2nd Gen Non-Engine/Transmission Is this Correct??

[JKuehl78]

Gear Help

I'm trying to figure out what gear ratio to put in my truck.



It's a 98. 5 CTD and the sticker on the door says it has 245's on it stock. Did they come that small? With 3. 55's it would have been turning 1916 RPM at 70 MPH. Mostly I hear of 265's but never 245's. I have 315 BFG AT's on it now and have never driven it with anything less. (these were on it when I bought it) so I have no basis for judgement to decide if "I want the performance I had stock. " I don't know what stock is!!!



I'd ratner ask you guys about your experience rather than slapping a set of 245's and 265's on to see what I like better, THEN swaping gears to match the performance I choose.



I'm considering 3. 90, 3. 92, 4. 10, & 4. 11 ratio's. Help me out here, I've been reading for days and I am still lost.



This truck is my daily driver and tows 4000-7000 lbs on weekends (Jeep & Boat)



Thanks in advance,

Jeff

 

[AKAMAC]

With the 410s you'll be close to stock ratio with the 35" tires.

 

[GMincher]

Yeah, 245's are stock. Yeah, 245's look too small. I tow heavy and without changing ratios I don't want to go any larger. Definitely too small though, hehe!

 

[JKuehl78]

Thank you for the input. Any ideas what type of mileage I can expect running 80 (empty) at 2200 RPM?



TIA

 

[pwerwagn]

Ok, 4. 10's and 4. 11's are the same. no noticeable diff. some axle types use 4. 10's and some use 4. 11's. Just depends on the axle. I dont believe you can get 3. 92's for a dana 80. only 3. 55's and 4. 10's and lower. My 98 came stock with 245's. I believe the sports had 265's. 3. 55's and 245's are pretty close in final ratio to 315's and 4. 10's. I have 285's on my truck, with 3. 55's. running 75mph on the speedo (which is actually closer to 80 when corrected) I get about 17mpg empty. If I run 62 on the speedo (close to 66mph) I get about 19mpg empty. I cant go slower than 62, my foot wont let me!!! My grandpa claims if he runs 55 or so in his 96 he gets ~24mpg empty. The best I've got so far is 20. 5 empty, mixed highway/city. In those figures, I also take into account that my odo is off about 6%. I have towed about 12,000lbs running 70mph on my speedo, and I averaged 14mpg.

 

[Dane]

try this...

http://ejelta.com/tiresize/index.html

 

[JKuehl78]

Thanks for the replys. I haven't been able to find a straight answer or rather an answer that satisfies me on all the posts I've read. I think I'll just slap in some 4. 10's or 4. 11's, what ever fit's a Dana 70 and call it good... Now i just have to figure out which chip/box to use.

 

[pwerwagn]

4. 10's and 315's will make you happy. It will run pretty good.

 

[JKuehl78]

That's what I needed to hear. I'm going to go for it.