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Re: Adjustable Front Upper Control Arms
The primary reason for caster adjustment is to have proper driveline angles.
Caster doesn't have an affect on alignment like a drag link or tie rod, but caster changes will affect the "on-center" feel of the steering wheel. According to the FSM, proper driveshaft angles are priority over on-center feel of the steering wheel. "Mike Romain" <romainm@sympatico.ca> wrote in message news:469237c1$0$18489$9a6e19ea@unlimited.newshosti ng.com... > To keep the front end alignment within specs. When you lift, the pumpkin > tilts which throws off the alignment bad. Same for the rear, you need to > keep the driveshaft u-joints aligned also. > > Mike > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > Canadian Off Road Trips Photos: Non members can still view! > Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 > (More Off Road album links at bottom of the view page) > > > Scotty wrote: >> I understand the need for adjustable rear upper control arms for a >> lift with a SYE and CV shaft. What reason would someone use >> adjustable front upper control arms? >> >> Scotty >> |
Re: Re: Adjustable Front Upper Control Arms
On Tue, 10 Jul 2007 18:15:56 -0400, "Matt Macchiarolo"
<matt@nospamplease.com> wrote: >The primary reason for caster adjustment is to have proper driveline angles. >Caster doesn't have an affect on alignment like a drag link or tie rod, but >caster changes will affect the "on-center" feel of the steering wheel. Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, most of the center feel is from steering box not caster but caster will effect how it follow or track road when centered. ----------------- TheSnoMan.com |
Re: Re: Adjustable Front Upper Control Arms
On Tue, 10 Jul 2007 18:15:56 -0400, "Matt Macchiarolo"
<matt@nospamplease.com> wrote: >The primary reason for caster adjustment is to have proper driveline angles. >Caster doesn't have an affect on alignment like a drag link or tie rod, but >caster changes will affect the "on-center" feel of the steering wheel. Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, most of the center feel is from steering box not caster but caster will effect how it follow or track road when centered. ----------------- TheSnoMan.com |
Re: Re: Adjustable Front Upper Control Arms
On Tue, 10 Jul 2007 18:15:56 -0400, "Matt Macchiarolo"
<matt@nospamplease.com> wrote: >The primary reason for caster adjustment is to have proper driveline angles. >Caster doesn't have an affect on alignment like a drag link or tie rod, but >caster changes will affect the "on-center" feel of the steering wheel. Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, most of the center feel is from steering box not caster but caster will effect how it follow or track road when centered. ----------------- TheSnoMan.com |
Re: Re: Adjustable Front Upper Control Arms
On Tue, 10 Jul 2007 18:15:56 -0400, "Matt Macchiarolo"
<matt@nospamplease.com> wrote: >The primary reason for caster adjustment is to have proper driveline angles. >Caster doesn't have an affect on alignment like a drag link or tie rod, but >caster changes will affect the "on-center" feel of the steering wheel. Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, most of the center feel is from steering box not caster but caster will effect how it follow or track road when centered. ----------------- TheSnoMan.com |
Re: Adjustable Front Upper Control Arms
Yes but in a solid axle vehicle caster is less critical than say in an IFS.
Death wobble is due to a combination of caster, worn linkages and poor toe-in. <Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, > Nevertheless, page 3-15 of my FSM: "Having the correct pinion angle does have priority over having the preferred caster angle." <most of the center feel is from steering box not caster> <but caster will effect how it follow or track road when centered. > In other words, caster effects the on-center feel. Didn't I already say that? "Matt Macchiarolo" <matt@nospamplease.com> wrote in message news:-PKdnWGk8uFDmQnbnZ2dnUVZ_o2vnZ2d@comcast.com... > The primary reason for caster adjustment is to have proper driveline > angles. Caster doesn't have an affect on alignment like a drag link or tie > rod, but caster changes will affect the "on-center" feel of the steering > wheel. > > According to the FSM, proper driveshaft angles are priority over on-center > feel of the steering wheel. > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:469237c1$0$18489$9a6e19ea@unlimited.newshosti ng.com... >> To keep the front end alignment within specs. When you lift, the pumpkin >> tilts which throws off the alignment bad. Same for the rear, you need to >> keep the driveshaft u-joints aligned also. >> >> Mike >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 >> 88 Cherokee 235 BFG AT's - Gone to the rust pile... >> Canadian Off Road Trips Photos: Non members can still view! >> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 >> (More Off Road album links at bottom of the view page) >> >> >> Scotty wrote: >>> I understand the need for adjustable rear upper control arms for a >>> lift with a SYE and CV shaft. What reason would someone use >>> adjustable front upper control arms? >>> >>> Scotty >>> > > |
Re: Adjustable Front Upper Control Arms
Yes but in a solid axle vehicle caster is less critical than say in an IFS.
Death wobble is due to a combination of caster, worn linkages and poor toe-in. <Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, > Nevertheless, page 3-15 of my FSM: "Having the correct pinion angle does have priority over having the preferred caster angle." <most of the center feel is from steering box not caster> <but caster will effect how it follow or track road when centered. > In other words, caster effects the on-center feel. Didn't I already say that? "Matt Macchiarolo" <matt@nospamplease.com> wrote in message news:-PKdnWGk8uFDmQnbnZ2dnUVZ_o2vnZ2d@comcast.com... > The primary reason for caster adjustment is to have proper driveline > angles. Caster doesn't have an affect on alignment like a drag link or tie > rod, but caster changes will affect the "on-center" feel of the steering > wheel. > > According to the FSM, proper driveshaft angles are priority over on-center > feel of the steering wheel. > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:469237c1$0$18489$9a6e19ea@unlimited.newshosti ng.com... >> To keep the front end alignment within specs. When you lift, the pumpkin >> tilts which throws off the alignment bad. Same for the rear, you need to >> keep the driveshaft u-joints aligned also. >> >> Mike >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 >> 88 Cherokee 235 BFG AT's - Gone to the rust pile... >> Canadian Off Road Trips Photos: Non members can still view! >> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 >> (More Off Road album links at bottom of the view page) >> >> >> Scotty wrote: >>> I understand the need for adjustable rear upper control arms for a >>> lift with a SYE and CV shaft. What reason would someone use >>> adjustable front upper control arms? >>> >>> Scotty >>> > > |
Re: Adjustable Front Upper Control Arms
Yes but in a solid axle vehicle caster is less critical than say in an IFS.
Death wobble is due to a combination of caster, worn linkages and poor toe-in. <Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, > Nevertheless, page 3-15 of my FSM: "Having the correct pinion angle does have priority over having the preferred caster angle." <most of the center feel is from steering box not caster> <but caster will effect how it follow or track road when centered. > In other words, caster effects the on-center feel. Didn't I already say that? "Matt Macchiarolo" <matt@nospamplease.com> wrote in message news:-PKdnWGk8uFDmQnbnZ2dnUVZ_o2vnZ2d@comcast.com... > The primary reason for caster adjustment is to have proper driveline > angles. Caster doesn't have an affect on alignment like a drag link or tie > rod, but caster changes will affect the "on-center" feel of the steering > wheel. > > According to the FSM, proper driveshaft angles are priority over on-center > feel of the steering wheel. > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:469237c1$0$18489$9a6e19ea@unlimited.newshosti ng.com... >> To keep the front end alignment within specs. When you lift, the pumpkin >> tilts which throws off the alignment bad. Same for the rear, you need to >> keep the driveshaft u-joints aligned also. >> >> Mike >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 >> 88 Cherokee 235 BFG AT's - Gone to the rust pile... >> Canadian Off Road Trips Photos: Non members can still view! >> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 >> (More Off Road album links at bottom of the view page) >> >> >> Scotty wrote: >>> I understand the need for adjustable rear upper control arms for a >>> lift with a SYE and CV shaft. What reason would someone use >>> adjustable front upper control arms? >>> >>> Scotty >>> > > |
Re: Adjustable Front Upper Control Arms
Yes but in a solid axle vehicle caster is less critical than say in an IFS.
Death wobble is due to a combination of caster, worn linkages and poor toe-in. <Caster plays a BIG roll in how vehcile tracks and responds to road forces and whether or not it is prone to death wooble. It is not just for steering wheel return to center. BTW, > Nevertheless, page 3-15 of my FSM: "Having the correct pinion angle does have priority over having the preferred caster angle." <most of the center feel is from steering box not caster> <but caster will effect how it follow or track road when centered. > In other words, caster effects the on-center feel. Didn't I already say that? "Matt Macchiarolo" <matt@nospamplease.com> wrote in message news:-PKdnWGk8uFDmQnbnZ2dnUVZ_o2vnZ2d@comcast.com... > The primary reason for caster adjustment is to have proper driveline > angles. Caster doesn't have an affect on alignment like a drag link or tie > rod, but caster changes will affect the "on-center" feel of the steering > wheel. > > According to the FSM, proper driveshaft angles are priority over on-center > feel of the steering wheel. > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:469237c1$0$18489$9a6e19ea@unlimited.newshosti ng.com... >> To keep the front end alignment within specs. When you lift, the pumpkin >> tilts which throws off the alignment bad. Same for the rear, you need to >> keep the driveshaft u-joints aligned also. >> >> Mike >> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 >> 88 Cherokee 235 BFG AT's - Gone to the rust pile... >> Canadian Off Road Trips Photos: Non members can still view! >> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 >> (More Off Road album links at bottom of the view page) >> >> >> Scotty wrote: >>> I understand the need for adjustable rear upper control arms for a >>> lift with a SYE and CV shaft. What reason would someone use >>> adjustable front upper control arms? >>> >>> Scotty >>> > > |
Re: Adjustable Front Upper Control Arms
The front driveshaft on my Rubicon is a CV shaft, with the double cardan
joint just in front of the t-case. Isn't that the same for all TJs? The manual says the driveline angles are more important than the caster, but the specs appear to be for a single cardan front drive shaft instead of a double cardan. The specs are: Within 1 degree u-joint cancellation Operating angles less than 3 degrees At least half a degree operating angle. Your t-case factory mount should give you 3 degrees down from horizontal. Factory front pinion angle is 3.2 degrees up from horizontal. This gives a u-joint cancellation of .2 degrees. The t-case output yoke operating angle is 1.9 degrees and the pinion input yoke operating angle is 1.7 degrees. You can increase the operating angle by about one degree at the t-case yoke. Any mathematicians know how much lift that is? I don't know the length of the front drive shaft, but I'd have to say not much. That's why you see a lot of t-case lowering kits. If the driveline angle is greater that three degrees, you will get a steady vibe in the pinion shaft which will eventually wear out the pinion bearing. If you have a single cardan joint in the drive shaft, you will get a similar vibe in the t-case output yoke. The vibe will be twice the rotational speed of the drive shaft because the pinion will actually speed up and slow down twice per revolution. At 2000 RPM, the vibe is like a hum (close to 60Hz), so it isn't that noticeable. At slower speeds, there is less force on the u-joint, and also hard to notice the vibe. You won't see the damage coming! If you have a double cardan joint in your front drive shaft, I think the specs in the repair manual are less critical. On my rubicon, the double cardan is up near the t-case yoke, so the critical angles will be down near the pinion. You want a small operating angle, probably half a degree. If the operating angle is zero, the u-joint at the pinion will not stay lubricated and may freeze up due to no rotation in the bearing caps. However, the operating angle at the double cardan can be larger than 3 degrees. This means you probably don't need a t-case lowering kit, but you might need to increase your pinion angle to more than the factory 3.2 degrees. to keep the operating angle small. Paul in article meh893ds4s8220kab9kbv2185r213vo3ha@4ax.com, SnoMan at admin@snoman.com wrote on 7/10/07 9:54 PM: > On Tue, 10 Jul 2007 18:15:56 -0400, "Matt Macchiarolo" > <matt@nospamplease.com> wrote: > >> The primary reason for caster adjustment is to have proper driveline angles. >> Caster doesn't have an affect on alignment like a drag link or tie rod, but >> caster changes will affect the "on-center" feel of the steering wheel. > > > Caster plays a BIG roll in how vehcile tracks and responds to road > forces and whether or not it is prone to death wooble. It is not just > for steering wheel return to center. BTW, most of the center feel is > from steering box not caster but caster will effect how it follow or > track road when centered. > ----------------- > TheSnoMan.com |
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