03 XLT with New 17" Wheel/Tire Problems

Great Forum!!
I just changed my stock 16" wheels and Michelin Cross terrain 235/70/16's for some great looking wheels through Discount Tire. The wheels are MB Wheels, 17" 'Gunner 5's and I opted for the exact same tire in the appropriate 245/65/17 size. Sidewall drops only about 5mm and as my old tires had hardly any tread left, I expected similar or better ride quality. The wheel offset is -6 ... so vs my old wheel standard offset, they sat another 2 to 2.5 inches wider in the arches - looked great without encroaching outside the arches.
UGH!- Performance was another thing!

Discount tire had 3 attempts to balance them and failed (steering wheel shimmy at 75mph).

Ride quality over any sort of bumps was harsher. It felt like they were over inflated yet I ran them at the same 30psi/35psi pressures front/rear.

These wheels were NOT hubcentric. While that 'may' have been the balancing problem I doubt that would cause the harsher ride.

Sadly, I ended up returning them all for a refund and I'm back to my boring standard wheels and tires

HAS ANYONE GOT ANY SUGGESTIONS WHY RIDE DETERIORATED ? COULD THE INCREASED OFFSET ACCOUNT FOR THAT?
SHOULD I ONLY CHOOSE HUBCENTRIC WHEELS ?
ANYONE ELSE HAD A SIMILAR EXPERIENCE?

Advice is greatly appreciated.
simonusa0 is online now Report Post Edit/Delete Message

 

[Donner]

Installers...

As long as the installers know what they are doing, there should be only an improvement in ride quality... However, mine came with 17" stock, and offsets I can't address... but my rims have been changed and my tires are 265/70/r17... I have no ride quality issues. Shop around for a tire dealer that can get you where you want to be...

 

[sjr033]

our new tires have a high load rating at a lower psi. Basically a stiffer side wall. That with the lower sidewall height causes a stiffer/harsher ride.

 

[Donner]

Our tires?

our new tires have a high load rating at a lower psi. Basically a stiffer side wall. That with the lower sidewall height causes a stiffer/harsher ride.

May I ask, are you an employee of the above named tire store, or are you with the poster? Thanks!

 

[sjr033]

Just a poster. Sorry I ment to say your not our.

 

[Donner]

No problem!

I'm just a poster too It's allll good! But keep talking, it sounds like you know what the issue is... teach!

 

[sjr033]

It is the same thing as when someone goes from say a 30" tall tire on a 15" to a 35" tire on a 15" rim. There is more sidewall, so the ride will be more "mushy" and not handle corners as well. Being that he decreased the side wall the ride is rougher (there is not as much tire to take the shock of a bump) and a tire with a higher load rating means it has a stiffer side wall to support more weight. For example an Expedition or F250/F350 usually run a higher load rated tire to support the carrying capacity and the heaver truck than say a Ranger. Looking at the web site the increase in load rating is not much but you need to mutliply it by 4. At the decrease in side wall is again not much. But I bet the 2 things together is the cause.

 

[simonusa0]

Sidewall and load rating

SRJ thanks , greatly appreciated the advice and teaching. (and others who posted)

I am still a little confused.....sure, I know any decrease in sidewall means a decrease in bump absorption capability (ride) but with a probable improvement in cornering - apples for apples. In this case the sidewall heights calculate at 159.25mm vs 164.5mm , or only a 3% reduction and that doesn't appear significant. Also going to a new tire with a lot more tread and absorbing rubber I'd think that would also help cushion the ride. Actually my all season 18" tires on my Z4 with 225/35/18 and 255/30/18 rears give a better ride!!

Most interesting though is you mention that the load rating and so sidewall stiffness is higher...yeah that will do it....so since this is supposed to be the same brand and type of tire why is the load rating different and the sidewalls so much stiffer? Did Michelin deliberately stiffen the sidewalls up so much going from the 235/70/16 to 245/65/17's? Do they make these tires in different speed ratings but same size? I can't imagine Ford would release the 17" wheel option with a drastic ride deterioration.

I'm not trying to be clever or argue ...just understand. Thanks again!

 

[stang7tl]

is your 03 a explorer or the explorer sport trac truck and how far out did the rim come the reason for I am asking is that i have a 01 sport trac truck and about to buy new rims and tires I have 3 that i like one is 16x8 with a -6 offset and the other is a 17x9 with a -12 offset or i can get a 18" with a 0 offset and my stock ford rims say they ar a +12 offset so i want to bring my wheels out about a inch or 2 past the fender and i am going to go with a 265-75 tire intell i put a body lift and then a 33" tires then some time
so if anyone has any advice
thanks