Two (2) issues that seem to have anecdotal responses.
12-30-2010 | 09:52 AM
#1
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 67
Likes: 0
From: Elk Grove, CA
Year: 1993
Model: Cherokee
Engine: 4.0L, PowerAid, AirAid, hi-flow Cat, Magnaflow
Two (2) issues that seem to have anecdotal responses.
I've been lurking around off-road forums for the last few years and have seen a HUGE number of newby, noob, new guy type posts. Personally, I like to research A LOT before posting so there is at least a minimum of understanding before asking a question. There is so much available wisdom and experience it is rare for me to post a question. My thought is if you don't understand the question, you don't tend to understand the answer, right? So here are my questions ...
1 - As soon as the topic of wheel spacers come up there are typically a few "you'll wear out your bearings" responses or someone knew someone who knew someone that had a bolt break, spacer crack, etc. No doubt this is true but we all know someone who snapped off a bolt, broke an axle, bent a wheel, blew out a u-joint ... and these, often times, have been quality products.
From where I sit, a wheel with less back spacing will place that wheel's centerline further out from the wheel bearing same as a wheel spacer. So, what is the difference between a quality built wheel with less backspacing and a properly manufactured wheel spacer?
2 - Same argument typically tends to follow lifting blocks for leaf springs. "You'll wear out your springs faster." Why? If the contact area of the spacer is the same as the axle perch and spring pad then why would the spring wear out faster?
Not trying to start a s**t storm, just trying to understand. THANKS!!
1 - As soon as the topic of wheel spacers come up there are typically a few "you'll wear out your bearings" responses or someone knew someone who knew someone that had a bolt break, spacer crack, etc. No doubt this is true but we all know someone who snapped off a bolt, broke an axle, bent a wheel, blew out a u-joint ... and these, often times, have been quality products.
From where I sit, a wheel with less back spacing will place that wheel's centerline further out from the wheel bearing same as a wheel spacer. So, what is the difference between a quality built wheel with less backspacing and a properly manufactured wheel spacer?
2 - Same argument typically tends to follow lifting blocks for leaf springs. "You'll wear out your springs faster." Why? If the contact area of the spacer is the same as the axle perch and spring pad then why would the spring wear out faster?
Not trying to start a s**t storm, just trying to understand. THANKS!!
12-30-2010 | 10:18 AM
#2
Honorary Moderator
Joined: Mar 2010
Posts: 8,135
Likes: 15
From: Gilbert AZ/Las Cruces NM
Year: 1996
Model: Cherokee
Engine: 4.0 upgraded
I've been lurking around off-road forums for the last few years and have seen a HUGE number of newby, noob, new guy type posts. Personally, I like to research A LOT before posting so there is at least a minimum of understanding before asking a question. There is so much available wisdom and experience it is rare for me to post a question. My thought is if you don't understand the question, you don't tend to understand the answer, right? So here are my questions ...
1 - As soon as the topic of wheel spacers come up there are typically a few "you'll wear out your bearings" responses or someone knew someone who knew someone that had a bolt break, spacer crack, etc. No doubt this is true but we all know someone who snapped off a bolt, broke an axle, bent a wheel, blew out a u-joint ... and these, often times, have been quality products.
From where I sit, a wheel with less back spacing will place that wheel's centerline further out from the wheel bearing same as a wheel spacer. So, what is the difference between a quality built wheel with less backspacing and a properly manufactured wheel spacer?
1 - As soon as the topic of wheel spacers come up there are typically a few "you'll wear out your bearings" responses or someone knew someone who knew someone that had a bolt break, spacer crack, etc. No doubt this is true but we all know someone who snapped off a bolt, broke an axle, bent a wheel, blew out a u-joint ... and these, often times, have been quality products.
From where I sit, a wheel with less back spacing will place that wheel's centerline further out from the wheel bearing same as a wheel spacer. So, what is the difference between a quality built wheel with less backspacing and a properly manufactured wheel spacer?
12-30-2010 | 10:22 AM
#3
Seasoned Member
Joined: Nov 2010
Posts: 469
Likes: 0
From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
I have a buddy running 20x10 wheels with 38x15.50 Toyos on his f150 with wheel spacers...He hasnt had a problem with them in 4 yrs. He drives the truck daily and puts over 400hp to the rear end. He is an engineer and a car/truck guru having built numerous vehicles frame up. I trust his word on them and he says they are not bad/unsafe. His view point is...if you are going to call wheel spacers unsafe, you might as well say almost anything aftermarket can cause a problem, let along stock parts...firestone tire issue many years back.
As for the blocks for the back, i have been told they just give more chances of axle wrap...dont really see how they could cause the springs to wear out faster.
As for the blocks for the back, i have been told they just give more chances of axle wrap...dont really see how they could cause the springs to wear out faster.
12-30-2010 | 10:24 AM
#4
Seasoned Member
Joined: Nov 2010
Posts: 469
Likes: 0
From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
Where the issue comes from is when the spacer and the wheel are 2 different metals. when they are 2 different metals they heat from the brakes will make the metal expand/contract at different rates causing the the lugs to come loose or the tolerances to not be met on torque and can actually stretch out the lugs. This is normally not so much a big deal on steel wheels but on aluminum ones is where the main problem occurs and where you see the issues of your wheel passing you while driving down the road. And most shops wont touch wheel spacers around here.
12-30-2010 | 10:27 AM
#5
Honorary Moderator
Joined: Mar 2010
Posts: 8,135
Likes: 15
From: Gilbert AZ/Las Cruces NM
Year: 1996
Model: Cherokee
Engine: 4.0 upgraded
this is why axle wrap wears out springs:
Axle wrap and wheel hop is a problem that plagues vehicles with rear leaf spring suspension. Before we drive into the actual definitions we should clear up some terminology. Axle wrap is the twisting motion of the axle housing when it reacts to torque from the engine during acceleration or braking force on deceleration. Wheel hop refers to the rapid up and down motion of the tires caused by Axle wrap. Axle hop is the term that refers to both axle wrap and wheel hop.
Axle wrap occurs when the rotational force of the tires causes the axle housing to twist and rotate. It’s most noticeable during hard acceleration from a standing start and on hill climbs while accelerating. This rotation of the axle housing forces the springs to bend into and S-shape. When the axle housing rotates far enough, two things happen: The spring force tries to push the housing in the opposite direction, and the U-joint attempts to make a straight line between the axle-assembly yoke and driveshaft. These forces cause the tires to loose traction, and “jump”, or “hop”. Once the traction is lost, the leaf springs snap back into their original position. This happens over and over until the truck either gains better traction or the drive reduces torque input by letting off the throttle. Axle wrap can also occur during deceleration, such as hard braking.
Axle wrap has a negative effect on several components. As the axle housing rotates under load, the pinion angle changes. This means the yoke on the axle housing moves up or down in relation to the driveshaft. During acceleration, axle wrap can cause driveline vibrations because of the increased U-joint angle at the pinion yoke. In the extreme cases, this increased angle exceeds the limits of the U-joint and causes it to fail or rapidly wear out. Wheel hop places shock loads on the internal components of an axle assembly, putting the components under excessive strain. Which can lead to failure. The springs are affected because the extra stress caused by bending under load wears them out more quickly. Finally, traction is reduced because the tires don’t transfer torque to the ground effic
Axle wrap occurs when the rotational force of the tires causes the axle housing to twist and rotate. It’s most noticeable during hard acceleration from a standing start and on hill climbs while accelerating. This rotation of the axle housing forces the springs to bend into and S-shape. When the axle housing rotates far enough, two things happen: The spring force tries to push the housing in the opposite direction, and the U-joint attempts to make a straight line between the axle-assembly yoke and driveshaft. These forces cause the tires to loose traction, and “jump”, or “hop”. Once the traction is lost, the leaf springs snap back into their original position. This happens over and over until the truck either gains better traction or the drive reduces torque input by letting off the throttle. Axle wrap can also occur during deceleration, such as hard braking.
Axle wrap has a negative effect on several components. As the axle housing rotates under load, the pinion angle changes. This means the yoke on the axle housing moves up or down in relation to the driveshaft. During acceleration, axle wrap can cause driveline vibrations because of the increased U-joint angle at the pinion yoke. In the extreme cases, this increased angle exceeds the limits of the U-joint and causes it to fail or rapidly wear out. Wheel hop places shock loads on the internal components of an axle assembly, putting the components under excessive strain. Which can lead to failure. The springs are affected because the extra stress caused by bending under load wears them out more quickly. Finally, traction is reduced because the tires don’t transfer torque to the ground effic
Last edited by 96_xj; 12-30-2010 at 10:33 AM.
12-30-2010 | 10:30 AM
#6
CF Veteran
Joined: Feb 2009
Posts: 5,900
Likes: 9
Model: Cherokee
The blocks make leaf springs sag quicker and even break leaves due to leverage. When you have a spring perch mounted on the leaf even tho the contact area on the leaf is the same the contact planes are even and there is no leverage on the leaves. when you move the contact plans apart (like with a block) you now create a situation of leverage which causes the axle to put more strain on a concentrated area. Think of it this way. trying to turn a nut with your fingers is hard to do right? that is because your finger and the nut are on the same contact plane. Now once you add a wrench you stick distance between the planes and therefore create leverage allowing you to turn the nut easier right? they are similar concepts. You are just allowing more leverage on the springs allowing them to turn into an 'S' easier and putting more strain on a concentrated area. blocks are bad to use for this reason.
Just to add a little to this in refernce to the leverage. Very well explained with the analogy of using your fingers vs a wrench to turn a nut. Now even with that wrench or ratchet it may still be difficult to turn that stubborn nut. How many of us have taken a piece of pipe and slide it over the handle of the ratchet to multiply the force applied by extended the leverage point with a longer handle.
12-30-2010 | 10:30 AM
#7
Seasoned Member
Joined: Nov 2010
Posts: 469
Likes: 0
From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
Ok now I feel dumb....good thing I went with full leaf packs
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12-30-2010 | 11:10 AM
#8
Thread Starter
Junior Member
Joined: Oct 2009
Posts: 67
Likes: 0
From: Elk Grove, CA
Year: 1993
Model: Cherokee
Engine: 4.0L, PowerAid, AirAid, hi-flow Cat, Magnaflow
GREAT answers ... and I feel guilty as the information was out there for the answers but was stepped over. Nothing like looking for the complex answer when the simple one is right in front of you. It makes me ...
1 - Want to go right out and recheck those lug nuts ... all 40 of them!! As I do have the factory aluminum wheels, I thought I had done a good job of researching before purchase of the wheel spacers and never thought once about the dissimilar metals, that being the steel hub and aluminum spacers/wheels.
2 - Research methods of lifting the rear using other than lifting blocks.
1 - Want to go right out and recheck those lug nuts ... all 40 of them!! As I do have the factory aluminum wheels, I thought I had done a good job of researching before purchase of the wheel spacers and never thought once about the dissimilar metals, that being the steel hub and aluminum spacers/wheels.
2 - Research methods of lifting the rear using other than lifting blocks.
12-30-2010 | 11:46 AM
#9
Seasoned Member
Joined: Nov 2010
Posts: 469
Likes: 0
From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
GREAT answers ... and I feel guilty as the information was out there for the answers but was stepped over. Nothing like looking for the complex answer when the simple one is right in front of you. It makes me ...
2 - Research methods of lifting the rear using other than lifting blocks.
2 - Research methods of lifting the rear using other than lifting blocks.
Most lifts will offer full leaf packs for about $100-$150 more than an add a leaf kit. And you could always do a 1" shackle instead of the 1" blocks.
12-30-2010 | 11:53 AM
#10
Seasoned Member
Joined: Dec 2009
Posts: 401
Likes: 0
Model: Cherokee
Where the issue comes from is when the spacer and the wheel are 2 different metals. when they are 2 different metals they heat from the brakes will make the metal expand/contract at different rates causing the the lugs to come loose or the tolerances to not be met on torque and can actually stretch out the lugs. This is normally not so much a big deal on steel wheels but on aluminum ones is where the main problem occurs and where you see the issues of your wheel passing you while driving down the road. And most shops wont touch wheel spacers around here.
The blocks make leaf springs sag quicker and even break leaves due to leverage. When you have a spring perch mounted on the leaf even tho the contact area on the leaf is the same the contact planes are even and there is no leverage on the leaves. when you move the contact plans apart (like with a block) you now create a situation of leverage which causes the axle to put more strain on a concentrated area. Think of it this way. trying to turn a nut with your fingers is hard to do right? that is because your finger and the nut are on the same contact plane. Now once you add a wrench you stick distance between the planes and therefore create leverage allowing you to turn the nut easier right? they are similar concepts. You are just allowing more leverage on the springs allowing them to turn into an 'S' easier and putting more strain on a concentrated area. blocks are bad to use for this reason.
The blocks make leaf springs sag quicker and even break leaves due to leverage. When you have a spring perch mounted on the leaf even tho the contact area on the leaf is the same the contact planes are even and there is no leverage on the leaves. when you move the contact plans apart (like with a block) you now create a situation of leverage which causes the axle to put more strain on a concentrated area. Think of it this way. trying to turn a nut with your fingers is hard to do right? that is because your finger and the nut are on the same contact plane. Now once you add a wrench you stick distance between the planes and therefore create leverage allowing you to turn the nut easier right? they are similar concepts. You are just allowing more leverage on the springs allowing them to turn into an 'S' easier and putting more strain on a concentrated area. blocks are bad to use for this reason.
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