After Market Wheels--SAFTY ISSUE [Archive] - Cadillac XLR Forum: XLR and XLR-V Forums

: After Market Wheels--SAFTY ISSUE

10-18-2004, 11:33 AM
There has been a lot of talk on this forum about aftermarket wheels on the XLR and those of you who have seen my comments know that I am very picky about what I think you should put on the XLR. Like I said before, I have put a lot of time and research into this and Highly reccommend using a 19" wheel with Michilen Pilot tires.

I will not bore you with the why's and how's of this, just want to re-affirm that staying with this size will increase performance while not affecting the speedometer, magna-ride, traction control, cuise control, suspension, and other features.

While returning home from vacation Sunday on a 3 hour plane flight I descovered some new information that I did not think of before. Basically, it was an article in one of the popular auto mag's about how GM is trying to educate people on the pit-falls and danger of after-market wheels. While reading the article it basically re-affrimed all the arguements I made earlier and added one other VERY important thing I overlooked. What is it? SAFETY! It seems that the wheels (size and materials) are very important in determining the crumple zone of a vechile. By putting on larger wheels & tires made of different design stiffness and durability, you have drastically changed how the car will perform in an accident! The article basically showed a pick-up truck that upgraded from a 16" steel wheel to 20" alumiumin wheel and doing so would have crushed the leg of the driver. The same accident with the standard wheel would have cause little or no injury to the driver.

So, I guess it is back to the drawing board for me. However, I don't think that I can solve the safty question without extentive help from GM which I don't think they are going to offer anytime soon. This does re-affirm why 20" are a very bad idea. In the end, it is buyer beware!

10-20-2004, 12:29 PM
Rick, I'll bet the XLR-V will come with 1" bigger wheels with no safety modification, but we'll have to wait and see.


10-20-2004, 12:46 PM
Just found this link:

It has a purported spy photo of 2006 XLR-V. The wheels are different, but can't tell the size.

10-20-2004, 12:48 PM
This link does state there will be 20" wheels.

10-20-2004, 08:07 PM
Remember, I am only against 20" aftermarket wheels. The article I was refering to made specific mention of 20" that are speciffically designed (stiffness, crush characteristics, etc) for the vechile are fine. But, that there is a big difference between wheels designed for the car and just any old set made for variouse cars.

10-21-2004, 10:02 AM
This link does state there will be 20" wheels.

Jiminy Christmas! That's only about 260 cubic inches! That engine must really be winding up to generate 400 HP.

A fairly radical departure from the approach in GMs Z06 or ZR1 engines in C4 and C5 'vettes - lots of cubic inches that breathe well. I sorta like that approach too, because the driver senses a kick in the butt from the minute the accelerator is depressed. These small displacement engines have to get wound up to deliver power - feels like turbo lag until you reach some magic rev level.

I did see some photos of a highly modified Cadillac CTS with a 7.0 liter engine. Here's a link:

Interesting this CTS is posted on the CORVETTE forum. :glol

10-21-2004, 12:44 PM
Damn, my lease doesn't expire until Jan 2008. I want the 4.2 supercharged, 20 inch wheeled XLR-V!

No room for a 4th vehicle in my garage/driveway anyway, I'm sure my wife will understand that we need to move so that I can collect nice cars, right?

Oh, its nothing another million dollars won't fix, based on house prices in my neighborhood.


10-30-2004, 08:08 PM
Tech note from Motor trend, 2006 V will have 20 factory wheels. Use the same engine we have now plus super charger. Big Big brakes and a hood with a bulge in it for the SC. Nov issue.

12-03-2004, 12:43 PM
If you have put on 20" wheels, you have severely comprised the car. The quality of the wheel makes little difference.

The XLR was never safty tested with 20" wheels. Also, your speedometer, traction control, supsension, and ECU are now all miscalibrated. You are also putting addition stress on parts that were never intended to handle 20" wheels. Your brakes will be the first thing to go.

There is a reason why GM, Ford, etc. don't just bolt on any old wheel.

12-03-2004, 12:45 PM
:lurk I'm going to try and attach a pic of my 04 XLR that is not compromised in the least and has deep dish chrome 20's. Maybe I'm due for a big crash but my "Dream Machine" handles them real nice. These of cours are after market direct from the dealer who only deals in the best.

PS: Are those FOOSE Speedster wheels? If so, I have the same ones in 19". I did not know they were made in 20's. You might want to re-measure them

12-03-2004, 06:13 PM
I apologize before I write this, because I have a tough time with people that think they know everything about everything. Was wondering where you lived and is everyone as negative as you. These rims and wheels are exactly, I repeat, exactly the same measurement as the original tires. Nothing has changed. Annnnnnnnnnnnnnnd, if it did, I would merely hold the TC button down for a count of 8 and not only turn off the TC but the suspension too. If you didn't know this, the vehicle goes into anagressive mode like the Vette. The only thing I compronised on was the run flat tires.

As I said before, it's five seconds, not eight.

I don't normally provide advise for free, however I will make an exception this one time.

Check your attitude at the door, this is by far one of the best automotive forums on the web, populated by a group of enthusiasts who will not take kindly to your methods.

12-03-2004, 06:25 PM

Let's keep our flames to the ones we can paint on the side of our cars.

12-03-2004, 08:16 PM
I will check my attitude at the door in hopes that you take a class in how not to talk down to someone a lot older than you. Think positive . I suggest also that we take Quixotic's idea. Thanks Quixotic

Take a class? You are assuming you are older and you may be but I would doubt by no more than 1-2 years if that much. At this point in life that difference and $.50 won't buy you a cup of coffee anywhere I shop.

However, I will heed Quixotic's advice - for the time being.

12-05-2004, 06:07 PM

gone for a few days and return to see that I have struck a nerve with someone. First, I am 38 years old--for those who care.

Anyway, I stand by my comments about compermizing the car with 20" wheels. There is an extensive thread already about this. LOOK, I am all for changing the wheels and customizing my car to my taste. However, I see the real challenge is to do it WITHOUT changing the drivability, security, saftey, etc of the car. This is why I spent so much time studing what would work and what would cause problems. If you don't believe me, read the october\november car & driver. There is an entire article on why not to change your wheels and the lengths GM is going through to educate people on all the factors.

As for your arguement that you have not changed the overall ride height so everything should be fine. I am not trying to insult you, but making that statement means that you are not fully aware of all the issues. Mostly, saftely and WEIGHT. Read the article and you will understand.

12-05-2004, 09:42 PM
Your tires & wheels were done by a dealer not by Cadillac the Mfg.The dealer will not assume responsibility for another Mfg. product. The Wheel mfg. would be responsible not the dealer. Also the wheel Mfg. is only responsible for defects in the wheel as is the tire mfg. responsible for defects in the tires. The vast majority of tire & wheel mfg. will not cover collateral damage done to the vehicle.

All the safety items that are installed on the XLR don't mean anything compared to the #1 critical item on the XLR, that would be the tires. From crash testing to speed & endurance testing are done with the factory Michelin ZP tires. With the total amount of friction between the tire and the road, is a small patch of rubber on the bottom of the tire. That small patch is about the size of the palm of your hand.

My client that blew out his tire by hitting a pothole was in one of the worst and potentially dangerous areas of Chicago when it happened. The ability of being able to drive to my office instead of standing by or sitting in his XLR, waiting for his XLR to be hauled on a flatbed and then having to pay for the service. The service would not be covered since an XLR with stock tires would be able to continue on their merry way. Lastly it was all covered by the Michelin ZP warranty and did not cost him 10 cents. (

Thank You