not really anyway to tell. that said massive spring rates and sticky tires will shorten life significantly...new 991GT3 has gone to a double-shear arrangement

 

Hrm, since alignment changes I may hold off having it done with my toe links and just do it all together come Spring. Would be less for Garth to deal with while doing other things. If you have built arms in hand are they difficult to swap? Thinking Tarett GT3 with solid thrust and monoball ends. Doubt I'll ever need to shim the ends, is there a better option? Tarett is around $1300 a set, looked at RSS, didn't find PMNCA pricing yet.

Have to find a shop local I can trust to do an alignment.

Good info here guys! Sorry if I've dragged it off topic VGLNTE1! When do you think you'll have your's done and on the road?

 

That's the problem Jim, there is really now way to tell. It's simply metal fatigue that eventually leads to failure. It won't really be a player for street use but for hard track use it's a matter of time depending how hard you drive the car. Stiff suspension set ups and sticky tires resulting in high loads are the recipe. Once you start driving these cars at or near Cup car pace, things will start failing in a hurry. There is a threshold you cross where metal fatigue becomes a factor. At least that is what I have noticed and as such follow a pretty aggressive change out schedule on suspension components. Last year I replaced every suspension component in the rear including axles. As an example, I've found hubs to be a weak point on these cars when tracked hard. I have broken two rear hubs over the last two years including the stronger GT3 versions. A hub is a $150 part but when it breaks it normally results in several thousand dollars of damage as you normally damage the the axle, brake rotor, brake caliper, bearing etc. These are things that people generally don't think about. Again, for street, this is not a player but for track use it's real.

[url=https://flic.kr/p/oBB2Px]

[url=https://flic.kr/p/yuMdAv]

 

hey John,
Have you considered any 'after-treatments' on the hub? Cryo, etc...
Could you share your source for hubs? $150 is a screaming deal!
Cheers, Happy New Year,
Rob

 

You can replace the LCAs in a couple of hours. It's not hard. You will need a tool to pop the ball joint but that's cheap. I bought one at Harbor Freight and modified it slightly to make it work.

The PMNA RSR LCAs were right at $2K for the pair a year ago but might be a little more now. Tarett sells the OEM GT3 LCAs for $1385 retrofitted with the Tarett solid TA bushing and inner mono *****. The outer joint on these is the same as the normal TT arms. They also sell aftermarket arms for $1395 (they appear to be made by Elephant racing) which have rebuildable inner and outer mono *****. The problem with the aftermarket arms is two fold in my book. The mono ***** on the aftermarket arms are generally lower grade Aurora or FK rather than the German made mono ***** you will get on the PMNA arms. Additionally, since the aftermarket arms are not the exact same shape as the OEM or PMNA parts, you will have issues attaching the factory brake ducts as the brackets are make specifically for the factory parts. As such you will have to modify the brackets or use zip ties and other means to attach them all of which will be less than ideal. Just something to think about when going the aftermarket route.

 

Hey Rob. I had several guys look at the failed hubs including a metallurgist. There is actually room to beef up the area of the hubs by several millimeters in the area that is failing. The failure point is in the section of the hub that forms the 90º angle of the neck of the hub. As you know, anytime you have a sharp angle you have a stress riser. There is actually some room to make the the 90º more gradual which would help. I am currently speaking with someone that might be able to mill out hubs out of a better material while beefing up the area in question as I would like to get a permanent solution to this problem. 997Cups have beefier hubs and I looked at that option but it would entail having the change to a center lock set up which I don't want to do.

It looks like the hubs have gone up in price a bit. They retail for $235 so you could probably get them around $200 or so.

 

Good info John!
I was just looking at the hubs and was wondering about exactly that: stress risers/material radius, and Cup hubs...knew the bearings/upright were beefier but couldn't remember if the hubs were any more substantial, and of course centre lock...
944 world has billet hubs, we should too! Hope something develops...
Cheers,
Rob

 

Just finished up last night. Tried to get the alignment back to where it was, but I know I'm off and will need to hit the rack. 20* and snow flurries here so not sure when she will get a test drive. She's still down now waiting for o2s to get here Tuesday.
The install was really easy.

 

Looking forward to the feedback man, hopefully you get some clear weather lol. I'm interested in how the steering firms up and whatnot. I've only got 50k light duty miles on mine but being able to just swap in the new would be nice. Don't think the aftermarket interests me on this, bummer the GT3 cannot be rebuilt but chances are I wouldn't kill them quickly That hub is terrifying John, I don't blame you for looking for a more permanent solution!

 

I don't think the steering will change. Just did the rears. My only goal was to get rid of the nasty mushy toe problem that's eating my tires.

 

Ah okay, thought you were doing all four. Shame that stock arms are apparently back ordered. Not sure I'd need the GT3 removable ends and the other end isn't rebuildable anyway. Will be a bit before I get to this sadly and the date for the work I'm ready to do has been slipping ever backward too (sigh). I too have issues eating tires!

 

I wouldn't worry about the ends grenading unless you road raced alot.

 

I just bought the race version of the powerflex poly bushings for my inner lca mounts front and rear and also my toe arm ends. It's a much cheaper option than the monoballs and is slightly less harsh. Looking forward to getting them installed along with my solid thrust arm mounts and adjustable dogbox arms.