Hey, thanks for the info. You can be sure that when I decide to upgrade I will ask more specific questions. Danno, I know what you mean about the "classic Porsche look". That was a primary reason why I chose the Simmons OM wheels. The real reason is that I love the way they look and fill the fenders with their polished lip, very aggressive. I will post some pics when I get them , probably 3 more weeks. They take between 4-6 weeks to get here.

 

Guys,
That is all I ever really advocate. Ask questions. Ask lots and lots of questions and be sure. It is not just about safety it is also about wasting money. Your own hard earned cash and damaging our Porsches. Good looks can end up costing a lot more. I got heavily involved in this because I followed the "Yes they fit no problems answer" and nearly wrecked the rear end of my C4 including damaging the rear oil line in the RH wheel arch. I had a huge job getting the correct approved wheels for my 944 but we did it by the book and believe me, my daughter is so happy with the improvement it was worth the effort.
This is also why I am writing a book on the 964 but one chapter is entirely devoted to Wheels and Tyres and applies across the whole model range.
I have another chapter on Performance Enhancements which also applies to all Porsches in general terms,
Ciao,
Adrian
911C4

 

Gents,

I was interested in some of the comments in this thread regarding spindle life. Apparently the spindles in the pre 87 offset cars are smaller diameter where they meet the steering knuckle (where bending stress is maximum) and there have been a number of fatigue failures in track use. I was at Nelson Ledges in Ohio this year when an 86 Turbo had one fail. This particular guy was lucky but this is not an appetizing thought!!

I have removed the spindles from my 88 924S. I suspect that they are the same as pre 87 944's but have had info to the contrary. Anyway, my plan is to have them magnafluxed and then cryogenically treated and also to get a set of spares.

Anyone else know anything on this?

BTW I installed a set of BLASZAK steel arms this year with Racer's Edge spherical bearings and they worked very well.

 

Well, now that it has been explained, I wonder if I should put my 18" on my '86 944.
I got a set of Kinesis Supercups 18x8.5 and 18x10 with rubber for about $1300 ($2000 Canadian). Rubber needs replacement soon and the wheels have some curbing but still useable and the price didn't seem too bad at the time.

 

Not that much, about $100 total per spindle for polishing, shot-peening and nitriding. Call around in the phone-book. I had to take it to three different places to get done, although one of them was for "secret mod" that I'll discuss (or not discuss later) depending upon the results... heh, heh..

 

So is the spindle the problem, while the hub is fine? I'm looking into getting a spare sent of spindles and hubs cryo-treated. What else can be done? Worldwide Motorsports makes billet spindles for the 951, but I don't know how much they are, does anyone?

 

Yeah, it's just the spindles that have problems. Hubs should be maintenance-free except for bearing replacements. I've been looking at the loads on the spindle in a CAD/CAM package and it looks like cornering forces actually balance out the weight-bearing loads on the spindle (bends down vs. bends up).

So I think the deciding factor on spindle failures is really numbers of load cycles. Which then correlates with time and hours of track usage. Probably good idea to inspect them at least twice a year and replace every two years.

 

every 2 years?!

What are those of us with TurboS spindles going to do? ($$$$)

or did you mean that for the '86 spindles?

BTW: post pics of those wheels when you fit them, please!

 

I'm thinking every two years with track usage every three weeks or so. Using giant 11/12" wide wheels and sticky rubber will definitely add some stress. On a street-driven car, I would guess that the spindle may actually last forever. Steel has a fatigue limit, so if you stay below a certain stress level, it should never fail.

 

Danno you are right on (and sound like you know something about stress analysis). As I just posted on the 924/944/951/968 board, both my spindles are toast after a load of track miles. The alternating stresses resulting from that use clearly result in fatigue failures that you don't see in street use.