« previous next »
Pages: 1 2 3 [4] 5   Go Down

Author Topic: Tire Roll out  (Read 9744 times)

0 Members and 1 Guest are viewing this topic.

Offline T8erhead

  • VIP
  • *
  • Posts: 199
Re: Tire Roll out
« Reply #45 on: August 31, 2009, 01:56:21 PM »
Quote from: Boostinjdm on August 30, 2009, 03:33:45 PM
The sidewalls won't "drag".  More rubber on the road causing more rolling resistance, yes.

The sidewall most definitely drags when the pressure is too low.  I know this first hand from this past saturday when I had extremely low pressure in a tire on my truck. After a few blocks at <10 psi I had visible abrasions on the sidewall.
Logged

Offline Boostinjdm

  • Hero Member
  • ****
  • Posts: 1609
Re: Tire Roll out
« Reply #46 on: August 31, 2009, 06:03:54 PM »
you guys are going to have to define "drag".  I'll agree that when the pressure is low enough the sidewall will come in contact with the ground, but it's going to be rolling right along with the rest of the tire touching the ground.
Logged
This post has been edited due to content.

Offline fabr

  • Administrator
  • *
  • Posts: 93177
Re: Tire Roll out
« Reply #47 on: August 31, 2009, 07:12:15 PM »
I have to agree with you boost. IMO the abrasion he sees is the sidewall scrubbing side to side as it flexes coming into contact with the road from being underinflated. Got a pic of the tire t8er?
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

Offline Boostinjdm

  • Hero Member
  • ****
  • Posts: 1609
Re: Tire Roll out
« Reply #48 on: August 31, 2009, 09:35:25 PM »
Quote from: Masterfabr on August 31, 2009, 07:12:15 PM
I have to agree with you boost.

Well it's about time... ff:
Logged
This post has been edited due to content.

Offline fabr

  • Administrator
  • *
  • Posts: 93177
Re: Tire Roll out
« Reply #49 on: September 01, 2009, 06:04:53 AM »
I do what I can. When I can.
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

Offline T8erhead

  • VIP
  • *
  • Posts: 199
Re: Tire Roll out
« Reply #50 on: September 01, 2009, 08:21:11 AM »
As you can see in the pic the abrasions run around the tire not out from the center.  To me it looks like dragging marks, not just side to side scrubbing.  You can decide for yourself.
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93177
Re: Tire Roll out
« Reply #51 on: September 01, 2009, 10:02:20 AM »
I think it is from the side wall progressively deforming as it bulges more and more as the tire comes into contact with the road. It appears like dragging but I feel it is from how it makes road contact. I don't know how to explain it better and that was probably clear as mud.
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

LiveWire

  • Guest
Re: Tire Roll out
« Reply #52 on: September 01, 2009, 01:06:49 PM »
if you have the tires aired so low as to have 2" of sidewall on the ground, then the radius of the rubber in the sidewall at that point is 2" less than the tire. If you figure about .5" for the difference from the tread to where the carcass flexes, then a 1.5" radius difference. At that low of pressure, there will be some cupping of the tread, but the roll out will still be greater than the circumference of a circle calculated at 1.5" less than the tire height. So the sidewall touching the ground needs to be dragged to maintain the same speed as the tread.
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93177
Re: Tire Roll out
« Reply #53 on: September 01, 2009, 01:14:35 PM »
what? ???
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

LiveWire

  • Guest
Re: Tire Roll out
« Reply #54 on: September 01, 2009, 01:53:36 PM »
Quote from: Masterfabr on September 01, 2009, 10:02:20 AM
I think it is from the side wall progressively deforming as it bulges more and more as the tire comes into contact with the road. It appears like dragging but I feel it is from how it makes road contact. I don't know how to explain it better and that was probably clear as mud.

Quote from: Masterfabr on September 01, 2009, 01:14:35 PM
what? ???

I think mine is at least clearer than yours  :-*
Logged

Offline Boostinjdm

  • Hero Member
  • ****
  • Posts: 1609
Re: Tire Roll out
« Reply #55 on: September 01, 2009, 03:03:23 PM »
 LMAO

As Fabr said.  The curved scratch marks are from the radius of the side wall changing as it meets the ground.  The same point on the side wall will have an infinite number of radiuses (sp?) as it deforms.  Hence the curved scratch marks.

One real example of a sidewall dragging would be a fully inflated tire being run up against the curb.  In that situation the tread meeting the ground would have one radius, and the sidewall on the curb another.  In that situation either the tread or the sidewall will have to be dragged.
Logged
This post has been edited due to content.

Offline Boostinjdm

  • Hero Member
  • ****
  • Posts: 1609
Re: Tire Roll out
« Reply #56 on: September 01, 2009, 03:05:39 PM »
Quote from: LiveWire on September 01, 2009, 01:06:49 PM
if you have the tires aired so low as to have 2" of sidewall on the ground, then the radius of the rubber in the sidewall at that point is 2" less than the tire.

No, because they are both on the ground.  On this planet, that makes them the same radius. :o
Logged
This post has been edited due to content.

Offline fabr

  • Administrator
  • *
  • Posts: 93177
Re: Tire Roll out
« Reply #57 on: September 01, 2009, 03:07:13 PM »
Quote from: LiveWire on September 01, 2009, 01:53:36 PM
I think mine is at least clearer than yours  :-*
Well,I can't argue with that! ;D ;D ;D
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

LiveWire

  • Guest
Re: Tire Roll out
« Reply #58 on: September 01, 2009, 05:07:40 PM »
Quote from: Boostinjdm on September 01, 2009, 03:05:39 PM
No, because they are both on the ground.  On this planet, that makes them the same radius. :o

Following that logic, if you were to have a 33" tire and a 31" tire mounted on a solid bar and both were aired so the center of the bar was 15" off the ground at both ends, it would roll in a straight line. It won't. The 33" tire side will roll ahead of the 31" tire side.
Logged

Offline fabr

  • Administrator
  • *
  • Posts: 93177
Re: Tire Roll out
« Reply #59 on: September 01, 2009, 07:43:25 PM »
Guys ,I think you're missing the point of why the air them up crowd says it saves fuel. Rolling resistance. Plain and simple. It has nothing to do with radius or anything else. A tire should not ever be aired up to where it is running just on the center portion of the tread or over inflated no matter what the reason is. It's not safe .
Logged
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"
Pages: 1 2 3 [4] 5   Go Up
« previous next »
 
SimplePortal 2.3.7 © 2008-2024, SimplePortal