Tyre Pal

[Hutch]

To open a new thread, I have bought a monitor for the caravan, only towed the van , 1645 kg max weight, single axle with tyre pressures at 65. Cold. On the first 10 mile tow the pressures went from 65 psi to 73 psi and 9c to 16 c. . So what help and hints can folk say. A friend has said a touch of grease on the valve stem can stop corrosion, ,

 

[otherclive]

To open a new thread, I have bought a monitor for the caravan, only towed the van , 1645 kg max weight, single axle with tyre pressures at 65. Cold. On the first 10 mile tow the pressures went from 65 psi to 73 psi and 9c to 16 c. . So what help and hints can folk say. A friend has said a touch of grease on the valve stem can stop corrosion, ,

Or a gentle smear of ACF 50

 

[Hutch]

To open a new thread, I have bought a monitor for the caravan, only towed the van , 1645 kg max weight, single axle with tyre pressures at 65. Cold. On the first 10 mile tow the pressures went from 65 psi to 73 psi and 9c to 16 c. . So what help and hints can folk say. A friend has said a touch of grease on the valve stem can stop corrosion, ,

Or a gentle smear of ACF 50

Still have a spray can they gave me when I retired. :dry:

 

[Dodger524]

Depends whether your valve stems are brass or aluminium, I think it is the latter that can be a problem. I've used the TyrePal system for three years and haven't had any problem with them sticking.

With regard to the temperature figures you quote, they match my experience.

 

[Hutch]

Depends whether your valve stems are brass or aluminium, I think it is the latter that can be a problem. I've used the TyrePal system for three years and haven't had any problem with them sticking.

With regard to the temperature figures you quote, they match my experience.

Dodger, I take it that nothing special has to be done after inflating tyres, just refit the sensors and secure the lock nut. In my case I would be bringing the van home from storage so would see the pressures on the monitor and would not need to remove refit the sensors.

 

[ProfJohnL]

If after being in storge for some time, all the sensors gave the same reading I'd be a little suspicious, as I've rarely found all tyres on a car or caravan seal so perfectly. I think I'd be tempted to check the tyre pressures if for nothing else to confirm the sensors are actually functioning proprerly.

 

[Dodger524]

Yes, you will soon see the temperature and pressures change, which may well be an asymmetrical change. e.g. the load on my caravan is very one sided due to its design, where all the appliances are on the off-side. The off-side tyre heats up a little more as a result of carrying a greater load.

Initially one can be a little fixated with the constantly changing tyre pressures and temperatures, this will fade as on learns just to check occasionally such as soon after starting off as the system wakes.

 

[Ironduke2018]

I've got one of these, I think its brill. But my thought goes to the physical size and weight of the censors vs wheel balance. I read some place that top end Elldis caravans come with their wheels balanced. Do Swifts and Baileys? I never thought of that until then. Balanced caravan wheels, yeah that's right! If your car wheels were not balanced, at sixty MPH I think you would notice it for sure with everything jumping and shaking about. So whats going on back there in the van with our unbalanced wheels? Are they un-balanced even more by the size of the Tyre-Pals censors? Me thinks so, more questions than answers!
Observations ? Yes, like you say, as the tire's get hot, up goes the pressure! There will be no getting around this unfortunately, this is a fact of the laws of physics. Do we then compensate for this new found information by under inflating the tires by a few PSI before setting off? That gets us all into a can or worms best left if you ask me. But yeah, what about your pressures driving through France and Spain in summer, red hot rubber bursting at the seems probably. Not so bad on a twin axle with 35 PSI, but a single axle van with 65 PSI in the tires....then all this may start to mean something entirely different, (pardon the pun).

 

[Dodger524]

You raised a couple of points in your post.

Balance, yes my car and caravan wheels are balanced and that was done with the sensors in place when new tyres were fitted.

The weight of the TyrePal sensors (about 9g) have no desirable effect on wheel balance according to TyrePal, so no need to rebalance when they are fitted.

Tyre pressures are, or should be set with the tyres at ambient temperature, so they need no further adjustment to counter the temperature/pressure rise in use, that is catered for in the design of tyre.

 

[ProfJohnL]

For reasons that have been covered in otherthreads tyre pressures actually vary just a tiny amount whwn the carried load changes, so asymetric loading has no significant effect of tyre pressure.

Temperature certainly does, but its difficut to establish the internal air temperature without specialist eqeuipment. The surface temperature can be very different to the internal, so touching the tyre is not a good way testing tyre temperature.

Tyre manufactures are not daft, and of course they know that a rolling tyre carrying a load will heat up. It will be influenced by the ambaient temperature, but also by heat generated by the friction of the tyres materials as they flex under load. They will have tested their products to make sure they withstand the amount of energy that is used to heat the tyres in usage, and the resulting pressure and temperature gains for the conditions they are designed for. For example winter tyres have a rated maximum ambient temperature above which the shouldnot be used. and all tyres have an optimum static pressure range covering a static load range neither of which should be exceeded.

Ideally tyre pressure should be set accurately, but there will be variation in the accuracy of pressure gauages. It is not uncommon to find a 10% difference in readings between gauges, it seems Trading Standards do not now regulalry test them, so it's effectively impossible to know how accurate any of the domesstic or garage gauages are. But we dont see cars falling off the road all the time, so it is reasonable to assume margins of 10% are not significantly dangerous.

I would suggest that whilst absolute pressure accuracy woud be ideal, what is probably more important is consistency of pressure for tyres on each axle.

No type of gauge that is not calibrated can be considered more accurate than another, but digital gauges will normally resolve to a smaller unit thus making reading easier than analog or pencil gauges. Consistency is equaly important, and some gauges will exhibit a hysteresis effect, where it may give a different reading for the same presure depending on whether the pressure is rising or falling. The trick is to always use the same metheod to check the pressure for example always slightly over pressure the tyre and bleed pressure to bring it down to your target value.

Some electric pumps will switch automatically when a preset presure is reached.

 

[chrisn7]

The Tyrepal type I have are secured to the valve stem with a grub screw. The TP kit should have adapter to unscrew the sensors for battery replacement. I recommend you partially release each one, and check that the very fine sealing o-ring is intact.
What seems to happen is that on intitial assembly, the plastic can pick up on the dry o-ring causing it break, which results in a leak and corroded battery. I found two out of four like this.A smear of your preferred lubricant and new ring is all that is required.

 

[Dodger524]

Those currently supplied rely on a neoprene gasket and a brass backnut which is tightened with a supplied spanner.

 

[otherclive]

I check my car tyres weekly and make sure that the sun isn’t on one side or the other. The van gets checked before a trip and again when cold and wiith no sun on any one side.

When we were abroad the van would be checked generally in the evening en route when it would still be warm ambient temperature but no direct sun onto a tyre. Any adjustments were made as required. But that generally only required one or two checks going to the Mediterranean and the same coming back.

As Prof says the tyre makers factor in changes in ambient temperatures.