Tyre pressure monitor system settings
Submitted: Tuesday, Oct 10, 2017 at 13:15
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raincloud
Have purchased a tpms for fitting to dual axle caravan. Usually run tyres at 40psi. What do you clever travellers, that use tpms, set the parameters at for pressure and temperature? e.g. pressure from 30psi to 60psi ? temperature say 20 deg to 80deg or greater variance?
Reply By: Mick O - Tuesday, Oct 10, 2017 at 14:36
Tuesday, Oct 10, 2017 at 14:36
Very much differs depending on the circumstances of travel. If on dirt, Tyre pressures are lowered but the alarm threshold set higher so as to pick up any discrepancy in pressure all the more quickly.
A hot late spring or early summer day on the blacktop up northish and you might be experiencing a lot more than 80C on the sun side. That's the joy of modern day TPMS's, you can easily adjust the parameters to suit the conditions.
On dirt for my vehicle; Front Tyres 40 top and 22 low Rear 40 Top and 30 Low
Trailer; 32 Top and 22 low Tyres set at 25 psi).
Bitumen; Front Tyres 45 top and 32 low Rear 45 Top and 32 Low
Trailer; 40 Top and 30 low Tyres set at 35 psi).
TPMS Review Blog
Cheers
Mick
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Reply By: catmandoo - Tuesday, Oct 10, 2017 at 15:16
Tuesday, Oct 10, 2017 at 15:16
Hi Raincloud,
I use the innawise TPMS system. This system requires that you set the parameters when the tyres are cold. I believe that it then uses an algorithm to calculate what the variation in pressure and temperature should be once travelling begins. This algorithm is apparently developed with regarded to established scientific principles pertaining to the relationship of pressure to temperature.
If the tyres become too hot (relative to the recorded pressure) an alarm is sounded. Likewise, if the tyre increases pressure too fast, or falls below the pressure that should correspond to the current temperature, the alarm will sound.
To answer your question directly, I too set my tyres at 40psi (dual axle van) and set my TPMS before commencing travelling. I then rely on the trickery inside my unit to do the rest.
Greg
AnswerID:
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Follow Up By: Shaker - Tuesday, Oct 10, 2017 at 17:44
Tuesday, Oct 10, 2017 at 17:44
How does the algorithm calculate the sun being on one side?
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Follow Up By: Member - Bigfish - Tuesday, Oct 10, 2017 at 17:50
Tuesday, Oct 10, 2017 at 17:50
Shaker...lol...its all done with smoke and mirros.
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Follow Up By: catmandoo - Wednesday, Oct 11, 2017 at 15:19
Wednesday, Oct 11, 2017 at 15:19
Shaker,
The system calculates for each wheel independently. Those on the sunny side may be warmer, but provided they are within tolerance (of the algorithm paremeters), all will be fine.
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Reply By: Member - Phil G (SA) - Tuesday, Oct 10, 2017 at 21:22
Tuesday, Oct 10, 2017 at 21:22
I set the lower pressure limit to just below the pressures I drop to on gravel.
So about 22psi front, 25 rear and 25 on the caravan.
The alarms on
mine are very easy to change so I go down to the 15 psi minimum on sand.
The temp and high pressures alarms are irrelevant, so I just set them high.
AnswerID:
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Follow Up By: Jackolux - Tuesday, Oct 10, 2017 at 21:55
Tuesday, Oct 10, 2017 at 21:55
I Do the same as Phil , agree about the high pressure and temp .
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Follow Up By: Member - Roachie - Wednesday, Oct 11, 2017 at 08:12
Wednesday, Oct 11, 2017 at 08:12
I spend about 95% (+ unfortunately!!!) on bitumen at the moment, so I would be reluctant to set my TPMS for the lower pressures used when on gravel roads.
I run the Chev @ 60 front, 65 rear and the Bushtracker @ 45 all-round.
So I have set the monitor to alarm @ 5 psi below those figures.
I'd be concerned if they were set to (say) 25psi they wouldn't alert me in time if I had a slow leak. By the time they went off, the tyre would probably have already blown-out OR at the very least would be rendered U.S. by virtue of the excess heat.
I do have the external monitors and acknowledge something already said.....that the temp readings are less likely to be of much value due to the excessive influence of the ambient temperature. I can't even recall what temp settings I put in, but think it was about 60 degrees.
Roachie
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Follow Up By: Member - Phil G (SA) - Wednesday, Oct 11, 2017 at 16:12
Wednesday, Oct 11, 2017 at 16:12
Gday Roachie,
60psi! Thats the limit of the pumps at the servos!
I'm guessing you'd have to get the compressor out to get to 65?
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Follow Up By: Member - Roachie - Wednesday, Oct 11, 2017 at 19:35
Wednesday, Oct 11, 2017 at 19:35
G'day Phil,
I use a PX07 compressor with an 18 litre tank...all on-board the Chev.
I used to only run about 50psi and since increasing the pressure in the 35s I'm getting in the high 13s/100 as opposed to the low 15s/100 previously; not bad for a 5 tonne truck in my book. It goes up to mid 19s/100 when the Bustracker is hooked on (around 8,300kg all-up).
Roachie
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Follow Up By: Member - Phil G (SA) - Thursday, Oct 12, 2017 at 08:54
Thursday, Oct 12, 2017 at 08:54
Yeah tyres can really cost you fuel. We're heading off to the eastern states soon to witness 2 more grandchildren come into the world. Our van is single axle with 10 ply tyres that can take 80psi, so I am upping them from 50 to 60 too. It has independant
suspension and the wheel alignment drifted out causing the tyres to scallop - after I fixed that and put a bit more pressure in towing consumption went from 21.6 l/100k to high 19's averaged over many tanks.
You and I are talking like old farts :-)
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Follow Up By: Member - Roachie - Thursday, Oct 12, 2017 at 18:40
Thursday, Oct 12, 2017 at 18:40
Old farts indeed mate!!! hahaha....Ahh
well, it sure beats the alternative I suppose!
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Reply By: Member - J&A&KK - Wednesday, Oct 11, 2017 at 01:37
Wednesday, Oct 11, 2017 at 01:37
Hi Raincloud
Some food for thought from what I recently learnt from Bridgestone.
If your TPMS has external sensors then tyre temperatures have limited value due to the fact that the temperature they display is strongly influenced by the external air heating/cooling influences.
If a tyre has a tread temperature of 80C then it is most likely that permanent damage to to the tyre structure is occurring. Most likely the internal air temperature of the tyre is less than 80C but I couldn't find any published literature linking internal temperature to trade temperature. Conclusion - none really but set temperature alarms at 60C as a starting point.
Major tyre destruction is usually a result of sustained high temperature. It may be short and sweet, due to blow out, or prolonged. It is the result of load, load rating, speed, tyre construction, tyre pressure and work that the tyre is experiencing. A rather complex subject.
I suggest you look carefully at the specs of the particular tyres you have on your van. Knowing the loaded weight of your van you should be able to calculate the load on each tyre. Based on the tyre max pressure at max load figures, placarded on the tyre, you should be able to arrive at a tyre pressure starting point. From that point your experimentation can begin.
Other people recommendations are always useful. However they are particular to their tyres, loads and speeds. So have fun working out what works for you. It will keep you busy for a while.
Safe travels
John
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Reply By: raincloud - Wednesday, Oct 11, 2017 at 09:20
Wednesday, Oct 11, 2017 at 09:20
Many thanks to all contributors for their input. At last all info was useful and to the point without the usual waffle . All replies were greatly appreciated. Just as an aside the reason I'm fitting TPMS is that on my last 3 months trip I destroyed 2 tyres and one rim on the van, expensive exercise, without knowing anything was wrong until too late. Thanks again fellow travellers!
AnswerID:
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Follow Up By: Member - Roachie - Thursday, Oct 12, 2017 at 18:46
Thursday, Oct 12, 2017 at 18:46
That's the moot point mate......
I had an interesting discussion with a mate of
mine 2 days ago about this very subject.
He said he'd had a blow-out on his caravan and I said he should consider fitting a TPMS system.
He said words to the effect of: "they're not worth the effort....it wouldn't have saved me from a blow-out".
I tried (in vain) to point out that in all likelihood his tyre didn't just go from being perfectly okay to all-of-a-sudden blowing out. It is more likely that it had a slow leak which may not even have been apparent to the naked eye if he had inspected it relatively recently.
However, had he had a TPMS it is likely that it would have alerted him to reduced pressure BEFORE the sidewalls heated-up so much that the tyre exploded.
Nup!!! He didn't get what I was saying at all.
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