Nitram T

Hi guys,
I’m told that early front wheel spindels are prone to break under track use.

when did Porsche change to the better type spildles? What must be changed when swapping to the newer type spindles?

944 t 1986.

thanks.

931guru

There are two separate issues:

1) Square dash 944 and 924 cars use a physical speedometer cable that is routed through the left hand side spindle, and the hole in the spindle weakens it compared to the cars with solid spindles.

2) The early offset cars (including your 1986 951) had a less beefy spindle. The 87 and newer cars, including the NA and the Turbo cars, had a spindle approximately 10-25 percent larger diameter.

For track cars using sticky rubber and wider wheels and tires, the front and rear spindles and stub axles should be disassembled and magnafluxed before every track season. Failure can be life threatening at speed.

V2Rocket

It’s certainly stronger and larger but not 25% larger.

Early outer bearing area (where they fail) is 19mm diameter. Late is 22. About 16% larger.

Inner bearing is 31.75 vs 35mm. About 10%.

You can put a 1987+ turbo spindle/hub on your 1986 951 no problem. It will bolt up to the strut and control arm ball joint. You will be limited in the amount of camber you can set though.

Gage

Is it the cross sectional area that is of greatest concern for strength or is it diameter or circumference?
The area calculations indicate increases of roughly 30% and 20% for outer and inner respectively.

931guru

I am not an engineer.

I would guess that the strength improves with the cross section of the knuckle (i.e. the square of the diameter).

One of the areas where I saw failuires is the point of the stub axle where if narrows quickly to accomodate the nut. Stress cracks seem to emanate from the abrupt change in diameter (and cross section).

Nitram T

Will I be able to fit new spindels with the Old lower arms?

What about the offset is that changed?

in other words is it a direct swap or du I need to change other bits?

thanks.

V2Rocket

yes new spindles fit old arms
offset on the front is determined by the arms. Old arms = old offset

direct swap (but you’ll need 87+ brake rotors)

beamishnz

This is really interesting info... so on an early offset car if I run early off set front control arms (ex '86 turbo) I can use 951S spindles and hubs and brakes Iand early offset wheels) and there is no change to the early offset dimensions.... So just 100% upgrade with no down sides vs using the '86 turbo spindles and hubs and brakes... Is that right?

Oddjob

Yes, cross sectional area, lbs/in2

V2Rocket

other than the limited camber adjustment. The intended angle of the strut vs the spindle on -86 vs 87+ is a pretty stark difference but the eccentric bolt can compensate somewhat.

Nitram T

Can anyone please tell if this is a early or late style spindel?

beamishnz

Thanks for that... Can't quite visualise that. I will need to get some out side by side...

V2Rocket

Early

V2Rocket

Some good info in this thread

https://www.924board.org/viewtopic.php?p=236428

Nitram T

hmmm they are listed as 1988. Can anyone please post a picture of a late model. What am I looking for to tell the difference?

thanks.