After market TPMS

[Sagitar]

I have been offered an after-market Tyre Pressure Management System (a Tyrepal TB99) and I am sorely tempted to give it a try.

 

I have never been keen on the OEM systems for a wide variety of reasons, but this after-market system overcomes most of my objections.

 

It does have downsides however e.g. the security arrangement looks flimsy and would make re-inflation more of a hassle.

 

My biggest concern however is that the sensor assembly, which screws onto the end of the inflation stem, weighs 9 gms. The inflation stem is flexible and I have a vision of this 9 gm lump wiggling the valve stem vigorously as the wheel rotates at speed.  I am assured that balancing is not a problem, but no-one has offered an answer to my questions about the stability of the assembly at speed and the possible fatigue effects that might arise. I suppose regular visual inspection would show signs of the start of any deterioration of the valve stem rubber?

 

Having just done a couple of long, high-speed, motorway trips, I am conscious of the extra safety that can be offered by the ability to monitor tyre pressures while on the move,but I do have these other doubts in my mind.

 

I would be interested to know if anyone else has tried this (or a similar) system, or if there is any testing evidence that relates.

 

I believe that cars introduced after 2012 must have TPMS and there seems to be doubt about whether after-market wheels also need to be fitted with a system, so I think this is going to be a growing issue in the near future.

[parthiban]

Interesting question regarding having that weight on the end of the valve stem - perhaps metal valves would solve that issue but then that brings with it all the other problems of metal valves (corrosion etc).

 

 

What are your concerns with OEM sensors? Except for the fact they can be easily broken if care isn't taken, on the whole I can't think of many negatives?

[Sagitar]

Interesting question regarding having that weight on the end of the valve stem - perhaps metal valves would solve that issue but then that brings with it all the other problems of metal valves (corrosion etc).

 

 

What are your concerns with OEM sensors? Except for the fact they can be easily broken if care isn't taken, on the whole I can't think of many negatives?

 

The stems themselves are already metal, but they are affixed to the wheels using an elastomeric mount that allows angular movement to the stem when lateral force is applied. I had looked at the possibility of corrosion between the sensor and the stem, but the Tyrepal threads are brass as are the stem threads on my wheels so they ought to be OK with appropriate lubrication and the movement that comes from occasional re-inflation.

 

The "easily broken" issue is an important one and seems to be a regular source of complaint on sites that I have looked at. Corrosion seems to be a problem too, but that may be because a lot of early devices used aluminium stems giving rise to electrolytic corrosion - perhaps manufacturers have improved them. They can go wrong for other reasons - they are radio devices - battery failure for example, or loss of calibration and since they are inside the wheel, maintaining or replacing them becomes a big deal. They have to be coded to the receiver and you may find that only a main dealer has the necessary equipment. I think some of the later models allow replacement of the stem alone but many require replacement of the whole unit and it is quite expensive. I read somewhere that it can add 50% to the cost of a new tyre, but that may be alarmist.  I believe an error in the display is now an MOT fail? Can anyone confirm or deny this? If so you cannot just ignore it. 

 

After-market devices screw to the end of the stem, so changing a battery is easy, they can be moved to different wheels easily and a complete replacement is a simple owner job, including coding them to the receiver, with the unit costing about £30 

 

However, I have no direct experience, so others may be able to give a better view. Which brings me back to my original question . . . . 

[Tony]

Tony Barber at wim is very wise to these systems, i'll get him to look at this thread.

[MondeoGhiaX]

Any more thoughts on these devices? I have been looking at the Tyrepal TB99,which is around £135 and also the much cheaper Steelmate TP-70 (£69).

 

The Steelmate monitor is a tiny unit that plugs directly into the 12v socket. This is quite a neat design but has the drawback of permanently occupying the 12v socket. It is also not as configurable or easy to read as the Tyrepal. At the end of the day though, they both do the same job.

 

Maplin also sell a system for around £75, but it doesn't look as good as the others to me.

 

My main concerns about these devices are the hassle of removing the sensors if you need to top up your tyre pressures regularly, the size and vulnerability of the sensors to kerb knocks, and the possibility of an air leak at the sensor. This could potentially result in a sudden tyre deflation, as the tyre valve is in effect open all the time.

 

Regards.

[Viking]

My VW Jetta has TPMS fitted, and uses the ABS system to monitor road wheel speeds in relation to the others (while also looking at the steering angle sensors etc.). From this it calculates the rolling circumference of the tyres, and if one starts to lose pressure it sees a differing reading and flags up a warning. It's not wheel specific, and it doesn't give you tyre pressures on display etc., but it's fairly simple, not easily broken, doesn't get impacted by tyre change monkeys with less than careful practices, and most of all it works.

 

If only I could educate the wife that a warning light on the dash invariable means something needs attention, not "I'd better wait til I get home and see what my husband says when he finds out at 10.00pm as he puts the car in the garage.".

[chrisgixer]

After a recent rear puncture that took about a minute to deflate, 30 seconds of which was spent driving on a flat tyre which destroyed it internally looking for a safe place to stop, it's become clear that an instant warning of low pressure and high temp would of saved me two rear tyres at £400

 

Why two? Because now the new tyre is fitted, the car pulls right on the power and left off the throttle, as the other rear is 2/3rds warn. Ok I've had the best out of them but I could do with getting the full life out of tyres this expensive. They where handling ok.

 

Anyway, after being sceptical, I've now seen the potential benefits of tpms. Especially as some systems are cheaper than a pair of rears for me, plus I like the idea of live data on pressures.

 

My concerns are the response times. My preference is for the external valve mounted type, and wonder how quickly this system can warn the driver? Every millisecond counts, it seems to me, to allow the driver as much time to stop before the rim grinds the internals to bits.

 

Also , the experience has shows why used tyres are a risk. If a valve fails and runs flat, the tyre would look fine externally, but inside half the rubber is missing with little to show the fault on the internal pattern.

[NickT]

I know that scenario. .. About 4 years ago Mrs told me at 23:30 one Friday evening that there was "some steam" that came out of the exhaust on her corsa earlier that day. I was home at 16:30! I could have had the engine striped down in that time. Needless to say I wasn't impressed and had to see the car (in my dressing gown)......... I'm sure she waits until my head hits the pillow, or my arse to settee has gone past "V1" (ie cannot stop) until she tells me something I could have done earlier. .....

 

 

 

My VW Jetta has TPMS fitted, and uses the ABS system to monitor road wheel speeds in relation to the others (while also looking at the steering angle sensors etc.). From this it calculates the rolling circumference of the tyres, and if one starts to lose pressure it sees a differing reading and flags up a warning. It's not wheel specific, and it doesn't give you tyre pressures on display etc., but it's fairly simple, not easily broken, doesn't get impacted by tyre change monkeys with less than careful practices, and most of all it works.

 

If only I could educate the wife that a warning light on the dash invariable means something needs attention, not "I'd better wait til I get home and see what my husband says when he finds out at 10.00pm as he puts the car in the garage.".