Traction difference between 225 and 205 tires

**spetz** · 07-01-2012 08:10 AM

Hi guys,

Assuming all thing equal, how much of a traction advantage would 225 wide tires have over 205 width?
So, same car, same tire (bar width), same sidewall height etc.

Thanks

**trism** · 07-01-2012 09:02 AM

Well. You can't really measure it. But of course the wider tyre will have more traction.

This is a bit of an odd question...

**DakDak** · 07-01-2012 10:13 AM

Are you asking same width rim? Like say a 8 inch rim with 205 or 225?

**Oz_Striker** · 07-01-2012 10:32 AM

Definately depends on what width the rim is

**bennjamin** · 07-01-2012 10:38 AM

It's like 11% wider...so that's like 11% more grip. Ofcourse there is a million other variables like tyre pressure , sidewall height , tyre compound tyre depth tyre age , car power , car corner weight etc

But a very vague answer to your very vague question is YES. A wider tyre than initial on the same rim will provide more grip

**dc2r-0636** · 07-01-2012 11:50 AM

yes of course it will give more traction.

what would be widest tyre you could put on a stock 15" dc2r wheel (i believe theyre 6" wide?) would it be 205 or 215..

**hondapop** · 07-01-2012 12:30 PM

Personally on 6" I wouldn't go any more than 205 (I'm going 205 on 6.5") 'cause you'll lose sidewall stiffness and they'll be a bit "balloony", softer riding maybe but not as good directionally.

**spetz** · 07-01-2012 09:33 PM

What about in terms of 60ft times, does anyone know if there would be much of a difference?

And why would rim width play such a big role, as for example couldn't both 205 and 225 tires be mounted on 7" rims?

**hondapop** · 07-01-2012 09:49 PM

Well I guess if 195's can be fitted to 8" rims, 7" shouldn't be a problem. As far as what difference it would make in such a short distance, I guess the proof of the pudding would be in the eating.

**dc2r-0636** · 07-01-2012 11:03 PM

I pulled a 2.1 60ft with 195/55/15 on toyo r1r

**Rayle** · 08-01-2012 09:37 PM

Given the same car weight and tyre pressure, a larger tyre width does not mean there will be a larger contact patch with the road. The contact patch will be the same area, but of a different shape, becoming shorter and wider as the width increases.

One of the reasons a wider tyre provides more grip is because since the contact area is shorter, meaning less tyre deformation thus giving less rolling resistance and creating less heat. A round tyre with a 10cm long contact patch will obviously deform more than one with a 5cm long contact patch since the contact patch is in contact with the ground, and therefore flat.

Additionally, the shorter contact area has more time to cool before it is in contact with the ground again. As the rubber heats up, after a certain point its grip will diminish as it gets hotter and hotter. This is another reason why wider tyres can be more grippy.

At the end of the day, though, you'll probably notice a much bigger difference if you just change your tyres to a softer, stickier compound.

You could also decrease your tyre pressure to increase the contact area, but that's a whole 'nother can of worms.

More info can be found at http://www.carbibles.com/tyre_bible_pg3.html or
http://www.eng-tips.com/viewthread.cfm?qid=102250. There's an interesting post about 3/4 way down the latter link about how wider tyres may provide more grip on the limit, but breakaway much more abruptly than narrower tyres...

**hondapop** · 08-01-2012 10:14 PM

It seems though that the OP's interest lies in drag racing and not in whether there will be better handling. I think he's hoping that someone will give him their winning formula which they have gone to great lengths and probably expense to prove for their own benefit. Apart from all the variables that have been mentioned by posters to this thread that might affect his own car, the nature of competing and competiveness would probably mean such findings would be closely guarded secrets.