Tire size

[DCottrell]

I have a 92 D250 that I am doing a dually conversion on. The coversion components are from a wrecked 89 D350. I am changing beds, rearends, and front hubs and rotors. The 89 was a non-overdrive truck so I will be changing gears from one rearend to the other. The 92 calls for 235/85/16's, the 89 had 215/85/16's. Which tire size should I use? Will the 235's be too close to each other in a dual rear setup?

 

[AKimmel]

I don't think the 235's would be a problem, I've seen 255's run on a dually before with space between them.

 

[Philip]

On that 89 rear axle. You say it was a nonOD turck. If your talking about a automatic based truck. It should have a 3:07 axle under it. No other gears will fit that housing without lots of machine work. That is a model 71 Dana where your 92 has a model 70. If you don't tow heavy all the time the 3:07's with a OD in front of them make a good highway package.



Use the 235's. They fit the body style better than 215's do.



Welcome to the TDR.

 

[pepecat]

just a note on tire size/speedo calibration witht the 3. 07's from your '89. I just swapped in a getrag from a '92 and that truck had 3. 54's. in order to maintain speedo calibration, you need to remove the speedo gear from the tailshaft of the '89 transmission and put it in your '92. it will be a red gear (forgot teeth #'s) and the 3. 54's will be a green gear. you will have to clock the speedo gear housing in such a way that it will fit with the new gear. it is a circular housing &oringwith an offset gear mount hole. you will see a tooth count on the gear and corresponding numbers on the gear housing, it can only be clocked in 90 degree incriments so you really can't go wrong it will only fit one way, and with the securing tab in place it will indicate the gear tooth count range you are using. good luck. my speedo works great, and the swap worked from a 727 to getrag just fine.

p. s. and philip you ain't kidding about od & 3. 07's mpg is up from 15-17 to 22 mpg at 80mph. I am going to drive the speed limit everywhere and put my starwheel back in and see how high I can get mpg.