Jeff91

I have a plain-Jane 91 pickup 2wd 22re 5sp and at highway speeds 65-70 mph it sounds like its turning 5000 rpm. I'm sure its not but it sure sounds like it is. I don't have a tack in it. I am thinking of going with a taller tire to try to bring the highway rpm down and maybe get a little better gas mileage.
The tires on the truck are dinky 185/70/14's. The truck is geared so low and with the small tires I drive in town in 5th gear quite often.
What is a common tire size for this truck and what highway cruising rpm should I expect?
Thanks for any help.
Jeff

kyle_22r

that sounds like a pretty tiny tire -- i always thought stock was something more like a 205 tire?

Jeff91

a 205 would be 1.10 inch taller than the 185 I am running. This is an increase of about 5%. Does this mean the rpm would be reduced by the same amount?
I tried finding a calculator for this online but no luck.

Thanks

kyle_22r

assuming you have 3.42 gears(just a shot in the dark, a typical 5 speed 2wd has 3.42, 3.54 or 3.73 gears), at 70mph in 5th gear, you'd be turning a little over 2800 with 185 tires.

2WDRJ

When I bought my 91, it had 195/75/14's on it. That's supposed to be the stock tire size on the base model 2wd's, while the extra cabs had the 205's mentioned above.

When I first drove it, I too though the RPM's were a bit high. I wanted to go up to 15" wheels and put on a set of 215/75/15's and it lowered the RPM's a bit. It also helped with the fuel mileage.

jsnby

i had a 91 2wd 5spd....it seems that around 75mph was where i was hitting the 2800-3000 RPM's. I can't remember what size tire i had for sure, but i think it was a 215

Joyota

Check the label on the drivers side door jamb. It will tell you what size the truck came stock with. Could be that someone regeared the truck at some point too.

Zetoe

I have the same truck but with a 4-speed.

I installed a tach in my truck, and I can tell you that going 70 mph in 4th gear (1:1) on the stock 195/75 -14s has the motor spinning at about 3000 rpms.

You are most likely not spinning 5 grand in 5th (0.850 OD). As for your tire, it is less wide, but I don't know if it is actually shorter in height. The tires OD is what changes your RPMs.

Anyways, 22res do sound very loud. A tach is a very easy install so it's worth the added benefit.

HTH,
Chris

Jeff91

Thanks for all your input.
I know that the motor is not truning 5000 rpm. I don't have a tach in it and it just sounded like it was above 3000.
My plans are to change to at least a 205/75.

Thanks