Ride Height and wheel and tire size

[Mark Davis]

I have a 1985 Carrera Targa ROW and my ride height measures 24.5 front and rear on the drivers side and 25.5 on the passenger side. I have 15 inch rims on the car and with the tires I have the diameter of the wheel is 23.9. I think the stock 16 inch rim and tire package would have a diameter of 24.9. Does ride height sag over time. I will need to lower my car farther to achieve the same look with the 15 inch rims then I would with the 16 inch rims. I already have to be careful pulling into steep driveways. What is the widest tire that I can put on the rims that I have. The fronts are 15X7 and the rear are 15X8.

Thanks
Mark

[anthony]

Originally posted by Mark Davis
I will need to lower my car farther to achieve the same look with the 15 inch rims then I would with the 16 inch rims. I already have to be careful pulling into steep driveways.

A larger diameter wheel will fill out the wheel well even more. If anything you may have to raise the car to make the fender gap look the same. 16" wheels should give you a 1/2" more clearance on driveways.

[Miguel Antonett]

IMHO by looking at the picture, your car needs to be lowered. Regardless of the meauring from the ground, the gap between the top of tire and fender lip is just too big. A 16" wheel with the right tire size would help to fill the gap, but then the entire car will be higher.

[stlrj]

Does ride height sag over time.

No. But it looks like someone lowered the front (one screw which takes two mins to do) below ROW height for that "boy racer rake" look that is so appealing to some.

You might want to raise the front back to ROW spec and eliminate your driveway problem too.

Cheers,

Joe

[Mark Davis]

Joe

Do you think that by lowering the driver side front that raised the passenger rear. Would it have that much of an effect.

Thanks for all the responses.

Mark

[Gunter]

Keep the 15" - 7's & 8's.
Regardless of wheel size, the correct alignment/height needs to be set first.
The front is easy to do but..........
It is possible that the indexing on the rear passenger side is wrong.
Without the right indexing in the rear, it won't work.
If you index the rear:
Set the smaller plate in the center of the larger spring plate with the eccentric bolt in the middle of the adjustment so you can go either up or down for the final adjustment.
Do a search, lot's of info here.
If you are not comfortable doing it, let a competent shop do it.
A 911 without proper alignment/corner balance is no fun to drive.

[kilodawg]

just FYI,

Here is mine with 15 X 7's & 8's. The car sits about as low as I'd want to go but the wheels still look small in the wheel wells compared to 16's especially with todays lower profile performance tires.

[Mark Davis]

Gunter

I will keep the rims I like them on the car.

Kilodawg

Thanks for the picture I like the way it looks. What is your ride hieght set at. I would be happy if my car sat like yours does.

Thanks

Mark

[Gunter]

Originally posted by Mark Davis
Gunter

I will keep the rims I like them on the car.

Kilodawg

Thanks for the picture I like the way it looks. What is your ride hieght set at. I would be happy if my car sat like yours does.

Thanks

Mark

The aim is to get a 1deg nose-down attitude by having the front lip about 1/2" higher than the rear.
24.5" rear and 25" front is a good setting but.........
What camber and toe-in are you planning to do?
Height and alignment go together; changing the height will affect the alignment. When you have that much difference between sides, something is not right.
If you try and re-index the rear, do you understand the 40/44 spline principle on the torsion bars?
Do you have the bump-steer kit installed?

[Mark Davis]

Gunter

I have had the car a little over 3 months. I have no understanding of the 40/44 spline principle and I am not sure if the car has a bump steer kit installed. I just recieved the Bentley manual and 101 Projects for Your Porsche 911 today. I am not preperred to do the height adjustment my self at this time. I will read up on it and see if I feel comfortable tackling this project. The car handles great and I don't notice any bump steer isuses. Is the 24.5 rear and 25 front the stock ROW height. When this car was imported in 1986 would they have had to adjust the ride height to meet US standards.

Thanks
Mark

[HarryD]

Originally posted by Mark Davis
Gunter

I have had the car a little over 3 months. I have no understanding of the 40/44 spline principle and I am not sure if the car has a bump steer kit installed. I just recieved the Bentley manual and 101 Projects for Your Porsche 911 today. I am not preperred to do the height adjustment my self at this time. I will read up on it and see if I feel comfortable tackling this project. The car handles great and I don't notice any bump steer isuses. Is the 24.5 rear and 25 front the stock ROW height. When this car was imported in 1986 would they have had to adjust the ride height to meet US standards.

Thanks
Mark

Mark,

A good alignment/ride height/corner balance will do wonders for your car in terms of handling. Before you put the time in (either your own or a decent shop) for this work, be sure your bushings and shocks are in good shape as well.

If you want to DIY, contact Steve Weiner (he's local to us). Not only will you get the advice you seek. For suspension work, I would can think of several shops that would do great work. I had my chassis tuning done at Rothsport Road and Race (owner is a former LeMans Crew Chief of the year).

As an aside, have you joined the local PCA Chapter? The Oregon Chapter has great folks and events. On 8/27 we have an Autocross coming up. It is great place to meet other enthusiasts and learn a ton about the handling of your car.

[Gunter]

Harry: Good point about the bushings, shocks, etc.
Mark: Alignment/ corner balance is involved and time-consuming, especially the rear.
Since the car is new to you, I suggest you let someone do it for you.
24.5 rear and 25 front is a good setting for the street.
The bump-steer-kit is basically 2 spacers under the steering rack with longer bolts. Also, it is desirable to replace the stock tie rods with 930-tie rods.
Why don't you let Steve Weiner look at the car and point out what needs to be done? They can tell you if you have the spacers, 930-tie rods, need bushings, condition of shocks, etc........
Proper set-up will make a huge difference.

[Mark Davis]

Thanks guys

Sounds like I need to have some one take a look at the car and give me a run down of what work the suspension needs to get it all sorted out. Make myself a list and do what I can and have the rest done.

Harry

I have joined the Oregon chapter of the PCA and have been to 3 out of the last 4 autosrosses. I have not driven in one yet but I am planning on driving at the one on the 27.

Thanks again for all the information I was looking at the ride hieght problem as one issue not thinking about all of the other things that could be effecting it.

Mark

[HarryD]

Mark,

I'll see you there. I will be doing registration and we can talk some more. Be sure to pre-resgister to save some money.

Some time with Steve Weiner can help you figure out where you need to go.