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General Forums => The Mess Hall => Topic started by: neale_rs on January 18, 2012, 04:07:54 PM

Title: Rear pinion angle
Post by: neale_rs on January 18, 2012, 04:07:54 PM

I finally got around to actually measuring the rear pinion and drive shaft angles (CV rear shaft).  The pinion is pointed about 3 degrees above the drive shaft angle.  I'm not getting any noticeable vibrations, neither when accelerating nor when compression braking.  Do you think it is worth setting the angle to the typically recommended 1 or 2 degrees down?  Will having it 3 degrees up make it any more likely to break a u-joint under torque when the pinion rises?

I mostly would like to leave it like it is because it is not causing vibrations and has no angle shims in place right now, but would adjust if it could cause a reliability problem.

Thanks

Title: Re: Rear pinion angle
Post by: sharpxmen on January 18, 2012, 04:16:45 PM

ideally you'd want them lined up but i think the 1 or 2 deg down is recommended for 2 reasons - when applying gas the axle wrap would push the yoke upwards, secondly the u-joint needs a bit of movement to keep the needle bearings lubricated - but this is just what i heard, i can't tell you for sure.

in your case the second one is covered but the first is actually adding to the angle rather than reducing it - dunno how much if any this would harm your setup, so i can't help with that.

Title: Re: Rear pinion angle
Post by: neale_rs on January 18, 2012, 04:46:18 PM

Thanks. 

In general I don't think these 3 degrees up will contribute to u-joint breakage because it is not all that much, .... but it's better to hear from anyone who might have experience with this.

From my experience it seems the CV shafts avoid vibration even when the angles are not perfect, maybe the angle can just be set by eyeball with good results.  I've had it in the range between 4 degrees down and now 3 degrees up with no noticeable vibrations.

Title: Re: Rear pinion angle
Post by: Jeffy on January 18, 2012, 05:32:11 PM

I don't think 3* is that big of a deal.

Title: Re: Rear pinion angle
Post by: neale_rs on January 19, 2012, 10:37:30 AM

Ok, I'll run it as is and let it prove itself out on the trail (when I get a chance again).  Thanks for the replies.

Title: Re: Rear pinion angle
Post by: neale_rs on October 11, 2012, 01:32:29 PM

The YJ has been out on three fairly demanding trails with the pinion 3 degrees higher than the DS angle and has had no problems.  So it looks like 3 degrees up, although not ideal, works fine with the SUA suspension.