All season tire advice

celeron_266

Hello all,

Background - my car is an 2007 BMW 323i, tire size 205/55R16, 55000km and needs a tire change, all seasons with good wet traction, ideal if it has some capabilities in light snow, V-speed or higher

I will be ordering tires through tire rack and pick up myself at the border
I do not want run flats

Past tire experience (on other cars)
1.  Pilot sport (summer) - awesome tires, love it
2.  Bridgestone Turanzas (Run flats/non-run flats) - loud tires, reasonable traction
3.  Dunlop signature - similar to bridgestones in terms of traction, but significantly quieter
4.  Falken 912 - quiet, good dry traction, but sucks in rain/snow

After some research, I find the following to be pretty good options
1.  Continental ExtremeContact DWS
2.  Goodyear Eagle GT
3.  Hankook Ventus V4 es H105
4.  Kumho Ecsta ASX KU21

I understand that the korean tires (kumho/hankook) are at a completely different price point compared to the Goodyear/continental, I actually am not sure if the extra $20/tire will give me a significant difference in terms of performance.

So...which one should I go for?...or should I consider something else?

thanks in advance!!

Lik

Stock class autox-ers regularly run the widest possible tire they can find on their stock-sized wheels, and these guys are the ones who care the most about lateral grip. So you can expect the 225 tire to have more ultimate lateral grip than the 205 even though the sidewall support is poorer. On the other hand, you should also expect poorer steering response (more vague, greater delay as there is more sidewall flex in the tires) from the wider tire.

Either will be fine for street use, but I wouldn't bother with the 225 tire since the 205 tire will be cheaper. But seriously, on the street, I'd rather have sharper steering response since you would rarely need the slightly higher grip levels of the wider tire anyway.

-Lik

celeron_266

Minor correction here:

When you go with a wider tire on the same car, the contact patch doesn't ne ...
Lik 發表於 2011-7-16 21:26

    this probably applies to when there is equal sidewall support for both tire widths, but like you said in a previous post, i only have one set of tires (7Jx16), and putting 225mm tires into 7in wheels will reduce sidewall support for a bit, resulting in tire deformation during turning, how will this counteract the increased lateral acceleration provided from the wider tires?

Lik

If you pay attention to how your car responses when you are behind the wheels, then yes, you will notice a difference. If you enjoy spirited drives, then yes, you will notice them. If you track your gas milage, then you will also notice a few percents' worth of differences. Heck, whenever my car gets an oil change done, I notice the minute difference in my car's throttle response and smoothness too.

But if you are a typical Richmond C9, then ha, you probably won't notice it la~

-Lik

celeron_266

i am starting to think with all these precision analyses...they may apply to racing conditions...but everyday use..even with spirited driving style...it wont really make a difference....

Lik

so mr. lik i think you are correct, the distortion of the tires basically cancels the positive effect of the increased footprint from the wider tires, resulting in no increase in cornering ability....
celeron_266 發表於 2011-7-11 23:55

Minor correction here:

When you go with a wider tire on the same car, the contact patch doesn't necessarily increase in size. However, the shape of the contact patch will change. The thing to keep in mind is that the contact patch is dependent on both the tire size and just as importantly, the weight of the vehicle. In Celeron's case, the vehicle weight change is, for all practical purposes, negligible regardless of whether a 205/55/16 or 225/50/16 tire is used. Since the vehicle weight is the same, the pressure on the tire is the same. With a narrower tire, the contact patch is gonna be longer and skinner (narrower). With a wider tire, the contact patch is gonna be shorter but fatter (wider). So the shape of the contact patch changes, but it is not clear which contact patch has a larger overall area. What would happen though is, the narrower tire should actually have a better longitudinal acceleration (accelerating in a straight line) but poorer lateral acceleration (turning). The reverse would be true with a fatter tire.

Essentially, it's a tradeoff between longitudinal acceleration vs lateral acceleration.

-Lik

satil

use Yokohama Avid Enviger V for summer and Nokian WRG2 for winter here.
no 'real' all season good in SNOW.

celeron_266

quoting from http://www.carbibles.com/tyre_bible_pg4.html

A rim that is too narrow in relation to the tyre width will allow the tyre to distort excessively sideways under fast cornering. On the other hand, unduly wide rims on an ordinary car tend to give rather a harsh ride because the sidewalls have not got enough curvature to make them flex over bumps and potholes.

so mr. lik i think you are correct, the distortion of the tires basically cancels the positive effect of the increased footprint from the wider tires, resulting in no increase in cornering ability....

celeron_266

7Jx16 wheels with 205/55/16 tires (323i no sport package)


7Jx16 wheels with 225/50/16 tires (323i sport package)


i guess pretty hard to see the oversize tire bulging at this view...

Lik

You can still mount 225/50/16 on 16x7 wheels, but the tire will bulge out a bit, and sidewall support will be a bit lacking, so steering feel, reaction time will suffer a bit as the car's reaction feels a little more rubbery. For a street car, I wouldn't bother la. Just stick with 205/50/16 bah la.

If you want to use 225/50/16, 16x8 is the size you want, although 16x7.5 would be acceptable as well. But the problem is, 16" is not a popular wheel size. Selection is a lot better with both 15" and 17".

-Lik