Tire Thumping?
01-02-2017, 10:53 AM
#1
Racer
Thread Starter
Tire Thumping?
Hi All,
Been meaning to inquire with you about this. When I reverse out of a parking spot - or drive out in the forward direction - if my wheel is hard right (or left I think) It feels like my tires in the front are locked in the position they are in and the car is literally thumping over itself. You feel a shutter and hear it quite audibly. Anyone know what this is?
Thanks - and to all of you - Happy and a healthy new year to you and your families. May this year be only good things to us all.
Been meaning to inquire with you about this. When I reverse out of a parking spot - or drive out in the forward direction - if my wheel is hard right (or left I think) It feels like my tires in the front are locked in the position they are in and the car is literally thumping over itself. You feel a shutter and hear it quite audibly. Anyone know what this is?
Thanks - and to all of you - Happy and a healthy new year to you and your families. May this year be only good things to us all.
01-02-2017, 10:54 AM
#2
RL Community Team
Rennlist Member
Rennlist Member
Known character trait. Not a problem. Due to suspension geometry and wide tires.
Search on here for Acorns.
Rest easy.
Search on here for Acorns.
Rest easy.
01-02-2017, 10:55 AM
#3
Three Wheelin'
Search Acorns. Toss on some winter tires.
01-02-2017, 11:22 AM
#5
Three Wheelin'
Man... a few years ago I saw this hot *** Pirelli at a bar. Bought her a drink and we got to talking all through the night. One thing led to another and...
Oops. Misread the title of your post
Oops. Misread the title of your post
01-02-2017, 11:28 AM
#6
Racer
Thread Starter
03-18-2018, 11:36 AM
#7
Racer
Thread Starter
We sure this is normal 100%?
Had a friend in my car the other night when temps were in the 30s and the thumping noise as I pulled out of our office parking lot was akin to the tire and wheel literally bolting off the car. The entire car vibrated and the noise was loud enough for people walking across the street to turn and look.
I know it was stated to be normal above - but would this have been solved had I put winter tires on? I know low temps and summer tires are not suggested.
I have Rear Axle Steering on mine FWIW.
Had a friend in my car the other night when temps were in the 30s and the thumping noise as I pulled out of our office parking lot was akin to the tire and wheel literally bolting off the car. The entire car vibrated and the noise was loud enough for people walking across the street to turn and look.
I know it was stated to be normal above - but would this have been solved had I put winter tires on? I know low temps and summer tires are not suggested.
I have Rear Axle Steering on mine FWIW.
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03-18-2018, 11:41 AM
#8
Rennlist Member
We sure this is normal 100%?
Had a friend in my car the other night when temps were in the 30s and the thumping noise as I pulled out of our office parking lot was akin to the tire and wheel literally bolting off the car. The entire car vibrated and the noise was loud enough for people walking across the street to turn and look.
I know it was stated to be normal above - but would this have been solved had I put winter tires on? I know low temps and summer tires are not suggested.
I have Rear Axle Steering on mine FWIW.
Had a friend in my car the other night when temps were in the 30s and the thumping noise as I pulled out of our office parking lot was akin to the tire and wheel literally bolting off the car. The entire car vibrated and the noise was loud enough for people walking across the street to turn and look.
I know it was stated to be normal above - but would this have been solved had I put winter tires on? I know low temps and summer tires are not suggested.
I have Rear Axle Steering on mine FWIW.
03-18-2018, 11:50 AM
#9
Racer
Thread Starter
I did, but just wanted to make sure this was absolutely normal.
(https://rennlist.com/forums/991/1051...o-excited.html)
(https://rennlist.com/forums/991/1051...o-excited.html)
03-18-2018, 11:50 AM
#10
Race Director
Yes, winter tires would help this phenomenon.
Get a set of 19's. Wheel and tire set to swap out.
This is 100% normal and abnormal in cold temps, Porsche, and 20" wheels.
Get a set of 19's. Wheel and tire set to swap out.
This is 100% normal and abnormal in cold temps, Porsche, and 20" wheels.
03-18-2018, 11:51 AM
#11
Rennlist Member
03-18-2018, 12:09 PM
#12
Banned
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Start parallel parking.
03-18-2018, 12:41 PM
#13
I did, but just wanted to make sure this was absolutely normal.
(https://rennlist.com/forums/991/1051...o-excited.html)
(https://rennlist.com/forums/991/1051...o-excited.html)
(Occasionally someone cites Ackermann https://en.wikipedia.org/wiki/Ackerm...ering_geometry nope, sorry, wrong.)
Caster angle, when driving straight ahead, produces a force that makes the wheel want to go straight ahead. So, stability. It also means turning the wheel requires force. And the more you turn, and the more traction you have, the more force required. So, steering feedback. Good stuff.
Going backwards however, caster angle creates a scrubbing action. Just look at a diagram, its pretty evident. Again, all cars have caster angle. They all do this. How obvious it is depends on a lot of things like how hot or cold the tires are, width and profile, tread blocks, road surface, bunch of things. Nobody ever notices the family sedan does this, the overall cushyness soaks it all up. Hardly anyone even notices that their 911 does this all the time. Until it gets cold, or the road surface and angles are just right, then all of a sudden something that was always there pierces their consciousness and WTF was that?! Something, trust me, that always was and always will be there.
03-18-2018, 01:52 PM
#14
Racer
Thread Starter
Absolutely normal. In fact all cars do this to some extent. Its due to suspension geometry called caster angle. https://en.wikipedia.org/wiki/Caster_angle
(Occasionally someone cites Ackermann https://en.wikipedia.org/wiki/Ackerm...ering_geometry nope, sorry, wrong.)
Caster angle, when driving straight ahead, produces a force that makes the wheel want to go straight ahead. So, stability. It also means turning the wheel requires force. And the more you turn, and the more traction you have, the more force required. So, steering feedback. Good stuff.
Going backwards however, caster angle creates a scrubbing action. Just look at a diagram, its pretty evident. Again, all cars have caster angle. They all do this. How obvious it is depends on a lot of things like how hot or cold the tires are, width and profile, tread blocks, road surface, bunch of things. Nobody ever notices the family sedan does this, the overall cushyness soaks it all up. Hardly anyone even notices that their 911 does this all the time. Until it gets cold, or the road surface and angles are just right, then all of a sudden something that was always there pierces their consciousness and WTF was that?! Something, trust me, that always was and always will be there.
(Occasionally someone cites Ackermann https://en.wikipedia.org/wiki/Ackerm...ering_geometry nope, sorry, wrong.)
Caster angle, when driving straight ahead, produces a force that makes the wheel want to go straight ahead. So, stability. It also means turning the wheel requires force. And the more you turn, and the more traction you have, the more force required. So, steering feedback. Good stuff.
Going backwards however, caster angle creates a scrubbing action. Just look at a diagram, its pretty evident. Again, all cars have caster angle. They all do this. How obvious it is depends on a lot of things like how hot or cold the tires are, width and profile, tread blocks, road surface, bunch of things. Nobody ever notices the family sedan does this, the overall cushyness soaks it all up. Hardly anyone even notices that their 911 does this all the time. Until it gets cold, or the road surface and angles are just right, then all of a sudden something that was always there pierces their consciousness and WTF was that?! Something, trust me, that always was and always will be there.
Curious - why can't Porsche solve this?
03-18-2018, 01:53 PM
#15
Three Wheelin'