Tires that are designed to pull right or left
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From: Edina, Minnesota
Tires that are designed to pull right or left
One of our members who purports being a tire expert posts this information on a different thread.
Then he goes on to say…
And finally…
Anyone have any personal experience with this? It doesn’t make any sense to me.
For example, designing a tire to handle right-hand drive vs. left-hand drive makes no sense since expressways are often crowned on lanes moving in the same direction.
Anyone know what he is talking about (he claims to be a tire engineer so I assume he knows his business).
Spike
It could be a conicity issue. Every tire is somewhat cone-shaped and has an inherent pull to either the right or left. Since you have no way of knowing what conicity your tires have when you buy them, you might have ended up with two that have high values in opposite directions, which is causing a large pull to one direction at the rear. Try switching them left to right and see if the car pulls the other way. If it does, then it is just due to their conicity and you can't do much about it. It will change with wear, and since the rear has a good amount of camber, that wear will cause them to achieve a neutral pull at some point.
If your previous tires were the OE ones that came with the car, they will have been matched by Nissan so that their conicity values mostly cancelled each other, but produced a slight pull to the left. This is so that your vehicle drives straight on the inside lane of the highway, which usually has a 1-1.5 deg crown. All OEs do this, but with trade tires it's luck of the draw.
If your previous tires were the OE ones that came with the car, they will have been matched by Nissan so that their conicity values mostly cancelled each other, but produced a slight pull to the left. This is so that your vehicle drives straight on the inside lane of the highway, which usually has a 1-1.5 deg crown. All OEs do this, but with trade tires it's luck of the draw.
As I mentioned above, every tire pulls by some magnitude in one direction or the other. Several factors contribute to pull including conicity (which i described above), residual aligning torque (which we can design into the tire), coupling stiffness of the lugs (also a design parameter) and others. A tire is not "bad" because it pulls - this is normal and not a manufacturing defect. I'm not sure what kind of conicity limits Kuhmo puts on their trade tires, but if it's a high limit, and he managed to get two tires at the top of that limit that are opposite direction (pretty rare), the car will pull.
I'd recommend switching the tires left to right and driving on the same stretch of road to see if it pulls the other way. If it does, you likely have high axle conicity. If it doesn't, you could have high plysteer (does not change with direction). Whatever the case, if it's not alignment related, there's not much you can do about it!
I'd recommend switching the tires left to right and driving on the same stretch of road to see if it pulls the other way. If it does, you likely have high axle conicity. If it doesn't, you could have high plysteer (does not change with direction). Whatever the case, if it's not alignment related, there's not much you can do about it!
No, you've missed my point - ALL tires track to one side or the other. It's NOT a manufacturing defect. Dave simply described plysteer, whereby the nature of the belt arrangement causes a pull to one side, which agrees with what I said, that all tires pull. Dave is incorrect however, in saying that this is a manufacturing defect. The plysteer is specifically designed into the tire. For example: tires built for use in Japan are have the belts going the opposite direction. This is because the highway crown is opposite (since they drive on the other side of the road) and they want the tires to pull the other way, up the crown. Coupling stiffness is also designed into the tire by the shape of the lugs. We even design tires to pull certain directions and magnitudes based on what OE vehicle they will be sold. So it is FAR from any kind of defect.
Conicity is a manufacturing variation, and all tires made (at least at Bridgestone) are screened for conicity before leaving the plant. However, you can have two tires that measured within limits when leaving the plant that, when put on the same car, can have an adverse effect (bingo - pulling on the highway!!)
Spike, you should know better than to argue with a tire engineer. This is my job - I'm even in the Tire/Vehicle Dynamics department who work with OEs to do studies on this exact stuff. If you don't understand it, look up the SAE papers on conicity and other tire topics; you'll learn a lot. All of this is information is out there
Conicity is a manufacturing variation, and all tires made (at least at Bridgestone) are screened for conicity before leaving the plant. However, you can have two tires that measured within limits when leaving the plant that, when put on the same car, can have an adverse effect (bingo - pulling on the highway!!)
Spike, you should know better than to argue with a tire engineer. This is my job - I'm even in the Tire/Vehicle Dynamics department who work with OEs to do studies on this exact stuff. If you don't understand it, look up the SAE papers on conicity and other tire topics; you'll learn a lot. All of this is information is out there
For example, designing a tire to handle right-hand drive vs. left-hand drive makes no sense since expressways are often crowned on lanes moving in the same direction.
Anyone know what he is talking about (he claims to be a tire engineer so I assume he knows his business).
Spike
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From: San Mateo
hmm... interesting. just looked on tirerack about that:
http://www.tirerack.com/tires/tirete....jsp?techid=12
"When this occurs with a brand new tire it is typically due to conicity, a manufacturing glitch where a tire's tread has cured slightly cone shaped rather than in the desirable uniform cylinder shape."
http://www.tirerack.com/tires/tirete....jsp?techid=12
"When this occurs with a brand new tire it is typically due to conicity, a manufacturing glitch where a tire's tread has cured slightly cone shaped rather than in the desirable uniform cylinder shape."
Ohhh Spike.
I tried doing a quick google search for SAE articles. Came up empty, although the topic of tire conicity was mentioned indirectly in several articles. Maybe you could ask him for some of the SAE articles he refers to??
Last edited by guitman32; Aug 5, 2009 at 08:05 PM.
Quick search for "tire conicity":
http://www.automotiveforums.com/vbulletin/t518317.html (second post)
and:
http://books.google.com/books?id=jK9...nicity&f=false
Actually this paper is probably the best - easy to understand and lots of pictures:
http://210.101.116.115/fisita/pdf/G353.pdf
Page 6 mentions about the different road crowns in different countries. Lots out there guys... and sorry about the SAE stuff I guess you have to pay for those - we get them at work. Enjoy!
http://www.automotiveforums.com/vbulletin/t518317.html (second post)
and:
http://books.google.com/books?id=jK9...nicity&f=false
Actually this paper is probably the best - easy to understand and lots of pictures:
http://210.101.116.115/fisita/pdf/G353.pdf
Page 6 mentions about the different road crowns in different countries. Lots out there guys... and sorry about the SAE stuff I guess you have to pay for those - we get them at work. Enjoy!
Last edited by bdblackz; Aug 5, 2009 at 08:15 PM.
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From: Edina, Minnesota
^^ Here are more points to ponder.
The Autobahn driving lanes in Germany are flat (sans crowning), and it is designed to drain moisture from the roadway “right-to-left.” The wet is gathered to a drainage system that is in the center of the roadway. There is no crown in the roadway.
Expressways in the USA are crowned at the center line. That means that a tire biased to tracking left or right won’t provide consistent results on the same roadway. But, I’ve never seen this as a problem.
Designing a tire for left-hand drive vs. right-hand drive makes no sense at all since the tire is likely driven on a unidirectional roadway that is center-crowned and accommodating multiple lanes.
A better tire rolls true, without any pull to the left or the right.
Spike
The Autobahn driving lanes in Germany are flat (sans crowning), and it is designed to drain moisture from the roadway “right-to-left.” The wet is gathered to a drainage system that is in the center of the roadway. There is no crown in the roadway.
Expressways in the USA are crowned at the center line. That means that a tire biased to tracking left or right won’t provide consistent results on the same roadway. But, I’ve never seen this as a problem.
Designing a tire for left-hand drive vs. right-hand drive makes no sense at all since the tire is likely driven on a unidirectional roadway that is center-crowned and accommodating multiple lanes.
A better tire rolls true, without any pull to the left or the right.
Spike
I agree completely that tires will encouter different road crowns, but they spend most of their time on a -1 to -1.5deg crown in the US (opposite in RHD countries). It's just an industry standard - design the tire to track straightest where it will spend most of its time.
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From: Edina, Minnesota
^^ Why not make a tire that tracks straight all of the time? That fits every configuration.
That's your project Mr. Tire Engineer. Do it... Do it NOW. Heck... a tire is round... wanting to roll in the same direction. What's so difficult about this?
--Spike
That's your project Mr. Tire Engineer. Do it... Do it NOW. Heck... a tire is round... wanting to roll in the same direction. What's so difficult about this?
--Spike
Anyway, the belts aren't arranged like that to get pull - there's other reasons such as ride and handling. Pull is just one of the trade-offs, so we allow it to be there but control it in the design.
Starting this thread was pretty childish... "Is he really a tire engineer?" "How can any of this be true, when I, the great Spike, have not heard of it?" LOOK IT UP!
Now that you realize you didn't (and still don't) know squat about tires, next time someone starts a thread for help do some research before arguing with an actual tire engineer.
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From: redondo beach, ca
yes, tires are designed to pull one way. i did some measurement when i worked at ford. driving straight down the test track with one set of tires, car went straight. changed all 4 tires and/or their orientation, car drifted one way or the other. the big difference in drift really surprised me.
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From: Edina, Minnesota
Because on the highway your vehicle would be pulling to the right, and you'd have to apply torque to the steering wheel all the time to get it to go straight. Believe it or not, pull is one of the most common customer complaints with a new vehicle.
Anyway, the belts aren't arranged like that to get pull - there's other reasons such as ride and handling. Pull is just one of the trade-offs, so we allow it to be there but control it in the design.
Starting this thread was pretty childish... "Is he really a tire engineer?" "How can any of this be true, when I, the great Spike, have not heard of it?" LOOK IT UP! Now that you realize you didn't (and still don't) know squat about tires, next time someone starts a thread for help do some research before arguing with an actual tire engineer.
Anyway, the belts aren't arranged like that to get pull - there's other reasons such as ride and handling. Pull is just one of the trade-offs, so we allow it to be there but control it in the design.
Starting this thread was pretty childish... "Is he really a tire engineer?" "How can any of this be true, when I, the great Spike, have not heard of it?" LOOK IT UP!
Now that you realize you didn't (and still don't) know squat about tires, next time someone starts a thread for help do some research before arguing with an actual tire engineer.C'mon now, I didn't say that.
I do kind of like the label you've put on me though ("the great Spike"). Yeah... I like that.I think my question is legitimate. I don't experience a left or right pull with my Z, and that's with different brands of tires I've mounted over the last 5+ years. I'm asking if other members here notice this.
--Spike
I like how TireRack calls it a manufacturing glitch, but bdblackz says it is intentionally designed into the tire.
If it is intentionally designed into the tire (to pull one way or the other), why isn't it marked on the tire which way that particular tire is designed to pull so they can be properly matched? You know, like directional tread is marked for rotation and matched at the POS.
I'm not saying the phenomenon is or isn't there, just pointing out something I found amusing.
If it is intentionally designed into the tire (to pull one way or the other), why isn't it marked on the tire which way that particular tire is designed to pull so they can be properly matched? You know, like directional tread is marked for rotation and matched at the POS.
I'm not saying the phenomenon is or isn't there, just pointing out something I found amusing.
Last edited by StreetOC192; Aug 10, 2009 at 10:07 AM.
I like how TireRack calls it a manufacturing glitch, but bdblackz says it is intentionally designed into the tire.
If it is intentionally designed into the tire (to pull one way or the other), why isn't it marked on the tire which way that particular tire is designed to pull so they can be properly matched? You know, like directional tread is marked for rotation and matched at the POS.
I'm not saying the phenomenon is or isn't there, just pointing out something I found amusing.
If it is intentionally designed into the tire (to pull one way or the other), why isn't it marked on the tire which way that particular tire is designed to pull so they can be properly matched? You know, like directional tread is marked for rotation and matched at the POS.
I'm not saying the phenomenon is or isn't there, just pointing out something I found amusing.
Conicity is a manufacturing variation, and all tires made (at least at Bridgestone) are screened for conicity before leaving the plant. However, you can have two tires that measured within limits when leaving the plant that, when put on the same car, can have an adverse effect (bingo - pulling on the highway!!)
Thread Starter
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Joined: Dec 2006
Posts: 7,337
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From: Edina, Minnesota
I like how TireRack calls it a manufacturing glitch, but bdblackz says it is intentionally designed into the tire.
If it is intentionally designed into the tire (to pull one way or the other), why isn't it marked on the tire which way that particular tire is designed to pull so they can be properly matched? You know, like directional tread is marked for rotation and matched at the POS.
I'm not saying the phenomenon is or isn't there, just pointing out something I found amusing.
If it is intentionally designed into the tire (to pull one way or the other), why isn't it marked on the tire which way that particular tire is designed to pull so they can be properly matched? You know, like directional tread is marked for rotation and matched at the POS.
I'm not saying the phenomenon is or isn't there, just pointing out something I found amusing.
--Spike
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