lucky131969

The bushings are 10mm and 12mm.....not inches.

lionelhutz

Well, the bushings are the same except that the bolt holes are either 10mm in diameter or 12mm in diameter. So, both are constructed the same way and are the same size. I'd say both will fail about equally.

Peter

B Neat

I switched to the newer tube with m12 fasteners and the larger couplers are much more robust. Same general construction, just bigger. If you're at near stock HP, then it's just mileage I would be concerned with. I drove my car for almost a year with a broken bell-housing which was allowing the torque tube to sag and caused a lot of abnormal load/wear on my couples, and they still lasted to 114,000 miles. And even then, they didn't fail until I added the blower...did I mention I drive it like I stole it?

At near-stock horsepower and normal driving (non drag-racing), I wouldn't be concerned with them until at least 150,000 miles. That goes for the earlier couplers too.

81c3

wow a 4 year old thread

John Shiels

When mine came out they were ***** of string and black powder. Biggest problem was I drove 13 hrs each way to a track event when it happen. I got 2 sessions in instead of 10

B Neat

Been there (minus the 13 hour drive). How many miles were on them and how much power? Check out the pix in post #105 of this thread, I'm sure it looks familiar.

DRM told me they change couples on their track cars every weekend! Cheap insurance evidently.

Corvette Don

Yep and I remember this thread the day it was posted

mmichel

Oops... typo, along with using 'is' instead of 'are' and 'precious' instead of 'previous'. Sorry.

-Mike

lionelhutz

Can you prove that? A couple of people here have drilled and tapped the 10mm bolt holes out to 12mm and re-used parts of their driveshaft by installing 12mm couplers instead of 10mm. Seems to me if they are bigger and more robust they wouldn't have the same bolt pattern.

Peter

Corvette Don

^He may be thinking about the BMW bushings vs. the GM bushings, they are infact different, I have pics to prove it, stay away from the POS BMW bushings.

Paul 75 L82

My 02 Z06 at 64k miles, pulled the couplings and you couldn't tell the difference from the old ones and the new ones. Go figure?

B Neat

Yeah, I'm one of those people that have tapped the holes bigger. The Z06 driveshaft that was given to me had been chewed up by the pilot bearing so I used my 2000 front shaft. And yes, they are exactly the same bolt circle radius. But the couplers are still bigger, and more importantly, they're thicker. The actual drive shaft out of the Z06 is shorter than my 2000 driveshaft because of the increased thickness of the couplers.

As far as proving it goes, sorry, you're on your own there. You'll just have to take my word on it. If I feel like it tomorrow, I'll post up some pix of the couplers side by side. I'm on my iPhone ATM.

And "real" BMW couplers are exactly the same as original GM couplers, at least on the C5s they are. I took some out of a '99 FRC that had the BMW logo molded right on them. Maybe the newer C6 parts have been improved upon but I'm not sure, I've only worked on one C6 torque tube and it was an 05 with German made couplers. (no GM or BMW logo) The problem I've found is the same problem with everything these days: there are Chinese copys being sold and they're crap. I've bought several sets of BMW couplers from bavauto.com with no problems. But the last set they sent me were garbage. After checking, they apologized saying their latest shipment was all the same junk! They sent me good parts as soon as they got them.

B Neat

You would think that molding the 3 letters "BMW" into one of those things would cost more than molding the 2 letters "G" and "M". But the "GM" cost about 3 times as much to mold for some reason! Go figure?

AJ Powers

Have these been out for a while or are they new design? Just saw the ad in Vette Mag. Not much info on the site, but the ad says they're have an aluminum carrier wrapped around a special polyurethane for strength AND flexiblity.



http://prothane.com/whatsnew.php

lionelhutz

I bought a set. I would give them a 10/10 for the idea and about a 7/10 for the execution. In my install it seems the carrier is a little too thick and the poly bushing a little too long. The bushings are being crushed at the ends. Also, I think the side that bolts up to the flange should really have a washer or something similar to give the end of the bushing a flat surface to be against.

Peter

lionelhutz

Cool, they are thicker which should allow them to transmit more power.

Peter

B Neat

Here are a couple of pix of the M10 and M12 couplers. The M12s actually look a little bigger in person. I had forgotten how much bigger the newer drive shaft was until I looked through my album, and as you can see the flanges are quite a bit beefier too. I don't have a picture of the Z06 front-shaft, but other than the larger screw holes, it measured identical to my 2000 front shaft.

Left-M12 (Z06), Right-M10 (2000)




Approximate difference in length (Note larger diameter of Z06 shaft)

Increasing to M12

RanBurVette

I am in the process of installing a Yank ss3200, an RPM A4 and new bearings along with couplers. I got to the couplers today and they are chewed up and the front bearing is a
little loose. It is a 10mm diveshaft with a 105 on the clock. I am putting out 400 @ the
rear wheels with H/C and went with two rubber couplings per Mike at Eastcoast Super
Charging. Will press the new bearings tomorrow and will let you know the results.

WKMCD

CHeck the install length very carefully. People have trashed the thrust surface on the crank by letting the prop shaft grow longer when rebuilding. It's not a factor with the M6 and M12 tranny's but certainly is with the A4.

FWIW: I started this thread a few years ago when I trashed the bushings. Next month I'll be installing the RPM poly bushings.

Toxiclemonade

Yeah, well you are gonna wish all you have to do is drop the exhaust when you go to replace them. Try droping the entire rear subframe, trans, and diff...Might as well do a clutch while you are in there.