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OT: Poster & Posts Disappeared + Continued Discusion on Boxter Big Brake Conversion.

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OT: Poster & Posts Disappeared + Continued Discusion on Boxter Big Brake Conversion.

 
Old 06-05-2009, 06:52 AM
  #16  
xschop
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The fact that the early hub has smaller outer bearings doesn't make it a weaker hub. The bearings have to be checked more often and replaced sooner than the late ones, Especially if tracked. I wonder how many people had checked their outer bearing preload before a track event prior to their hub failing. This is the #1 cause of bearing failure in any drive system I have ever worked on......( Ring and pinions are no exception either)
When the bearing fails, then the hub will crack under severe load/stresses no doubt.
Since the outter bearing on the EARLY car is the weak link then, do you see a problem with machining that 45mm outter bearing seat to 50mm or 48mm even and installing a larger bearing.( I don't have a late hub on hand to compare right now). I won't get into technicalities, but there are bearings now that put the stock stuff to shame....

magk944 quoted """"""Porsche engineers designed the later hub/spindle combination with bigger bearings and thicker spindles at the same time as they moved the brake discs outboard. Now I can only assume that this was required to support the extra forces from moving the brake disc, but if you disagree you have to ask yourself why they did it"""""

.....Because the service techs were pissed they had to do all the extra steps, (mainly outer bearing preload adjustment) just to change the friggin rotor...LOL
I agree with you that the outer bearing on the late hub is stronger to a degree. If you want to get into the real debate about weather the late outer bearing is ????? stronger than the early bearing, you would dismantle the two different bearings and do a surface contact calculation between each's roller and races. I'm sure the Late outer bearing would be a little more, but not so significant because of the fact that the EARLY SPINDLE's axle is a smaller Dia. allowing for larger rollers in it's smaller outter bearing. Depending on how much can be machined from the EARLY outer bearing seat, the stock Late outer bearing size/strength can be surpassed.

Last edited by xschop; 06-05-2009 at 07:51 AM.
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Old 06-05-2009, 08:32 AM
  #17  
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I believe IB issue is offering anything en mass requires the offeror to be a Sponsor, not just a member... this is regardless of size.

That being said, it is up to the Mods to police this, and a simple heads up to a MOD can prevent thread deletion if you ask for permission first... I have seen a number of "MOD OK'd" group buys by non sponsors... BUT if you abuse it (like asking for permission every other week) you will most likely be told no, get a sponsorship (they do have entry level sponsorships for little guys, but it is still prohibitive unless you can create enough depth in you offerings, or are that much of an entusiast to not mind spending a few hundred dollars a month to be able to offer to the comunity...

There are other sites available, sites that do not require sponsorship, but they following there is smaller than here, so you get a smaller audience, and yes IB does monitor those other sites as well as comms here, so don't try trolling RL re-directing buisness to the other sites, it can get you banned for TOS violations...
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Old 06-05-2009, 09:01 AM
  #18  
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Originally Posted by xschop View Post
...magk944 quoted """"""Porsche engineers designed the later hub/spindle combination with bigger bearings and thicker spindles at the same time as they moved the brake discs outboard. Now I can only assume that this was required to support the extra forces from moving the brake disc, but if you disagree you have to ask yourself why they did it"""""

.....Because the service techs were pissed they had to do all the extra steps, (mainly outer bearing preload adjustment) just to change the friggin rotor...LOL
...
True, that might be the case, but you still have to ask yourself why they increased the size of the spindles and the bearings when they moved the brakes about 1.5in outwards on the hubs. They also added some extra material in the casting on late hubs, thick supporting webs running from the middle to the front of the hub at the flange.
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Old 06-05-2009, 09:30 AM
  #19  
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I see exactly why they did that from your pic provided. The braking forces transferred through the wheel studs are now transferred through more of the hub body. If you look at the Early Hub there is almost as much material there as the late one and a stronger outter ribbing of the early hub to boot.....If you look at the upper left of the 4 pictures, you would be surprised to see that the Late hub (very left) could be argued to be even less strong to the Early hub (2nd pic from right) due to the larger outter ribbing of the Early hub....


The hearsay that was mentioned about avoiding the 86T spindle/hub (2nd from left) can be understood from looking at it's comparison. It is the red-headed stepchild of the bunch.

***NOTE**** The very right hub is an 944 early hub modified for a VW swap.....
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Old 06-05-2009, 10:45 AM
  #20  
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I see your point and I still believe in my own mind that all the hubs are well designed for purpose and that the failures we have seen, including mine, were most likely due to an incorrect freeplay adjustment on the outer bearing/spindle nut. That bearings takes a lot of load and it's not the spindle or bearing that will fail in an overlaod situation, it's the hub (weakest point).

These are the 86T (R) and 87T (L) hubs, so it shows the time the design was changed.



The 87T hub has ribs applied at the back where the earlier disk used to mount, they are approx 1-1/2in x 2in and seam to provide extra support for the hub flange. The only changes from early to late is the offset, which would have no effect on the hub/spindle and the addition of abs. There were no wheel changes, they both ran 16in stock. I have placed an early disc on the rear of a late hub and it would fit fine if there wasn't any ribbing, the abs would not have required a thicker spindle and bigger bearings. So again, I think the change of spindle thickness and bigger bearings was done because the brake disc was moved 1-1/2in outwards and would put more load on the spindle bearings.

So I still think the safest way to run outward brake discs is to use 87+ spindles and hubs, which is exactly what I have done to my early car by replacing the spindle/hub combo for a late set and keeping the early offset arms. With a set of camber plates the set-up aligns just fine.

You could modify the early hubs to accept a bigger outer bearing, there is lots of metal there to accept them, not so much on the inner bearing, but the outer is where you want the extra strength. The only issue with that is that you will be taking metal from the hub at it's weakest point.

Some of the hubs you have in your pic above I am unfamiliar with but they look like they might do the job due to beefier material at the hub flange.

Mike
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Old 06-05-2009, 12:14 PM
  #21  
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if you can tell me these will fit under a 15" wheel ill buy one lol
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Old 06-05-2009, 02:43 PM
  #22  
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I have heard of early spindles failing on NA cars because the speedo cable made one of them (left or right depending on your country) hollow. Larger wheels(then factory fitment) cause all kinds of problems. Its usually a bad idea on any car. Offset changes with diameter as well.
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Old 06-05-2009, 02:55 PM
  #23  
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Originally Posted by whalebird View Post
...Offset changes with diameter as well.
What do you mean, offset changes with diameter?

I agree that larger wheels will produce a greater leverage and force at the hub, however the main problems with 944's is the control arm ball joint binding when larger wheels are fitted, especially 18's. There is an old Porsche tech bulletin issued about just that, but nowadays there are solutions using geometry corrected ball joint pins.
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Old 06-05-2009, 04:46 PM
  #24  
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My point was, the 86 Turbo spindle you have next to the 87 turbo is the weakest of them all (2nd to left in my pic). The early spindle (3rd from left )which I designed my Lexus Caliper/Boxter Rotor Brake setup for, is arguably as strong or even stronger than the late spindle. There is even more alloy to be able to machine out for a larger Diameter outer bearing, which I agree with you, is the concern.
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Old 06-06-2009, 12:38 AM
  #25  
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Originally Posted by xschop View Post
My point was, the 86 Turbo spindle you have next to the 87 turbo is the weakest of them all (2nd to left in my pic). The early spindle (3rd from left )which I designed my Lexus Caliper/Boxter Rotor Brake setup for, is arguably as strong or even stronger than the late spindle. There is even more alloy to be able to machine out for a larger Diameter outer bearing, which I agree with you, is the concern.
I see, that might just work, it sure looks like a solid piece. I don't have much knowledge on the other hub/spindles, my cars are all 86 so they were quickly changed to 87+ turbo/S2 versions after I had one fail. I think you are on the right track there xschop.
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Old 06-06-2009, 06:04 PM
  #26  
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I'm finished with the cryo-treatment of my Early spindles and hubs, so I will look into machining out the outer bearing seat for a larger bearing. I may do a 48 OD bearing as they are easy to come by and that will still leave plenty alloy.
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Old 06-23-2009, 09:52 PM
  #27  
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Hey Magk944, I'm going to machine the bearing seat for a larger outer bearing in the next few days. I haven't forgot about our tech discussion here, you have been a big help in my decision where to go next. I am keeping the EARLY spindles and offset since I already Cryo-treated the spindle and hub before I drilled and reamed it for the custom Bump steer Kit I designed......Thanks for the knowledge.....XSchop

I cross-drilled the custom drop bolt at 90* for another cotter pin location for more adjustment/tightening.....Used only the best for the drop-bolt....4130 chromoly steel (95,000 lb/in stress)


After setting spindles in vice and positioning the mating face perfectly flat....



I Drilled the spindle attachment CONCENTRIC 1st with a 39/64 drill bit......


Then I Reamed that drill hole with a new 0.625" (5/8") Reamer for an exact tight slip fit of the 5/8" drop-down bolt


PLENTY of spindle meat left with the beefier 5/8" shaft that replaces the 944 tie rod 12mm-13.5mm taper....


Everything bolts up beautifully and most importantly TIGHT....




Where's the beef!?.....Puts the stock 944 tie-rod shank to shame....


Side by side comparison of the upgrade. The Toyota inner tie rod fits the 944 Steering rack M14 x 1.5 threads and has the exact pivot offset.....


And the icing on the cake (besides $38 for the Toyota pair shipped).....Is the Inner rubber boot catch is machined exactly where the stock 944 boot catch is located!....


Almost forgot after this long post..........yeah you guessed it......P.O.R.H.

Last edited by xschop; 06-25-2009 at 09:02 PM.
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Old 06-25-2009, 08:50 PM
  #28  
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I found the 86 Turbo dimensions. The 86 Turbo spindle is an exact copy of the 944 EARLY spindle except for the fact that Porsche made the caliper mounting points 94mm center to center. So the Lexus LS430 4-pots will bolt on with the brackets drilled 94mm....FYI
I am putting on the Lexus 4-pots to the rear also. I just need to know what the rotor dimensions are for the 83-85.5 NA cars?
I am hoping that the 87-up Turbo Rear rotors (299mm wide x 100mm offset) will fit right on the 83-85.5 NA car so I can design a bracket for the Lexus Calipers to fit the Turbo rotors to the Early rear car....
Any input?
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Old 06-25-2009, 10:43 PM
  #29  
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Originally Posted by xschop View Post
I found the 86 Turbo dimensions. The 86 Turbo spindle is an exact copy of the 944 EARLY spindle except for the fact that Porsche made the caliper mounting points 94mm center to center.....
Any input?
If I remember correctly the early 944 and the 86 turbo spindles also differ in the thickness of the lug that the struts mount on.
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Old 06-26-2009, 12:05 AM
  #30  
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Are the bolt hole spreadwidths different from the 86T to 87T?
Also have you ever heard about those strut lugs on the spindles being @ 3 degree caster?
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