I just browsed a Tire Rack brochure and saw that some wheels were labelled as "Flat Tire Sensor Compatible" (or something like that), while others were not. Why would some wheels work with the sensor and other not?

 

On current models of the MINI, "flat tire monitoring" is via a passive system that detects wheel spin rate variations, and therefore do not require special rims. When one tire looses air, it loses its volume as it deflates (it shrinks), and therefore, the now smaller tire turns at a faster rate to keep up with the remaining 3 wheels. Sensors in the MINI's axle/bearing area detect when one wheel spins proportionally faster than the rest, and turns on a lamp on the dash board to warn the driver. Because the sensor is in the axle shaft/bearing area and not the rim, you do not need any special wheels--anything with the proper dimensions will work.

Some vehicles have an active "tire pressure monitor" (as opposed to a "flat tire monitor"). These active systems have a screen inside the car that displays the actual air pressure of each tire. This is accomplished via sensors installed in, or built into, the actual wheel or valve stem.

It is said that within a few years, all new cars in the US will require active tire pressure monitoring, which will have reprecussions throughout the entire wheel/tire industry, including places that do wheel sales/mounting/installing, as the shade-tree mechanic of yesterday will no longer be able to perform work on tires. Specialized, non-destructive equipment and training will be required for wheel mounting and installation that won't damage these sensors, and to reprogram the car's monitoring system when the job is complete.

I don't know what type of flat tire warning system the 2007 MINI's will have, but the change to an active system is inevitable at some point in the future.

Any non-compatible wheels you buy now will not be able to be installed onto future MINI models once they go to the active system, so if you planned to trade in your MINI for a newer model but keep your old wheels, you wouldn't be able to do so. Barring that scenario, it is not necessary to buy wheels that are "compatible" for current models.

 

Tarzan thanks for taking your time to answer ofioliti's question because I had the same question and was just waiting until I made it to the dealership to ask. We took our wheels off and currently we are in the middle of a nightmare but this an entire different topic. In doing so I noticed we had no sensors on the wheels or electrical connections. Now I know why.

ofioliti, we drove past you guys Saturday on 270 north....the Mini was looking good! You wouldn't have noticed us becasue we were in my 2500 GMC. If you are not into diesel trucks we look just like any other truck on the road.

 

2 types of tire monitors.

1) via RF sensor on wheel inside tire. (only selected wheels can be used)
2) via ABS sensors (MINI - any wheel can be used)

 

By 2008 ALL car manufacturers will have to have sensor mounted (in tire) monitors in the U.S.

Aftermarket rims are screwed, some of them don't even work with the sensors we have now.(Excluding Mini of course)

2 Cents

 

i am sure there will be ways to strap the sensors inside the rim even if they weren't designed for the TPS RF sensor by the valve stem.

 

Why's that? Was there some Federal or DOT requirement for that?

 

maybe this?

http://www.detnews.com/2005/autosins...C03-143935.htm

 

Go to:

http://www.nhtsa.dot.gov/

and search “TPMS”

Alex

 

This has Ford Explorer written all over it.

 

On some cars, yes. For example the system on newer Fords (including the '07 Mustangs) uses a large band clamp that fastens to the inside of the wheel and can be used on most (if not all) factory and aftermarket wheels.

-Keith

 

Thanks for the great replies/explanations and links, folks.

I was aware of the MINI's indirect system using the ABS, hence my confusion as to why that wouldn't work with all wheels.

Although probably not the best system, the MINI's ain't bad. Mine went off one time because one of my tires had a slow leak. I stopped immediately and checked the tire pressures. It had detected ~5 psi less pressure in one of the tires.

 

Hey, you should've honked!

 

imagine someone filling up the tire with fix-a-flat...

 

I just put Goodyear F1s on a set of 17" S-Lites. I drove about 2 miles at normal street speed limit speed and my flat tire sensor kicked on. I KNOW the tires are fully inflated and are not flat. After stopping and parking for about an hour, I started my MINI again and the light was still on. I hit the reset button and after about 15 seconds the flat tire light went out. I drove another 5 miles or so and the light is still off.

Is this normal after installing new tires other than runs flats?

 

Though the procedure may be different for earlier year models, on 2005 and newer ones, you must reset the flat tire monitor anytime you change, rotate, or adjust air pressure in the tires. It takes 10 miles or so of driving from the time you press reset for the car to "learn" what average wheel rotation variance is, and will throw the lamp when outside that "average."

Turn the key on, without starting the engine. Wait until the lamps cycle off, then press and hold the tire sensor reset button until its lamp stays on. Then start the car. In a few seconds, the light will go out, and the car will spend the next 10 miles or so learning.

 

Tarzan (post above) is right. If you didn't reset the monitor after changing the tires, the senor detects a different rotation rate and sets the light off.

Tarzan, my manual says to start the engine then reset the button (not reset then start). Does it matter?

 

I dunno, I only know what works for my model year. I know for fact that the location of the button has changed over model years, and quite possibly the function as well. Best resource is the owner's manual at this point.