arpunk

I’m not home until the 14th but I want to order new tires online. 1990 Laredo 4 door manual transmission. 225/75r15

What load index do I need? Everything is stock.

Red1992XJ

Standard load tires. I doubt you will be able to find many 225/75R15, try looking for 235/75R15. You will have a bigger selection at a better price.

4.3L XJ

Load range C is plenty for a stock XJ

arpunk

you’re right I asked my girlfriend to check (I’m in FL for work) and they are 235. Stock is 195 apparently according to my door sticker. Is this true?

arpunk

@Red1992XJ @4.3L XJ
if I currently have 235s and go back to stock (195), what will the difference be in terms of how the Jeep drives? I assume MPG may go up slightly (currently 19mpg highway) and my speedo will be accurate.

Speaking of which, is it difficult to recalibrate the speedo for my 235 tires?

Lynn Gräber

Not to throw a wrench in your theory, but my speedo is pretty accurate with 31's up to about 65-70. Then its off about 3 mph.

vroomvroom

You shouldn't need to change the speedo gear for such a small tire change. I only changed my speedo gear after going from stock to 33s. Changing the speedo gear is easy and doesn't require many tools.

arpunk

@Lynn Gräber @vroomvroom
My door sticker lists P195/75r15 so with 235/75r15, speedo will show:
50mph @ 54.5mph
60mph @ 65.4mph
70mph @ 76.3mph

Now, the door sticker could certainly be wrong based on what I’ve seen but when I compare my speed on Waze to the speedo, I’m currently off by about 5mph @ 50mph with the 235 I currently have on.

exasemech

As far as your speedometer error is concerned, it seems like you're assuming speedometers read dead on when the vehicle is first sold. If there's one out that didn't read at least a couple mph high it would be a real unicorn .I think it's the corporate "don't sue us when you get a ticket" thing.

Also, a general comment on your shiny new 33 year old Jeep. Don't sweat the tiny stuff now, enjoy it before all the 33 year old electrical stuff, seals, etc start to go. Should be interesting.
I do hope it works out for you

Red1992XJ

Personally I do not notice much of a difference in my speedometer with the 235's. I think it may only be off by about 5% or so. It is honestly not enough to worry about. Your speedometer may be off a little more, but you can account for that when driving.

I think you MAY have a speedometer gear, which isnt too bad to change, but finding one that is appropriate would be the toughest part.

4.3L XJ

Best way I know to check speedometers is with your phone. You can get a free app for a GPS speedometer. The one I have is Ulysse Speedometer, but there are others. Compare your speedo to what the phone says when you hold a steady speed. If it is off too much, you can correct it to pretty close with a new gear in your speedo drive with a different tooth count. If you get that far with it we can help you a little more. easy fix

PCO6

I rely on the speedo on my Garmin GPS which I understand to be very accurate. If I go 1 km/h over the limit red bars appear on both side of the speed I'm going. The faster I go the closer the red bars get to one another. I have yet to go fast enough to have the red bars meet ... but maybe that's because it's a Jeep.

cruiser54

Just put the 235s on.

Here. I'll make it easy https://www.discounttire.com/buy-tir...6#read-reviews

arpunk

@cruiser54 how do you feel about XL tires? I know some can be noisier than others and your mpg can drop. I was looking at the Cooper Discoverer AT3 4S because they’re all season and 3 Peak.

cruiser54

I don't like noisy tires. That's why I suggested what I did. I've used them.
We get snow where I live. Look at the ratings. If not them, Kumho makes some nice tires which I have used with excellent results.
I will not recommend anything other than the tires I have personal experience.
You always answer a question with a question.