Getting new run flats installed on a 2010 MINI Cooper S, 18k miles on the car. Do I need some kind of tire pressure replacement kit thing that Pepboys is trying to sell me? Seems like a waste of $20, it's some kind of washer thing that goes inside the tire.

Thanks

 

Tire pressure sensor? I'm not 100% sure what they're talking about but maybe that's it?

 

No they don't change the sensor itself. The guy was not very clear on what it was which led me to think it was sketchy.

 

What you need is a tire repair kit that includes "Slime" and a 12v air compressor. Run-flat tires are considered trashed if you go over 50 miles or over 50 mph. Many shops refuse to repair them, even a MINI dealer. I can't tell you the headache I had trying to get a flat repaired. Only had 500 miles on the tire but none of the chain stores would repair and being out of town i didn't have access to any of my hometown mechanics.

 

Ah, my mistake. This does sound weird indeed.

 

Vehicles with TPMS require a "service kit" to be used when tires are mounted / dismounted. Consists of rubber seals for around the tire valve that presumably could age and leak.

My tire guy(s) have said they are "required by law" to change these out whenever tires are mounted, but I've never checked for myself.

$20 or so is consistent with what I've paid.

 

Not sure about the required by law part but I think this is spot on. I had some new wheels and tires switched around etc and the tire guys did not make me buy the kits because the wheels, tires and sensors were all new. But in normal circumstances it is a good idea to buy the kits. My tire dealer charges $7.95 for each wheel kit. I would recommend the kit if the sensors have been in the wheels for a length of time.

 

Ok, so I did look.

FMVSS 571.138 covers Tire Pressure Monitoring Systems.

You can read it on the Fed's e-CFR site (Electronic Code of Federal Regulations) here:

http://ecfr.gpoaccess.gov/cgi/t/text...2.7.32&idno=49

It has a lot to say about what it should do, that a system is required, how a mfr. will need to test/certify it.

It is *silent* about any servicing / maintenance requirement, i.e. there isn't any such requirement.

That puts this into the same category as (in older times) replacing valve stems when you replace tires, or similar. Are they old, brittle, or iffy? Then replace them.

So now, with the rubber seal and valve parts of the TPMS monitors? Change them when the same conditions apply? Particularly when the TPMS monitor doesn't need to be removed and replaced. On a tire replacement, it needn't be; it would be on a rim replacement. If the shop didn't have to remove / replace the TPMS unit/valve, potentially damaging it, or if it isn't very old and holds air just fine, then my opinion would be that using a service kit would be...unneeded.

$10-20 a tire/wheel, cheap insurance against a failure? Ok, perhaps. But shops saying "it's required by law" isn't factual.

Unless it's a state law that requires such. There is no federal one, I just looked. A google for "tpms kit required by law" shows this to be a *popular* topic on a zillion forums.

 

Local tire shops have boxes of the o ring seals. They charged me a dollar or two.