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ZUKIWORLD Discussion Forum => Technical Discussion - Performance / Modify => Topic started by: one mile on May 28, 2010, 10:52:39 AM

Title: Pinion angle on RUF with spring under axel
Post by: one mile on May 28, 2010, 10:52:39 AM
Two questions, I have just installed RUF with TT Missing Link set up on my stock '87 Samurai with 235/75/15's with springs under Axel but don't know what the Pinion Angle should be to avoid "Bump Steer" and where do I measure it from?
Title: Re: Pinion angle on RUF with spring under axel
Post by: Drone637 on May 28, 2010, 02:53:11 PM
The pads where the axle mounts to the springs should be flat.
Title: Re: Pinion angle on RUF with spring under axel
Post by: one mile on May 28, 2010, 06:45:07 PM
Do you have an Idea as to what Degree of Angle it needs to be?
Title: Re: Pinion angle on RUF with spring under axel
Post by: ack on May 28, 2010, 08:56:49 PM
Two questions, I have just installed RUF with TT Missing Link set up on my stock '87 Samurai with 235/75/15's with springs under Axel but don't know what the Pinion Angle should be to avoid "Bump Steer" and where do I measure it from?


Here is the steering data from the '88 Samurai FSM:

http://www.acksfaq.com/steeringspecs.htm (http://www.acksfaq.com/steeringspecs.htm)

If you park your Samurai on a level spot and put an angle measuring device on top of the kingpin bolts with the wheels pointing forward, you'll get a basic reading of what the pinion angle is.   I can't remember what that measuring device is  called, but they have round face with degrees of angle marked around the edge and a pointer that always points down. They are sold at hardware stores and home improvement centers.  Compare the angle readings to the data in the link above.  The pinion angle is directly proportional to the kingpin angle when the wheels are pointing forward.

Pinion angle has nothing to do with bumpsteer but EVERYTHING to do with caster - which can induce death-wobble. 

Death wobble can also be caused by loose steering components like tierod links, Birfield seals, worn/loose wheel bearings and poorly balanced tires in addition to a bad caster angle.

Bump Steer is explained here:

http://www.acksfaq.com/bumpsteer_explained.htm (http://www.acksfaq.com/bumpsteer_explained.htm)

I hope that this helps!
Title: Re: Pinion angle on RUF with spring under axel
Post by: one mile on May 30, 2010, 05:06:20 AM
Man I just love this Site.......Thanks for the Input everyone!
Title: Re: Pinion angle on RUF with spring under axel
Post by: ack on May 30, 2010, 09:44:45 AM
...Also, Death Wobble can be caused by worn spring and shock bushings.
Title: Re: Pinion angle on RUF with spring under axel
Post by: one mile on June 04, 2010, 09:30:52 AM
Thanks ack ! love the drawings. What Degrees are everyone using with Small Lift Big tire setups on the Samurai ? I know everyone likes there on setup but I need a good idea of what works "Out There" for everyone else besides OEM Specs.
Title: Re: Pinion angle on RUF with spring under axel
Post by: Skyhiranger on June 04, 2010, 11:54:56 AM
If you park your Samurai on a level spot and put an angle measuring device on top of the kingpin bolts with the wheels pointing forward, you'll get a basic reading of what the pinion angle is.   I can't remember what that measuring device is  called, but they have round face with degrees of angle marked around the edge and a pointer that always points down. They are sold at hardware stores and home improvement centers.  Compare the angle readings to the data in the link above.  The pinion angle is directly proportional to the kingpin angle when the wheels are pointing forward.


As odd as it is, the device is called an angle finder. :P  At least that is what I have always heard them referred to as.
http://www.harborfreight.com/dial-gauge-angle-finder-34214.html (http://www.harborfreight.com/dial-gauge-angle-finder-34214.html)
Title: Re: Pinion angle on RUF with spring under axel
Post by: one mile on June 04, 2010, 10:30:10 PM
I will pick one up in the morning. It is a "Must Have". Plus I am a tool nut anyway.
Title: Re: Pinion angle on RUF with spring under axel
Post by: ack on June 05, 2010, 11:27:45 AM
If you park your Samurai on a level spot and put an angle measuring device on top of the kingpin bolts with the wheels pointing forward, you'll get a basic reading of what the pinion angle is.   I can't remember what that measuring device is  called, but they have round face with degrees of angle marked around the edge and a pointer that always points down.


As odd as it is, the device is called an angle finder.  At least that is what I have always heard them referred to as.
[url]http://www.harborfreight.com/dial-gauge-angle-finder-34214.html[/url] ([url]http://www.harborfreight.com/dial-gauge-angle-finder-34214.html[/url])


Yeah, That's it!  :D
Title: Re: Pinion angle on RUF with spring under axel
Post by: one mile on June 05, 2010, 08:23:18 PM
something ODD today.....my Sammy started Squeaking underneath!!???? Could it be a Universal Joint if my pinion Angle is way off?   It would seed up as I went faster....Any thoughts?
Title: Re: Pinion angle on RUF with spring under axel
Post by: Skyhiranger on June 07, 2010, 03:36:50 PM
something ODD today.....my Sammy started Squeaking underneath!!???? Could it be a Universal Joint if my pinion Angle is way off?   It would seed up as I went faster....Any thoughts?

If the noise speed increases with vehicle speed, then you know it is something that is spinning faster as the vehicle speed increases.....like a ujoint, wheel bearing, etc.
Title: Re: Pinion angle on RUF with spring under axel
Post by: one mile on June 07, 2010, 05:03:05 PM
Thanks , I will check that this weekend....