4 Inch lifts?
Moderator
Joined: Jan 2001
Posts: 56,990
Likes: 2,740
From: Virginia
The problem is the steeper angles when the suspension drops from the lift. When you drive it now, it should be smooth with no vibration or humming. After you put the lift on it, if you have any vibration or humming coming and going from the rearend area, you know you might need to do something back there. They make wedges to put under the axle mount pads to point the nose of the rearend up, and you can get a driveline shop to help you get it zeroed in correctly.
Why don't you do some research on people in your area that specialize in driveshaft work? Get it scoped out before you do the deed, and then you will be ready in case you need their help. Talk to them and see what they say about it.
Lead Driver
Joined: Feb 2013
Posts: 5,006
Likes: 72
From: Roseville, MN
U-joint angles are the next concern. You probably won't get into trouble with a 4" lift, but lowering the rear of the transfer case is sometimes needed to get away from binding, or vibration. CV (double Cardan) joints, moving spring perches to rotate the pinion up, or high-angle U-joints are other tools that can be used (Jeeps can also go to a slip yoke eliminator, but I don't think any kits are available for our t.cases).
Slip yoke (or slip joint) travel is another possible problem if the new suspension will have more travel than the original suspension. But that shouldn't be an issue with a bolt-on 4" lift.
Senior User
Joined: May 2005
Posts: 334
Likes: 4
With only a 4" lift added, a stock length driveshaft will be fine. Once you get into 6"+ you have to start lengthening things (brake lines/driveshafts/ect)
5th Wheeling
Joined: Jan 2016
Posts: 26
Likes: 0
" I put a 4" Pro Comp lift on it from Summit Racing"
"Also had 33-12.5 tires on it with absolutely no clearance issues."
I have those tires with no lift and only rub at 100% lock. I'd hope there's no issue rubbing with 4" of lift.
"Also had 33-12.5 tires on it with absolutely no clearance issues."
I have those tires with no lift and only rub at 100% lock. I'd hope there's no issue rubbing with 4" of lift.
Posting Guru
Joined: Apr 2011
Posts: 1,636
Likes: 5
From: Orlando area
I didn't see it mentioned, maybe I missed it, but be aware that going to larger tires is like reducing the gear ratio.
When my truck was new I swapped the stock 29" tires for 33"s and it really "killed the power". The truck had 3.54 gearing.
Later I swapped in 4.56 gears and went to a 37" tire. The 4.56 with 37s are about the same as the 3.54 with 29" tires. So unless, you have the gearing, or plan to upgrade, be careful not to go too tall on the tire size.
When my truck was new I swapped the stock 29" tires for 33"s and it really "killed the power". The truck had 3.54 gearing.
Later I swapped in 4.56 gears and went to a 37" tire. The 4.56 with 37s are about the same as the 3.54 with 29" tires. So unless, you have the gearing, or plan to upgrade, be careful not to go too tall on the tire size.
Thread
Thread Starter
Forum
Replies
Last Post
Jonnyuma
1973 - 1979 F-100 & Larger F-Series Trucks
4
May 26, 2018 08:06 AM
78'fordtruckguy
1973 - 1979 F-100 & Larger F-Series Trucks
16
Oct 19, 2006 05:11 PM
supercab4x4dually
Brakes, Steering, Suspension, Tires, & Wheels
19
Sep 6, 2004 03:44 PM
