4.30 gears with 35inch tires????

[renyren]

I can't seem to find the perfect rpm range towing with 3.73 gears and 35inch tires. So I want to change gears. I have talked to several rear end shops and all of them recommended 4.30 gears. Just wanted to get some feed back from anyone running 35inch tires with 4.30 gears.

[JSchuricht]

4.10 with 35's or 4.30 with 37's would be close to stock. How much weight are you pulling?

[renyren]

only about 6000 now but plan on getting a 5th wheel that will be 10000+. Problem is towing I have to do 60 out of OD or 67+ in OD to have the rpm's up enough and not lug. My truck is happy 1950+ rpm's for some reason.

[JSchuricht]

1800 RPM is about where the turbo starts helping out and the torque starts to really come in. I got to thinking about it, 35's with 4.30 would be similar to the stock tires and 4.10 that came standard on the DRW trucks. I have the same issue with 33's on 3.73's but much more weight on a 11.5x8.5x36' trailer with a flat front. My truck is happy at 50MPH in D or 70MPH in OD, the gearing just isn't there to hold speeds in between unless you go below 2000RPM in OD or 2500RPM in D. The thing is these trucks like RPM, 2500RPM all day won't hurt it.

I would wait till you get your 5th wheel. You may find it doesn't fit with 35's and decide to go back to stock tires. I can barely clear my gooseneck on 33's at stock height and lifting the trailer would require cutting all three axles off, welding in blocks then welding the axle back in. If it weren't for the trailer I would be on 37's right now.

[renyren]

That is pretty much the problem I have. My truck is happy with rpm's 1900+. So it looks like you have 4.10 and 35's on one of your trucks right. Every rear end shop said the same thing, 4.10's are not a big enough change. All said to go with 4.30's. I was just looking for real world data. I go in monday and am getting 4.30's so hope it is the best choice.

[JSchuricht]

3.73-4.10 is about 200RPM at 70MPH. My 95 had the 4.10 option from the factory and did about 2200RPM at 70MPH on stock tires. I only have 300 miles on the 35's and haven't towed anything but I am about 2000RPM at 70MPH now. Hopefully the 4.30's work out for you. Just remember you need to do both axles.

[Joel]

Let us know how it feels once its done

[1BADTON]

Should have went with 4:30s in mine with 37"s but have to save up to change back. Tried to install 4:56's like i used to have, cause I felt they were all around good off the line and gas mpg's but they don't make that gearing for dana 80 so I opted for 4:88s. Built the truck to pull my "DREAM HAULER" a 40+5 WW but the economy fell, lost 15% at work and thank god never bought it. You will be happier with the 4:30s and if you go up to 37"s you still won't mind.

[djen223]

I went with 430's and have 35's, best mod ive done, I tow a 40ft toyhauler often.

[jetjock15]

I have 4.56s and my bald 37s barely measure 35", tows like a monster but max speed without trailer is 75-80, and the RPMs are up there. I'd say 4.30s/35s is perfect.