Retro fitting TPMS sensors

gvcmel · Motorist

Retro fitting TPMS sensors

the_copi · Member

I believe that all you need to do is reset the flat tire monitoring system by holding the button near the e-brake in for 5-10 seconds. Then the next time you start the car the light will be off.

It happens every time I put new tires on my MINI. The flat tire monitoring sysem works based on wheel rotation, not by actually measuring air pressure. But it's pretty sensitive - it's informed me of as little as a 3lb. difference in tire pressure.

Hope that helps!

gvcmel · Motorist

Ok, my bad.

I have an R56 with the newer active TPMS system so there are transmitters in every wheel.

From what I have learned reviewing the data available they are amazingly light at about one ounce each for any of the OEM systems. Oh, and for anyone that cares the estimated battery life on the active units seems to be 10 years so that should not be a problem for a while. The batteries are not field replaceable though.

The only requirement that seems to be mentioned is a "flat spot" inside the rim where the valve stem is inside. It seems I can buy just about any rim and retro fit the sensors if I want new rims so I can't imagine the "flat spot" has to be too extravegant. Found no spec on the "flat spot" yet, still looking.

I have not found a picture of the R53 rims without tires to see if there is a suitable mounting point or not. I was hoping that someone might have been down this path already and could say if it was possible or not. Considering the manufacturers knew this requirement was coming for years I will not be surprised to find out that all new rims now can be retro fitted with TPMS.

I may just have to dismount a tire and see what it looks like. Still lots of time on this project before the weather gets warm enough to use these rims and tires.

buzz · Member

I have an early 2007 mcs with the tpms in the hub not in the wheels (rubber valve stems).
I bought a set of 2004 MINI R83 wheels 16". I put snow tires on them and they work fine!
I also bought a set of 2007 MINI R94 wheels 16".
The difference is on the inside of the rim where the TPMS (valve stem) sets.
The inside of both wheels are flat where the valve stem goes.
The flat area for the 04' wheel is smaller then the 07' wheel.
My guess is that if you have the TPMS (metal valve stems) that goes inside the wheels you will need to have newer wheel.

The 2007 MINI R94 7 spoke wheels are for sale.

Les

gvcmel · Motorist

According to the BERU reference I located the hole on the inside is not a critical reference point. The valve stem is assumed to seal against an 11.3 (+0.4)

mm hole. The head of the valve stem looks to be about 12mm or slightly larger.

Looks like I should order a set from MiniMania and see what I am up against. Hate to have to dismount these tires to work on this but I supose that is life.

Got pics and a $$$ for the rims you are selling? The wife is going to kill me

gvcmel · Motorist

Just an update to bring this to a close. Received the TPMS parts from MiniMania and installed one into the R53 Mini rims I picked up. As expected once the tire was off and the old valve stem removed the new TPMS valve stem slipped right in and tightened down nicely. Installed the monitor head and torqued that little screw while praying to all imaginable gods that the screw did not fail as the final torque seems pretty high. Remounted the tire and balanced the whole thing.

The tire sensor weighs in at 1.28oz and the valve stem is only slightly heavier than a regular rubber stem. The tire needed exactly 2 oz of weight about 170 degrees from the valve stem to bring it into balance. It had about 1/2 oz of weights before.

YMMV but I expect just about any rim made in the last two years by a big manufacturer like Mini will have the valve area machined to mount these sensors. This conversion will end up costing about $350 in the end. Tire rack just started selling the TPMS sets on Ebay at about 2/3 the cost of the parts other vendors are charging so you may be able to do this update for less then my cost.

If you are in the Rochester area Ekstens now knows how to do this so a spare set of rims for your 07 MCS with TPMS are a lot easier to come by.

Enjoy