04 oem yukon tire sensors on 20's ?

[GdubMc]

i picked up some 20's and was curious if my wheel sensors (located in valve stem) off my oem 17's can be transfered to my new 20's to keep the monitor workin. Discount tires said that the sensors only work with the oem size tire and that i need to get ones that correspond to a 20" tire(different pressure on a 295/45/20 than on a 265/75/17).ANy oneknow where i can pickup some "20''sensors" if they even make them. Was going to ask my local dealer but you all know how that is.

[tonytone]

To be honest with you, I don't know/remember exactly what condition the GM OEM tire pressure monitors expect to see before alerting you to a low-pressure condition--i.e., how does the monitor determine how "low" low tire pressure is? If one were to assume it does so based on a numerical reading (e.g., pressure goes below 25 psi), then I would think that the monitor should work (in theory) no matter what sized rim it goes on, since X psi is X psi, no matter what sized tire the reading is taken from, no?

The only problem that might arise from using the sensors on an aftermarket wheel is that the sensor (it includes the entire valve stem, IIRC) might not fit correctly into the valve stem opening depending on where the opening is on certain rims; other than that, there is no reason why they wouldn't work correctly otherwise. I mean, people have gotten them to work on 22's and larger...then again, I haven't read anything about whether the sensors have accurately reported a valid low-pressure condition on such wheel sizes.

[04KON]

Originally Posted by GdubMc

i picked up some 20's and was curious if my wheel sensors (located in valve stem) off my oem 17's can be transfered to my new 20's to keep the monitor workin. Discount tires said that the sensors only work with the oem size tire and that i need to get ones that correspond to a 20" tire(different pressure on a 295/45/20 than on a 265/75/17).ANy oneknow where i can pickup some "20''sensors" if they even make them. Was going to ask my local dealer but you all know how that is.

i have the same problem but i have 22" wheels. im still working on solving this problem. Im going to try to remove the factory sensor of the factory wheels. I will see if it will work crossing my fingers hope it works.

[BoatCop]

The OEM Tire Pressure Monitor Sensors should work just fine on the 20s or even the 22s. The stock number for TPM sensors is the same for GM 16 or 17 inch wheels.

I swapped the TPM sensors from the stock to custom wheels (albeit, from 17" to 17") and they work just fine.

They work by sending a signal to a reciever. They don't register exact tire pressure, but compare the strength of the signal (determined by pressure in the tire) to that of the other sensors. It sets off the alarm (dash Light) if one of the sensors reads a different input than the other three. In theory, only one tire at a time will lose pressure, so if it reads a difference, it signals a fault. I think the variance is 5-10 PSI.

The only way they would fail, would be if all 4 tires lost exactly the same amount of air at the same time.

What the Discount Tire guy may have been thinking about was a different type of monitor that works through the ABS system. In that kind, it reads and compares the revolutions of the tire(s) and since a tire low on air will tend to drag, it will signal that the tire is low. Those kind have to be matched to the wheel diameter.

He may also be thinking about the kind of sensors that are attached to the inside of the wheel by a rubber band kind of strap, not the valve stem sensors.

Just remember to put the sensors back in the exact location they came off of. That is, right front to right front, right rear to right rear, etc. If you mix them up, you'll have to re-calibrate them to their location, which isn't hard to do, but a PITA.

[tonytone]

You know what's really stupid about the GM OEM tire pressure sensor feature on their full-size SUVs is that even though each sensor has to be calibrated to a specific tire, the '04 DIC doesn't even tell you which tire is low on pressure, just that the receiver has detected a low tire pressure condition. Guess GM figured out that this made no sense, hence now the '05+ models will tell you which tire is low...

[turbojimmy]

Originally Posted by BoatCop

What the Discount Tire guy may have been thinking about was a different type of monitor that works through the ABS system. In that kind, it reads and compares the revolutions of the tire(s) and since a tire low on air will tend to drag, it will signal that the tire is low. Those kind have to be matched to the wheel diameter.

I was thinking that too, but they don't really measure drag - just a difference in diameter and thus revolutions as compared to the other tires (as you mentioned). The thing about those systems, though, is that they are dynamic, i.e. they are not associated with any particular rim/tire size. When you hit the reset button (in the fuse panel), the system will learn the characteristics of the wheels/tires. This is why you make sure you have all the tires properly inflated before you reset the system. When there's a deviation from the learned parameters it will light up the tire pressure warning light. I would think that there is some limit to the deviation from stock diameter you could get away with, but if you're simply putting bigger rims on and the overall diameter of the rim/tire stays more or less the same there shouldn't be a problem.

Jim