Tire question

[Coupe]

My MM has a SCT chip inside. In one of the menu points, i can set the tires.
Is it possible to change any adjustment, so that i can drive the same size in front and rear? The Grand Marquis has the same ABS module so far as i know and the MGM is equipped with the same size

[SC Cheesehead]

My MM has a SCT chip inside. In one of the menu points, i can set the tires.
Is it possible to change any adjustment, so that i can drive the same size in front and rear? The Grand Marquis has the same ABS module so far as i know and the MGM is equipped with the same size

Point #1: You can't adjust anything through the tuner to correct for changes in tire size.

Point #2: It's the Traction Control system that will give you issues, not the ABS module.

Point #3: If you have an early model '03 (i.e. 300A - pre-T/C), no problem running the same size tire on all four corners. If you have T/C, still not a major issue, you'll just have to turn off the T/C whenever you drive the car, or the T/C system will get confused by all four tires rotating at the same speed (it's programmed to sense the front tires rotating faster due to their smaller diameter), and will engage the T/C. End result: The more you try to speed up, the harder the T/C system will apply rear braking pressure, and the slower you'll go.

Hope the above helps.

[Coupe]

Thank you for answer!


Point #2: It's the Traction Control system that will give you issues, not the ABS module.
but which module will steer the T/C? The PCM? I mean, maybe i can swap a module with a Crown Victoria or MGM!?!?



Point #3: If you have an early model '03 (i.e. 300A - pre-T/C), no problem running the same size tire on all four corners. If you have T/C, still not a major issue, you'll just have to turn off the T/C whenever you drive the car, or the T/C system will get confused by all four tires rotating at the same speed (it's programmed to sense the front tires rotating faster due to their smaller diameter), and will engage the T/C. End result: The more you try to speed up, the harder the T/C system will apply rear braking pressure, and the slower you'll go.

Hope the above helps.
i know, as i bought the MM, it has the same tires. It was silly.

[Comin' in Hot]

If you have T/C, still not a major issue, you'll just have to turn off the T/C whenever you drive the car, or the T/C system will get confused by all four tires rotating at the same speed (it's programmed to sense the front tires rotating faster due to their smaller diameter), and will engage the T/C. End result: The more you try to speed up, the harder the T/C system will apply rear braking pressure, and the slower you'll go.

Hope the above helps.

so what your saying is that if i have a 300B with the factory rears on the front and 255/55 - 18s on the rear its possible that my T/C is killling my fuel mileage? i thought it was only if the tire sizes were too far apart?

[Mr. Man]

Point #1: You can't adjust anything through the tuner to correct for changes in tire size.

Point #2: It's the Traction Control system that will give you issues, not the ABS module.

Point #3: If you have an early model '03 (i.e. 300A - pre-T/C), no problem running the same size tire on all four corners. If you have T/C, still not a major issue, you'll just have to turn off the T/C whenever you drive the car, or the T/C system will get confused by all four tires rotating at the same speed (it's programmed to sense the front tires rotating faster due to their smaller diameter), and will engage the T/C. End result: The more you try to speed up, the harder the T/C system will apply rear braking pressure, and the slower you'll go.

Hope the above helps.
Babcock mentioned something about the ABS system at MV9 that had to do with tire size while we were discussing the T/C issue. Unfortunately I don't recall the specifics, but there was a correlation with wheel size. It may have been in the software Mercury used in the T/C cars.
Maybe someone who has a better grasp on the ABS system can remember what he said. :)

[ctrlraven]

so what your saying is that if i have a 300B with the factory rears on the front and 255/55 - 18s on the rear its possible that my T/C is killling my fuel mileage? i thought it was only if the tire sizes were too far apart?
So you have 245/55 on the front and 255/55 on the rear?

[SC Cheesehead]

but which module will steer the T/C? The PCM? I mean, maybe i can swap a module with a Crown Victoria or MGM!?!?




I don't know if it's a stand alone module, or if it interfaces with other electronics in the car. Also, don't know how much work it would be to change over, AFAIK, everybody that's run the same sizr tires just turns off the T/C as that's a pretty easy habit to get in to.


Babcock mentioned something about the ABS system at MV9 that had to do with tire size while we were discussing the T/C issue. Unfortunately I don't recall the specifics, but there was a correlation with wheel size. It may have been in the software Mercury used in the T/C cars.
Maybe someone who has a better grasp on the ABS system can remember what he said. :)

Yeah, I remember him saying something as well, but can't recall exactly what it was either.

I know the 3% - 6% stagger is required for the T/C to function properly, and I ran 845/45s on all four corners of my car for about two years without issues, as long as I turned off the T/C. Don't recall having anything come up with the ABS, but then, I didn't really ever have the need to really try it out.

[Comin' in Hot]

So you have 245/55 on the front and 255/55 on the rear?

I do, I can't say I like how it looks, but thats only because I havent found a set of Eibachs yet

[ctrlraven]

I do, I can't say I like how it looks, but thats only because I havent found a set of Eibachs yet
As long as you don't have T/C you can run whatever you want front and rear. If you have T/C then there needs to be a 3% or greater difference between the front to rear tire (rear being larger of the two) for the T/C to function properly.

I ran 235/50 all the way around for a short period of time, I had to always turn the T/C off before driving otherwise under heavy throttle it would engage or 45 mph or faster it would engage. Since then I've gotten into the habit of always turning it off anyways even though I run 255/45 Front and 265/50 Rear size tires now.

[RF Overlord]

but which module will steer the T/C? The PCM? I mean, maybe i can swap a module with a Crown Victoria or MGM!?!?


i know, as i bought the MM, it has the same tires. It was silly.Your signature says you have a 300A, so you don't have traction control. You can put whatever size tires wherever you want.

[Coupe]

Your signature says you have a 300A, so you don't have traction control. You can put whatever size tires wherever you want.

That the curious thing: my MM has T/C and a clock in dash board. It´s discuss in an other thread, so tell you, is it an A or B?

[jdiding]

ive got a 03 w t/c no dash clock, black valve covers and no front map pockets and heated seats maybe they are just a mid change special like built in between the 300a and the official begining of 300b production

[Coupe]

mine is a canadian modell w/ km/h speedo

[Bluerauder]

ive got a 03 w t/c no dash clock, black valve covers and no front map pockets and heated seats maybe they are just a mid change special like built in between the 300a and the official begining of 300b production

Could be one of the 300A/300B changeover cars that we use to call the "Pre-Decontented" MM that had a mix of 300A and 300B features.

Your VIN sequence would put your build somewhere in the mid-November 2002 timeframe right around the end of the switchover. Did you get a full size spare and a thumb lip on your gas filler door?

Since you have the Canadian speedo, I think you officially have a 300eh. ;)

[SC Cheesehead]

mine is a canadian modell w/ km/h speedo


That explains it. IIRC, all MMs built for Canadian sales were equipped with T/C and a km/h speedo.