First off, this is here so it gets a lot of views, probably be moved shortly after.

Here is my aol convo with mike:



RevvinRx7: can't remember the thread but some guy at the club was making like BIG HP numers

RevvinRx7: numbers and he had 205s on his car???

RevvinRx7: and he was getting traction control

RevvinRx7: wtF?

RevvinRx7: why wouldn't he get bigger tires???

j9fd3s: haha

RevvinRx7: http://www.rx7club.com/forum/showthread.ph...25&pagenumber=3

RevvinRx7: RICE RACING

j9fd3s: bigger tires dont equal traction

RevvinRx7: what?

RevvinRx7: how so?

RevvinRx7: im a little lost mike

j9fd3s: think of it like a knife

RevvinRx7: ok

j9fd3s: big tires = dull knife

j9fd3s: sorta

RevvinRx7: thats what my dad said too

RevvinRx7: i was like wtf dad?

j9fd3s: haha

RevvinRx7: so why do people put bigg ass tires on their cars then?????

j9fd3s: to a point bigger is better

j9fd3s: cause they dont know

RevvinRx7: huh

RevvinRx7: damn I really am just starting to learn.

RevvinRx7: so whats the limit of how big a tire can be before it won't provide better traction?

j9fd3s: it depends on the car

j9fd3s: like the spring, how much it wieghs

RevvinRx7: is this only true on street tires?

RevvinRx7: or all tires...

j9fd3s: it works for all tires

RevvinRx7: so why do funny cars/drag cars have HUGE tires

RevvinRx7: like 345-400

j9fd3s: cause they can make it put more rubber down

RevvinRx7: cuz they have a lot of power?

RevvinRx7: i don't realy know what you mean by that

j9fd3s: cause they get the tire to deform

RevvinRx7: ah yea, but i thought the deforming part was to get even more contact patch

j9fd3s: yah

RevvinRx7: more contact patch = more traction, wider tires = more contact patch????

RevvinRx7: thats how i always thought

j9fd3s: kinda

RevvinRx7: I just don't understand

RevvinRx7: i see how my car burned rubber like a mofo

RevvinRx7: cuz it has 205s

j9fd3s: yah its kinda of a grey area

j9fd3s: yah

RevvinRx7: so if i threw some 265s

RevvinRx7: it would hookup right?

j9fd3s: maybe

RevvinRx7: damn im starting a thread about this



I have always been under the impression that widder tires will always provide better traction, hence watching races/fast cars and they always have huge tires. Then I read what Rice Racing said and I was dumbfounded. So can anyone elaborate or help me explain why wider tires don't always provide better traction? I just don't want to get some wider tires and be wasting my money...

damn that just confused me

I think I understood it.. only problem is each car is going to have different power.. which will cause a different "tire limit." So.. there's not going to be any real guideline.. I don't guess.. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

Wider tires? Couldn't hurt. https://www.nopistons.com/forums/pub...#>/biggrin.png



A set of wide hard, cruddy tires won't hook up as well as narrower sticky tires that are made to hook up well in a straight line. But that's just a generalization. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

yeah thats what i thought too

no no no the thread about the wider tires not equaling traction was started by marcus williams. it had a link to a page with a 68 mustang twin turbo small block that was running 205 tires. the mustang owner was an engineer for garret and he proved through mathmatical formulas that the small increase in traction you get from wider tires is negated by the increased rolling resistance.



he had done acceleration tests with an accelerometer and proved it



i'm too lazy to search for it now, if nobody else posts it by tomorow, i'll find it and post here

heres the thread, the link that he posted is down, but you can read the discussion in the thread



http://www.rx7club.com/forum/showthread.ph...threadid=123741

misleading thread..

wider tires does mean wider contact patch..

does it mean more power to the ground... yes..

great deal of factors involved to consider when discussing efficiency of the power transmitted..

coefficient of rolling friction on a tire...suspension geometry.. psi...tire compound..sidewall rigidity..application...

to basically make a statement that bigger tires dont equal traction

and that it works for all tires is vague..and misleading....

in a sense there is some truth in the reference above of wider tires equals dull knife...

which is applied to mud and snow traction....

if the power remains static...

although consider the conservative limitations for tire application ...

versus the aggressive amount of power you can provide...

its all relative...

This is what happens when people try to apply something they heard in physics class to the real world. https://www.nopistons.com/forums/pub...DIR#>/wink.png

race tires: traction is very dependant on temperature. If the tire is too wide for a light weight car then the tire will never get up to temperature, and never produce it's maximum grip. For most production cars this is never a problem. 315's on a 1500 lb. 75hp civic might fall into this category... Why do you think drag racers do a burn out... to get the tire HOT!

street tires: designed to work over a wide range of temperatures, so you don't have to get the tire hot for it to grip. There for weight is not a big factor... so just get the widest tire you can fit under your car and go have fun. https://www.nopistons.com/forums/pub...#>/biggrin.png

that garrett guy is nuts, but he's right



mike

here's a working link to the hot rod article here



mike

wow great responses thxs guys!

im lost...... maybe i should take physics again

I loved smashing this misguiding piece of info in physics class earlier this year. https://www.nopistons.com/forums/pub...#>/biggrin.png

In theory, theory and practice are the same. In practice, they are not.



It's annoying when people throw out a bit of knowledge they just learned in school and try to explain stuff with that. But most of that stuff should remain in the classrooms.

There is this one guy that I remember, that read a few books on suspension and knew some physics. He though he'd apply that to his street car. I don't know if he ever did any of the stuff he said he was going to do. But his thing was, if it worked on this sort of car (think F1) then why couldn't it work on his car (think POS). Unfortunately, everybody that replied to him did not have the doctorate in physics that he needed in order to believe anything anybody wrote. In spite of all the real world advice he got, it didn't seem to sink into his head that maybe he should follow some sound advice instead of chasing general theories about how suspension works. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

One concept which helps here is to think of the number of pounds per square inch of contact patch. A narrow tire has a small contact patch, but the psi is pretty high. Put really wide tires on the same car and you have a bigger contact patch, but the car weighs the same, so your psi is much lower. Remember this has nothing to do with tire inflation pressure, which is a different thing altogther. As with all things, there is a point of diminishing returns. Wider is better to a point.