box has MOST of the things I would want in a race vehicle such as...
- adjustable camber
- adjustable front/rear-toe
- high speed gear set (allows aftermarket spur gears)
- Tamiya 419 suspension (more durable than the basic TT-02 suspension)
- front spool/rear oil filled diff
- clamping wheel hex adapters

Here are some negatives with all the TT-02 kits including the SRX
- The stock ride height is tall when using VTA tires. Consider buying shorter dampers and/or shorter springs. I personally like Yeah racing.
- Plastic steering rack/components. Tamiya offers aluminum steering components/kits which work well, but there are plenty of aftermarket options available.
- No kit comes stock with down stop/droop adjustments. Consider buying an aftermarket solution. (You can also use Tamiya 54638 with the TT-02 Type S suspension - requires parts 54636 (front) & 54967 (rear-adjustable toe) or 54634 (front & rear-fixed toe)
- No kit comes with a fully adjustable motor mount. Consider buying an aftermarket mount to achieve appropriate gearing for 25.5/VTA motors (gear ratio will depend on local track size)
- No kit comes with sway/roll bars. There are aftermarket and DIY solutions available.
- All kits come with plastic shock towers/damper stays. Tamiya offers carbon fiber towers as well as aftermarket companies. The S/SR/SRX kits come stock with FRP (Fiber Reinforced Plastic) towers.

The TT-02 kits have been a fairly durable race vehicle for me. But be mindful when removing/tightening screws to not strip the plastic on the lower deck/chassis. This is especially important when tightening down the motor/spur cover. Thankfully replacement chassis are inexpensive, although I would use the hard chassis Tamiya 54926 for racing (This chassis comes with the SRX kit). The only issue I've seen with anyone having trouble with an SRX kit was a fellow racer who was breaking his Double Cardan Joint axles and spool cups. I have not experienced any issues with Tamiya DCJs on the cars I've raced. I would however recommend having Tamiya 42221 & 22064 as spare parts if racing a TT-02 Type SRX.

I should mention that before buying a Tamiya TT-02 kit, make sure that the kit is legal for the class you intend to race in now or in the future. Some Tamiya Championship (TCS) classes do not allow the TT-02 Type S kits - such as the Tamiya (TCS) GT PRO Spec Porsche/ Ford/Mercedes/Toyota class. You can find the 2025 TCS rules at the following link...

https://www.tamiyausa.com/tcs/rules/

I highly recommend anyone racing a Tamiya kit to check out the following website...

https://www.thercracer.com/

Just getting into TT02 racing with our local spec on black carpet. Any recommendations on shock setup with the Yeah Racing 55mm kit? Spring feel awfully soft compared to my Xray TC & VTA cars. Seems like I should’ve gone with the 50mm kit, but even then the springs seem too long and soft.

Stoked to have a nice driving car that doesn’t involve a $700usd kit.

SRX, Holmes 27T, HW 1060, USGT tires



I’ve also designed a few printed items if anyone is in need:

Fan Mount:
https://makerworld.com/en/models/957...ofileId-926785

Battery Strap:
https://makerworld.com/en/models/957...ofileId-926494


Battery strap for 22mm thick batteries

30mm fan mount

Very insightful tips & advices here ! The RC-racer website is indeed a plentyful place where to find all kind of info.

I personally run with a TT-02 SRX full options (Tamiya, except for the FR & RR shock towers (from PSM, to allow using SSBB+ Tamiya shock dampers) and the adjustable motormount (YR)), toghether with a 21.5t Reedy motor and a tad of turbo timing just to keep up with the local guys using 13.5t combo. I drive it on black carpet for the moment.

The car is insanely simple and allow me to drive 15+ min with one battery (in order to improve my consistency over long runs). To cope with the lack of droop setting options (because SRX suspension does not allow to use #54638 with the rear toe block), I've simply put some o-rings into the damper body, so that I have a kind of droop setup. But is does not allow to make adjustements on the go and requires to disassemble the dampers everytime.

What I've experienced the last time I drove the car however, is the fact that the chassis break where the rear toe block is attaching to the chassis :


I did not have a huge crash but I suspect the constraints being applied there made the fixing holes split and the rear suspension fell apart. I'm thinking either of using the lower part of the front bumper holder (B8) at the rear to offer some kind of additional support there, or (more likely) design a small carbon plate to fix on the existing 3 holes at the bottom of the chassis and long enough to support the bottom of the MB42 part.

What do you think of that ? Did anybody experienced this kind of issue ?

Regards,
G-rem

I have experienced the chassis holes splitting where the front/rear suspension plates are mounted (see pictures in the previous post). I've had this happen multiple times on my S/SR spec kits.

Here are the reasons why this happened to me.
- Installed the screw at an angle/not straight.
Make sure to pay attention when screwing in the 3x10mm machine screw into the plastic. If possible use a thread forming tap before installing screws. This will make it easier to install aluminum/titanium M3 screws into the TT-02 hard lower deck. Here is a link to Tamiya 54232 (Rc M3X0.5Mm Thread Forming Tap)
https://www.tamiyausa.com/shop/optio...d-forming-tap/

- Used the wrong length/too long screw to attach Tamiya 54967 (adjustable rear toe) when replacing Tamiya 54637 (3 degrees fixed rear toe).
In my case I was switching from the fixed 3 degree rear toe mount (3x15mm screws & DOES use the plastic rear bumper) to the adjustable rear toe mount (3x10mm screws & DOES NOT use the plastic rear bumper ). I didn't notice that the screws used for the 3 degree mount were longer than the adjustable mount. When installing the new mount without the bumper, the longer screws stressed the plastic which inevitably led to it cracking from a collision to the rear of the car.

Please refer to the pics in his post of an S & SR kits for the differences in the rear mounts.

A simple solution to make the rear end more secure on a TT-02 SRX (when using internal droop limiters in the dampers) is to slightly modify the plastic bumper so that you utilize the 3 holes on the bottom of the chassis (under the diff case). This will require removing a small amount of plastic where the rear bumper contacts the rear toe plate, but it should be easy to do with a hobby knife of a rotary tool. You could even go one step further and use longer M3 screws to attach the plastic bumper through the rear toe plate (similar to the TT-02 Type S kits). The only drawback to this solution is that it will require removing the rear bumper to service the rear toe/suspension arms on an SRX kit.

I tend to take lower spec Tamiya kits and slowly upgrade them to better/higher spec versions. As such I recommend to download the different versions of the TT-02 manuals available freely from Tamiya. Here are links on TamiyaUSA.com to the TT-02 S/SR/SRX kits. Just look for the White Down Arrow in a Red Circle to download a .pdf version of the manuals.

TT-02 Type-S
https://www.tamiyausa.com/shop/110-4...s-chassis-kit/

TT-02 Type-SR
https://www.tamiyausa.com/shop/110-4...r-chassis-kit/

TT-02 Type-SRX
https://www.tamiyausa.com/shop/110-4...x-chassis-kit/

IndyRC_Racer , what droop tabs are those? Looks like a clean solution

How to adjust droop/downstop on a TT-02 with basic kit suspension/lower a-arms

The basic TT-02 kits (often sold new with a body & ESC/speed control in the US) usually come with simple plastic friction dampers. The friction dampers are included on Tamiya 51528 B Parts (https://www.tamiyausa.com/shop/spare...-tt02-b-parts/). These basic TT-02 kits do not have the parts necessary/holes in the lower a-arms to adjust drop. The simple way to have drop adjustment on these basic TT-02 kits is to upgrade to oil-filled dampers and use limiters inside the dampers. I have installed Tamiya 54753 TT02 CVA Super-Mini Shock (https://www.tamiyausa.com/shop/optio...er-mini-shock/) on TT-02 kits that I've raced in the past. These oil filled dampers are shorter than the stock friction dampers and also allow the installation of internal droop limiters (plastic spacers or o-rings on the shaft between the piston/bottom of the damper/shock).

Kits that use basic suspension/lower a-arms (Tamiya 51528 B Parts) & include oil filled dampers/shocks
- TT-02 Drift Spec
- TT-02 R
- TT-02 RR (discontinued)

Kits that use Tamiya TA-05-IFS suspension/reversable lower a-arms (Tamiya 51297) & include oil filled dampers/shocks
- TT-02 D Type-S (discontinued)
- TT-02 Type-S (discontinued)

Kits that use Tamiya EVO IV suspension/reversable lower a-arm (Tamiya 51104) & include oil filled dampers/shocks
- TT-02 Type-SR (discontinued)

Kits that use Tamiya TRF419 Suspension Upgrade Set (Tamiya 54886) & include oil filled dampers/shocks
- TT-02 Type SRX

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How to adjust droop/downstop on a TT-02 kit with upgraded suspension (has existing holes in the lower a-arms for droop screws)

If you own a Tamiya TT-02 S/SR/SRX the simplest way to have external droop adjustment is to buy an aftermarket droop piece/plate. Here are links to a couple of products that I know of (buyer beware as I don't own/can't vouch for any of these products)...
- Yeah Racing TATT-033 (https://www.yeahracing.com/yeah-raci...t-033-00106030)
- MTTR (https://mttr-rc.com/products/low-fri...7t-f-r-2-bando)
- Fiber-Lyte (https://www.fibre-lyte.co.uk/fl/cars/tamiya/tt02s.html) - please also refer to the following link to show these parts installed (https://www.thercracer.com/2023/10/t...420-lower.html)

I should note that I have raced with someone who had the Yeah Racing TATT-S04 TT-02 Competition Touring Car Upgrade Kit For Tamiya TT02, which includes their droop plate. His car was very fast in a local class that we created for plastic tub chassis/shaft drive cars. That kit also has sway/anti roll bars. Here is a link

https://www.yeahracing.com/yeah-raci...t-s04-00106044

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Please refer this section of this post if you need to use 100% Tamiya part on your car (if racing TCS for example)

If you own a TT-02 S kit, Tamiya sells the following parts to add external drop adjustments to those kits...
- Tamiya 54634 - Rc Type-S Steel Sus Mount Set (https://www.tamiyausa.com/shop/optio...sus-mount-set/)
- Tamiya 54638 - Rc Steel Rebound Stopper Tt02 Type-S 2Pcs (https://www.tamiyausa.com/shop/optio...bound-stopper/)

One advantage of buying Tamiya 54634 is that it include 4 hinge pins which I've bent from racing damage. Please note that you will have to buy x2 of item Tamiya 54638 to complete the front and back of your vehicle.

This is the solution from the pictures I posted earlier
If you own a TT-02 SR kit, note that the rear of the car already had the appropriate rear toe adjustable suspension mount Tamiya 54697 (https://www.tamiyausa.com/shop/optio...ble-sus-mount/) which will accommodate Tamiya 54638. You will still need to buy the following parts to add external drop adjustment...
- Tamiya 54636 - Rc TT02 Type-S Steel Sus Mount Front (https://www.tamiyausa.com/shop/optio...eel-sus-mount/)
- Tamiya 54638 - Rc Steel Rebound Stopper Tt02 Type-S 2Pcs (https://www.tamiyausa.com/shop/optio...bound-stopper/)

One more thing to note on Tamiya 54697 rear suspension mount (adjustable rear toe), it will ALSO allow you to adjust the squat settings at the rear. I would recommend installing this part if you racing a TT-02 S kit as Tamiya 54634 includes a 3 degree rear toe suspension mount.

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If you have only owned a Tamiya TT-02 SRX, Tamiya 54638 - Rc Steel Rebound Stopper Tt02 Type-S 2Pcs will not work on that car because the droop screw hole in the suspension arms is on the wrong side of the arms (rear/front RF instead of rear/rear RR). This is due to the difference in the TT-02 S/SR reversable lower a-arms that have 2 holes versus the 419 lower a-arm that only have 1 hole.

Again your options for droop on the TT-02 SRX are as following...
- Internal droop limiters (TCS legal)
- Add a hole/drill the lower a-arms and use Tamiya 54638 rebound stopper (probably not TCS legal due to modifying parts)
- Use an aftermarket solution (not TCS legal)

---------------------

One thing I forgot to mention that you can also adjust droop externally by how much you thread the eyelet onto the shock shaft of an oil-filled damper. This can allow you to make small droop adjustments without having to take a damper/shock apart with internal droop limiters. Tamiya usually includes different length eyelet/ball cups that can be useful for this purpose. Please note though if when building shocks it is always best practice to make sure your damper/shock length is identical.

Here is a basic setup guide for the Associated TC3 that might be useful that also discusses droop setting this way.

https://site.petitrc.com/reglages/as...uningGuide.pdf