Factory Toe Specs Chopping Tires (non vw specific)

[theKbStockpiler]

Hello again.
I worked at a auto repair chain for years in which part of the job is giving the vehicle a look over to try to inform the vehicle owner and maybe drum up some additional work.
My experience is that most domestic pick ups/full frame suvs, will chop the front tires even if the toe was good. Most toe is from 1/16 to 1/8th and inch.
My guess is that the factory specs are wrong. As toe changes with speed and is dependent on bushing flex, this makes me believe that the auto makers put the specs (too much toe in) so at high speeds the vehicle will not toe out for safety reasons. That or they assume that the vehicle is always going to be driven at 70mph or maybe the AT tires are causing too much drag causing the wheels to toe out.
Any insights on this? Thanks for your expertise!

[Ol'fogasaurus]

https://www.bing.com/search?q=front+end ... b2&pc=LCTS

Try this as it has several articles that explain toe-in and toe-out and other things that can affect the front-end alignment... and there can be a lot of them.

Lee

[oprn]

One thing that I don't think most consider is the effect of turns on tire wear. A vehicle that spends a lot of time in the city could very well appear to have toe in issues when it is really just the tires scuffing in turns. The toe out on turns built into the spindles is effected by wheel offset and wheel base. If there are tires and wheels outside of factory spec the toe out on turns could be incorrect.

I also discovered years ago that when ordering spindles for my Chevy pickup truck there is no consideration for the wheel base of the truck. It is the same part number for a short box truck as it is for a crew cab with an 8' box. It could well be the same for other vehicles of differing wheel base too. My Dodge crew cab scuffs badly in parking lots.

This leads to our Manx style Buggies with their shortened wheel base. The toe out on turns is just wrong when you take 14.5" out of the pan. The saving grace is that the front end is very light so the scuffing will not be as readily apparent.

[Ol'fogasaurus]

One of the main differences, that is a lot of the problem anyway, is that in the city tires are turned at slower vehicle speeds or, even worse, static speeds causing the tire wear to go faster.

It is the same reason for things like the ball-joints and tie-rod ends to wear out faster also.

Lee

That is also why your shoes wear out so fast when you dance a lot .

[oprn]

Another thing that came to mind driving around at work today is that toe in is there to compensate for the slip angle of the tire tread. Different tire construction produces a different slip angle, ie: 10 ply rated tires have a lower slip angle than 4 ply rated tires and radial tires have a larger slip angle than bias plies. Higher tire loading changes the slip angle as does different tire pressures. Tire slip angles change depending on whether that tire is propelling the car, being pushed or braking. So yes there is a need to optimize toe in to each individual car and it's set up. The factory setting should be a good starting point, nothing more.

[theKbStockpiler]

I was thinking that the amount of straight driving would completely compensate for scrub on turns but I'm probably wrong.So enough scrub is happening during turning that straight driving is not wearing the tires flat apparently. I really was not including slip angle but I do think that it has more importance indirectly. Feathering can be caused by slip angle.

A lot of automotive information in my opinion, is just paraphrased from person to person without an actual understanding taking place, dogma. Tires are always scrubbing in a turn to some degree. With caster ,I'm doubting that toe actually stabilizes anything in the front end. I can appreciate having neutral toe at 50mph though but I think toe should be closer to neutral while stopped. All vehicles bump steer which is going to change the toe as the suspension is travelling. I guess I'll go with close to a neutral toe or higher tire pressure.

[oprn]

I truly believe the older fellows that understood wheel alignment are mostly gone now. Today's crop of front end technicians do as the computer tells them, collect their pay and go home without giving what they are actually doing a second thought. The last 4 or 5 alignments I have had done I know the car was not test driven after because all of them had cockeyed steering wheels afterward. How hard is it to center the steering wheel?

I have watched from the sidelines enough to know that there is far more to it than meets the eye and there are a lot of cars on the road that are far from optimum. Back when the whole world was changing over from bias plys to radials we had an alignment guy in our neighborhood that told Dad and I that "These new tires need different alignment than we normally do." He was the kind of guy that took a test drive after every alignment, readjusted things and took it for another drive until he was happy. He was a craftsman.

I wish I could turn time back and learn from those fellows now!

[Ol'fogasaurus]

Throw in all the weight factor in such as when starting, stopping, turning, backing up, drifting, engine power changes, loading people and their "stuff" (balance for example) and about most everything/anything else you can and can't think of including "goodies", e.g. most everything effects the war on the tires, shock, spring/torsion bars, suspension, metal joins and the body and frame (pan in this case) deterioration. We all know most of this stuff but don't always put it into play when thinking about stuff/things.

One of the interesting things I learned when doing my job was how much dialogue changes/changed throughout the country and the world. Body language, facial language and dialogue changes using the same words in a different order or the vocal effects during conversation about things.

Lee

[oprn]

So true. Back to our cars I find it frustrating that alignment "specialists" today cannot think beyond the "specs for your car" when we present them with a modified one. I took my short pan, lowered front beam Buggy in for an alignment and handed them a set of castor shims saying that due to the short wheel base and rake I felt it needed more castor for highway stability. When I picked the car up they were handed back to me with a "You didn't need them, it was in spec."

I took the car home and put them in. The difference was night and day for the better! It went from a car that needed constant correction/attention on the steering wheel and left you weary after 3 hours on the road to a very enjoyable ride that gave you time to enjoy the scenery.

[Ol'fogasaurus]

In the time frame of "knowledge" now days, the new stuff in vehicles isn't prepared to be changed much... unless it is a big replacement change.

I play with glass buggies on VW "Bug" pans also but not on the street anymore. There is a big difference between "street and strip (off-road)" to use an old vernacular. "Big and little" (tires and rims) are still around but are for different use so the effects of what they cause to the front and rear suspension is getting further and further away from people.

There is a lot of knowledge here so keep posting and you just might get some very good advice on difficult things.

Lee

[oprn]

The "street vs strip" applies to suspension, brakes and tires, but it also applies big time to engine building, set up and tuning as well. The result is that many air cooled VW engines on the street today do not run well at all and have a negative reputation for issues that did not exist with the cars VW put on the market. It's been so many years since the hey days of the Beetle that very few people today know how they were supposed to run. They accept crappy running, poor fuel economy and poor drivability as normal.

[Ol'fogasaurus]

The "street vs strip" applies to suspension, brakes and tires, but it also applies big time to engine building, set up and tuning as well. The result is that many air cooled VW engines on the street today do not run well at all and have a negative reputation for issues that did not exist with the cars VW put on the market. It's been so many years since the hey days of the Beetle that very few people today know how they were supposed to run. They accept crappy running, poor fuel economy and poor drivability as normal.

There are a lot of good upgrades to the VW engines and vehicle things but a lot of that old good knowledge is in now in so few hands. There is new stuff also that seems to be good for the ACVWs but there is also not so good stuff, or the good stuff not completed/matched up to other stuff correctly.

One of the reasons that specialty places like STF are so good to have around.

Lee

[oprn]

True again, I have learned a lot about today's ACVW parts offerings vs what we used to do in the '60's and '70's from this and other VW forums. I also see a lot of old falsehoods that continue to be perpetuated. Such is the nature of the "net" and one must learn to be a discerning consumer.

[Ian Godfrey]

A few observations, for a light short wheelbase buggy..... more caster helps a lot with straight line stability, and with a short wheelbase that is even more important. The only down side is a bit heavier steering when parking, but your buggy is really light so no issue. Also more caster increases 'turn in' as it gives an effect similar to more negative camber, this makes for a much more responsive car. I can attest though more caster (6 - 8 deg) and more neg camber (2 - 3 degrees) does lead to chewing out the inside of the front tyres Re the toe in, just a bit is good so when you stand on the brakes the wheels are slowing and the car is pushing forward and it probably adds up to zero deg toe in. You just don't want toe out in a high speed stop. Autocross is a different situation where you might want that 'instability'. I think is is really useful to take your car on a spirited drive around a windy road, stop and take a temp gradient across your front tyre: outer edge, middle and inner edge, I'm looking for a pretty even temp across the tread. If the middle is colder more air pressure is needed (reverse if it is hot), and if the outer is noticebly hotter than the inside edge, add more neg camber or caster or both. A great discussion. As to wheel alignment, i think you have to get a few tools and DIY. Strings and a camber/caster gauge.

[Ol'fogasaurus]

Also, where the fuel tank is located comes into play. My blue buggy has the fuel tank in the rear taking some of load off the front end. Shocks can be changed, and the torsion bars could be changed (the preload angle) and the beam could have an adjuster added pus, if you are playing hard with the buggy the shock tower should be braced and the A-arms could have stops added.
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A front beam adjuster

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The suspension stop.

DSC04124 - Copy.JPG

"Cause and effect" come into play with seemingly any changes made.

For what it is worth.

Lee