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Did you know you can install your own tire pressure monitoring system (TPMS) on older cars? Turns out it’s a pretty simple system. Most aftermarket (and stock) systems rely on one of three sensor types: They either mount on a metal strap tightened around the center of the wheel, attach to the inside of the wheel right behind the valve stem, or replace the valve caps.

Obviously the valve cap type is the easiest to install — and thus the most common aftermarket install — but they’re bulky and a little funny-looking. Most OEM systems install behind the valve stem and require careful torque consideration to function correctly. A tool like the one pictured above makes the job quicker and easier, but any high-quality torque wrench (accurate in the right range) will do the job.

If you wonder what the behind-the-valvestem type sensors look like, eBay Guides features a How to Install TPMS post that includes photos of a typical install — though it fails to mention torque specs, which you’ll likely find in the instructions that come with aftermarket models (or in the shop manual for OEM replacements). The strap type works just fine, too, at least in my basic internet research. The G35 Driver’s forum shows some pictures of a strap type installation (with good feedback).

A little searching turned up a variety of aftermarket kits starting at around $100. My favorites:

Accutire’s MS-4378 Remote Tire Pressure Monitor ($100)

It’s pretty much a plug-and-play install, with valve-cap sensors and a cigarette-lighter-powered receiver with a range of around 40′. This strikes me as a kick-ass solution to trailer TPMS. Just screw the caps on your trailer tires (you get four with the kit — perfect for tandems) and plug the receiver into the cigarette lighter on whatever the hell you’re driving to tow the trailer today. Then again, this probably isn’t the most aesthetically-pleasing unit for a daily-driver car install.

Street Pricing [Google Products]
Via Amazon [What’s This?]

Orange Electronic P409S Retrofit TPMS ($140)

Its behind-the-valvestem sensors are lithium-ion powered, so they should last a while. And the dash-mountable receiver looks pretty slick, so this might make a good system for mounting in your muscle-car. Plus, it’s not all that expensive.

Street Pricing [Google Products]
Via Amazon [What’s This?]

Revolution Supply’s Strap/Bracket Set ($60)

While technically not a full sensor kit, some aftermarket installs (like the one on the G35 forum above) don’t work with every possible wheel combination. If you’re stuck with wheels that don’t match up with existing sensors, you’ll need to go the strap route. Here’s a good example of what appears to be a well-supported strap kit. You match the strap up with various brackets to install the sensors. This can also work to help you retain the factory TPMS when you install incompatible aftermarket wheels on your newer vehicle.

Strap Kit [Revolution Supply]

One last thought: If you’re heading to Discount Tire or Tire Rack to buy aftermarket wheels, don’t be afraid to ask about TPMS systems or system relocation. It looks like both outfits — and probably most other major wheel/tire vendors — are prepared to help you through the process for a fee.

I’ve owned two cars with TPMS, but since the system never glitched I never really learned how they work. Now I’m intrigued. Of all the gizmos on my newer vehicle, this is one that I really do appreciate. Catching tire leaks early prevents unnecessary tire wear — and saves serious cash.


10 Responses to Retrofitting And Retaining Tire Pressure Monitoring Systems

  1. Blind says:

    I’ve heard that the valve cap style ones had a nasty habit of a slow leak due to how they are designed to work.

  2. Harry says:

    Are you really too lazy to check your tire pressure? Let’s remember 1998 Exploders and all of the roll overs that probably weren’t caused by bad tires, or a poorly designed vehicle but, by people that can’t check the air pressure in the vehicles. Fear not though, the government helped us by mandating TPMS systems on all of our new vehicles. Now there is one more warning light on the dash for drivers to ignore. However, TPMS systems mean more money for a shop as now a trire rotation costs a little more as the tech “relearns” the new tire positions. Of course the butterfly type OEM sensors below the valve stem get pretty expensive when snapped by a careless tire mmachine operator. I don’t really see the value of a TPMS system if you maintain your car properly, although it is the perfect companion to the oil life monitoring system.

  3. Duncan says:

    I was surprised to find that you can not tell the OEM TPMS systems what PSI/Bar you would like the warning to come on with, they are set to warn when the tires are grossly under pressure, i.e. in a dodge rental van the tires should have been at 36psi and the TPMS system only warned when they got down to 30psi.

  4. Joe says:

    Harry–I agree with you, these systems are no replacement for taking care of things properly.

    I believe that many (most? all?) “safety” controls/interlocks/alarms just cause people to think that the inanimate object that they are operating is now watching out for their safety, and they can think about other things…

    What does this lead to? More need for controls, more complicated machines (when will my saw have an “operating system”?), more expense, etc.

    Unfortunately, the die has been cast, and we’re unlikely to return to a position of personal responsibility/liability.

    But what do I know? I’m the guy who posted a couple of days ago about still using a fixed-blade utility knife, and I use a tractor built in the 1940s.

    “You know the good thing about metal dashes? After you wipe the blood off from the previous owner, you can just put in out on the lot for sale.”

    (That last comment may be carrying the theory a little too far)

  5. JML says:

    A related caution: the OEM and most aftermarket systems use a bolted-in aluminum valve stem, not a rubber coated brass stem . You MUST use a plastic valve cap with the aluminum stems, not a metal one. Galvanic corrosion will cause metal caps to stick to the valve stem, and when you try to remove the cap, you’ll snap off the stem, which causes a flat and requires installation of an expensive new stem.

    TMPS valve caps are gray, and come with a tiny rubber seal in the end. Green ones are supposed to accompany a nitrogen gas fill.

  6. KMR says:

    I should get these for my sister, she is an utter moron when it comes to taking care of her car. Told her for months to replace the timing belt on her 1.8turbo VW, nope nope nope…. BOOM. Instead of $300 she paid $3000 to fix the damage.

    One time she drove up from Delaware to NY to visit, pulled into the driveway, I noted that the 17″ tires looked low. Sure enough, TWO had ZERO air pressure the other two were at 10psi and 13psi. How do you drive 300+ miles and not know this? I yelled and screamed, it made no difference. A few months ago a tire came off of her car while driving on I-95 in PA. Likely cause is probably it was not inflated at all. Of course she didn’t have the wheel lock key in the trunk – seriously, why would you put it anywhere else?

    People like my sister should be arrested for driving poorly maintained vehicles on the road. They endanger other drivers because of their laziness and lack of caring.

  7. russ says:

    I came across these tire pressure monitoring systems during a car rental of a chevy impala a couple of years ago. The next morning driving to a customer I got a warning about low airpressure. I finally pull over and sure enough it was low. After stopping by a gas station I filled it up with air and didn’t have another problem afterwards. I thoughts I had picked up a nail the day before but it was fine the rest of the week.

  8. Thomas says:

    To KMR, I like to think i take fairly good care of my car. (I do put oil in it every once in a while) went to a mechanic once and told him there was something wrong with the back driver’s tire. He checked the pressure, looked at it. Said it was the brakes. I was like OK, sqeaky brakes will wait till payday (a week). Three days later, whole wheel fell off the car. If ya see a three wheeled car..

  9. Toolaremia says:

    TPMS isn’t a bad idea, but like most government-mandated safety nannies it’s been so poorly implemented (by law!) as to be nearly useless. They don’t say which tire is low, by how much, and the threshold pressures are so low that by the time it displays a warning some damage has probably already been done. And worse yet, the system can’t be disabled (by law!) when it fails. So the light on the dash keeps blinking and beeping long after the nearly-useless system has become completely useless.

    If the factory systems would display which tire was low, and by how much, it would be far more useful. Some systems on higher-end cars do that. But the crippled systems on most cars just add yet another aptly-named “idiot light” of little value. Responsible drivers will never see it (until the system fails) and irresponsible drivers will ignore it like they ignore every other idiot light.

    The factory sensors not fitting aftermarket wheels has been another big problem, and I didn’t know there was a strap solution. That’s great!

    The two retrofit solutions covered here look like they are not useless. The Accutire version gets horrible reviews on Amazon, but the Orange system gets lots of praise and is only $40 more. I think I will get that system to monitor my car trailer tires.

    Thanks, Toolmonger, for enlightening me about the Orange system and the retrofit straps!

  10. MeasureOnceCutTwice says:

    I’m a car guy – before I moved to China, I autocrossed, went to track days, and did just about all my own maintenance (FWD clutches included). I was obsessive about tire pressure if only because of all the wheel swapping that I did.
    On two separate times I got a flat tire while on a longer highway trip. At speed, the wide short tires gave little indication of the lack of pressure – the first time I only noticed the problem as I slowed to exit. The second time I noticed the car’s handling felt a little different – not much, and not enough that a typical driver would likely notice. But certainly enough that an emergency maneuver might be dangerous because of the low tire pressure. If I had the low pressure warning systems, it would have flagged these problems. I wouldn’t depend on them for normal inflation maintenance, but they would be a nice backup.

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