How much does the weight of your wheel and tires play on braking and accelerating?

[docjohn]

Quote by v12nsx"After all, it's much lighter than our cars".Actually P.D.'s car wieghed up to 3100lbs! with his rewards wieght.That makes his crews susp. tuning even more amazing.

 

[Andrie Hartanto]

Originally posted by gheba_nsx:
Lud, exactely my point. The wider contact offer more friction between the tire and the ground.

The wider contact does not offer more friction. The formula of friction is:

Friction = Coefficent of Friction X Normal (force acting perpendicular to working surface)

Wider/more rubber simply means it won't wear as much, as the force is distributed to a larger area.

I think the contact patch should vary at speed. Simply because of downforce created.

 

[Andrie Hartanto]

Originally posted by The DON:
IMO, I think us weekend warriors shouldn't worry much about the weight of the wheels and tires so much. It's quite insignificant unless your wheels alone are like 40lbs each or something.

For me, these are the rules I go by:

1. Learn to drive the car at the limit in stock form.
2. Beef up the suspension and use sticky tyres. Learn how to drive the car with the new mods.
3. Change to a well balanced big brake kit (front and rear). Again, learn to drive the car with the mods.
4. Lastly, explore options for hp gain.

YMMV

The Don

BEST ADVICE SO FAR!!

 

[Jimbo]

Is Gheba referring to "rolling resistance"?

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
1976 Honda Accord 5 spd, 3 door Blue/Blue
1977 Honda Accord - Custom - Under Construction
1986 Chevy Suburban
http://homepage.mac.com/jimanders/PhotoAlbum1.html

 

[sjs]

Originally posted by gheba_nsx:
sjs,

here are some lecture about wide tires and improved braking:
http://www.vdat.de/prg17e.htm
http://www.datsuns.com/Tech/tech_tires-2.htm

Having taken the time to reread the test article I see that they didn’t use the same tire in different sizes (hence the repeated use of the term “tuner/tuning” tires). They used 195/65 R 15 Dunlop SP Sport 200 and 225/40 ZR Dunlop SP Sport 9000.

Well heck, that’s got to account for some of the improved braking, maybe a lot of it. R rated tires are typically much harder than VR tires, not to mention they probably have different carcass construction, tread pattern etc. And the wet tests are even less reliable. So much for scientific studies!

I take back what I said about it being a good article.


[This message has been edited by sjs (edited 28 November 2002).]

 

[nsxtasy]

Originally posted by docjohn:
P.D.'s car wieghed up to 3100lbs! with his rewards wieght.That makes his crews susp. tuning even more amazing.

Keep in mind that his car has had a full roll cage added. Does that 3100 pounds include the weight of the driver, too?

Originally posted by Andrie Hartanto:
Wider/more rubber simply means it won't wear as much, as the force is distributed to a larger area.

I think the contact patch should vary at speed. Simply because of downforce created.

Originally posted by Andrie Hartanto:
Wider/more rubber simply means it won't wear as much, as the force is distributed to a larger area.

Wider does not mean more rubber in contact with the road. It means a different shape of rubber.

Originally posted by Andrie Hartanto:
I think the contact patch should vary at speed. Simply because of downforce created.

When downforce is created, it's just like adding weight to the car. Yes, it will increase the size of the contact patch - but this is true regardless of whether the tires are wide or narrow.

 

[docjohn]

Yes Ken that is with driver and fuel.Last season it was interresting to watch how the weight slowly degraded P.D.'s performance at the max penalty, he was able to hang in the top 5 though.Also it was nice to see the trouble Probst had when he had weight piled on.

 

[Andrie Hartanto]

Originally posted by nsxtasy:
When downforce is created, it's just like adding weight to the car. Yes, it will increase the size of the contact patch - but this is true regardless of whether the tires are wide or narrow.

But if the tire is narrow, it might be under sized for a given weight.

 

[nsxtasy]

Originally posted by Andrie Hartanto:
But if the tire is narrow, it might be under sized for a given weight.

It will still have the same size contact patch.