Tyre sensors on a Bailey 740 2015

[colin.tarbard]

Help

if the tyre pressure should be 55psi front 80 rear (as per label) When checked fronts where set at 68.

When lowered to 55psi the message NOW reads on the dash saying " tyre pressure low left and right". Found the menu button and found " tyre pressure" but can't alter the settings.

The motorhome has had a 45 min. run.

Tyre pressurers have been checked when cold.

Any ideas

Colin

[Derek Uzzell]

Welcome to the Out&AboutLive forums, Colin.

 

You’ll find this issue was discussed here

 

http://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/New-Ducato/37504/

 

The expectation for a ‘coachbuilt’ motorhome fitted with 215/70 R15CP tyres (like Michelin’s “Agilis Camping” pattern) and an Al-Ko chassis is that the recommended tyre inflation pressures will be 5.0bar/72psi (front tyres) and 5.5bar/80psi (rear tyres) irrespective of the vehicle’s actual axle loadings.

 

It’s well known that motorcaravanners enjoy fiddling about with those pressures (usually to counter an overly-hard ride) and, historically, this has not presented problems. However, when the motorhome’s base-vehicle (Peugeot Boxer in Bailey’s case) has been factory-fitted with a Tyre Pressure Monitoring System (TPMS) and the system’s sensors have been programmed to reflect high recommended inflation pressures, if the motorhome converter then advises significantly lower pressures it’s pretty much inevitable that the TPMS will react by issuing low-pressure warnings.

 

I hesitate to say this, but much of the tyre-pressure discussion on motorhome forums is simplistic. Studying a tyre manufactuer’s technical data and weighing the motorhome is fine, but it won’t necessarily result in optimum on-road performance. While a Bailey 740 may be ’safe’ with a 55psi front-tyre pressure, it’s handling and braking may be better if the pressure were higher. When asked for advice on what pressure would be appropriate for measured axle-loadings, Michelin used to state a ’safe’ pressure for front tyres and suggest that this should be increased by 10% to deal with weight transfer during braking and cornering.

 

As I said in the earlier forum thread, I think 55psi is low for 215/70 R15CP front tyres on a large coachbuilt motorhome. If I were the owner of a Bailey motorhome with a ‘false warning’ TPMS I’d inflate the front tyres until the warnings ceased and check what that pressure was. If it were (say) 65psi, that’s what I’d use and sod Bailey’s recommended 55psi. The alternatives would be either to follow Bailey’s 55psi advice slavishly and accept the TPMS will issue warnings, or for the TPMS sensors to be reprogrammed to the lower pressure (assuming that’s practicable or desirable).

[colin.tarbard]

Thanks for the info.

[Rayjsj]

Derek Uzzell - 2015-05-29 8:58 AM

 

Welcome to the Out&AboutLive forums, Colin.

 

You’ll find this issue was discussed here

 

http://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/New-Ducato/37504/

 

The expectation for a ‘coachbuilt’ motorhome fitted with 215/70 R15CP tyres (like Michelin’s “Agilis Camping” pattern) and an Al-Ko chassis is that the recommended tyre inflation pressures will be 5.0bar/72psi (front tyres) and 5.5bar/80psi (rear tyres) irrespective of the vehicle’s actual axle loadings.

 

It’s well known that motorcaravanners enjoy fiddling about with those pressures (usually to counter an overly-hard ride) and, historically, this has not presented problems. However, when the motorhome’s base-vehicle (Peugeot Boxer in Bailey’s case) has been factory-fitted with a Tyre Pressure Monitoring System (TPMS) and the system’s sensors have been programmed to reflect high recommended inflation pressures, if the motorhome converter then advises significantly lower pressures it’s pretty much inevitable that the TPMS will react by issuing low-pressure warnings.

 

I hesitate to say this, but much of the tyre-pressure discussion on motorhome forums is simplistic. Studying a tyre manufactuer’s technical data and weighing the motorhome is fine, but it won’t necessarily result in optimum on-road performance. While a Bailey 740 may be ’safe’ with a 55psi front-tyre pressure, it’s handling and braking may be better if the pressure were higher. When asked for advice on what pressure would be appropriate for measured axle-loadings, Michelin used to state a ’safe’ pressure for front tyres and suggest that this should be increased by 10% to deal with weight transfer during braking and cornering.

 

As I said in the earlier forum thread, I think 55psi is low for 215/70 R15CP front tyres on a large coachbuilt motorhome. If I were the owner of a Bailey motorhome with a ‘false warning’ TPMS I’d inflate the front tyres until the warnings ceased and check what that pressure was. If it were (say) 65psi, that’s what I’d use and sod Bailey’s recommended 55psi. The alternatives would be either to follow Bailey’s 55psi advice slavishly and accept the TPMS will issue warnings, or for the TPMS sensors to be reprogrammed to the lower pressure (assuming that’s practicable or desirable).

Why is it that Tpms cannot be adjusted to match the tyre pressure the user wishes to run with ? Surely it was invented to keep the driver informed of slow deflation, not to impose a mandatory level of pressure , no matter what the conditions? Sounds a very inflexible system to me.A very good idea being misused. If the 'Alarm level' could not be adjusted to MY choice of running pressures, hence a constant alarm, I would be looking to remove it.

[Derek Uzzell]

Ray

 

If you read my comments in the earlier forum discussion I provided a link to, you’ll see that the type of TPMS sensor (apparently) fitted to Ducatos/Boxers/Relays can be programmed to match a specified inflation pressure.

 

That reprogramming needs to done using a specialised ’tool’ may seem undesirable to you, but TPMS is a factory-fitted safety system and - in the case of a Peugeot-based motorhome factory-fitted with ‘camper’ tyres designed to be inflated to a high pressure and with those high pressures advised in the Boxer’s Owner Handbook and by the manufacturer of the vehicle’s Al-Ko chassis - it’s hardly surprising if a Bailey motorhome’s TPMS sensors will have been set ‘high’ in the Italian factory where a Boxer starts life.

 

A TPMS won’t have been chosen by a vehicle manufacturer to allow for a driver wishing to alter the vehicle’s tyre pressures radically from those advised in the handbook. In Bailey’s case it would seem that the motorhome converter has decided to specify a front tyre pressure of 55psi that is well below the 72psi that would be the normal recommendation for 215/70 R15CP Michelin Agilis Camping tyres on a motorhome’s front axle. That the TPMS then warns that a Bailey motohome’s front tyres are some 17psi down in pressure is the predictable outcome of the 55psi recommendation and (as I suggested in the other forum thread) owners of TMS-equipped Bailey motorhomes with this problem should be doing the obvious thing and seeking advice from Bailey.

 

As 72psi is the normal inflation-pressure recommendation for a front-axle 215/70 R15CP Michelin Agilis Camping tyre, it’s reasonable to assume that the TPMS sensor is set to warn at a pressure a fair bit lower than that to allow for ambient temperature variations. This is why I suggested inflating tyres currently at 55psi (and producing TPMS warnings) to an above-60psi pressure as a stop-gap measure to overcome te TPMS warnings issue. Doing so would certainly not harm the tyre and I doubt if anyone would notice much change in the motorhome’s ride quality.

 

 

[mgnbuk]

" If the 'Alarm level' could not be adjusted to MY choice of running pressures, hence a constant alarm, I would be looking to remove it."

 

YOUR choice of tyre pressure has nothing to do with the situation as, according to UK legistation (from the gov.uk website)

 

Tyres MUST be correctly inflated to the vehicle manufacturer’s specification for the load being carried. Always refer to the vehicle’s handbook or data.

 

That seems pretty clear cut to me - it is the VEHICLE MANUFACTURER who sets the tyre pressures applicable to the vehicle as far as the UK authorities are concerned. In my case. my Roller Team T-Line 670 has a sticker in the front door reveal stating 5 bar front 5.5 bar rear - that is what a roadside check would refer to as the "recommended pressures" should I be stopped & checked, so that is what I run at. IIRC there is only a 10% leeway on the "recommended pressures" from a legal point of view. Harder ride ? So be it ! And as for "removing" the system, I seem to recall that these systems are now (or are soon to be) a requirement - removing will not be an option and will most likely be subject to a functionally check at MoT time.

 

This does not help the original poster - if his manufacturer states 55 psi front, then it would not be unreasonable for said manufacturer to set the TPS monitors to suit. But then who is the "manufacturer" here - Bailey who do the conversion, or Fiat / Peugeot who build the chassis (arguably the bit that matters from the tyres point of view ?). As Fiat, Continental & Michelin all seem to recommend 5 bar front / 5.5 bar rear for "Camping" tyres, those would appear to be the values to use in preference to Bailey's lower recommendation.

[Rayjsj]

mgnbuk - 2015-05-30 10:33 AM

 

" If the 'Alarm level' could not be adjusted to MY choice of running pressures, hence a constant alarm, I would be looking to remove it."

 

YOUR choice of tyre pressure has nothing to do with the situation as, according to UK legistation (from the gov.uk website)

 

Tyres MUST be correctly inflated to the vehicle manufacturer’s specification for the load being carried. Always refer to the vehicle’s handbook or data.

 

That seems pretty clear cut to me - it is the VEHICLE MANUFACTURER who sets the tyre pressures applicable to the vehicle as far as the UK authorities are concerned. In my case. my Roller Team T-Line 670 has a sticker in the front door reveal stating 5 bar front 5.5 bar rear - that is what a roadside check would refer to as the "recommended pressures" should I be stopped & checked, so that is what I run at. IIRC there is only a 10% leeway on the "recommended pressures" from a legal point of view. Harder ride ? So be it ! And as for "removing" the system, I seem to recall that these systems are now (or are soon to be) a requirement - removing will not be an option and will most likely be subject to a functionally check at MoT time.

 

This does not help the original poster - if his manufacturer states 55 psi front, then it would not be unreasonable for said manufacturer to set the TPS monitors to suit. But then who is the "manufacturer" here - Bailey who do the conversion, or Fiat / Peugeot who build the chassis (arguably the bit that matters from the tyres point of view ?). As Fiat, Continental & Michelin all seem to recommend 5 bar front / 5.5 bar rear for "Camping" tyres, those would appear to be the values to use in preference to Bailey's lower recommendation.

. I would take the convertors recommendation on tyre pressures, as they know the changes made, and loads imposed on front and rear axles, also, if the unusually high tyre pressures caused an uncomfortably hard ride, then I WOULD lower them, provided it didn't affect the handling. So,TPMS a good idea? Only if the driver stays in control of the pressure set, and the alarm system is also level set by the driver. Otherwise I would remove it, to be replaced at MOT time if necessary. As I said a good idea to monitor for disastrous slow punctures and prevent blowouts, but potty if not adjustable for conditions by the driver.

[Pete-B]

HI,

I contacted Vanco tech dept about suggested pressures for my 217/70 R15s on a Bessie E460, I gave them the weight when loaded, taken from weighbridge ticket, they came back with front, 47.1 psi and rear, 68.8 psi. The van always seemed to run and handle well using these pressures. so I often wonder when people talk of up to 70psi in the fronts and 80 in the rears just how hard their van rides and handles?