Learn from this Mistake!

[Wizco]

Originally Posted by jwight

Correct me if I'm wrong here, but wheels don't have profiles, high or low. A 15 in wheel is a 15 in wheel. Tires do have profiles, as indicated by their designations; a 70 series tire is high profile - more distance between the inside and outside diameters. A 35 series tire is low profile - less distance, therefore less "give" to protect the wheel rim from potholes, etc.

A 15" wheel is indeed a 15" wheel. (There are different offsets and widths to contend with, but that has nothing to do with tire size.

The "series" of the tire is a measure of sidewall to tread ratio (aspect ratio).

A 15" wheel with a 175/55/15 has a 3.8" sidewall. A 15" wheel with a 195/55/15 has a 4.2" sidewall, but of course the diameter is now larger as well.

A 205/45/15 has just about the same sidewall at 3.6" as the original 175/55/15, but has a 45 vs 55 aspect ratio.

This page, Tire size calculator , contains a pretty useful tool for understanding what different tire/wheel sizes will change.

And yes, all things being equal, a taller sidewall will protect a given wheel better than a shorter one. As in the Mazda 3 example, the stock tires on the wagon are 205/50/17, with a 4" sidewall. The 205/55/16's are the same diameter, with almost a 1/2" more sidewall.

[SmartOwner]

Originally Posted by Fredvon4

Connecticut SmartOwner

I would get that front end checked...Hard to believe a smack that hard did not tweek the strut and associated components in some way

I intended to ask them to do whatever checks they're capable of, & will then pull the wheel & go from there myself.

The sharpness of the edge of the pothole, the "right in between the spokes", the yield strength & elongation of cast aluminum (approaching Play-Doh) = folding the flange open like the lips of fish. The aluminum did a tensile split of about 3/8" @ the outer flange. The wall thickness is in keeping with the car...

In short, It was ugly, I think it was a good "fuse", will thoroughly check it anyway.

I would be interested to get some intelligent feedback on front tire pressure. Car was delivered with 36 psi front cold & door jamb says 29 psi. I backed it down to 30 on the belief that possibly there would be an understeering preservation for Her Wifeliness @ the limit. I don't see her at the limit, but then again she didn't see the pothole.

So what are the thoughts? Run +5 to +7 psi up front for a better margin against potholes (at the expense of ride also), or leave it the hell alone & sign up for the dealer's wheel protection plan?

[SmartOwner]

This is just a follow-up to the post urging you to be ever mindful of potholes:

The bill for 2 new wheels, inspection & labor was $822.00.

The good news is that you can prang the wheel pretty damn hard & do nothing to the suspension.

Not that you should, just so you know. The little beasts are pretty rugged.

The $325 (for 5 yrs.) wheel & tire protection package the dealer offers is looking pretty good...

[4-2NV]

As I recall the wheels are designed to crush easily, as part of the impact absorbtion engineering. That is why the Pure steel wheels are also spokes rather than solid discs, right?

[DieselVan]

thanks wizco - that was informative

[Evilution]

Originally Posted by SmartOwner

My wife, used to a much more formidable ride, hit a pothole @ speed yesterday & took out both passenger side wheels.

That's what she told you. I have hit some potholes that shook the car plus I have heard very few cases of non brabus wheels deforming on impacts like that (where the tyre pressures are correct). She is probably to scared to to admit she ran over the side of a road island. ;)

[MinnySmart]

It's amazing how loud it can be when you hit a pot hole.. it makes you think you've completely ruined the entire car only to find that nothing happened. But MAN it makes you nervous... I guess if I was giving a piggy-back ride and stubbed my toe on a step or something I would yelp pretty loud, too! ) Poor little Ike...