Understanding the friction telemetry

I’ve been through the forums (and google) and found no detailed explanation on the friction telemetry in FHs. It seems that the in the FM series it’s just a standard friction circle, but in FH5 and FH4, so far as I see, it looks a bit different. For starters, when you accelerate the lines point down instead of up, which doesn’t make sense to me because the static friction is actually poniting forward pushing the car right? Also, there are orange lines and blue lines, what does each of them mean? Sometimes they even point to different directions.

Newton’s 3rd law - for every action (force) there is an equal and opposite reaction. The ‘reaction’ is the car moving forward, therefore the friction force must point backward. It’s not intuitive, initially.

Tuning in all the Forza games is like this. Each setting has a vague description of the effects of an excessive or inadequate setting (many of the penalties overlap penalties of other settings making the source of the problem unclear). The descriptions seem like they exist just to add confusion to the tuning process.

Telemetry also seems like it exists solely to confuse the tuning process. Unlike the tuning settings, none of the telemetry information provided offers even a vague description. You’re expected to just know what they mean and what settings affect them.

It would be nice if there was some sort of in-game tutorial that would explain how tuning works and give some examples of the penalties for excessive settings (too low and too high) and the goal of adjusting the setting (what you should be looking for in the telemetry or the feel of the car).

Unfortunately, we’re stuck with confusion and guessing.