Whats the difference between Lt(light truck) and P(passanger) tires?
Also i have 95 Blazer 4door, 4wd with a full size spare tire. it currently has tire size 235 70 15 on the spare tire under the back. Will tire size 235 75 15 fit under if i change size? i know the tire fits on the rim. just wounder if it ill fit under and if theres enough room.

 

LT (Light Truck) Metric tires have higher maximum inflation pressures and higher load carrying capacities at higher inflation pressures than P-Metric (Passenger Metric) tires. Conversely, below 35 psi Passenger Metric tires carry higher loads than LT Metric tires of the same size.

For example: A Passenger Metric tire sized P245/75R16 109S carries its maximum load at 35 psi which is 2,271 pounds.

A Light Truck Metric tire sized LT245/75R16 at 35 psi carries a load of only 1,700 pounds. At 50 psi though the load increases to 2,205 pounds. At 65 psi it is 2,623 pounds and at 80 psi it is 3,042 pounds. 50, 65 and 80 psi are the maximum loads for C, D and E load range tires respectively.

If you have a truck that specifies LT Metric tires under no circumstances should you install P-Metric ones as replacements. P-Metric tires will not have sufficient load or inflation capability for your truck.

(taken from somewhere else)

As for the second part of your question I honestly don't know but if you had the later tire you could drop the spare and see if the other fits.

 

my spare was a 235/75/15 and it fit. was a tight fit but it does fit

 

Thanks. the recommed tire pressure for my 95 blazer is 32psi all around. Now if i put Lt tires on and you say it has a highter tire inflation and i inflate the tires to 50psi or even 80psi. isnt that bad cause it recommends 32psi? also witch runs smoother on the road LT or P? what bout handling better?

 

Unless you drive alot off road you will be better off with p metric tires.

 

x2 on what Mczuk said. LT tires have a lot stiffer sidewall then a p-metric tire. Stiffer sidewall=less tire flex= harsher ride. For example a 31x10.5x15 has six plies whereas the metric size 265/75/15 while being real close to the same overall diameter the metric only has 4 plies (easier to poke a hole in offroad). Airing a LT tire to like 50lbs won't hurt a thing, but your ride will be rougher.