Me Dumb
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"But, Mercedes had concerns that the car was so gentle on its tires, drivers wouldn't be able to quickly get heat in the fronts, a potential problem during qualifying and safety-car restarts. DAS solves this by allowing toe angle to be changed on the fly. Race cars typically run a bit of toe-out to improve cornering, but this comes at the expense of scrub on straights, which can reduce tire temperature. With DAS, Mercedes drivers could reduce toe angle on the fly, helping generate more heat at the front."
Can someone smarter than I explain to my neanderthal brain why / how alignment-based tire scrub REDUCES tire temperature?
I assumed that a tire trying to rotate in an axis not parallel to the direction of travel would induce ...more... friction, and thus more tire temperature, but apparently I am an idiot. Can someone help me out here?
FYI, the snippet from the embedded video at the link that explains DAS doesn't at all explain theory. -
0 toe = no scrub, less heat. but for turn-in/etc you probably want some toe in/out, or to balance the car, this scrubs and creates heat+rolling resistance down the straights.
Original wording is confusing but what it means is now they can run more toe angle generally to generate heat/cornering G's, but use DAS to pull toe out to avoid over heating/scrubbing speed on straights when not needed
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@flatisflat they misworded the last sentence. The first sentence alludes to the problem and it's easy to deduce from that what the solution would be.
Also could be clever for use during qualifying where some toe out might be advantageous in corners and even under braking, and then toeing it back closer to 0 would be better down straights.
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@Echo51 @dieseldub OK, I can understand the benefits if the baseline toe-out setting is effectively 'extreme', and then DAS can be employed when that extra scrubbing isn't required to keep up front tire temperatures. So yeah, the last couple sentences in that quote is inherently off the mark RE: the intent and benefits.
Thanks for the sanity check!
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I'd say it's an error in sentencing structure by writer and editor not really versed in setup. Yes, writing like this annoys me (and it's prevalent in our Wiki era). If it was a tech manual I'd fling it across the shop into a bin.
If I were to re-arrange it: With DAS, Mercedes drivers could help generate more heat at the front, then reduce toe angle on the fly.
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@dieseldub It's a bit confusing how it' worded, but it's technically correct. Toe out is represented by a negative number, so reducing toe out would mean more toe out (further from 0). Increasing toe out would mean getting closer to 0.
But generally in non-technical layperson terms more toe out would mean further from zero.
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@mastermario it's worded "reducing toe angle.... helping generate more heat"
I guess it depends on how they're viewing it. I would consider it an increase in toe in either direction away from zero as someone who used to do wheel alignments as my primary job, but maybe they're wording it that negative toe is still reducing toe numerically speaking. I could see that.
And in general, these cars tend to be setup with some toe-out to begin with for handling purposes. But DAS allows them to take it to further extremes, and also then bring it back closer to 0 for better straight line speeds and/or helping prevent tire temps from getting out of hand if they find themselves in that position.
So, the car would never be toed in from what I understand of how these cars are setup. They're almost always toed out, but the DAS system allows them to run even more extreme toe out if they want, and the ability to bring it back close to 0 on the fly if need be.
But, going further negative away from zero (toe out) can be called "reducing toe" in a numeric sense, as negative numbers are infact lower than 0, right? Just not how someone familiar with performing wheel alignments is likely to word it is all.
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@dieseldub yea, I was just thinking of it in a pretty mathematical stand point. Whether that was their intent it not it still is a confusing way of wording it.
