Overland LJR built to explore and expedition
- Thread starter tomtaylz
- Start date
I'll answer for Tom since his is still working on his jeep. Yes the measurement was taken after tt.
So I might be going insane, but I think I mitigated the vibes by about 70% to a point their tolerable, I could be really insane but I think the same applies for idle. Still there but not as bad as it’s been.
The changes I did? Removed and put the rear drive shaft back in, removed the spare (driving spareless)
The spare was put touching snubbers on the exogate.
For those following along at home, one discovery we made today was driving with just the front drive shaft in there was no vibes, changes to rear pinion has not made a difference, rear pinion is sitting about 1* below driveshaft.
So why’s this the case with the probable difference of the spare?
One idea I have is the spare is pulling the tub down in the back and causing contact somewhere. But why would no rear driveshaft with a spare result in no vibes? Maybe the contact is towards the back of the transfer case, I’ve heard the pinion raises a bit at speed, would this cause the rear transfercase to raise? We did clearance quite a bit today but most of the focus has been at the front as this seems the largest area.
Another is the spare could be acting as an amplifier in some way making things worse.
I’m baffled and very tired
The changes I did? Removed and put the rear drive shaft back in, removed the spare (driving spareless)
The spare was put touching snubbers on the exogate.
For those following along at home, one discovery we made today was driving with just the front drive shaft in there was no vibes, changes to rear pinion has not made a difference, rear pinion is sitting about 1* below driveshaft.
So why’s this the case with the probable difference of the spare?
One idea I have is the spare is pulling the tub down in the back and causing contact somewhere. But why would no rear driveshaft with a spare result in no vibes? Maybe the contact is towards the back of the transfer case, I’ve heard the pinion raises a bit at speed, would this cause the rear transfercase to raise? We did clearance quite a bit today but most of the focus has been at the front as this seems the largest area.
Another is the spare could be acting as an amplifier in some way making things worse.
I’m baffled and very tired
Whoops, probably not clear there in my post. With the rear driveshaft on and no spare was the ~70% reduction in vibes.
On the very short drive with no rear drive shaft (4H) and spare on there was no noticeable vibes
Have not tried no spare and no rear driveshaft.
If I had to guess, I would assume it was only 70% reduction as maybe I still need to dial in he angles for my Jeep, not sure about the idle vibes though, those were there driveshaft or not, ensured there was contact on the passenger MML.
I’m guessing the weight from the spare won’t change driveline angles? That seems silly
Not sure I’ll try and get a good picture today. One thing I noticed at idle is that you can still hear the vibes but feel then a lot less which makes me think the tire amplifying it might have credit. Which is weird as the spare is rubber and touching rubber, which is normally used to isolate vibes. Of course I’m probably totally wrong.
On level ground, put your angle finder on the flat step portion of your slider toward the rear of the slider and note angle. Then, put the spare tire back on and note the angle change. What is the change?
That is correct, no other changes the vibes are really minor and I’ve had it up to 70. I’d say 60-70lbs.
I’ll have to experiment and get back to you, I was trying to put my 35 on last night but didn’t get around to it and it’s not set up to do so just yet.
It is pretty nice and smooth except for the rough as crap ride without the spare on lol
Im dumbfounded. You do have the spare 35 in the trunk though so its not like all the weight is gone. Maybe take that out?
I’ll try that. And yeah but I’m the back I’m sure it’s a lot more distributed than hanging at one spot.
I have very little vibration with mine. But they go away completely when the kids hop in back. Little changes can make a difference at times.
Interesting. Do you think this would effect angles or would that stay pretty consistent?
The idle part puzzles me also. I can still hear vibes at idle but it isn’t as much of a fee in the seats. If it didn’t drive so rough without the spare I wouldn’t care as much lol.
I’ll need to get some measurements and do more tests when I have time but what are your guys theories
I think more experimentation is needed. Placement of the spare can change how the jeep sits. You hang 70lbs. of spare behind the bumper vs. laying it in the tub behind the seat will be different. My suggestion, mount the spare on the exogate, fill the tank full of fuel, then take an angle measurement of the rear ds. Drive thru a the tank of fuel till 1/4 tank, then remove the spare all together, then re-measure ds angle.
One reference point was yesterday. Half tank of fuel with spare, 17 drive shaft 15.8 pinion horrible vibes
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