1968 912 rear torsion bar size

[BAO B]

This is the size of my rear torsion bar which shows 22 mm. Can i replace it with a 23 mm torsion bar? How critical is 1 mm?? Any input will greatly be appreciated.

Thanks,
Bao

Hi Bao,

You can replace the 22 mm with the 23 mm, but I would not do that. The 23 mm is the factory torsion bar for the 911 with the heavier engine in the back. If you would use the 23 in combination with the lighter 912 in the back, it will be relatively too stiff with respect to the front of the car. In other words, you also should replace the fronts with larger ones to get the right balance.

I think it doesn't make sense to do the change, unless you are making a track car of your 912 or just want to spent your time on an interesting experiment.

Otto

[djdsc]

Using the 22mm in '68 was a one year only thing. Prior to '68 the 912 used the same 23mm as the 911. Search around and you will confirm. No reason not to use the 23mm if you like.

djdsc,

You are right with the difference between the '68 22 mm and the 23 mm for the pre '68. My info was based on my memory regarding my own '68. I just assumed the pre '68 uses the same diameter. This could explain the minor difference in driving my '68 or '66, both with new bushings and new Koni's. Of course the front sway bar in the '66 will also have his effect on the character.

A "search around" confirms my note regarding the differences in performance with changing the torsion bar diameter and the correct balance between front and rear bars.

Otto

[BAO B]

Thank you for the input. As Otto mentioned also upgrading the front torsion to balance the 23 mm for the rear, i think is a great idea. I will then use the 23 mm rear torsion bars.

I also know about the 22 mm t.b. used only on '68 model, but wasn't sure about upgrading to 23. 1968 model is unique then other years but also a pain in the ass when it come to parts replacement.

Thanks again

[djdsc]

Exactly. The pre '68 912's had a front sway bar in relation to the rear 23mm TB's whereas with the smaller 22mm rear bar the '68 did not come stock with a front sway bar.