JKromberg
Member
I recently completed a road trip with my RV (2017 Thor 23u on E450) pulling a toad (98 Jeep Wrangler). Based on advice from this group, I put in an EEZTire TPMS system for both the RV and toad. This was my first trip pulling a toad along with having a TPMS system. It was quite interesting and educational watching the dynamics of tire pressure throughout the trip.
As per spec, the TPMS alarm thresholds were set to -10% and +20%. Before leaving, tire pressures were very carefully set cold as per the door stickers. Specifically: RV Front: 75psi, RV Back: 80psi, Wrangler: 32psi. All +/- 1psi.
Once I hit the road, I found it very interesting how much the pressure went up. I even got to the point of a couple of high pressure alarms. On rare occasions, the RV rears hit 96psi to trigger the alarm. They never went over that. The Wrangler had a case where one tire hit 39psi (but not over). The fronts went up but not quite enough to trigger an alarm. It should be noted that all alarms were during times of higher outdoor ambient temperature. When it was cold out, pressures were lower. This was an eye opener for me to see the radical pressure change as a function of driving and the temperature. I asked a tire shop and they said this behavior was normal. They also mentioned that they see people making the mistake of letting air out of a hot tire to match the cold temp spec.
The other thing that I saw that surprised me was the difference in morning cold pressure based on local temperature. Original pressure was set at home at around 40 degrees F. at one point, I was at an ambient temp in the morning of around 60. Tire pressure was up accordingly. Later, I was down into the 20?s overnight. Pressure was low.
I think one action I learned from this is to be sure to check pressure each morning cold and adjust as per local environment. Should I adjust for where I will be during the day? That is, I start cold and will be in a hot environment later in the day.
As I said, this experience was very educational for me. Before TPMS, I never realized the dynamics of tire pressures.
Jeff
As per spec, the TPMS alarm thresholds were set to -10% and +20%. Before leaving, tire pressures were very carefully set cold as per the door stickers. Specifically: RV Front: 75psi, RV Back: 80psi, Wrangler: 32psi. All +/- 1psi.
Once I hit the road, I found it very interesting how much the pressure went up. I even got to the point of a couple of high pressure alarms. On rare occasions, the RV rears hit 96psi to trigger the alarm. They never went over that. The Wrangler had a case where one tire hit 39psi (but not over). The fronts went up but not quite enough to trigger an alarm. It should be noted that all alarms were during times of higher outdoor ambient temperature. When it was cold out, pressures were lower. This was an eye opener for me to see the radical pressure change as a function of driving and the temperature. I asked a tire shop and they said this behavior was normal. They also mentioned that they see people making the mistake of letting air out of a hot tire to match the cold temp spec.
The other thing that I saw that surprised me was the difference in morning cold pressure based on local temperature. Original pressure was set at home at around 40 degrees F. at one point, I was at an ambient temp in the morning of around 60. Tire pressure was up accordingly. Later, I was down into the 20?s overnight. Pressure was low.
I think one action I learned from this is to be sure to check pressure each morning cold and adjust as per local environment. Should I adjust for where I will be during the day? That is, I start cold and will be in a hot environment later in the day.
As I said, this experience was very educational for me. Before TPMS, I never realized the dynamics of tire pressures.
Jeff