Printable Version of Topic

Posted by: buck toenges Apr 29 2022, 06:44 PM

I have 2 914s. The green one is a 71 with 195/50 R15 tires and the other has 225/50 R16 tires. I have been reading up on ride height and rake. I am curious to what you guys think about my ride height.

I am measuring at the top valance lip were they connect to the metal of the body. I measure behind the front tire well and in the front of the rear tire well.

The green car has the front height at 10 1/4" and rear of 10 3/4". Again the tire size is 195/50 R15.

The blue car front height is 11 1/8" and rear is 12 1/4". The tires are 225/50 R16 rear and 205/50 R16 front. The blue car has a 1988 911 front suspension and a 3.2 engine. Blue car also has a front oil cooler that fits through the front bumper.

I am looking for ride heights for both cars. Should the blue car have similar height and rake as green car? Or should it be taller since the tires are probably taller than the green car?

Posted by: Freezin 914 Apr 29 2022, 06:58 PM

I am no expert, but generally when you change diameter of a wheel, you usually change sidewall profile to compensate for tire diameter changes.
I know overall it is a ratio between the sizes, but between the two tires you listed, are they the same diameter? Since they are both 50 series, but you have a difference of an inch between the wheel size. That alone may account for the difference in ride height.
At a glance, I would prefer the stance of your green car. But everybody has different tastes. Both of your cars look great btw.

Posted by: GeorgeKopf Apr 29 2022, 07:39 PM

Doesn't changing the tire diameter change the speedometer and odometer readings as well as the gear ratio between the tire and the pavement. (e.g. smaller diameter = more torque on starts and slower top speed)
?????

Posted by: Freezin 914 Apr 29 2022, 08:00 PM

QUOTE(GeorgeKopf @ Apr 29 2022, 08:39 PM)

Posted by: wonkipop Apr 29 2022, 08:11 PM

not sure where you are measuring your ride ht to on the car?

i have a 74 1.7 set up dead level. running orig correct profile/size 165 tyres.

i measure exactly 200mm either end of sill panel - to that little fold down lip between bottom of outer sill panels and floor pan/longs.

200mm = 7.87 inches.

it used to be "up at front" in that crazy stock way. natural understeer vw engineer caution?

i like it dead level. feels real sweet.
914/6s look like they were set up dead level stock? but just going off old pictures.

Posted by: ClayPerrine Apr 29 2022, 09:40 PM

There is a procedure in the factory manual on how to setup the ride height in the front.

You measure the height at the inboard pivot point for the control arm, and the height at the ball joint. I don't remember the exact number, but I know there is a specified difference between them.

On the rear, there was no right height adjustment from the factory. But with adjustable coil over perches, I like to set it with about an inch of rake. Most 914s without some kind of splitter start to lift the front end at speed. While not a total fix, adding rake will somewhat mitigate that.

Clay

Posted by: rhodyguy Apr 30 2022, 08:57 AM

Factor in the corner balance. Using the Haynes, don't know about FMs, proceedure results in a nose high posture.