fordtech
NAXJA Forum User
- Location
- Amherst NY
snip from Jeepforum:
...For an example I’ll use a tire rated at 2270 lbs @ 50 psi and a vehicle that weighs 4850 lbs.
Step 1 - Multiply the max load times 4. This is the maximum weight your four tires can safely carry.
2270 lbs * 4 = 9080 lbs
Step 2 - Divide the weight of the vehicle (placard on driver’s door jam) by the number you got in the first step. This is the percent of the max load you are actually carrying on the tires.
4850/9080 = 53%
Step 3 - Multiply the psi stated on the tire for max load by the percentage you got in step 2. This will give you an optimal pressure for you tire on the road.
50 psi * 53% = 27 psi
I used this with my xj at 3,386 LB (internet xj curb weight, I'll use my door sticker later), tires rated at 2270@50 PSI (off Coopers website), and got 18.5 PSI, which seems low. I also have used Gojeeps method (pasted below) and have been in the 26-28 PSI range. I haven't gotten a chance to do the chalk or crayon method due to the wet weather we have had in NY lately...
Interested to see what others have tried, and if either of these methods resulted in positive results.
Snip from Gojeeps site:
...you take front and rear pressures cold, and then again immediately after at least 20 minutes at highway speeds or more and there should be a 4 psi increase. If there is more than 4 psi, than you had too little to start with and if there is less than 4 psi, than you had too much.