Newbie getting wheels aligned. 77 911s

[AndreasK]

Been trying to search, but didnīt get much wiser. Probably just a bit more confused

My wheel alignment is somewhat off. A local garage is the only one who previously has proper experience working on old Porsche's. (Mechanic has had a couple him self.) But Iīm not confident they know "everything".

At the same time Iīm having turbo tie rods and a bump steer installed. The car is a 77 911s, on 205/55-16 and 225/50-16 wheels, RS flairs. Car is pretty low. Lower than euro height. Spirited driving on roads and 1-2 track days per year.

Is there any specific requests I should make with regards to the alignment? Is there a standard set of numbers for toe in, chamber and so on? Is there any point in deviating from those numbers?

Added photo for interest

[Bill Verburg]

Originally Posted by AndreasK

Been trying to search, but didnīt get much wiser. Probably just a bit more confused

My wheel alignment is somewhat off. A local garage is the only one who previously has proper experience working on old Porsche's. (Mechanic has had a couple him self.) But Iīm not confident they know "everything".

At the same time Iīm having turbo tie rods and a bump steer installed. The car is a 77 911s, on 205/55-16 and 225/50-16 wheels, RS flairs. Car is pretty low. Lower than euro height. Spirited driving on roads and 1-2 track days per year.

Is there any specific requests I should make with regards to the alignment? Is there a standard set of numbers for toe in, chamber and so on? Is there any point in deviating from those numbers?

Added photo for interest

Here's the range of common settings, You'll likely want something in the middle or to the left side, towards the right usually has additional mods like larger t's and sways and race tires

[Goth]

I can't find the article... but it recommended camber specs for sport driving of -0.75 degrees front and -1.5 degrees rear. I think caster and toe were OEM specs. I've run this setup with stock TB's and sways, and also with 21/28 TB's and 22/21 sways. It seems to work well on my 84 canyon carver.

[AndreasK]

Very nice! Thanks🖒

[Flojo]

Originally Posted by Goth

I can't find the article... but it recommended camber specs for sport driving of -0.75 degrees front and -1.5 degrees rear.

sure? not the other way round, e.g. more camber on front, less in rear)

I have front -1,40 /rear -1,10 (*)

result: more cornering ability.

(* front 63cm/7x16/205-55, rear 62cm/8x16/225-50 )

[Goth]

Originally Posted by Flojo

sure? not the other way round, e.g. more camber on front, less in rear)

I have front -1,40 /rear -1,10 (*)

result: more cornering ability.

(* front 63cm/7x16/205-55, rear 62cm/8x16/225-50 )

Yep I'm sure....guess it's just more streetable and safer for the masses.

fyi.. In general, I'm a big fan of oversteer too.

[T77911S]

it depends on if you are after tire wear or track times.

since it don't race my 930 and I spent $1k on tires I just went with stock specs.
I still enjoy driving the car just as much as if I went with a more radical setting.

I also did an $80 alignment on it. I went to a shop that had the state of the art alignment machine but also lucked out that the guy had done porsches. (he was an old guy). no need to to spend $500 on an alignment. if you want it balanced, have someone balance it then align somewhere else.

[Driven97]

Meh, modest camber doesn't wear tires, toe does. The factory 0° front camber spec is a crime with modern radial tires & any intent of moderately sporty driving, IMO. You'll wear the outside shoulders off and have full tread in the middle.

If you legitimately do track days I'd max out the front camber. Probably can't even get a measly 2 degrees with the stock front camber plates, even with the car lowered. Then set the rears 0.5° more. A touch of toe in up front will keep the car tracking straight on the freeway, a touch of toe in rear will stabilize the back. Too much rear toe in and the car will have unpredictable breakaway characteristics and will chew the rear tires up.

If it's mostly a street car I'd still run at least a degree of camber up front. We're not on the bias ply tires these suspensions were designed for anymore.

One minor disagreement to Bill V's input - with OE torsion bars the car is going to roll more than if it had upgraded ones, so additional camber is even more important. To make things worse, lowering your car also drops the roll center, so it's going to roll even more.

[Bill Verburg]

Originally Posted by Driven97

...

One minor disagreement to Bill V's input - with OE torsion bars the car is going to roll more than if it had upgraded ones, so additional camber is even more important. To make things worse, lowering your car also drops the roll center, so it's going to roll even more.

Yes stock t's roll more than larger but you only need more camber for track use where you are almost always on 2 wheels, for street use you don't need and won't use the extra camber and not all tires respond to extra camber to the same extent anyway. When on track tires w/ flexy sidewalls on track ots of neg camber can be great. Again for street use a little extra camber is ok but lots doesn't necessarily gain you anything. same w/ toe, 0 pressed is great for street, for A/X some toe out helps turnin, some guys even use it on track cars.

[AndreasK]

Thanks for good feedback! I think I'm learning😉I'm pretty sure I have bigger t's installed by a previous owner, but no idea what they are. Not to woried about tire wear, but I'm not after anything extreme.

[T77911S]

you start playing with something like ride height and it turns into a domino effect.
the suspension is designed to ADD neg camber as it moves up, to a point. so if you lower it, without making any changes you are adding neg camber. now as said, lateral forces are higher due to lower CG so the suspension wants to compress even more. problem is you have eliminated the suspensions design of adding neg camber as it moves up so now you have to add springs and sway bars to reduce the suspension movement.
now if there is any suspension movement left you have to add even more neg camber because if the suspension moves up it is now adding pos camber.

take at look at your lower control arm. as designed it should angle down. that way as the wheel moves up it adds neg camber.
if the arm is parallel to the ground and it moves up it will add pos camber.

as you go lower you start to hit the limit on how much camber can be added.

I would probably goto euro ride height and start with goths setup. start conservative and make changes as needed. if you have understeer try adding some neg camber.
take it to a skid pad and get some video of how the outside wheels look at max traction.

what works for one car does not mean it will work for another and as you see hear you already have a variety of settings.

I had a friend that had an MR2 that he autoXd and did some track time with. everyone always told him he needs to lower his car. it actually sat quite hi. he would just na, that's ok, I m good.
he new about the need for suspension travel and its effects.
he was always 1 or 2 at the autoX and even set an unofficial track record for his class at a local track.

trust me, I enjoy the heck out of my 930 with stock settings. I could change the settings but on the street I would never know.
and yes, camber will wear out tires faster. even with stock settings my inside rears are more worn than the rest of the tire and on my last 911 I had lots of camber on the rear and it wore out a set of tires long before the rest of the tire was worn, and I had it aligned.
other thing is I am running pretty wide tires. 285's I think. narrow tires the effect is less.

[Driven97]

Originally Posted by T77911S

take at look at your lower control arm. as designed it should angle down. that way as the wheel moves up it adds neg camber.
if the arm is parallel to the ground and it moves up it will add pos camber.

Are you sure this is correct? I think it'll gain negative camber until the line defined by the center of the torsion bar and the ball joint reaches 90° to the kingpin incidence - which would be 90° to the strut on a 911. I don't think it can at all, or if it can it's really high up the the wheelwell. I could be visualizing it incorrectly.

[AndreasK]

Ok. Does this seem like a good reasonable set up. Just slightly tweeked from original:
Camber, rear: -1deg, front: neutral
Toe, Rear: neutral, front: slight toe in (how much is slight?)
Caster, front, 6,5 deg.

[Flojo]

Originally Posted by AndreasK

Ok. Does this seem like a good reasonable set up. Just slightly tweeked from original:
Camber, rear: -1deg, front: neutral
Toe, Rear: neutral, front: slight toe in (how much is slight?)
Caster, front, 6,5 deg.

what ridehight

[AndreasK]

Originally Posted by Flojo

what ridehight

Sorry, about 1,5-2 cm below euro.

[Flojo]

below Euro you'll probably need negative camber up front as well.
fender lip rolled?

again, for comparison:

Originally Posted by Flojo

I have front -1,40 /rear -1,10 (*)

(* front 63cm/7x16/205-55, rear 62cm/8x16/225-50 )

[Driven97]

A degree of camber isn't going to make a night and day difference in handling, it's not worth agonizing about.

The car is a lot more sensitive to toe, especially in the rear. The 10' in Bill V's chart is 0.167 degrees, or about 1/16" difference if you measured the distance between the fronts of the tires and the rears of the same two tires. That's "slight."

[AndreasK]

Originally Posted by Driven97

A degree of camber isn't going to make a night and day difference in handling, it's not worth agonizing about.

The car is a lot more sensitive to toe, especially in the rear. The 10' in Bill V's chart is 0.167 degrees, or about 1/16" difference if you measured the distance between the fronts of the tires and the rears of the same two tires. That's "slight."

I missed that. Bill's chart says slight toe in rear. Tech article says slight toe in front. Which is it? I suppose rear. What does the rear toe in give me?

[AndreasK]

Originally Posted by Flojo

below Euro you'll probably need negative camber up front as well.
fender lip rolled?

again, for comparison:

Lip rolled yes. I'll need the negative camber for space? Or cornering improvement?

[Driven97]

Originally Posted by AndreasK

I missed that. Bill's chart says slight toe in rear. Tech article says slight toe in front. Which is it? I suppose rear. What does the rear toe in give me?

Rear toe in gives stability, especially mid corner and corner exit. You do not want rear toe out IMO. Front toe in keeps the car from wandering on the freeway, front toe out speeds initial turn in slightly. Use either very lightly or plan on replacing tires often.

Originally Posted by AndreasK

Lip rolled yes. I'll need the negative camber for space? Or cornering improvement?

Yes and yes, plus better wear if you drive the least bit spiritedly often. 0 camber if it's just a beauty cruiser most of the time.