Over the years I've had quite a few flat tires caused by nails and screws etc - so I investigated various means of tire pressure monitoring for all my vehicles, especially the 911 TT and Mini Cooper S as their tires seems to be like magnets for nails !

I bought three sets of these 'safety caps' from the vendor below:

http://www.accu-pressure.com/

All was well for about 12 months, then one of the 'safety caps' sprung a slow leak on my 911 actually causing a flat so I got it changed.

Now another one has failed on the Mini again causing a flat.

Bottom line, I've taken then all off - I'd stay away from these things, they seem to cause more trouble than they're worth.

I had tried other makes which fit inside the tire and radio link the pressure information to a display unit, but couldn't find one which would fit my rims.

Tim

 

Tim -- Thanks for the info. I had read that some of those products can actually cause leaks if they break. Probably better to just check tire pressures every few weeks.