TPMS Low Pressure Too Low

[Willum]

Has anyone any experience of doing battle with one of these aftermarket TPMS systems?

They are listed as being capable of dealing with 8 bar (116PSI), so well within my max of 76 PSI on the rears (yes, I have got a max rear axle load of 2490Kg and 120/121 LR tyres👍)

Apart from the following issue, I'm very pleased with the result, the pressures are shown clearly and accurately and the display is much brighter and easier to read than the Tyrepal I had previously.

I've struggled through the minute print in the (dreadful Changlish) instruction leaflet and managed to activate the sensors OK and adjust the rear overpressure warning up to 87 PSI.  Whatever I try, I can't see how to get the under-pressure warning above 37 PSI - or the overpressure above 87 PSI, for that matter.

If anyone has experience on how to solve the problem, or seen anything on Youtube/whatever, I'd be very grateful for a pointer?

Will

[Steve928]

I have a unit (used it for a double-axle trailer not for the motorhome) that looks exactly like yours but with external sensors that screw onto the valve in place of the dust cap. As with yours, the highest low pressure alarm programmable is 37 p.s.i.

That aside it's been a great unit and is still working after 4 or 5 years. Unfortunately the sensors do eat batteries though (max. 6 months) seemingly because they do not have a sleep mode; I've just turned it on now and all 4 trailer wheels have reported their pressure within a couple of minutes despite the trailer not having moved for a month or so. Not a big problem with external sensors and easily-replaceable coin cells, but it would be less than ideal should your internal sensors have similarly short battery life.

[onecal]

Hi

I think your product is geared towards a car (with much lower threshold pressure levels) You may need to go for a Truck based product for the threshold levels you require for your tyre pressures. 

Regards

[Steve928]

3 hours ago, onecal said:

Hi

I think your product is geared towards a car (with much lower threshold pressure levels) You may need to go for a Truck based product for the threshold levels you require for your tyre pressures. 

Regards

Mine (and the OP's, given the 116 p.s.i. that he quotes) are the higher pressure van/truck/whatever model - there are car versions available with a lower max. pressure.

The point, surely, is that for a unit with a 116 p.s.i. maximum pressure, a 37 p.s.i. highest low pressure alarm is inadequate; I would estimate that anyone pumping their tyres up to anywhere even approaching the 116 p.s.i. that the unit supports would like to be notified of a deflation prior to the tyre reaching 37 p.s.i.

Edited August 27, 2023 by Steve928

[onecal]

Hi

I think maybe ,you should take that up with the sellers of such products lol and not direct it at me,as you say  (strange it's actually showing a car icon) so it really looks as a lot of those have only applicable threshold  for a car (sellers are easily checked out on google) Anyway as they are cheap on line if you look at the Truck models you will see they have a much higher lower threshold pressure that may suit the O.P's  needs

Regards 

Edited August 27, 2023 by onecal

[Willum]

Interesting range of replies.  The system was bought because, as Steve928 notes, it covered a range up to 116 PSI (8 bar) and well beyond my max requirements.  There are plenty that offer a max of 46 PSI (3.2 bar) but this system is, in part at least, designed for high pressures because the sensors in the tyres are able to cope with the higher pressures, reading accurately at 76 PSI.  The overpressure values are readily reset to 87 PSI (although no higher), so why cannot the under-pressure value be set above 37 PSI?  It is, after all, probably the most important warning function of all!

The original question was:

Does anyone know what the routine is for setting the under-pressure value above the current 37 PSI limitation, as it's obviously nothing more than a software function.  There may well be something in the less than informative and badly worded instruction manual - but it's beyond my ken to work it out.

Yes, I have asked the seller the same question but since he probably speaks the same language as the instruction manual - I'm not holding my breath.  Luckily, it's quite common to find some wizard who has managed to work out the frequent shortcomings of similar instruction manuals and we're often lucky enough to find that they have shared the results of their struggles on the likes of Youtube.

That's all I'm hoping for - someone who has spotted the appropriate wizard offering an answer for my problem case and can point to said missive.  😃

[onecal]

Hi

Again I think if you look on line the truck model may just suit your needs if you are just looking for a threshold level of a low pressure higher than 37psi. Again I don't think the higher pressure makes any difference only maybe a misleading selling point Maybe the threshold levels may be programmable But I am not so sure on these cheap models 

Regards 

[Steve928]

21 hours ago, onecal said:

Hi

I think maybe ,you should take that up with the sellers of such products lol and not direct it at me,

That usage (like this) is called quoting a post and isn't directed at anyone; it makes it clear to all readers of the new post to which previous discussion points the new post refers.

Directing a post at a particular person would be, for example, starting a post with 'Hi {insert username here}'.

I hope that helps any forum user who isn't up to speed on forum etiquette.

[Derek Uzzell]

I fitted a Tyrepal "Solar" TPMS system to my 2015 Rapido motorhome. This system (like Steve's) had removable sensors screwed on to the top of the tyre-valve stem.

https://www.tyrepal.co.uk/wp-content/uploads/2017/06/User-manual-TyrePal-Solar-Colour-V3-20170920.pdf

The pressure range was 0-99psi and the suggested 'alert' levels were

The sensors were said to 'sleep', but the sensor batteries (inexpensive) in my early monochrome Solar system needed to be in good condition and I replaced them annually. If I remember correctly, later colour Solar systems have sensors with larger batteries with a 2-year expected lifespan.

It was an useful system (though occasionally could be cantankerous) and it was interesting to see the effect on tyre pressure/tyre temperature of variations in the weather, the road surface and vehicle speed.

[onecal]

Hi

I really think one gets what one pays for and some of these are unreliable and sold with very little information or backup, As the O.P was looking for a higher ( low pressure alarm above 37 psi) The cheap truck models of these units may just suit him

Regards 

[Willum]

Whilst generally true, sadly my experience doesn't always bear out the phrase 'you get what you pay for'.  My TyrePal (at well north of £100) has been back to Tyrepal because, despite being carefully looked after, it has become unreadable in bright light.  Unfortunately they seem unwilling to accept it has dimmed and can see nothing wrong with it.

I think the photos say it all.  The first image is in the most shaded area of the dash, the second being dead centre but well back from the screen - and the TyrePal is turned on.

A punt at less than £20 for the aftermarket option is no great loss if I can't manage to get around the software/awful description problem but as onecal says, a truck version will doubtless get me out of difficulty.  The £20 punt will go nicely with the wife's Citigo, or my old Saab.

Edited August 28, 2023 by Willum

[onecal]

Hi Will,

This model is for cars ? The higher pressure they quote may just be a misleading selling point Your original post was about the low pressure not exceeding 37psi and I am afraid one does get what one pays for in most cases poor quality,it may be better backlit but not fit for your purpose as you quote with not high enough low pressure threshold . Again maybe a truck version may serve your needs, it too has very bright backlit screen for daylight viewing ,but I am afraid a lot of these cheap models may not just cut the mustard  with very little backup or instructions with same 

Regards

Edited August 28, 2023 by onecal

[Derek Uzzell]

The instructions pages for the £20 TPMS product advertised here

https://www.ebay.co.uk/itm/235161437039?hash=item36c0b6c36f:g:ixoAAOSwInZk7IVz

quote a 'detecting pressure range' of 0-116psi, but the advert itself quotes 87psi (I'm not sure what the exclamation mark signifies!)

'Truck' retro-fit TPMS systems are marketed. This is an example

https://www.steel-mate.co.uk/product/tp-81e-commercial-diy-tyre-pressure-monitoring-system-tpms/

and a sensor pressure range of 0-174psi is quoted.

My experience of TyrePal readouts is that an over-pressure alert based on a maximum pressure of 87psi would be marginal for motorhome tyres inflated to 72psi. For a 72psi recommended inflation pressure I'd want to set the under-pressure alert to 60psi and being unable to set that alert above 37psi would be a serious limitation.

Given the price of OEM TPMS tyre-valves, if I were only going to spend £20 on a retro-fittable TPMS product, I would never choose the type with 'internal' sensors. At least if the sensors are 'external' (like Steve's) it is not necessary for wheels to be removed to fit the sensors and, if problems/limitations subsequently come to light (eg. a short battery lifespan) the £20 outlay can be written off without much heart-searching and without worrying about the  longevity of the tyre-valves included in the TPMS 'kit'.

[Willum]

Hi Derek.

I take the point ref internal versus external pressure sensors.  Being one who trys to be keep tyre pressures properly set - and hence put the airline on them fairly regularly - I got fed up with getting black fingers, messing about removing the external sensors and refitting them every time I wanted to apply the airline.  Hence the idea of using internal sensors.  A 5 year battery life is quoted, so, thinking I'd swallow the £10/tyre remove and refit in 5 years time, I'd go down that route.  I also have a manual tyre fitting machine and, although I find these big tyres quite hard work, the tyre doesn't have to come off to swap the sensor.  Just (very carefully) push the tyre off the bead on valve side.

There seen to be a couple of contradictions in the listing for the Excelvan but I suspect the '87 PSI!' exclamation mark bit is a result of the same limitation I found:  they probably won't set higher than 87 PSI as a high pressure warning and the listing also notes they are not suitable for tyres inflated to more than 87 PSI.

Altogether, not very confidence inspiring.

As for working temperatures and pressures:

I contacted Falken Tyres HQ (in Germany) and got an answer very quickly.  I asked the questions ref correct inflation pressures for given axle loads, based on the tyres I've used.  Here's their response:

"We are glad that you are considering the use of Falken tires.

Unfortunately, we do not have data limiting operation under lowest or highest temperatures. However, since these are extremely durable tires, I would not worry about this.

The highest and maximum possible inflation pressure per tire is 575 kPa / 5.75 bar.

 According to your information, the required inflation pressures for 225/75R16C 121/120R VAN11 are as follows:

 Front = 1750 Kg = 3.5 Bar

 Rear = 2490 Kg = 5.2 Bar

 Please note: For a trouble-free and also safe operation of our tires, we always assume the application of the full load inflation pressures, regardless of the actual axle load driven."

As yet I've had no response from Nankang, ref their seriously failing tyres that I've just taken off and replaced.

[Derek Uzzell]

15 hours ago, Willum said:

...I also have a manual tyre fitting machine and, although I find these big tyres quite hard work, the tyre doesn't have to come off to swap the sensor.  Just (very carefully) push the tyre off the bead on valve side...

Plainly, if one can DIY the valve installation, that makes 'internal' sensors more attractive.

I agree that needing to remove 'external' sensors from tyre-valves is a pain, but I found with the Michelin tyres fitted to my Rapido motorhome's steel wheels that 'natural' air-loss over time was minimal (and I could regularly monitor the pressures via the TyrePal system).

Although it is simple enough to obtain pressure-to-axle-load data for van tyres using Continental Tyre's on-line listings, I'm not aware of information on maximum temperature limitations being available.

[Steve928]

21 hours ago, Willum said:

  I also have a manual tyre fitting machine and, although I find these big tyres quite hard work, the tyre doesn't have to come off to swap the sensor.  Just (very carefully) push the tyre off the bead on valve side.

I agree, I managed to change the internal TPMS sensors into my 225/75R16C winter wheels using the very common bright red manual 'tyre machine' to break the bead and a block of wood to hold the bead down while the valve+sensor is installed.

[Willum]

22 hours ago, Derek Uzzell said:

Plainly, if one can DIY the valve installation, that makes 'internal' sensors more attractive.

I agree that needing to remove 'external' sensors from tyre-valves is a pain, but I found with the Michelin tyres fitted to my Rapido motorhome's steel wheels that 'natural' air-loss over time was minimal (and I could regularly monitor the pressures via the TyrePal system).

Although it is simple enough to obtain pressure-to-axle-load data for van tyres using Continental Tyre's on-line listings, I'm not aware of information on maximum temperature limitations being available.

Agreed, the TyrePal/whatever system is very good for watching gradual loss, the only awkwardness I found was that you either had to drive off, or walk round and wiggle all the sensors about manually to get them to trigger.  Doubtless the internal systems will need some sort of motion trigger as well.

The only reason I asked Falken about a safe temperature range is that it seems its shown on all the aftermarket TPMS monitors - and I'm curious.  I've often seen tyre temperatures approaching 50°C in recent Spanish summers.  It's not in the same league but from a previous life I know some motorsport tyres get hot enough to give a nasty burn on your hand if grabbed hold of without gloves too soon after stopping.  Falken think it of no great consequence and I can understand that.  I can also see that any road tyre that gets above 70/75°C figure, the default for most of these system, is going to have some sort of problem that should be addressed - so fair enough.