re: "Google Wallet may be making a return" (and "Why is it so complex

No one here that I saw used that phrase.

The camber gain from KPI/SAI will always wear tyres more on the outside edge during high or full lock turns. Mountain driving, with sharp hairpin bends, will guarantee it. Even in normal city street driving, camber gain will be prevalent and worse on the nearside tyre. If you have a comprehensive understanding of steering and suspension design, then it is quite an easy thing to visualise. Weber Auto, on You Tube, did something on steering some time back and, IIRC, they explained the aspect of KPI/SAI that causes the issue. It is not a well understood issue, even in the trade, but is *one* of the reasons tyre rotation is essential. Just turn your steering to full lock and look at the camber angle of the *inside* wheel - camber gain will be very evident. The effect is worse if the vehicle has wider low profile tyres.

Quantify that gain...

...or admit you don't know what you're talking about.

Load matters too, sunshine.

And you have it backwards.

King pin inclination will reduce positive camber.

Just a little follow up:

'If we now compare the effects in Figs. 7.16 and 7.17, we can see that if kingpin is introduced first, undesirable positive camber results from steering but if castor is then added in, negative camber is introduced. By including both camber and castor, the designer can have the benefits of kingpin inclination but offset the disadvantageous camber gain. For this reason, it is common to introduce approximately equal amounts of both.'

Technically, it should *reduce* the effect but, given the typical speeds where the tight turns are made, weight transfer will be minimal. Besides, the effect of camber gain from the combination of KPI/SAI plus Caster will far outweigh any camber gain from suspension bump or rebound, especially in the case of vertical guide suspensions like McPherson Struts.

The greatest effect comes from *King Pin Inclination*, or SAI as it is known these days, but that effect is compounded by the *caster angle*.

What you need to be aware of is that when you change the camber angle, you have made no change to the *included angle*, that is designed in and cannot be altered. So, if you reduce the camber, you will be

It is quite possible but it would be hard to say given all manufacturers use different suspensions each with compromises in different places. Generally, any change from manufacturers specifications risks a disruptive change in handling characteristics. My own take, I would say yes.

That's a nice summary.

I looked for the youtube you speak of but it's not one of these.

Weber Automotive Tire Care & Wheel Alignment

The Importance of Vehicle Suspension | Weber Automotive

Beg to differ, the inside wheel camber tends to go more positive in a turn thus increasing camber gain. Just turn your wheels hard in one direction whilst parked and you can see that effect. The effect will be less on the *outside wheel*. You are thinking of higher speeds where body roll becomes significant but sharp turns aren't possible at such speeds and it is the slow speed sharp turns where camber gain becomes a significant issue in tyre wear on the nearside wheel.

I could do the same but I rely more on the fact that I am a motor mechanic by trade, done more wheel alignments and steering repairs than I care to remember, and taught steering and suspensions at a college for

FWIW, good texts on the topic are these;

Steering Handbook - Springer

Before you waste too much time on Alan Baker, he's a moron. He has an IQ of about 40 and, worse, he loves to disagree with _anything_ you can claim.

You can reference any number of links and he won't even _read_ them before denying that they say what they say. Then he'll find some random link that has a couple of the keywords, and he'll paste that verbatim, as if he wrote it.

In short, the Alan Baker you're dealing with is a moron. Everyone on the smartphone newsgroups already has him plonked.

Just so you know.

Wrong.

As I have already shown you.

The wear on twisty roads is to the outside edge of the front tires, specifically due to increased positive camber on the inside front tire.

This increased positive camber on turns causes uneven tire wear on the outside edge of the inside tire even on a properly aligned vehicle.

Read this.

The thrust force reality gets even more complicated when you read further.

"What appears to be positive camber is actually negative camber with respect to the turning force. So it only looks like positive camber - in fact it's really negative camber, because it's the inner edge of the wheel that is leading in a turn."

This is a photo of the added positive camber on the inside front wheel that you are explaining happens during a slow speed sharp turn almost to lock.

You can beg all you want.

Does caster add camber when a wheel is steered outward (left for a right wheel)? Yes.

Does king pin inclination oppose that change? Yup.

Clearly...

...because you've definitely not figured out that KPI acts to reduce camber.

Yes: that wheel is in SLIGHTLY positive camber...

...when standing still.

Now: what happens when the vehicle is moving?

Are you capable of examining that question quantitatively?

The inner wheel has camber gain from positive caster. No one is disputing that.

Sorry, but that is completely wrong.

That's true but not helpful, because it fails to mention that normal king pin inclination acts to cause camber loss and thus opposes the effect of positive caster on the inside wheel of a turn.

Because caster and KPI combine to BOTH influence camber to the negative.

"The thrust force reality"?

Do you have the slightest idea that you're talking gibberish?

That almost makes sense...

...but then you didn't write it.

Thank you for that helpful clarification. The inside wheel on a tight turn goes from negative camber of a degree or half degree or whatever to positive camber of a degree or half degree or whatever in the process of negotiating that slow tight turn, which is a huge change in camber.

Here is a photo of that positive camber position in the middle of the turn.

Yes. The geometries all tie in together such that even a perfectly aligned vehicle will prematurely wear the outside edge of the front tire on the inside of a curve if they frequently negotiate slow speed tight turns.

Is that your understanding of the net result on premature tire wear as a result of the suspension geometry changes if a vehicle negotiates hundreds of slow speed tight turns daily?

But not nearly enough to cause significant tire wear.

Remember: most of the time, the tire is running in a straight line.

KPI opposes camber change on the inside wheel of a turn.

Caster is driving it positive: KPI is driving it negative.

And vehicle roll is driving it negative.

It was, I think, this Weber Auto Youtube Channel;

Yeah, not much available on the net that adequately explains it all.

Even though I retired from teaching the topic at college level some 20 years ago, I still retain an interest in education hence scan videos looking for good teaching material. John Kelly at WeberAuto YouTube Channel is a good source of inspiration. I can just imagine the preparation and planning he has put into his videos, after all, used to do it myself. Back then, in the 80s and early 90s, I was heavily into computer animation for educational purposes. Of course, that has all been eclipsed by the numerous advances and developments in computers since then. An example of my early graphics animation attempts;

Yes, my understanding precisely. And my car has to negotiate a lot of such tight turns on a daily basis, tighter to the left because we are in RHD country, on the right for LHD country. That's why I use the terms; nearside and offside rather than left side and right side. Anyway, the outside of my left front tyre is always rearing the most, that's why I need to rotate tyres regularly.

KPI creates a positive camber change.