proper gearing for 35s

[6.2Blazer]

I would recommend at least 4.56 gears with 35" tires and the OD tranny. Granted, 4.10's would be worlds better than the current 3.08's but I still think 4.56's are the way to go. With that said keep in mind that there is not a huge difference between 4.10 and 4.56, so not like you will magically get a lot better mileage with 4.10's.

What I always tell people is that running 4.56's on the highway with a 700r4 tranny would be equivalent to a truck without an OD tranny (th350 or th400) with 3.20 gears.

 

[89-Blazer]

Not to hi-jack the post, but what about driveline vibrations with anything over 4.10's? I'll have 4" lift and 35's soon also. Has anyone encountered DL vibe problems and if so, what was your fix. My rig is my daily driver also and it has to serve dual duty.

Mike

 

[6.2Blazer]

Not to hi-jack the post, but what about driveline vibrations with anything over 4.10's? I'll have 4" lift and 35's soon also. Has anyone encountered DL vibe problems and if so, what was your fix. My rig is my daily driver also and it has to serve dual duty.

Mike

The gear ratio itself should not cause any vibrations, nor is there any reason that 4.10 would somehow be the magic number.

Granted, lower gears will cause rest of the drivetrain (driveshafts, trans, engine) to spin faster for any given vehicle speed and I suppose you could see a vibration in another component start at a certain rpm but it's only because that component has an issue.

 

[resurrected_jimmy]

Not to hi-jack the post, but what about driveline vibrations with anything over 4.10's? I'll have 4" lift and 35's soon also. Has anyone encountered DL vibe problems and if so, what was your fix.

I used to run 35's on a 6" lift no O/D and it would run down the hwy smooth as glass at 70 mph..... granted it did it at 3000 rpm but no vibrations

 

[89-Blazer]

The gear ratio itself should not cause any vibrations, nor is there any reason that 4.10 would somehow be the magic number.

Granted, lower gears will cause rest of the drivetrain (driveshafts, trans, engine) to spin faster for any given vehicle speed and I suppose you could see a vibration in another component start at a certain rpm but it's only because that component has an issue.

True, but it seems I remember reading a post awhile back about DL vibes,,,, but that may have been with greater than 4" suspension lift (ie: greater DL angle). I also recall from that post that there were many more people with DL vibes with gear ratios over 4.10's than those with less gear than 4.10's. That was the only reason I used 4.10's as a reference in my first post. I would venture to say that the greater the ratio, the higher probablility for a vibration issue to occur. Just one more thing to keep in mind for those looking to add gears to a daily driver.

Mike

 

[djsblaze]

I would go with 4.88. Here is why. Whether you know it or not, your truck wants to keep growing. 33 then 35 then 38. Just how it is (at least for me). I put in 4.88 with 38 inch tires w/ 700R4. WISH I had done 5.13. You can go 4.88 with an OD tranny. If your concerned about tranny temp, put in a torque converter lock up switch for when you are cruising in OD, and the tranny WONT hunt, keeping you cooler. Now my truck is telling me it wants 42 inch tires, and I wish I had the 5.13s. I'd seriously consider the 4.88, b/c your truck might live to regret 4.56 when it has growing pains...

 

[muddybuddy]

i was originally gona do 5.13s and 35's. but now decided to jus got with 42's hehe

 

[sandawgk5]

I will have 37s with 4.10s as it is on blocks right now. I will have 5.13s just don't have the money to gear a front 60 and 14FF before I drive cross country .

Ira

 

[Chris_T]

I have a 350/700R4/205 with 4.56 and 35's and wish I had gone 4.88 or 5.13. I find that the rpms are just a bit too low on the highway in OD.

 

[bugbait]

My 85 sounds real similar, and I am going 5.13. not a lot of highway miles for me though- just to the trail and back. My 35's are on 4.10's now. o k on road, but hills and thick mud make it huff and puff.

 

[jekbrown]

same proper gearing for every other tire size... 5.13s.

j

 

[JohnDeere]

thanks guys im going with 4.56

 

[89GMCSuburban]

4.10's with 36's is fine on mine, although I wish I had 4.56 for hills and things. With the hills around here, I can't run OD.

EDIT: just read the rest, good choice!

 

[Hossbaby50]

I have 4.56 gears and I ran 35" tires for 2 years on road and off. I was in the same dilema when I chose my gears. 4.10's or 4.56's. I will tell you if it were me I would never even consider doing 4.10's now and I am glad people here talked me out of it.

If I had it to do over knowing what I know now I wouldn't even consider 4.56's if you plan to stay with the 700R4 tranny. With the OD the minimum gear for 35's IMHO is 4.88's and if you plan to go taller then 35's ever then 5.13's.

The ONLY reason I could see to run 4.56's now is if you plan to do ALOT of highway cruising at 75+ MPH or if you are going to swap in a non-OD tranny down the line. Both are dependent with you staying with 35" tires.

If you don't fall into one of those catagories then I say 4.88's or 5.13's all the way.

Harley

 

[4xcrazy]

I am running TBI 350/700/241 with 4.11's and actually think it's just about right for the city/freeway type driving.

about the same size tires as well, 35's

when i was running the 33's it seemed to hunt between O.D. and Drive quite abit on the freeway, just the tire change has eliminated this problem.

 

[4xcrazy]

I see alot of you saying 4.88's and up, i'd kinda like to know, and i think this is a good question for the original poster to see, what the RPM's you guys are pulling running around 75mph with your gears?????

just curious as i mentioned before, i am running 35's with 4.11's and it just seems that the higher speeds, nearing 75mph, the the engine is running quite high in the RPM band.

Now i personally cannot say exactly what mine is doing, as i don't have a tach hooked up at the moment, but it is on my to-do list soon.

 

[tin man]

I had 410's and 36" tires. I loved it. The truck was my daily driver. It also saw some highway driving. When I put the 33" tires back on for towing, I thought it was too low for the highway.

 

[6.2Blazer]

I see alot of you saying 4.88's and up, i'd kinda like to know, and i think this is a good question for the original poster to see, what the RPM's you guys are pulling running around 75mph with your gears?????

just curious as i mentioned before, i am running 35's with 4.11's and it just seems that the higher speeds, nearing 75mph, the the engine is running quite high in the RPM band.

Now i personally cannot say exactly what mine is doing, as i don't have a tach hooked up at the moment, but it is on my to-do list soon.

My DD/towrig came from the factory with 4.10 gears and small 245/75R16 tires (about 31" tall), auto trans with the same OD gear as the 700r4. It runs about 2,500 rpm at 70 mph. With your much larger 35" tires it is probably only turning around 2,000 rpm at 70 mph.

 

[6.2Blazer]

I am running TBI 350/700/241 with 4.11's and actually think it's just about right for the city/freeway type driving.

about the same size tires as well, 35's

when i was running the 33's it seemed to hunt between O.D. and Drive quite abit on the freeway, just the tire change has eliminated this problem.

I really do not understand your logic. If the transmission was hunting between OD and D with the 33's, then it would be worse with the larger 35" tires. The reason the trans would shift out of OD and into D would be that the engine did not have enough power to maintain speed in the really high OD gear. Adding larger tires would just exagerate this problem........unless the trans was staying in D most of the time now simply because the vehicle rarely had enough power to pull OD.