I went on the site today and found some rims that I really like and they offer them in 18" w/255-45-18 performance tires and 20" w/255-35-20 tires. But If 20" rims are not good for the suspension why would GM offer them for the CTS??, and since they are direct from GM, if the 20"rims so happened to cause a problem would the damage to the car caused by the GM rims still be covered under warrenty??
??? about GM parts direct.com
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05CTS I see your running 20", what's ur take on them.. Have u or do u plan on doing any suspension mods? Do they take away from the suspension system?
Nah they're for the CTS and other caddy sedans
20" RT29 Series Wheel & Tire Packages (Deville, DTS, Seville, CTS)
Here's the link, and the pic shows a CTS with the rims I'm referring to, they look like 20" in the photo.
http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=MC2CTS
20" RT29 Series Wheel & Tire Packages (Deville, DTS, Seville, CTS)
Here's the link, and the pic shows a CTS with the rims I'm referring to, they look like 20" in the photo.
http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=MC2CTS
Maybe you're mistaken. Who said they are bad for the suspension? The only thing they will be bad for is the transmission...and obviously ride quality.BishopRuger said:
Here's a clip from Pete regarding some of the pitfalls of oversized wheels and suspension changes. It's wordy but some common sense material.BishopRuger said:
"You just used the operative word; "impress". Because 20" rim plus sizing is nothing but "impression" disguised by the word "application" on any CTS platform utilizing the exisiting OEM factory suspension geometry and hardware.
At least the "low-riders" have enough common sense to know that a 20" plus size application on a CTS is a "teeny bopper hollywood impression for show and certainly not go". The low-riders also know the difference between putting on a hydraulics show and not trying to build a higher horsepower rated drivetrain platform while "monkeying" around with there suspension geometry without any quantitative engineering modeling to support the effects of what they are doing under those wheel wells!
Like we agree; the premature wear on the tires is the first visual sign of suspension degredation and now there scratching there heads thinking it's purely alignment or tire rotation. :bonkers:
We both know that the factory suspension components are taking an absolute beating and prematurely wearing and CTS owners will be able to line the bottom of their bird cage with the factory 5/50k warranty when they attempt to make a suspension component claim which is inevitable when the vehicle will no longer hold an alignment due to component wear.
For God's sake...it's all written it the 1800 page CTS GM technical manual by the design engineers about the dangers and premature wear to the suspension system by installing this junk!
These CTS 20" wheel/rim upgrades, lowering springs and rear luxury shocks are "backyard garage upgrades" and what is sad is that you have some GM technicians doing the installation???
What the hell kind of Cadillac dealership operates like that when you have a written GM technical manual that says NO to that "application or modification" and warns of the mechanical and safety dangers???
I just feel sorry for the young folks and the terribly misinformed on this Forum that rely on some of the absolutely wrong upgrades that are disguised as a so-called correct "application modifications" and then are supported with the statement of; "well I work for a Cadillac dealer and the GM tech told me......or Jiffy-Lube said; and therfore it's all ok!" :helpless:
It is an absolute fact that playing around with the suspensions ride height without properly engineering the suspension tuning will lead to setback problems with regard to the front and rear wheels where the rear wheels control tracking and the front wheels the vehicles aim or steering and ultimately the proper thrust angle. And as said and "printed"....problems, problems, problems with lead pull wheel alignment, memory steer, undesired wander, drifting and deviation and scrub radius angle which affects camber angle and directional stability.
And installing a camber kit to compensate for the premature tire wear without regard to the premature suspension component hardware problems that are inevitable is like putting a band-aid on a head fracture if folks think that's the answer!" Pietro
Yeah prior to Pete stating that info I was all about 20" rims but now I'm a bit cautious..
What he has to say makes a lot of sense i.e., the premature tire wear, the premature suspension component degredation, problems with lead pull wheel alignment, memory steer, undesired wander, etc... There's just a lot to consider and in the end I want my car to drive well not just look good.
What he has to say makes a lot of sense i.e., the premature tire wear, the premature suspension component degredation, problems with lead pull wheel alignment, memory steer, undesired wander, etc... There's just a lot to consider and in the end I want my car to drive well not just look good.
To be honest the 20's make the ride a little more firm than stock. I don't have the sport suspension either. I like a soft suspension w/big rear sway bars and low profile tires. At low speeds it's not the greatest but at higher speeds it's great. Would I buy 20's again? Hell yeah I would. I love the look no matter what anyone says or thinks.BishopRuger said:
My car is only a lease so no I don't plan on doing any suspension mods. I can remove and resell all of my mods when I'm done w/the lease except for the V exhaust. That was only $75 and I could care less about it.
I wish I had seen those before. They are nice.
If this was a car that I was going to keep, I would throw the rear V sway bar on it too and thats it. Guys lowering it have problems w/the inner front wheels wearing away and fast. Just my .02.
Something to consider when over sizing wheel/tire combos that is often overlooked (though it was recently covered in another CTS thread as Robert pointed out) is tire wear. Equipping a vehicle with an oversized wheel and tire package will often completely hose your suspension geometry resulting in excessive tire wear because the suspension is out of alignment and cannot be properly aligned.
Some manufacturers account for this by providing camber kits to adjust the alignment to accommodate the new suspension geometry, but that is only part of the solution as Robert cites per Pete because you are placing undue strain on the rest of the suspension. I am not trying to tell anyone how to spend their money, but running through tires in a quarter of their normal life seems silly at best.
I was stuck at a Discount Tire earlier this year waiting for a flat to be fixed and picked up a car magazine, I cannot now remember which, and read and article about aftermarket wheel/tire combos. This magazine took a Porsche 911 and ran it through some performance tests using the stock wheels and tires, then oversized wheels and tires. Shockingly, the stock wheel and tire combo performed best because the car's computer was programmed for it. Are you really going to second guess GM and all their exhaustive testing? Yes, the '06 comes equipped with 18's if you get the sports package, but that is a far cry from 20's no matter what the tire profile. New model year = new computer code, which combines into a reasonably workable system.
Finally, increasing wheel diameter typically increases unsprung weight which will slow you down, not help you go faster or perform better. If you are looking for 20's you are probably less concerned about performance than appearance, but you really should consider the impact that you are going to have on your ride quality and final performance long term.
I say all this because I have watched friends and family members upsize their wheels and tires, time and time again, only to spend more money switching it all back after they got sick of having bent rims repaired, living with excessive road noise, and replacing tires worn out before their time. Just because someone offers it for sale, doesn't make it right.
Some manufacturers account for this by providing camber kits to adjust the alignment to accommodate the new suspension geometry, but that is only part of the solution as Robert cites per Pete because you are placing undue strain on the rest of the suspension. I am not trying to tell anyone how to spend their money, but running through tires in a quarter of their normal life seems silly at best.
I was stuck at a Discount Tire earlier this year waiting for a flat to be fixed and picked up a car magazine, I cannot now remember which, and read and article about aftermarket wheel/tire combos. This magazine took a Porsche 911 and ran it through some performance tests using the stock wheels and tires, then oversized wheels and tires. Shockingly, the stock wheel and tire combo performed best because the car's computer was programmed for it. Are you really going to second guess GM and all their exhaustive testing? Yes, the '06 comes equipped with 18's if you get the sports package, but that is a far cry from 20's no matter what the tire profile. New model year = new computer code, which combines into a reasonably workable system.
Finally, increasing wheel diameter typically increases unsprung weight which will slow you down, not help you go faster or perform better. If you are looking for 20's you are probably less concerned about performance than appearance, but you really should consider the impact that you are going to have on your ride quality and final performance long term.
I say all this because I have watched friends and family members upsize their wheels and tires, time and time again, only to spend more money switching it all back after they got sick of having bent rims repaired, living with excessive road noise, and replacing tires worn out before their time. Just because someone offers it for sale, doesn't make it right.
Good info Mike. Many of us here that run 20's already know most of this but do it anyway b/c of appearance. I for one don't really care about longengevity b/c I have a lease. It's all going back to stock anyway. But non the less good info for future 20" buyers.
I work on vettes for a living and we too a lightly modified 01 and ran a road course w/stock 18" rims. Than we switched the rims to 17's and actually got better times on the road course.
I work on vettes for a living and we too a lightly modified 01 and ran a road course w/stock 18" rims. Than we switched the rims to 17's and actually got better times on the road course.
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