Wider is better some of the time

    Most of the time a wider tire will offer better performing and cornering but, not always.  Without the correct supporting parts and hardware wider tires may not always produce the desired results.

   While at a driving school in Utah I was able to participate in an interesting exercise involving different tire and wheel sizes.

    Three identical Ford Mustang GT's were outfitting with different tire and wheel packages.

Car #1 was fitted with OE 17x8 wheels with 235/55-17 tires

Car #2 was on 18x9.5 Ford wheels with 245/45-18 tires

Car #3 sat on the same 18x9.5" wheels with 285/40-18 tires

    We then ran them through and AutoX course. The results surprised most of the participants.

Car #1 predictably under-steered but, was easy to control and push to the limits of traction.

Car #2 was razor sharp when responding to any driver input. It offered the best feedback allowing for the fastest lap times for all of the participants.

Car #3 while offering more grip in steady state cornering, felt very vague and disconnected from the driving experience. All driver inputs were met with delayed response and a sluggish feel. When you are missing your marks due to sidewall deflection inconsistencies it can be very unnerving especially at speed.

So, in the end the 245 width tire on car #2 was able to turn faster laps than car #3 even thought the tire was about 1.5" narrower. From an appearance stand point those 285's on car #3 did have an aggessive stance.

My name is Luke Pavlick and I am a Car Guy


Tuesday, August 18, 2009 by Mike

Wouldn't the 40 aspect be a stiffer sidewall than the 45? Or is the 285 width too much grip? Would you expect a 285 30 to respond the same?
Wednesday, August 19, 2009 by Luke Pavlick

The aspect ration of a tire is a percentage of the width so the sidewall height differences between the 245/45 and 285/40 tire is only 3.75 millimeters. What was causing the sluggish response exerienced when driving the 285 tire was the sidewall roll and deflection because it was so much wider than the wheel. The 245 tire was not was not experiencing the roll and deflection because they almost the same width as the wheel making the sidewall stand straight up as opposed to being pulled into the wheel lip. thanks for the quesion and thanks for reading my blog
Saturday, November 15, 2014 by Jared

This was informative. Thanks!
Going with equal width.
Monday, September 21, 2015 by Bob

I know this article is 6 years old, however it raises more questions than it answers. I hope someone can take some time to help me here.
1) Were all 3 tires the same brand and model, other than size?
2) What were the lap times or placement for all three?
3) I am somewhat familiar with the affects of a tire that is too wide for the rim, but I am now curious about the affects of aspect ratio. Although related, what is more influential, the aspect ratio of the tire or the sidewall height? For example a 215/50 and 235/45 have nearly the same height, but different ratios. Mounted on an appropriately width rim, would the flex or responsiveness be the same or feel different?
4) I am planning on buying a car that will come with 235/40r18 and I am concerned that such a low tire will lack progressive feedback in cornering. Exceeding the grip limit with little warning is not pleasant, even if the tire offers tons of grip till it gives up.

Thankyou for your time if you respond

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