Adding TPMS to older BBS wheels.

Discussion in 'Car Builds, Projects, Idea's Experiments' started by SK8BRD, May 27, 2009.

  1. SK8BRD

    SK8BRD New Member

    May 4, 2009
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    In a three way deal including a player to be named later, I got some 17 inch BBS RGR wheels that had been chrome plated. The only problem was that my car was built in November of 2007 and therefore had the TPMS sensors inside the wheels.

    The older BBS wheels have a valve hole that is smaller than anyone else's, about 5/16". The TPMS sensors attach to the valve that needs a 29/32" hole.

    At first I just drove around with the warning light on. But recently my 17 year old daughter has learned to drive the car. I needed the sensors installed so that she would pay attention to the warning lights.

    So I drilled out the valve holes to 29/32" from the inside out. I did that because on the front side the new hole extended into the lip of the wheel. Of course that meant that the new valve wouldn't attach to the wheel, because the clearance flat for the nut that screws on top of the valve wasn't there.

    I decided that a countersink would be good enough and machined one into each wheel deep enough that the valve nut contacted the wheel all the way around.

    I went back to Discount and had the tires remounted and balanced. The warning light is out, and after 200 miles of driving everthing is A-OK.


    I took some pictures, but didn't realize how bad my son's camera was until after the fact, here they are;

    The two valves;

    [​IMG]


    The valve hole from inside the rim;

    [​IMG]

    The final install;

    [​IMG]


    Along with the crummy quality, the dates are wrong on the pictures. All work was performed this week.
     
  2. Mike

    Mike New Member

    May 4, 2009
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    Oh, I can hear the lawyers spooling up to spew disclaimers all over you! But so what, this is a cool mod.
     
  3. Deviant

    Deviant Banned

    Apr 23, 2009
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    Very cool what you did there, I don't think I'd have the guts to try something like this and would've instead just removed the bulb for the TPMS light.
     
  4. SK8BRD

    SK8BRD New Member

    May 4, 2009
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    Maybe I should paint the word "Experimental" on the doors like they do on airplanes.

    The real problem wasn't the light, I could live with that. On the R56 there is a general caution symbol (a trangle with an exclamtion point) on the tach display between the odometer and whatever else you choose to display. So unless I scrolled throught the info screens, I'd never see the second warning.

    All I really did was drill a hole and countersink in each wheel. The material in that area is pretty thick, and I used a brand new drill bit and counter sink. A little 3-in-1 oil to keep things cool.

    I used to work in a machine shop, note I was not a machinist. I was a draftsman/Co-op student. I wasn't even really a draftsman, I only drew schematics. But occasionly that part of the business would get slow so they put me to work in the shop tapping holes.

    But there is a world of difference between tapping a hole in a part that the boss owns and drilling a new hole in a perfectly good wheel that will cost $800 to replace. I should have done one and got the tire mounted to see if it would hold air before I drilled the other three. Fortunately it turned out OK.
     
  5. SK8BRD

    SK8BRD New Member

    May 4, 2009
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    Ugh

    Well originally I did have a small leak issue that was solved by tightening up the valve stem on that tire. I've even had a second set of tires mounted and had the associated valve rebuild kits installed. Then I had a slow leak occur in the passenger side rear.

    So I took the car into Discount Tire. I've used Discount tire for almost 20 years, I always buy the certificates. They've honored the road hazard for me several times.

    They found the leak around the valve stem, so they put rebuild kits in all four wheels. Now I have four slow leaks.

    The cause of the problem seems to be that the rubber gasket isn't resting on a flat spot on the inside of the tire, so I've decided to make one.

    What I plan to do is remove the valve and smear something like epoxy putty around the valve hole then install the valve with a large flat washer on the inside so that the epoxy will be flat when it cures. Then I'll remove the valve and washer and reinstall the valve. I'm pretty sure this procedure will yield a flat spot on the inside of the wheel that is perpendicular to the valve stem and should solve my problem.

    I'm not real sure that epoxy putty is the best choice, does anyone know of an alternate material>
     
  6. SK8BRD

    SK8BRD New Member

    May 4, 2009
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    Resolved!

    It turns out my the conical opening I used on these wheels is similar to the way Audi and Mercedes Benz wheels are made, but BMW uses a flat spot. So when I had DT install OEM valves, they didn't work either. I finally scheduled an appointment for a less-busy time at DT and got their expert to go through the box and find the proper replacement valve for my wheels.

    It took lots of my time, but congrats to Discount Tire for doing their end for free.

    Lessons learned,

    TPMS sensors and valve stems are finicky, DT admitted that they've had problems getting them leak free in the past.

    Only use genuine BERU replacement valves, and know which one is right for your wheels (not your car, your wheels). DT has rebuild kits which consist of a rubber grommet, the part of the valve that unscrews, washer and nut. The rebuild kit's grommet was way too big for my valve stems. Don't use the rebuild kit, get a whole new valve.

    There are four different BERU valve kits, the bottom of each is a different color, so it's not that hard to figure out which one you need.

    BMW switched types of BERU valves sometime after my car was made. I had the plain bottom valve, they now only use a green bottom valve.

    Check your tire pressure after having your car serviced. DT only had 25 psi in all four tires when the car came off the jack, it's was unnerving to put the key in and have the tire low light come on. They filled them with the 32 psi hose and I was on my way.
     

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