View Poll Results: Do wider tires/ on wider wheels increase contact patch, all else the same (pressure e
Yes
49
74.24%
No
17
25.76%
Voters: 66. You may not vote on this poll
Does added tire width actually increase contact patch?
#31
Burning Brakes
If you measure the air pressure in your now-deflated tires when the load from the vehicle is applied, is it any different from that when the vehicle weight is removed ? No.
Red herring.
#32
...which allows the sidewalls to deform more, which allows them to bend more, which allows the horizontal centerline of the tire to drop.
If you measure the air pressure in your now-deflated tires when the load from the vehicle is applied, is it any different from that when the vehicle weight is removed ? No.
Red herring.
If you measure the air pressure in your now-deflated tires when the load from the vehicle is applied, is it any different from that when the vehicle weight is removed ? No.
Red herring.
cherry picking what people say, out of context, and then quoting it back to them along with your own opinion hardly advances the sum total of knowlege.
my point is that how much the tyre is inflated can alter the shape of the contact patch.
Imagine a balloon half inflated, resting on a level surface, the contact patch is tiny. Now rest a weight on the balloon and the contact patch increases in size. Finally, increase the amount of air in the balloon and the contact patch will become smaller.
R+C
#34
Burning Brakes
If you were referring to my initial reference to one item in the first "wanna911" post, then I still don't understand your point. If we're going to consider a 'real' tire, then #2 on his 'keep this in mind' list needs to be refuted. You won't get a proper analysis of the mechanical system know as 'tire' if one of your basic assumptions ("keep this in mind" sure does sound like a list of basic premises) is faulty.
#35
ALL other things being equal the area of the contact patch is the same.
The shape is different.
The wider tire has a shorter but wider contact patch. This is desireable for a performance car because it runs at a lower slip angle than the longer narrower patch of the narrower tire.
The lower slip angles allows the tire to generate more cornering force and run cooler.
In addition the slip angle vs lateral force curve is non linear and varies according to the shape and construction of a tire. The wider tire has a curve that is more favorable for generating lateral forces.
The shape is different.
The wider tire has a shorter but wider contact patch. This is desireable for a performance car because it runs at a lower slip angle than the longer narrower patch of the narrower tire.
The lower slip angles allows the tire to generate more cornering force and run cooler.
In addition the slip angle vs lateral force curve is non linear and varies according to the shape and construction of a tire. The wider tire has a curve that is more favorable for generating lateral forces.
I was actually just reading about this in Carroll Smith's "Drive To Win" last night... fabulous book...
#36
Generally speaking, people who race cars prefer tyres which are as wide as allowed by the regulations and the limitations of their suspension system.
Having done this, efforts are devoted to finf´ding the best suspension set up in terms of camber, toe, ARB, spring and shock settings and tyre pressure, hot and cold.
My understanding is that the science behind what works and what doesn't work in tyre design is still imperfectly understood. Everytime I look at a race team budget I have to sit down before I look at the line called tyre testing.
Faux de mieux, design of GT cars is pretty damn simple, we make them as wide as possible with a long wheelbase, big overhangs and the widest tyres allowed. The Maserati is a good example. We then stick on the biggest wing allowed, twist the rules about the underbody and borrow a fork lift truck if any 'remodelling' is required.
At the same time it is most important to get on the most favoured customer list with the tyre supplier, remember X may supply 10 teams but only 3 will have the best tyres.
Most favoured status with the tyre supplier is really important, right up there with getting rid of drivers who crash the car and sponsors who don't pay.
I think that it is pointless getting theoretical about tyres when an empirical approach is adopted by the experts.
R+C
#39
Burning Brakes
Re: tire widths - I'll differ with you just a bit - 'as wide as possible' isn't always best. Low horsepower cars will struggle if they carry too much tire. Inability to get tires up to design temperature, excessive rolling resistance, etc. can conspire to raise lap times as tires get wider. Lack of access to tire manufacturers inner workings means that most of us have to 'run whatever's on the tire truck', and that means that we'll get compounds and constructions that aren't always ideal.
#40
#41
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
ALL other things being equal the area of the contact patch is the same.
The shape is different.
The wider tire has a shorter but wider contact patch. This is desireable for a performance car because it runs at a lower slip angle than the longer narrower patch of the narrower tire.
........................
The shape is different.
The wider tire has a shorter but wider contact patch. This is desireable for a performance car because it runs at a lower slip angle than the longer narrower patch of the narrower tire.
........................
#43
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
#44
Race Car
Thread Starter
Join Date: Apr 2005
Location: With A Manual Transmission
Posts: 4,728
Likes: 0
Received 2 Likes
on
2 Posts
Like what? The test clearly shows that the wheel diameter, tire type, Inflation PSI, and weight applied are the same. It was done to show this exact thing, so why would it be different, tire company had nothing to prove.
I think there are more factors with complex tire designs to be determined by a simple equation.