Lol yeah they are some prototype 93" iroks and 40" gold wheels, NOT. I hate those stupid things all the bluehairs slam on brakes when they see them even when they aren't speeding, hell I've even seen them say 12mph on the interstate.

 

jsnby - did manual hubs really make that big a difference in your mpg? im about to add the manual hubs on my 95 and that would be sweet if I could get better mileage - a definite bonus to convince the wife!

 

Manul hubs gave me about 1mpg on fwy driving, nothing around town.

33's arent really 33, while the formulas were accurate the difference is only 15.5%. 33's roll at 31.7, 225's at 27.4 (based on BFG's)

15mpg indicated would be 17.3, pretty darn good for 33's and stock gears. I get 18-21 with 35's and 4.88's city and 16-18 fwy.

 

No its not that easy, and runs about 1100 bucks.

For cheaper you can either add a correction unit to your speedo cable, or if you have an elec speedo add a calibration box.

 

With 31's you can get a different gear in for your speedo cable but with 33's they can't correct it that much. I went through this with 35's and ended up swapping axle gears which I wanted to do anyway. If you have an electronic speedo I think you have more options but I don't have one so I don't know for sure.

 

Yep, ISSPRO in Portland will take your speedo cable and splice a removable "gear reduction" box into it. This is calibrated to your tires. I had it on my 95, pretty reasonable price.

For my 92 I bought a Dakota Digital sepdo recalibration box for my 285's, since with 4.88's I was getting the low rider effect and adding more miles that traveled. Never installed it, and now the truck is for sale, as is the calibration box. If its reading fewer miles I dont care, I just dont want it adding miles

 

I have an 89' (don't know if it matters) and I searched all over a couple years ago and they were all discontinued and the only shop that recalibrates speedos in my town said it was to far off to fix. I do live in kindof a small town (Pensacola) but hey we have a real dyno now so I don't have to drive over to Mobile anymore.

 

I was unaware you could calibrate a mechanical speedo? I bought that ISSPRO setup in 03. And as far as I know they still make em..

 

The manual hub conversion was really the only worthwhile mod that did anything good for my mileage.

tell your wife that you will also be relieving a lot of stress on your CV's and that you shouldn't have to replace them as often

 

Yeah it looks like a coupler kindof but it's only good for 3mph max, there were different clors blue, green, and white (maybe yellow). These mph values were for my truck and are actually percentage values after they put it on rollers that look like dyno rollers. They put my truck on these rollers spun it up at different mph's looked at my speedo and get this calculated it on notebook paper. That's when they told me they couldn't fix it, they mostly work on cars that are trying to beat speeding tickets. Took about an hour and a half and they didn't charge me a dime.