Jeep Wrangler Forum

Jeep Wrangler Forum (http://www.wranglerforum.com/)
-   JK General Discussion Forum (http://www.wranglerforum.com/f274/)
-   -   Raising caster and resulting vibrations (http://www.wranglerforum.com/f274/raising-caster-and-resulting-vibrations-249190.html)

HK_Runner 06-13-2013 06:44 PM

Raising caster and resulting vibrations
 
So after my lift and alignment, my caster was around 3.3/3.7. The alignment guy (Jeep guy) said if he raised the caster too much, I could get some driveline vibrations. I have aftermarket drive shafts with u-joints. Anyway, so after I got some work (replaced control arms, beefed up the trackbar, and cleaned up the welds on the Cs) done today, the guy said he could raise the caster a bit and since I had those new drive shafts with u-joints, I would likely not have that problem.

However, I now have a pretty noticeable vibration through the steering wheel and only after 65-70 MPH. It is fine till that speed. I suspect that is what it is...the driveline vibrations caused by a higher caster. I have no idea what the caster is now...need an alignment soon.

So do you guys think that is what it is- the higher caster?

rics1997 06-13-2013 06:58 PM

What is the new caster angle?

Here is an article I had saved. Not sure if it will help or not

Project-JK.com - Jeep JK Wrangler Resource Jeep JK & Caster: What is it? How do I measure it and how does it affect my Jeep?

HK_Runner 06-13-2013 07:03 PM

Not sure yet. I have to take it to an alignment shop. It is apparently higher than 3.5 now. I will try to take it in tomorrow. Drives just fine till 65+.

Kssting 06-13-2013 07:28 PM

My caster is right at 4 and I can feel a slight vibration around 65 but I have the stock driveshafts. It will be interesting to hear what you find out.

HK_Runner 06-13-2013 07:46 PM

That is exactly when I feel it too but it has gone from a very slight vibration at 65, and then okay above that to a pretty bad one at 65 and it gets worse and worse as the speed goes higher. I will see what the readout says but I bet my caster is above 4 degrees now, and that is causing the problem. I'll try to get to the alignment shop early tomorrow.

HK_Runner 06-14-2013 09:43 AM

Caster was 5.1 and 5.4. They dropped it back down and it now sits at 3.6 and 3.9. Back to normal...vibrations are gone. So it was the high caster, in this case. I prefer the highway feel at a higher caster levels, but not if I have to deal with the vibrations after 65-70.

jakestgermain 06-14-2013 10:29 AM

When I put on new duratracs 285/70 on my jk they did an alignment. He mentioned that I might need after market casters. Does this make sense?

HK_Runner 06-14-2013 11:06 AM

Not sure what that (aftermarket casters) means. Apparently, aftermarket drive shafts with the u-joints are more sensitive to a higher caster due to that driveline angle I mentioned. One way to combat this (if you want a 5-6 degree caster) could be to go with the AEV drop brackets. I just wanted a more solid drive shaft to begin with and did not know all this anyway. With a 5+ caster, it was more planted-feeling for sure. However, I have a slight pull to the right that I think may be a tire. I will cross-rotate the MTRs today and see if that does anything to help with the pull.

kjeeper10 07-04-2013 09:40 AM

I'm sorry I missed this.
Yea .... The driveline is more stressed lifting and adding caster makes it worse.
There's not much you can do without spending money on locking hubs or a prorock with 10* separation. Some people cut and rotate the C's also.

RK recommends 4.5* to everybody regardless of lift. Most guys seem to be in the 3.5-4" range that are having issues anyways.
Any higher in lift, your very lucky to not have vibes running stock caster. Esp with a aftermarket DS.

Before I installed the AEV brackets I shot out a few PM's to people running them. I was concerned with caster.
I was around 4* on a alignment rack w/ no vibes so I turned my joints out 1 turn. 4.5* I was after.

Seems the brackets set you around the same 4.5* so I wasn't worried about caster running them. Well it turns out my caster (off pinion) is around 4* (pinion 2*)

Driveline vibes from what I read don't taper off. They get worse with speed. Could be wrong here ??Vibes at a certain speed in most likely the tires.
Does seem you may have a angle issue.


Little late but hope this helped :)

HK_Runner 07-04-2013 11:03 AM

I'll have to look into what people have been doing with Cs. My pull is less now and bearable since I lengthened the right lower CA a bit. Before this it was pretty unbearable. Have a vibe at 60-70 so a tire may still be a problem. DT already replaced one MTR for being WAY hard to balance even with a ton of weights. Another was pretty bad so will take it back to them after this week.

kjeeper10 07-04-2013 12:26 PM

You rotate front to back?

HK_Runner 07-04-2013 05:16 PM

Yeah, the back ones were worse when they came in front...does not make as big a diff when in back, I guess.

kjeeper10 07-04-2013 05:33 PM

Quote:

Originally Posted by HK_Runner (Post 3927231)
I'll have to look into what people have been doing with Cs. My pull is less now and bearable since I lengthened the right lower CA a bit. Before this it was pretty unbearable. Have a vibe at 60-70 so a tire may still be a problem. DT already replaced one MTR for being WAY hard to balance even with a ton of weights. Another was pretty bad so will take it back to them after this week.

Rotating the C's is a pretty hard work. This involves removing the axle. Grinding the weld to remove the knuckles and then rotating them a few degrees. Saving up for a Prorock or TF Housing is more common.

Kssting 07-04-2013 05:59 PM

I agree aftermarket axle's are the way to go if you really want to fix the caster. I thought about rotating the C's when we had the axle out for the installation of the truss and armor but it definitely isn't something I am willing to try.

HK - I am looking forward to our Ouray trip in a few weeks!

HK_Runner 07-04-2013 07:22 PM

Now you guys have me doing "Teraflex vs Prorock" searches. :)

Yeah Kssting- we are looking forward to it! I have next week off so am tempted to A) Rebuild my deck or B) Go try Pearl Pass/something near Aspen. The JK is almost there...one more session tomorrow and then the CB wiring and tuning. The coax routing and antenna install are done.

Kssting 07-04-2013 09:03 PM

Or you can grab a last minute flight to Vegas on Saturday and spend a few days gambling, eating, and drinking with us :)

My next project on the jeep is probably going to be the Synergy steering upgrades but that will probably have to wait until after we get back from CO.

HK_Runner 07-05-2013 10:51 AM

Sounds like a great time. However, since I will soon be unemployed (by design, thankfully) for 80-90 days and will be traveling overseas for at least half that time, I am trying to restrict my usually-wanton spending pattern. Have fun in Vegas, and see you in a few weeks!


All times are GMT -5. The time now is 03:19 AM.