Suspension Tech General discussion of suspension for the Ford Ranger.

Why you WILL get uneven tire wear with a torsion bar crank

Thread Tools
 
Search this Thread
 
  #1  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
Why you WILL get uneven tire wear with a torsion bar crank

[originally posted in reply to another topic, but it deserves it's own, since t-bars are such a hot topic in general]

I've found that there is no way you DON'T get uneven tire wear from the torsion bar crank. You may not notice it at first, but you will when the tires get more worn.

Know why? We have the "SLA" (short-long-arm) suspension that has a shorter upper arm than the lower arm. As your suspension cycles DOWN, this causes the camber to go negative (bottom of wheel sticking out more than the top). This eventually wears your tires down.

It's takes a cam kit to correct it and most shops charge extra for that. When you get a wheel alignment the only thing they adjust is the toe-in, typically.

So spindles, for example, will allow you to keep your full suspension travel, with near zero camber at rest. An ideal situation if what you want is 3" of lift with the factory ride.

That having been said, I'll be keeping mine cranked WITH the spindles on it and adding cams to get back as close to zero camber as I can.

A torsion bar crank will give you negative camber (no matter what anyone says -- it's impossible for it NOT to) that will cause uneven wear. Only a cam kit for the upper arms will fix that.

I know this because I've been riding with a torsion crank for 30,000 miles plus now, and the wear is very visible on the tire.

Bottom line: no matter what you hear, alignment, by the physics of our suspension, HAS to be affected by the torsion crank. If you want to fix it, put a full cam kit on both sides and adjust the upper arm position. Just the kit is about $40 wholesale, and more in most retail places when you can get it.

That having been said, I'll be keeping mine cranked WITH the spindles on it (when I get them) and adding cams to get back as close to zero camber as I can.
 
  #2  
Old 04-04-2005
Redneckstone's Avatar
Level III Supporter
iTrader: (2)
Joined: Jun 2004
Posts: 24,936
Likes: 9
From: usa
if you want the look you pay the price.. owell...
 
  #3  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
Yeah, that's about my feeling also. Hey, most of it can be corrected.

The saving grace here is if you do it small, the effect is small. But if you go to 2" or more, it's really severe. Mine is VERY visible just looking at the front of the truck. You can see the tire wear now at 30K, but if you take the tire off and place it perpendicular to the ground, you can really see the "angle" of wear on the tread because it gaps to one side.
 
  #4  
Old 04-04-2005
Trevelyn1015's Avatar
Still El Presidente...
Joined: May 2004
Posts: 4,903
Likes: 5
From: Texas
after cranking mine, i had my tires aligned and a camber kit installed...

i have had no uneven tire wear, almost totally perfect on all four...

i have 45k on my mud terrains now and they can go another 5k+...

before tbar crank, after tbar crank(and mine are just about maxed out)
 
  #5  
Old 04-04-2005
ncervantes's Avatar
Member
Joined: Apr 2005
Posts: 11
Likes: 0
From: San Diego
Originally Posted by Trevelyn1015
...and a camber kit installed...
^ I think that's the key.
 
  #6  
Old 04-04-2005
2004edge's Avatar
Member
Joined: Oct 2004
Posts: 387
Likes: 0
From: Oswego, IL
part #'s for the camber kit? and where did you guys get yours?
 
  #7  
Old 04-04-2005
gatorblue92's Avatar
RF Veteran
Joined: Jun 2004
Posts: 8,238
Likes: 2
From: Delaware
i had a camber kit put on as well due to my knowledge that this would happen and my tires are wearing quite nicely... about 12,000 on them so far
 
  #8  
Old 04-04-2005
Trevelyn1015's Avatar
Still El Presidente...
Joined: May 2004
Posts: 4,903
Likes: 5
From: Texas
Originally Posted by 2004edge
part #'s for the camber kit? and where did you guys get yours?
treff can tell us that...
 
  #9  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
Specialty Products sells a nice kit. I have to get it from a local wholesaler or online -- most retail auto parts stores don't sell them over the counter, believe it or not. At least, not out here. I think it's a "racket", lol.

The full kit for all 4 pivot points (2 on each side) lists for well over $50 in most places anyway, so it's not cheap!

And yes the camber kit is the "key" to not having tire wear.
 
  #10  
Old 04-04-2005
TremorJon's Avatar
Member
Joined: Jun 2004
Posts: 638
Likes: 0
From: Cape Coral, FL
When i had my ranger, i had the torsion bars cranked, and right before I traded it in, I saw that the tires were wearing VERY unevenly, I was surprised at the time, the inside of the tire was more worn than the outside. Now I know why that was.
 
  #11  
Old 04-04-2005
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 23
From: Michigan
I'm not a big fan of cranked torsion bars myself but I understand why people do it. Just for grins, I tried a 2" crank on mine and I thought the deterioration in ride quality was just not worth it. A crank of 1" is not nearly so bad.

Production SLAs go to negative camber at both extremes of travel, jounce and rebound. At static factory ride height, they generally have neutral or slightly positive camber. Whether your SLA will be in spec after a torsion bar adjustment depends on two things:

1) Where the alignment was within the adjustment range initially; and
2) How far you crank them.

I believe that some trucks will still be in spec after a 1" crank but that none will be in spec after a 2+" crank. Installing a camber kit on a jacked up SLA suspension can bring the static camber adjustment back and improve tire life. It will also make for very weird geometry as the suspension cycles. The alignment will go very positive in midstroke and then return close to neutral when bottomed. This is not the hot ticket for street use.

Still, if you crank your torsion bars a bunch, you don't have much choice - unless you choose to live with the tire wear caused by the camber change.
 
  #12  
Old 04-04-2005
Trevelyn1015's Avatar
Still El Presidente...
Joined: May 2004
Posts: 4,903
Likes: 5
From: Texas
Originally Posted by rwenzing
Still, if you crank your torsion bars a bunch, you don't have much choice - unless you choose to live with the tire wear caused by the camber change.

i am fine... 45k out of bfg mud terrains already is outstanding, and they have been on since the day of the tbar crank...
 
  #13  
Old 04-04-2005
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 23
From: Michigan
Originally Posted by Trevelyn1015
i am fine... 45k out of bfg mud terrains already is outstanding, and they have been on since the day of the tbar crank...
Because you had the camber kits installed.
 
  #14  
Old 04-04-2005
2004edge's Avatar
Member
Joined: Oct 2004
Posts: 387
Likes: 0
From: Oswego, IL
haha u think u guys have bad camber. Try looking at it on a truck with a tbar flip anyone have a link to what i need i cant find them when i search on google
 
  #15  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
Originally Posted by rwenzing
Because you had the camber kits installed.
Exactly!

I can't make up my mind if you're arguing with the point or not, Christian? It WILL wear your tires if you don't adjust the camber -- which you did. So what are you saying exactly? Are you confirming the worth of the camber adjustment or what? It seems like you're disagreeing but it's hard to tell because you're not saying much, lol!
 
  #16  
Old 04-04-2005
Redneckstone's Avatar
Level III Supporter
iTrader: (2)
Joined: Jun 2004
Posts: 24,936
Likes: 9
From: usa
my buddy has a 02 off-road 4x4 and he has FULL crank on his and got it aligned and it wears fine even with his 33" thornbirds...
 
  #17  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
What did they do when the "aligned" it is the question. Also, how many miles on the thornbirds?

That's been my point all along. I'll say it again for those who aren't getting it. No one is saying you can't crank them and get even wear IF YOU DO THE ALIGNMENT. Only if YOU DON'T DO THE ALIGNMENT will you have issues.

If you want your tires to wear evenly after a torsion bar crank, with our SLA suspension, you must get a FULL alignment paying attention to camber.

There you go.

This post was meant to settle, once and for all, the alignment question on getting a torsion bar crank. It does, but some of the posts here are sure clouding the issue.
 
  #18  
Old 04-04-2005
Johawk's Avatar
Member
Joined: Sep 2004
Posts: 61
Likes: 0
From: Rochester, NY
I cranked the t-bars on my truck on the alignment rack at work. The camber is right on where it should be. -.5 degrees. And I just about maxed out the torsion bars.
 
  #19  
Old 04-04-2005
optikal illushun's Avatar
Joined: Oct 2004
Posts: 2,232
Likes: 4
From: Coal Region, MTC to be exact...heart of the coal region.
just like anything else u raise, camber is key. this is SO true for the TTB ford as well. i knew this all along, hence our edge's stock height. =-D
 
  #20  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
Originally Posted by Johawk
I cranked the t-bars on my truck on the alignment rack at work. The camber is right on where it should be. -.5 degrees. And I just about maxed out the torsion bars.
Then you either didn't have it right to START, or you measured incorrrectly. The geometry of the suspension is such that if you do that, it WILL go negative quite a bit. -5 doesn't seem like the right value anyway. Are you sure that's spec for an SLA Ranger? I'll have to look that up. It seems high.

What was it BEFORE you cranked it? You cannot tell me it didn't change because that's not possible unless you were right on the other side of center the same amount and went from -5, through zero to -5 again after the crank. Not likely for most people. You got lucky.

The geometry doesn't lie. Your experience doesn't prove an alignment isn't needed for everyone else: one data point does not make a trend.
 
  #21  
Old 04-04-2005
Trevelyn1015's Avatar
Still El Presidente...
Joined: May 2004
Posts: 4,903
Likes: 5
From: Texas
i thought you were still saying "crank the tbars and no matter you will have bad tire wear" in later posts... or something...

i wasn't reading your words correctly...

lo siento...

i originally replied to the topic's first post accordingly to back up your statements...
 
  #22  
Old 04-04-2005
n3elz's Avatar
Thread Starter
|
RF Veteran
Joined: Jun 2004
Posts: 10,623
Likes: 6
From: Kennett Square, PA
Yes, that's the problem, Christian. Too many of you read the titles and then POST without actually reading the text. I see it all the time. Very frustrating. My first post makes it clear if one were to actually read it thoughtfully.

Well, you guys have fun. I can't believe you all either don't read or don't get it. The geometry makes it obvious -- but apparently some of you just want to argue for something you can't prove, and flies in the face of the science. I won't waste my time any further.
 
  #23  
Old 04-04-2005
V8 Level II's Avatar
RF Veteran
iTrader: (4)
Joined: Nov 2004
Posts: 7,910
Likes: 23
From: Michigan
From the 2002 manual, I've got -0.5 +/- 0.7 for camber for both 4x2 and 4x4.
 
  #24  
Old 04-04-2005
Bigwill41's Avatar
Member
Joined: Jun 2004
Posts: 4,659
Likes: 0
From: Navasota, Texas
Originally Posted by n3elz
Too many of you read the titles and then POST without actually reading the text. I see it all the time.
Sorry if I don't read your post just the title...
 
  #25  
Old 04-04-2005
Trevelyn1015's Avatar
Still El Presidente...
Joined: May 2004
Posts: 4,903
Likes: 5
From: Texas
Originally Posted by n3elz
Yes, that's the problem, Christian. Too many of you read the titles and then POST without actually reading the text. I see it all the time. Very frustrating. My first post makes it clear if one were to actually read it thoughtfully.
no, i read your first post and agreed with you, showing you were correct in that i did the cam kit and had no problems...

and my reply was actually, looking back, to rwenzing:

Still, if you crank your torsion bars a bunch, you don't have much choice - unless you choose to live with the tire wear caused by the camber change.
so in actualiy, i never skipped over or misread any of your words... i just mixed you and bob up...

i just adjusted my above posts to make more sense... i just added in the "quote" so you could see what i was replying to...

you crazy old man...
 



All times are GMT -6. The time now is 02:36 AM.