Puget Sound MINI Motoring Club Homepage
Forum Home Forum Home > Technical Discussions > Tires and Wheels
  New Posts New Posts RSS Feed - PV / T = k  and where the run flats fall flat
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

PV / T = k and where the run flats fall flat

 Post Reply Post Reply
Author
Message
Beakerzor View Drop Down
PSMINI Driving Member
PSMINI Driving Member
Avatar
PSMINI Member

Joined: June/01/14
Location: Seattle
Status: Offline
Points: 120
Post Options Post Options   Thanks (0) Thanks(0)   Quote Beakerzor Quote  Post ReplyReply Direct Link To This Post Topic: PV / T = k and where the run flats fall flat
    Posted: September/07/14 at 8:39am
Susan and I are on an 2 week road trip deep into the Canadian Rockies with our new MINI.  Our first experience with Run-Flats.

We woke up in Jasper and the MINI saw its first frost.
Elevation  1,060m or 3,480 ft



Using the combined gas law, PV/T = k
as the (T)emperature dropped, with the (V)olume staying the same, and the (k)onstant not changing ever because of physics laws and what not, meant the (P)ressure had to drop with the temperature.

Basic physics 101 stuff.  It set off the "low tire" warning system, and sent us into a mini panic (pun intended).

Lessons we learned:
1. It takes a special machine to remove run-flat tires from a wheel, there are no such places near Jasper for hundreds of miles.  We would have had to buy new rims and tires, if we had a real flat.

2. The dash-board display system wouldn't tell us exactly which tire was low or by how much, it just said "tire(s) low".

I couldn't find any tire information using an OBD bluetooth device.  Is this even possible?  

TIP:  Always fix the tire pressure before leaving on a trip (which we did not).  Our repaired run-flat was at 41psi, and the other 3 tires were at 30psi.


Edited by Beakerzor - September/07/14 at 11:06am
Back to Top
CORNERS View Drop Down
PSMINI Expert Advisor
PSMINI Expert Advisor
Avatar
PSMINI Member

Joined: July/29/10
Location: Bothell, WA
Status: Offline
Points: 3733
Post Options Post Options   Thanks (0) Thanks(0)   Quote CORNERS Quote  Post ReplyReply Direct Link To This Post Posted: September/08/14 at 12:36am
OBD scanners won't talk to the tire pressure system. You'd need a special BMW/MINI software to do that. 

Back to Top
racingbmwm3 View Drop Down
MINI Motorer
MINI Motorer
Avatar

Joined: January/28/13
Location: Port Townsend
Status: Offline
Points: 101
Post Options Post Options   Thanks (0) Thanks(0)   Quote racingbmwm3 Quote  Post ReplyReply Direct Link To This Post Posted: September/09/14 at 8:00am
Check all fluids and tire pressures before any trip and ideally at least once a month of regular driving.
'05 Cooper, BRG, Aerokit, Sport Package, 135k
'89 325iX, Diamondblack, 270k
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.109 seconds.