Thanks so much! The 3D printed wheels are a great option if you want to save money and you already have a printer. The guy who uploaded the files gave several different offset options and even made the wider rear wheels. I don't have any wide tires so I just used26mm wheels with a higher offset in the rear.

Sometime when I'm feeling really nerdy, I will paint the hex adapter/brake rotors silver so they'll show through behind the black part of the wheels.

S and SR uses symmetrical arms from TRF415. SRX has TRF420 arms with different shape, so this part needs to be shorter.

Tamiya 53709 to replace BB26 and a couple of spacers will turn your SRX into short wheelbase.. I race mine as a GT2 car with Audi 90 body

It's got some battle scars but drives great.. and looks even better..

The newer BB26 part on SRX accommodates that 251mm wheelbase on the TT02 S type chassis. This was previously not an option with the original BB26 (54634)

I changed my 419XR from the original arms to the 420 arms when they initially came out. While the shape of the 420 arms are different, they have no effect to on wheelbase.

I also just installed the 420 arms on my TT02S.. with the original 54634 suspension mounts with no changes in wheelbase.

I don't see any mention of 251mm WB in the manual or product page. If there was a 251mm option, there would be an extra spacer in front of the rear arms in standard wheelbase instructions.
The shorter BB26 are necessary with 420 arms for correct wheel position. The front arms are also different, so you may have correct wheelbase, but wheels will be shifted by couple of milimeters compared to reversible arms.

TRF419 suspension upgrade manual shows 3mm increase in wheelbase on the rear arms... But on the TRF, that can be compensated for with spacers.

I don’t have any wheelbase spacing issues on mine with the original BB26 and 420x arms. 🤷🏻‍♂️

It is now summer and the days are longer, which means Fun in the Sun with Tamiya! This past weekend, we did 4 races of mostly TT-02s, but there were other chassis also in the mix (including an M-07R). Since this is a casual organized meet (1-2x / month), as long as the speed is comparable to the spec'ed TT-02s (Torque Tuned Motor, similar FDRs depending on the spur/pinion combo that is allowed in the ruleset), then really any chassis can be run. Any upgrades from any manufacturer are allowed.

The track was drawn out using chalk and there are some markers/bumps/circle dots to outline the corners. We use the EZ Lap timing system that plugs into the receiver and outdoor tires of course. Racing was intense with a lot of back and forth. To me, with all the door to door banging and close battles, this is what racing TT-02s is all about!

I hope you can see how much fun it is and if you are not already doing so, get a group of friends to do some outdoor RC driving and racing...

Race 1: Race 2: Race 3: Race 4
(Apologies if anime music is not your thing)

Lastly, I was stoked to see another 2002 Mercedes-Benz CLK AMG join in Race 3!

My local track is starting a TT-02 class using mostly "box stock" rules, so I need to run the stock diff. I want to stiffen the front but the Tamiya 42247 diff putty looks to be out of stock or on backorder everywhere. Does anyone know of an alternative? I saw silly putty and even silicone earplugs mentioned elsewhere but couldn't tell if it was a joke or a viable alternative.

Gravity RC, 1up, there's plenty of other folks that make diff putty too.

What is your experience with tires for parking lot racing in the summer?

Glad to read your track is getting started with this class, it's a lot of fun! What minimal upgrades are allowed?

For the front diff., I use the Tamiya 1 million grease. Kyosho also makes the same 1M and both companies have different lower viscosity greases or oil. The grease is thick and unlikely to leak out of even the stock diff.

For outdoor tires, I am currently using the Team Powers 34 Shore tires, but also have 32 and 36 available depending on the weather/temperature. Some people use Rush tires as well. I will add that a few months ago when the weather was overcast and the temperature was not as warm, the 34s took about a lap to warm up and get grip on the track. Initially the car would slide around like it's on ice so I don't recommend gunning the throttle when you first put the car down with cold tires. Doing a practice/formation lap or two helps a lot to warm up the tires just prior to our casual races. During the summer with warmer temperatures, 34s worked well and so do 36s.

You can also find my car setup in the video descriptions, hope this helps!

For upgrades we're allowed the front output shafts (u-joint), bearing kits, and motor heat sinks. Have to run stock friction shocks and diffs, but can mess with grease in diffs. There's some push to allow for oil shock upgrades but not allowed as of now... but we just had the first race this week so that might change depending on majority sentiment.

Thanks for the tips!