car and driver tests different wheel sizes.

http://www.caranddriver.com/features/10q1/effects_of_upsized_wheels_and_tires_tested-tech_dept
ill read it later. but it might be interesting

Skipdpad only for traction tests, no slalom, done on a slow and loose car, the base golf 2.5/automatic, pretty useless article IMHO, they were on the C&D loop, but only for economy testing, and they used a much stickier tire compound on the 18s and 19s than on the 15s through 17s.

 Here is the value of these tests. There are different people all over the web making blanket statements like  "I always knew big tires suck" etc, etc.... In my opinion there is more to be learned from finding where something did not perform well.

 Here are the conclusions that immediately came to my mind. We know that rotating mass absolutely makes a difference.

Accelerating:
We see that by watching this test, along with the fact that the stickier tire compound helping this underpowered car from slipping the tires in the first 10 ft. With the largest tires not being soft compound, slowing down. So the deepest conclusion would lead us to the conclusion that that the wider tire has a less pliable tread and did not conform as well to the surface as the smallest tires, therefore losing traction because there is actually less contact. This is why race slicks are 2 ply.... Better contact patch. At the same time could not overcome the added rotating mass. There is also the consideration that there was too much camber in the car for what the stiffer tire wanted for max flatness. This is even more critical on front drivers.

Braking:
Similar to acceleration except for the possibility the bigger tires caused more brake dive, unloading the rear wheels, and caused a loss of rear braking bias due to extra anti-lock "activity"

Skidpad:
Same again, but leads me more to the alignment question. There is no way the wider stiffer tires want the same alignment. These guys could have used tire temps to optimize the alignment, and the difference would have been FAR greater. Steady state testing of anything is incomplete at best, but can still offer good indicators if you gather the right empirical evidence and keep written records.

Fuel economy:
Wide tires are notorious for bad aerodynamic behavior(especially on a non lowered vehicle), add in big open wheels (instead of flat discs), and increased mass...... Again, no surprises.

My opinion:
I feel these guys really missed the boat on + size wheel/tire sales by virtue of inadequate knowledge or preparation. This article was written by people or for people with a lack of knowledge, or don't have the intellectual chops to be able to apply anything other than simple minded blanket statements.

The cool thing is that there was enough information for us tech/ racer types to make substantial improvements. It is amazing how any of us would have found substantial improvements over what they found. The scary thing is these guys are "pros" that do nothing more than help spread ignorance, and actually reverse the learning curve of the inexperienced, just to fill magazine space and pimp their sponsors.



 As a side note- skidpad tire temps and speed are an awesome way to baseline your vehicle by doing left and right steady state passes to get the best balance of tire temps. That will give ideal alignment settings. Then you have a baseline to start adjusting the shock/spring/swaybar and chassis stiffness for "dynamic" behavior. Once the dynamic behavior is to your liking, go back to the skidpad to ensure that is still optimum.

You obviously don't know much about these golfs, traction was not an issue during this test, I can guarantee it. The stock 195s had more than enough traction. The loss of acceleration and braking was due solely to increased mass and increased tire height. Your conclusions might be applicable if on a modified vehicle, but these Golfs just don't have the power to get that much mass moving or stopping very quickly.

I don't usually get in a Bic lighter with wheels unless it's turbo'd