TPMS - Accurate or Indicative?

Rapido925M

Rapido925M

Joined
Feb 5, 2014
Posts
1,827
Likes collected
4,475
Location
mid-Norfolk
Funster No
29,980
MH
A class
Exp
since 2006
Following a previous thread on Tyre Pressure Monitoring Systems I asked for one as a birthday present. (y)

Not surprisingly, the one I got was a cheap one. (n)

So my long-lived digital tyre pressure gauge says the tyres are 45psi (front) and 51psi (rear) in accordance with manufacturers recommendations. :winky:

My new toy tells me: FL=53, FR=51, RL=59, RR=56.
The temperatures also vary from 8deg to 14deg despite being parked in the shade and with RL being the highest.

As I drive all of the figures increase, with RL going slightly faster than the rest, achieving a maximum value during 700 miles of mixed travel (inc 70mph for miles on a motorway) of 65psi.
[Eventually I set the "over-pressure limit" to 68psi to stop the alarm going off!]

Should I upset my family and ask them to get a refund because it's not accurate OR should I just keep driving and accept that it will warn me if the pressure changes dramatically?

Gordon

PS I don't normally drive for miles at 70mph but we were in a hurry to get home after the second disappointing holiday this year. Interestingly, it didn't affect my consumption significantly.
 
Got some cheap ones on my jag, they seem ok.
Have tyrepal on the MH they are better but still not perfect, sometimes they take ages to wake op on one wheel, not always the same one.
So as you say use them as indicators rather than precision pressure gauges!
 
I have a Tyrepal Set. They do have a Psi or 2 difference, and like all these items are more a guide rather than an exact replication. The Garage forecourt gauges (used to) have to be periodically calibrated. I have a total of 3 Tyre pressure Gauges 2 are Aneroid and one digital. ALL give different reading to the Tyrepal units!. I notice an up to 10psi increase in Tyre pressure and an increase in Temperature when running.
 
I was more concerned that my cheapo TPMS would leak at 80psi - but so far so good and no leaks. Reads 76psi at garage set 80psi so happy enough with that. As above I'm more bothered about changes to values rather than absolute values. Pressure gets to 87psi max on a run which is scary but normal.
For the money they are a great piece of safety kit
 
Our TyrePal TPMS readings match with our (TyrePal) handheld gauge & the readings are consistent between sensors. As in leaflet supplied ours are set to alert at 20% over set (cold) pressure & 15% below set (cold) pressure.
As we often mention on here we wouldn't be without them (even in addition to manufacturer fitted TPMS) as consider these to be an essential safety product for both our car & motorhome. For anyone considering TPMS don't forget we have a Fun discount code for TyrePal https://www.motorhomefun.co.uk/foru...-code-for-funsters.194219/page-3#post-3710244 or keep an eye out for their sales a couple of times a year. TyrePal is tried & tested product with good after sales & technical support but many other versions are available & any TPMS should be better than none.
 
jezport said:
Got some cheap ones on my jag, they seem ok.
Have tyrepal on the MH they are better but still not perfect, sometimes they take ages to wake op on one wheel, not always the same one.
So as you say use them as indicators rather than precision pressure gauges!
Click to expand...
TyrePal are looking into the refresh function so it then would not be necessary to move the vehicle to check latest pressure.
 
Tyrepal seem pretty accurate on mine.
If you see one sensor getting hotter quicker it can be a sign of that brake binding or slide pins need lube

Subscribers  do not see these advertisements

 
Rapido925M said:
Following a previous thread on Tyre Pressure Monitoring Systems I asked for one as a birthday present. (y)

Not surprisingly, the one I got was a cheap one. (n)

So my long-lived digital tyre pressure gauge says the tyres are 45psi (front) and 51psi (rear) in accordance with manufacturers recommendations. :winky:

My new toy tells me: FL=53, FR=51, RL=59, RR=56.
The temperatures also vary from 8deg to 14deg despite being parked in the shade and with RL being the highest.

As I drive all of the figures increase, with RL going slightly faster than the rest, achieving a maximum value during 700 miles of mixed travel (inc 70mph for miles on a motorway) of 65psi.
[Eventually I set the "over-pressure limit" to 68psi to stop the alarm going off!]

Should I upset my family and ask them to get a refund because it's not accurate OR should I just keep driving and accept that it will warn me if the pressure changes dramatically?

Gordon

PS I don't normally drive for miles at 70mph but we were in a hurry to get home after the second disappointing holiday this year. Interestingly, it didn't affect my consumption significantly.
Click to expand...

The tyre temperatures you refer to - presumably off the TPMS readout - did you check the tyres with an infrared thermometer for comparison?
 
I've had a Tyrepal TPMS for ages - about 9 years I think. Excellent!

Tyre temperature and pressures increase VERY significantly when travelling at high speed in hot weather conditions ie on the Med...

Often notice the pressure difference side-to-side when the sun is shinning on one side.

Have only had to replace wheel sender batteries once, but I think they are ready to be changed again - one wheel was slow to register, and now has stopped registering. But I think new batteries will sort it. (y)
 
they seem accurate to me , I think the reason one of the rear tyres get hotter than the rest is due To exhaust
fumes expelling onto it
 
TPMS in my opinion is NOT to replace the act of checking your pressures aspart of your regime, as mentioned elsewhere, it is awarning system concerned with CHANGE whilst you are on the move
such as a slow puncture occurring on the move so that you can find somewhere safer to stop

As long as it is consistently inaccurate ( ?) then that’s fine
 
We have Tyrepal too. The temperature readings are useful if you are into altering tyre pressures from the recommended values. Lower pressures, I found, caused a significant increase in tyre temperature. Probably not a good thing!
Our pressures are very accurate. I used a good pressure gauge to set the pressures then screwed the sensors on and the display shows the same.

Subscribers  do not see these advertisements

 
dunnah01 said:
I was more concerned that my cheapo TPMS would leak at 80psi - but so far so good and no leaks. Reads 76psi at garage set 80psi so happy enough with that. As above I'm more bothered about changes to values rather than absolute values. Pressure gets to 87psi max on a run which is scary but normal.
For the money they are a great piece of safety kit
Click to expand...
What make/size tyres you got Borr?
 
I have the Tyrepal Solar and reckon from experiments I've done it's pretty accurate. I think the problem is until you use one you don't realise how much the tyre pressures vary with conditions.
When running 35° ambient the side facing the sun the tyres will often be well over 5 psi higher than the shaded side and the temperature 10° higher.
My rears apart from as described above are nearly always within 1 or 2 psi but the fronts often vary by 3 or 4 psi. I also find after setting them on the drive at home it is best to drive the van for a few miles then let the tyres cool down and recheck them.

You need to remember if you didn't have a TPMS you wouldn't have a clue what was going on. Has it worried most of you for the last 30 or 40 years?

A bit like battery monitors once you have you are constantly checking the current, voltage, percentage of charge etc., never bothered you too much before you had one.
 
bigguspeckus said:
What make/size tyres you got Borr?
Click to expand...
I've ended up with Michellin Agilis Camping 225/75-16 118R CP at 80psi rear and 65psi front. Not done many miles but seem absolutely fine on my Ducato Maxi (4.25T) chassis with a 1700kg/2100kg Front Rear axle weights in my full running order
 
SpeedyDux said:
The tyre temperatures you refer to - presumably off the TPMS readout - did you check the tyres with an infrared thermometer for comparison?
Click to expand...

I never thought of that!:notworthy:

But now that I've done it, all tyres show as being at approx the same temperature, slightly hotter in the sun and within a couple of degrees of the sensor readings. (y)

Jev88 said:
Tyrepal seem pretty accurate on mine.
If you see one sensor getting hotter quicker it can be a sign of that brake binding or slide pins need lube
Click to expand...

The first journey with them fitted was en route for a service and RR got hotter than the rest, so I asked the garage to check that. Result: new brake pads required (£45 approx).

RR still gets hotter than the rest. I've trusted the garage for the last 6 years so I'll accept the need was genuine. :rolleyes:

Scotch mist said:
they seem accurate to me , I think the reason one of the rear tyres get hotter than the rest is due To exhaust
fumes expelling onto it
Click to expand...

A really good thought! (y)

Unfortunately, the exhaust exits at the other side to the hottest tyre. ;)

Thanks for the comments: I'll stick with these ones and just accept that they can warn me of sudden, or even gradual, changes.

Gordon
 
Rapido925M said:
The first journey with them fitted was en route for a service and RR got hotter than the rest, so I asked the garage to check that. Result: new brake pads required (£45 approx).

RR still gets hotter than the rest. I've trusted the garage for the last 6 years so I'll accept the need was genuine. :rolleyes:



A really good thought! (y)

Unfortunately, the exhaust exits at the other side to the hottest tyre. ;)

Thanks for the comments: I'll stick with these ones and just accept that they can warn me of sudden, or even gradual, changes.

Gordon
Click to expand...

Re the RR still getting hotter I would go with what Jev88 said. Put your hand on the centre of the wheel after the journey, see if it is significantly hotter than the LR one. The brake pads may have needed replacement due to premature wear because the brakes on that wheel are binding slightly. I've had a similar problem. It may need another trip to the garage to fix.

Subscribers  do not see these advertisements

 
Rapido925M said:
I never thought of that!:notworthy:

But now that I've done it, all tyres show as being at approx the same temperature, slightly hotter in the sun and within a couple of degrees of the sensor readings. (y)



The first journey with them fitted was en route for a service and RR got hotter than the rest, so I asked the garage to check that. Result: new brake pads required (£45 approx).

RR still gets hotter than the rest. I've trusted the garage for the last 6 years so I'll accept the need was genuine. :rolleyes:



A really good thought! (y)

Unfortunately, the exhaust exits at the other side to the hottest tyre. ;)

Thanks for the comments: I'll stick with these ones and just accept that they can warn me of sudden, or even gradual, changes.

Gordon
Click to expand...

Or swap the sensors, LR to RR, see if the higher temp. changes sides, if so it's the sensor, if not then it is actually the wheel getting hotter.
 
RR is probably more heavily loaded - are gas,batteries, driver etc on that side?
 
For some strange reason they label it as if you are facing the van, so RH side is UK nearside.
All the "heavies" are on the offside (=LHS by their reckoning).

However, I will swap the sensors and see what that tells me.

Gordon
 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top