Modern trailing arms for the 914?, 986 carriers/calipers/e-brake, more adjustability, more tire? |
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Modern trailing arms for the 914?, 986 carriers/calipers/e-brake, more adjustability, more tire? |
horizontally-opposed |
Jan 26 2021, 12:21 PM
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#1
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Advanced Member Group: Members Posts: 3,432 Joined: 12-May 04 From: San Francisco Member No.: 2,058 Region Association: None |
I've been reviewing past discussions on these (links below) off and on, having test fit a 215/60R15 Pirelli P6000 on a 911R wheel into both rear fenders of my narrow-body 914. It seems doable, but it's going to take some massaging on the outer fender, custom spacers, and—maybe—narrowed trailing arms. Which got me to thinking about the current state of the 914 trailing arm, which is the same it's been since 1970.
Basically, those heavy, non-adjustable steel trailing arms are one of the very few things on the 914 that hasn't been addressed or evolved by the aftermarket. I'm running PMB-rebuilt trailing arms with PMB-rebuilt calipers, and can redo them again with reinforcements and/or some reshaping, but I wonder how hard would it be to do blade-type trailing arms of similar strength with less weight and/or more adjustment. Could a 911 spring plate, or a triangulated or otherwise reinforced version of it, be adapted? Looking at the basic design of the 914 arm, it doesn't look all that complicated, but I'm no engineer. EDIT: Possible use of a machined 986 wheel carrier, an aluminum casting by Brembo that incorporates the 986 e-brake and 986 four-piston caliper mounts, comes up later—a very interesting idea from @Chris914n6, particularly as the castings are available for $100-200ea used or new from Porsche. Bolting that carrier to a new steel trailing arm with a lower damper mount seems viable to me, but here to learn. The custom work to narrow factory 914 trailing arms looks extensive, but has been done by both @914timo and @sixnotfour as well as, it looks like, Rich Johnson. I could see doing it in the process of moving to 911 e-brakes and 986 2.5 brakes, maybe, but I wonder if a group buy might attract a 914 vendor we all want to support? Relevant threads: http://www.914world.com/bbs2/index.php?sho...p;#entry1247827 http://www.914world.com/bbs2/index.php?sho...ailing&st=0 http://www.914world.com/bbs2/index.php?sho...238144&st=0 http://www.914world.com/bbs2/index.php?sho...234391&st=0 |
Racer |
Jan 27 2021, 07:02 AM
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#2
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Senior Member Group: Members Posts: 787 Joined: 25-August 03 From: Northern Virginia Member No.: 1,073 Region Association: MidAtlantic Region |
its my recollection that the Maxlite 911R wheel is NOT an exact 911R replica. Maxlite is 47mm offset while the original 911R is 49mm offset.. and in this case, 2mm will matter!
We had a 74 911S (stock narrow rear fenders) and ran 911R wheels with 225/50-15 yokohama A008 (1980s here for reference). Despite fender lip rolling (like yours) previously on our 914/6 (to fit a 205/70-14 in period tire combo), that 911R combo just wouldn't fit on our /6 or on my /4. Both cars would require a slight pull of the fenders to work (but less pull than a 7x15 et23 wheel). fwiw, on our /6, the 205/70-14 was an extremely close fit, such that a 195/70 became the default tire in the 1970s on that car. You also need to take into account tire flex / expansion and suspension movement etc under use.. and the harder the use, the greater the movements. Another question, even if the trailing arm was made thinner, what is the relationship (plane) between the arm and the inner fender well? Does the arm protrude past the inner fender well or sit flush? ie, even if you thin the arm, will the tall tire still hit the inner fender? |
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