Fairtax4me Posted December 15, 2015 Share Posted December 15, 2015 Anyone using or have used in the past a custom driveshaft from The Driveshaft Shop? Driveshaftshop.com I've got a bad carrier bearing on my 96. A used driveshaft is more expensive than I want to pay for considering the probability of having another failure (20 year old dry u-joints). New Dorman is about $380. But I kind of wonder if it's worth it to simplify the whole thing and cut out the center u-joint and the carrier. I got a quote from DSS to build a steel one-peice shaft for about the same price as the Dorman. Wondering if anyone here has used them? Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted December 15, 2015 Share Posted December 15, 2015 You could get a bunch of vibration, and it could cause premature wear on the trans output shaft bearings/bushings if there is vibration. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted December 15, 2015 Share Posted December 15, 2015 I know that folks on NASIOC really like their one-piece carbon fiber driveshafts, I would expect their level of quality to extend down to their aluminum and steel shafts as well. Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted December 16, 2015 Share Posted December 16, 2015 If the shop does a good job balancing it and it's stiff and straight, yeah, probably a non-issue. Subaru maybe could do it but maybe smoothness or clunking when the AWD engages makles them keep the center bearing. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted December 17, 2015 Share Posted December 17, 2015 i've wondered why some people install one piece shafts and Subaru uses a two piece? i like the idea of one less ujoint and one less carrier bearing if i ever have to dig into one again personally. does the shaft stay closer to the chassis, more tucked up, is that a reason? Quote Link to comment Share on other sites More sharing options...
forester2002s Posted December 17, 2015 Share Posted December 17, 2015 It may have something to do with alignment. A 2-piece drive-shaft with a u-joint allows for some misalignment between the transmission and rear diff. And so the flexibility of a u-joint puts less stress on the transmission and diff bearings. But there may be other reasons. Quote Link to comment Share on other sites More sharing options...
nvu Posted December 17, 2015 Share Posted December 17, 2015 i've been in cars with dss carbon fiber shafts installed. all sti 6 speed, there is a noticeable humming on all of them on light throttle at certain speeds Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 18, 2015 Author Share Posted December 18, 2015 (edited) Thanks for the replies. Been super busy with work lately. Trying to learn all I can about golf carts and ATVs since those are the two major projects I'm facing lately. 15 Golf carts of all different years and configurations. Gas, electric, some that run, some that don't, most of them broken or in need of significant repair. So I've been perusing several golf cart forums and lots of websites for info on those. All u-joint drive shafts wobble when they're spinning, because of the nature of the way a U-joint works. They don't rotate perfectly on center, so the two u-joints on a typical driveshaft are offset so the amount of wobble is balanced, which cancels out the vibration that it causes. The angles of the u-joints also have to match so that the off-center distance of the shaft is equal at each end as it spins around. This is fairly common knowledge in the 4x4 and jeep off-road world since they regularly install large lift kits that require altering driveshaft angles. In Subarus case, I think they went with a two peice shaft for several reasons. One being clearance. To keep the COG as low as possible they have mounted the driveshaft very high up in the transmission tunnel. (Basically moved the frame and chassis of the car closer to the ground.) This requires using a small diameter driveshaft, only about 2-1/2". But due to the length of the shaft, there is a high chance of the shaft flexing and oscillating during certain load conditions and certain RPMs. To cut down on that the shaft is chopped into two peices, with a third u-joint, and a carrier bearing used in the center to support the driveshaft. The problem with that is it adds another point where lateral movement can occur, which can cause a sloppy feel and cause vibration if the carrier bearing support wears. It will also cause a major vibration if the u-joint angles are even slightly off, because there isn't a 4th u-joint to balance out the motion of the third. As a result, the driveshaft has to be almost a perfectly straight shot from transmission output shaft to differential pinion flange. DSS makes their steel and aluminum driveshafts out of 3" tube, which requires minor modification to certain parts under the car for clearance around the shaft (such as the lower rear diff cover). The driveshaft is less likely to oscillate due to the larger diameter tube. On a standard height vehicle, there may also be modifications necessary to the shift mechanism and linkage, and to the driveshaft tunnel. My car is lifted, with 2" crossmember blocks front and rear, so I have plenty of room for the wider diameter driveshaft, and plenty of room for adjustment if I need to adjust transmission output shaft and rear pinion angles. I've heard about similar humming/vibration sounds from other vehicles with carbon fiber driveshafts. Kinda wonder if that's a harmonic vibration occurring because of the rigidity of carbon fiber. As on case anyone is wondering, yes there are some vehicles with 3-peice driveshafts. (4 u-joints and two carrier bearings) Edited December 18, 2015 by Fairtax4me 2 Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted April 8, 2016 Share Posted April 8, 2016 I just bought one of the DSS's carbon 1-piece shafts and will report back in this thread once I have it installed. Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted April 8, 2016 Share Posted April 8, 2016 Talk about going overboard! Then again probably still cheaper than the stocker. Quote Link to comment Share on other sites More sharing options...
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