Choosing gear ratio

[Rockcrawler]

I'm about to trade my 01 with 5 speed 3. 55's and 33" tires for an 03. I've alway been a fan of 3. 55's vs 4. 10's because the 01 pulled so well (about 300/700 with a little help). I'm usually running 77-82 on the highway with a lot of long trips out west (I race the rockcrawling events). As it is, I'm often wishing I had another gear but that's just becasue i know how well it pulls in the lower rpm's.



I found a sweet deal from a motivated dealer on a 3500 srw sb with 6 speed and HO- but it has 4. 10's. I've already ordered the 35" all terrains to go on whatever I buy- looking at another truck with 3. 73's. Will the 4. 10's drive me nuts at the speeds I drive? will the mileage suffer from buzzing the engine or does it like it?



Looking for experienced feedback rather than generic "lower gears are better for towing". This truck is a third vehicle and won't leave the house unless there is something in the bed or the trailer is hooked up- towing 7k.

 

[JDanford]

You already know the answer! You just wanted to hear it from somebody else. Just like the earlier post about the towing mirrors. Don't just buy something for the sake of a "better deal. " When a guy is spending $40 grand for something, be sure to get it exactly like you want it. I've got the 3. 73 & there's still a lot of times I'd like another gear or two; can't imagine what it would be with the 4. 10 gears unless you're hooked up to sumthin' mighty heavy. I vote for the 3. 73! I also vote for the towing mirrors!

 

[Steve M]

With a loaded radius of 16. 5" or an effective 33" diameter with the 35" tires, you'll be running right around 2500rpm at 82mph. It'll draw some fuel at 2500rpm. But it'll be quiet compared to the '01. My '98 5spd/4. 10 used to run 2500 at 70mph. I got 10. 5-13mpg towin our 5th wheel. Never took it on a trip empty. The biggest turn off was noise. Not a problem with the '03. You might even like the responsiveness at 2500rpm. If it were a 3. 73 you'd be turning about 2275rpm at 82mph.

MPHXgear ratioXO/D ratioX336/ tire diam. =rpm

 

[Task125]

I got 410s on my truck because I am going to larger tires,if you were staying stock I would say no to 410s. but with 35s go for it.

 

[randyn]

Steve M,



Now look what you've done! I just finished (I thought) going through all this on the off road forum (3. 73 vs 4. 10?) & figured out that an auto 4. 10 (. 69 od) w/ 315x70x17 (34. 3") had a higher speed ratio than either a 3. 55 or 3. 73 w/ . 75 od and stock tires. Also had something like 73 or 76 mph at 2,000 rpm. Then you come along & point out the "actual diameter" of the tires... ... ... You realize now I have to rethink the whole thing!!!!!!!!!! Thought all I had left to decide was the color... ... ... ... ...



RandyN

 

[Steve M]

Well, you can always pump them up so hard the cat can't scratch 'em. Then they'll be closer to 35".

 

[randyn]

OOps, it was the towing, hauling & rv forum, not off road. Ok, Steve, so what color should I get!?



RandyN

 

[Steve M]

Aw heck, my favorite color is Patriot Blue with silver bottom and dark agate interior. So I bought a white one.

 

[4xquadrod]

I read a thread that stated if you went with 35's and 4. 10's this brought you back to around 3. 73's. I do not know how accurate this was but interesting anyways.

 

[wscott]

If you go to www.tirerack.com/tires/tiretech/lighttruck/trukform.htm

You will be able to figure out your new axle ratio regardless of where you started or where you are going in relation to tire size. I have seen The Tire Rack mentioned on this site several times and went there myself and found it very helpful. Hope it helps