What is the RC story behind Rear Toe-In?

[Saito]

I found that interesting to about early CATs too. Same with the front of the AYK Pro Radiant.

There is much about the Avante suspension/steering design and geometry that is puzzling. Rear toe might have calmed some that platform's nervous handling. Why did the Avante series have no kick-up with only 10 degrees of caster built into the uprights? Why the tremendous scrub radius? I'd really like to know where designers were going with those cars as earlier Tamiya efforts in 4wd did not have those issues to that degree. It then seems every effort made from Avante to Egress and finally to Jamie Booth Egress was an attempt at un-doing all those odd design choices to bring it more in line with what traditionally worked.

The answer is simple; Tamiya RC's are designed to be fun to build and set pretty on the self, not to be competitive on a track. They are essentially highly detailed static models that can be driven remotely.
Okay seriously, I really like all my Tamiya RC's (my first RC car was a Sand Scorcher circa 1979). It's when I actually drive them that I begin to question why I own such a poor performing car.

I guess the Avante is a particular mystery because it wasn't designed for "fun" but competition. Other than getting the Thundershot into the hands of a few racers, the Avante and subsequent Egress were an actual race effort as were the following Astute and eventually Manta Ray/Top Force. Its just that the Avante series in particular used odd choices that were different not only from other manufacturers but also other Tamiya efforts in 4wd. I imagine they had ideas on where they were going with it, different ideas. Even though they proved unfruitful, I'm still curious what the thought process was behind them. Or perhaps it was just Being Nuts Is Neat

[RCveteran]

When we started racing no prep 4 or so years back, mid motor cars didn't work at all. Way too finicky. In a year and a half everything competitive was mid motor. The tires unlocked the mid motor stuff. Belted and sauced to the moon. It's kinda funny as it isn't far from what happened with early loamy off road tracks and modern sugar tracks it just happened really fast.

Do you guys think like I do that the modern sticky clay or carpet (what I do occasionally) favors the set up and perfect drivers. Well of course tracks always favored them but I tend to think the bumpy old dirty unpredictable tracks created a little unpredictability that all the set up and perfect drivers ability simply could get caught up in. Maybe gave the average drive a bit more of a fighting chance. Today if you have the steady fast hand and fast motor set up of the week you can turn and burn in a way that an unpredictable track maybe you could not.

Or is that just nostalgic fog, I don't really know?

[RC10th]

I think the modern sticky tracks mask a lot of tuning problems so anyone that has some idea of car set up will be fast, but a driver that really knows car set up will always benefit from good car set up and be a step above.

In saying that I think there are different challenges in the different track styles. Old loose tracks teach you car control, where you have to be ready for some unpredictability. The smooth sticky tracks teach you consistency and rythem.

[1300GT]

The earliest buggy that included adjustable rear toe that I can think of would be the Kyosho Progress.

[LurkingCAT]

I have really not measured the built-in static toe-in on the early buggies. Of course, the static toe-in was part of the 1984 RC10. But early examples of adjustable toe-in on 1/10 buggies were the PB Mustang and Schumacher CAT in 1986. Both the Mustang and the CAT also have the toe adjusted on the hub carrier. Increasing toe will thereby not reduce the wheelbase in the same way as an adjustment at the inside of the rear arms.

Of course, both companies also had a clear awareness about how the toe-in link height are affecting the dynamic toe-in effect on suspension travel. After all this is the same as bump steer in the front. Seemingly a strange phenomenon not so clear to Tamiya...

Schumacher were opting for a route of 1-3 degree toe-in, with no deviation under parallel compression or roll.

On the other hand, PB was promoting active toe-in as a tuning aid and calling it RISE (Roll Induced Steering Effect). This gives the outside wheel slight toe-out progressively upon roll and the inside wheel (in a smaller degree) the opposite effect - all in all resulting in more steering. This concept was a simplified concept of the RISE taken from the PB Nova X5 (1/8 Track car).

[LurkingCAT]

The earliest buggy that included adjustable rear toe that I can think of would be the Kyosho Progress.

Yes of course! The four wheel steering platforms were natural candidates for the rear toe adjustment. In 1985 also the Mugen Bulldog.