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02 DeVille Base
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3 Posts
What's Up Everybody,

As it states in the title I am a newbie round here but I def have some questions to pick at peoples brains. I have my 02 Deville Base that I have just mainly done the sound system on cause at the time I bought this car I mainly bought to get myself out of trouble with the 350z I traded it for. I didn't realize at the time when I bought it (I was 22) then that it didn't have coil over set up but auto leveling which I was cool with at the same time always cringe at the thought of having to replace any parts if that system would go bad. Forward about 8 years and here I am today with a attempt at replacing this car and going for a Deville DTS but my questions have to do more with upgrading than anything. Making it a better to look at ride than anything.

My first question is on wheel offset and I know there is a bunch of post about offset here but all the ones I have searched and found are for 20x8, 8.5, 22's, 24's, etc. I am not interested in that I am more interested in keeping the performance and going with a sportier set up. my thoughts were on the V wheels (yes I know the bold patter is not 5x115 and you would need adapters) and on any other wheel with a wider track. How wide can we go on thesecar? Can we do a 9 like with the XLRV wheel or even a 9.5 with the CTSV (2nd Gen) wheel? What do our offsets max out at to get the most under that big body.....I am def into factory performance and styling but will go with a aftermarket wheel set up and offset any day if needed...

Hopefully this catches some interest and can ultimately be question I have yet to really even see here be answered and help out a lot of others like myself that aren't big into "big wheel" flash and more into ride, stability and performance.

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excuse my grammar I just noticed some of my typo's
 

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2013 ATS Performance 2.0T M6, 2016 Mustang GT Performance Pack, M6
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Re: Newbie to the Forum! WOOOHOOO!!!

Welcome to the forums. You should ask tech questions in the Deville forum to get the most answers.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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70,718 Posts
Re: Newbie to the Forum! WOOOHOOO!!!

Welcome !!!

Tech questions go either in the vehicle year/model forums or in a specialized forum - in the case of your wheels questions, maybe in Detailing and Bodywork; Wheels.

I believe your original wheel offset is about 50 mm positive and the original tire OD was about 27". Compare your original tire specs - driver's door sticker - with those in your desired tire range in www.tirerack.com. Departures from original OD by more than 0.2" or so cause speedo errors and powertrain controls/transmission shift point problems. Engine output speed, transmission output speed and all 4 wheel speeds are constantly compared. Errors equal messages and trouble codes.

Your ideas of 8.5" or 9" width wheels do nothing but cause suspension problems and excessive wheel bearing hub assembly wear - they're aout $100 each.

For wheel ideas within the Deville and later DTS fitment area, look through the year/model in www.wheelcollision.com. Click the little picture to enlarge. These cars do not take well to bolt circle adapters or oddball offsets. Your car is speed limited to 112 mph and uses the 275hp engine with a 3.11:1 economy final drive.
 

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1991 Cadillac Sedan deVille
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591 Posts
Sub,

How is the PCM going to know there are speedometer/transmission output speed problems/discrepancies? IIRC the speedometer shows a combination of VSS & transmission output speeds, so if the hubs don't get changed the wheels will turn with the intended speed, but since the OD of the tires is different the actual traveling speed will be different. I don't see how the computer will determine the actual change in speed, unless it measures actual air speed (like an aircraft does) :).

I'm not trying to question your expertise, I'm just curious.
 

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1973 Cadillac Hearse, 2002 Cadillac DHS
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288 Posts
Hi, and welcome :2thumbs: hmmm..."making it a better to look at ride" in my opinion 00-05 caddys are already a classy sight. I can pick these rolling sofas out of the crowd from a half mile away.

Regarding your wheels, have you considered one of the other factory wheel options that these cars came with? Perhaps a set of DTS wheels from a salvage yard or E-bay might catch your eye better?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Smaller tire OD gives you a faster speedo reading. Larger OD gives you a slower reading. Wheel (hub) speeds are part of the powertrain controls equation for the tires supplied on the car as built.

I see your question as to why wheel speed even matters - look at the diagnostic trees in the service manual - for speedo, wheel speed sensor, transmission input speed sensor, blah, blah and the possibilities for error codes are pretty high.
 

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02 DeVille Base
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3 Posts
Discussion Starter #10
Re: Newbie to the Forum - 2002 Deville base BUT getting a Deville DTS

thank you for the warm welcome so far everyone. I'm sorry I didn't post in the correct section but I will next time for sure but I appreciate everyone continuing forward and putting there input.

Sub, I know that weight factor can cause issues as well as rotational mass being a factor but I am def not planning on just buying any old cast alum wheel (i.e. the flashy stuff), I will be going lighter only and at a +1 or +2 in size but still keep the specs within range of stock OD. Also remember that I am considering into a Deville DTS and this idea I have is nothing to do with my Base now. I know your looking out for my pocket which I appreciate completely but honestly the factor of parts replacement is not a issue as I get Cost +10 in all my GM parts with a long time friend that we have been working in the dealer parts business for a while together plus I know GM techs there at that dealer that do work for me on the cheap as well and sometimes free because they like working on my cars cause I keep them clean for them lol weird relationship I know, either way they will calibrate as needed if needed with their computer, clear codes (which I have only had on this car twice, etc. For the factor of hubs I know to keep the wheel within weight specs cause the rotational mass will def cause these things to go bad and even though I can tell you that without AM wheels they still go bad fairly quick cause I have had this car since 08' and in 10' I had to replace the hub (stock base wheels and tires) at just 62,6xx miles on it and then again the same one, same side and the opposite side about at 81,3xx miles (still on oem wheels and tires) which was only a year later cause I drove a bit more that year and it still crapped out quick so the parts in general are not all the best in the world which happens. Since then no problems.

markmnj: your right my friend these cars can be spotted for sure from a distance and they are great but I just want that little more bit more of a stand out like the V's have. remember that im talking about getting a DTS already so it will come with the wheels.

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Sub, where would I post pics of my ride like to just show everyone?? was it in the introduction section, or Deville section?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Pictures - Post in the sticky thread for pictures on this forum's main page.
 

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1991 Cadillac Sedan deVille
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591 Posts
Ok, while I agree heavier wheels will cause problems down the road, I still don't think a slightly different OD of a tire (by itself) will cause problems. A tire with slightly bigger OD diameter will hardly be any heavier than the stock one. Yes, the speedo will read inaccurately, but it won't hurt anything. The only possibility for problems, I think, could arise from smaller OD tires which could cause earlier than intended upshifts and VCC lock. However, the computer doesn't just look for traveling speed when changing gears, it also looks at RPM (and a bundle of sensors). So, the possibility of even that are slim in my opinion.
 

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2003 deville
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604 Posts
If you see the speed wrong so do the sensors so if going smaller could cause problems so could going bigger.
 

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1991 Cadillac Sedan deVille
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591 Posts
If you see the speed wrong so do the sensors so if going smaller could cause problems so could going bigger.
The sensors are setup to exist in a perfect environment - that's why your speedometer will be off. If the computer had any way to readjust those things then the speedo will adjust it's output automatically (to be accurate with any tire size). The car's PCM has no idea you installed tires with slightly bigger or smaller diameter. It automatically presumes you're running the stock size, so unless the load on the engine, transmission, and the one on the suspension changes (like when changing to a heavier than stock wheel) you should have no worries. At the end of the day, as long as your replacement wheels are not exceeding the weight of your stock ones, and the tires you're running have sufficient load rating for your car (and are inflated properly) you will have no troubles.

I think we many times tend to over-complicate things, and think computers can detect just about anything. While the OBDII system definitely incorporates more sensors and is able to find a lot more faults because of that, it is still programmed to exist in a predetermined environment. Like I said earlier, the computer has no other reference sensor (which could detect actual driving speed) to check if the speedometer shows accurate readings.
 
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