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Front tire outer tread wear

Started by raueda1, 23 August 2021, 06:24 AM

raueda1

Yesterday I was alarmed to notice that the outer tread on my front tires is very substantially worn.  It seems like it was sudden, but maybe I just hadn't seen it.  I'll rotate the tire ASAP but this is troublesome.  What's the cause and what to do?  I know literally nothing about wheel alignment and front suspension adjustments. 

FWIW, the car tracks absolutely straight when road is absolutely level.  If there's a crown or slant the car will try to "follow" the slope downhill so slight steering correction is needed to go straight.  Also, I tend to corner hard on freeway entrance/exit ramps.  I wonder if that could be it.  Thanks and cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

daantjie

#1
Sounds like toe adjustment might be off.  Only way to fix is to have alignment done at a competent shop familiar with older Benzes which in itself is a challenge unfortunately. Be aware that the 6.9 has specific adjustments which are different to the 450 SEL so best to take the specs along to the alignment shop.
Daniel
1977 450 SEL 6.9 - Astralsilber

UTn_boy

Toe being out of adjustment will cause "cupping".  The OP is experiencing wear on the outer edges, which means that the camber is off.  I'd venture to say that is needs nothing more than an alignment, but be sure to check the upper and lower control arm bushings, too.  6.9 cars have tendency to eat them much sooner than a 450 or the like. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

floyd111

Not sure what your country looks like, but there's manual alignment, which requires a mechanic with experience and a sharp eye (cheap and fast). I rarely ever have them do the rear wheels of any car. I stick by the fronts to save money.
It can be also be done with modern (laser) equipment, which has a higher price, but is very exact. Again, front-only has sufficed for me, until there's any visual tyre-wear in the rear to tell me differently.

I had both types done over the years and both have been very satisfying. I have it done each time I replace any part related to steering or suspension in the front. 9 out of 10 times it was a noticably good move.

daantjie

On the 116 the rear wheels are not adjusted only the fronts.
Daniel
1977 450 SEL 6.9 - Astralsilber

Flogrates

Quote from: UTn_boy on 23 August 2021, 04:36 PM
Toe being out of adjustment will cause "cupping".  The OP is experiencing wear on the outer edges, which means that the camber is off.  I'd venture to say that is needs nothing more than an alignment, but be sure to check the upper and lower control arm bushings, too.  6.9 cars have tendency to eat them much sooner than a 450 or the like.
It would take extreme camber to wear the outside edge. You're not going to get this from slight positive camber imo

Def sounds like toe to me.

UTn_boy

Quote from: Flogrates on 24 August 2021, 04:24 PM
Quote from: UTn_boy on 23 August 2021, 04:36 PM
Toe being out of adjustment will cause "cupping".  The OP is experiencing wear on the outer edges, which means that the camber is off.  I'd venture to say that is needs nothing more than an alignment, but be sure to check the upper and lower control arm bushings, too.  6.9 cars have tendency to eat them much sooner than a 450 or the like.
It would take extreme camber to wear the outside edge. You're not going to get this from slight positive camber imo

Def sounds like toe to me.

You may want to do a little more research on this.  The W116 front axle geometry defies conventional scenarios/ideals on otherwise "normal" front axles.  Furthermore, any camber adjustment or misalignment from daily use will affect toe and caster. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

floyd111

#7
I would also look at toe, rather than camber. On 50+ cars over 40 years, only once do I remember dealing with that. I had to correct camber on a CR-V with a metal-fatigue issue in the rear, leading to a camber issue, even with all parts in place, new rubbers all over.
None of the garages visited even thought of looking for a camber issue, when faced with solving my persistant rear tire-wear-and-tear. Eventually it was my  instinct telling me and I had to point it out to the mechanics myself. After it was confirmed, there was no solution offered. Non adjustable. I had a look and suggested fitting thin spacers in the right places. The man had not thought of spacers in 30 years of doing alignments. Worked like a charm. Lasted longer than the car.

https://forum.w116.org/mechanicals/how-to-align-a-w116/
That seems to be a good write-up on the matter.
Another thread here, just to confirm.
http://www.peachparts.com/shopforum/diesel-discussion/377891-w116-300sd-alignment.html

My conclusion is: Take it to the Mercedes dealership. Have it done properly.

Flogrates

Quote from: UTn_boy on 24 August 2021, 05:49 PM
Quote from: Flogrates on 24 August 2021, 04:24 PM
Quote from: UTn_boy on 23 August 2021, 04:36 PM
Toe being out of adjustment will cause "cupping".  The OP is experiencing wear on the outer edges, which means that the camber is off.  I'd venture to say that is needs nothing more than an alignment, but be sure to check the upper and lower control arm bushings, too.  6.9 cars have tendency to eat them much sooner than a 450 or the like.
It would take extreme camber to wear the outside edge. You're not going to get this from slight positive camber imo

Def sounds like toe to me.

You may want to do a little more research on this.  The W116 front axle geometry defies conventional scenarios/ideals on otherwise "normal" front axles.  Furthermore, any camber adjustment or misalignment from daily use will affect toe and caster.
Have you got a source for that? Google has turned up nothing.

I am interested to see how camber can effect castor/toe.

UTn_boy

Quote from: Flogrates on 24 August 2021, 07:26 PM
Quote from: UTn_boy on 24 August 2021, 05:49 PM
Quote from: Flogrates on 24 August 2021, 04:24 PM
Quote from: UTn_boy on 23 August 2021, 04:36 PM
Toe being out of adjustment will cause "cupping".  The OP is experiencing wear on the outer edges, which means that the camber is off.  I'd venture to say that is needs nothing more than an alignment, but be sure to check the upper and lower control arm bushings, too.  6.9 cars have tendency to eat them much sooner than a 450 or the like.
It would take extreme camber to wear the outside edge. You're not going to get this from slight positive camber imo

Def sounds like toe to me.

You may want to do a little more research on this.  The W116 front axle geometry defies conventional scenarios/ideals on otherwise "normal" front axles.  Furthermore, any camber adjustment or misalignment from daily use will affect toe and caster.
Have you got a source for that? Google has turned up nothing.

I am interested to see how camber can effect castor/toe.

It's in the factory service manual.  Section 40.2-320.
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

Flogrates

Quote from: UTn_boy on 25 August 2021, 04:55 PM
Quote from: Flogrates on 24 August 2021, 07:26 PM
Quote from: UTn_boy on 24 August 2021, 05:49 PM
Quote from: Flogrates on 24 August 2021, 04:24 PM
Quote from: UTn_boy on 23 August 2021, 04:36 PM
Toe being out of adjustment will cause "cupping".  The OP is experiencing wear on the outer edges, which means that the camber is off.  I'd venture to say that is needs nothing more than an alignment, but be sure to check the upper and lower control arm bushings, too.  6.9 cars have tendency to eat them much sooner than a 450 or the like.
It would take extreme camber to wear the outside edge. You're not going to get this from slight positive camber imo

Def sounds like toe to me.

You may want to do a little more research on this.  The W116 front axle geometry defies conventional scenarios/ideals on otherwise "normal" front axles.  Furthermore, any camber adjustment or misalignment from daily use will affect toe and caster.
Have you got a source for that? Google has turned up nothing.

I am interested to see how camber can effect castor/toe.

It's in the factory service manual.  Section 40.2-320.

That's interesting, I'll have a read.

raueda1

Oh my.  Thank you, gentlemen.  This has been an eye-opener.  Happily I know a guy that works on these old cars.  When I get back to SLC the front end will get some sort of alignment.  I will report on the findings. Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Rolo

I had very excessive outer tread wear.  Tried aligning twice to no avail.  Finally bit the bullet and replaced most of the front end bushings.  Drives much better, and wear is even. 

ekipe

Sounds like camber to me. And when the camber is out, not always the car drives worse.