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official gear size for 35's with a 700R4, post

Discussion in 'The Garage' started by cybrfire, Oct 29, 2003.

  1. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    official gear size for 35\'s with a 700R4, post

    OK, first lets all keep a cool head. I'm not trying to start a flame war I would just like to discuss it as there seems to be quite a bit of rage on this topic plus I will be doing it soon.

    Secondly, lets assume that the torque converter locks up when it is supposed to.

    Third, lets also assume that the TV cable is adjusted for proper shifting points. And if somebody knows what those shift points are please elaborate. Mine hits third at about 35 and won't go into overdrive until 65. It shifts firm though.

    fourth, will assume that this rig spends more of its time on the road then off. let's say 70/30 split.

    fifth, we will also assume that the 350 engine runs decent is stock and under 100,000 miles.

    sixth, one last thing. Mileage is important.

    Tire size 35" x 15.5 x 15 which according to interco website is 34.8" outside diameter. If somebody has this size tire on now would they be so kind as to measure the roll out with say, how does 20 p.s.i. sound? I believe to get a real good idea of tire size you need to know the roll out.

    The entire drive train, 350, 700r4, np208, 14 bolt in the rear and a 10 or D44 up front. Again this is more of a highway rig that sees a little offroad use. Anybody have an approximate weight?

    In my "OPINION" 4.56 gears would be good for a rig that would mostly be on the road. This is just my opinion and I don't know the exact roll out and all the other things that would be of consequence for making this decision. According to my calcs (without tire roll out) 2000 rpms would be cruising at about 65 mph in overdrive. 2300 rpms at about 75. If my numbers are off please let me know.

    <FORM METHOD=POST ACTION="http://coloradok5.com/forums/dopoll.php"><INPUT TYPE=HIDDEN NAME="pollname" VALUE="1067471700cybrfire">


    Gear you would use.
    <input type="radio" name="option" value="1" />4.10
    <input type="radio" name="option" value="2" />4.56
    <input type="radio" name="option" value="3" />4.88
    <input type="radio" name="option" value="4" />5.13
    <INPUT TYPE=Submit NAME=Submit VALUE="Submit vote" class="buttons"></form>

    maybe we can get a good baseline here and people can consider what mods they have made and decide accordingly.
     
  2. jms

    jms 1/2 ton status Author

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    Re: official gear size for 35\'s with a 700R4, post

    Here's my setup: 700R4, 315/75x16 Goodyear MTR that measure 34.5", and 4.56 gears. Your numbers on rpm/speed are right on. Drove the truck from Omaha to Moab and back for BB'03 (~2000 miles total). I was very happy with the way the truck performed in Moab on 5 trails (4 rated difficult, one - Lower Heldorado - not rated).

    Mileage on the highway: high 13mpg, low 10.5 mpg, average 11mpg, which is what I also get around here; mileage on trails and roads with 20psi 6.5mpg, but due to slow/no speed gph would be a better unit to measure than mpg. Same numbers on a trip to Fulton for the FallCrawl 2003. Motor is a 350 w/ vortec heads and headers, and I usually baby the truck around, i.e. I'm easy with the right foot.

    Carb is a Q-Jet with size 70 main jets, timing at 8 degrees, Summit HEI cap'n coil, stock cam; TV cable set so tranny shifts very early.

    I'd like to have lower gearing for trails, but since I have 4.56 already, axle gears won't make a big difference anymore: 5.13 is only 12.5% deeper than 4.56. So for me, it'll stay at 4.56 until I'm ready for the Doubler.
     
  3. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    Re: official gear size for 35\'s with a 700R4, post

    Thanks for the verification on the numbers. I'm putting a 4" lift on my DD and 33's for now. I already have 4.10 axles so I'm gona stay there. In the future I see a little more tire and gear also but its hard to justify a small jump.
     
  4. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif
     
  5. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    Re: official gear size for 35\'s with a 700R4, post

    looks like peeps like 4.56s with 35s. That is what I run now, and Ive never thought much of the combo. 4.88s are a minimum IMO, and 5.13s would be best. /forums/images/graemlins/laugh.gif

    j
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: official gear size for 35\'s with a 700R4, post

    [ QUOTE ]
    looks like peeps like 4.56s with 35s. That is what I run now, and Ive never thought much of the combo. 4.88s are a minimum IMO, and 5.13s would be best. /forums/images/graemlins/laugh.gif

    [/ QUOTE ]

    I'd say 4.56 is the minimum, 4.88 might be ok, but I agree, I'd rather have 5.13s if I had O/D. For mileage I would chose 4.88s.
     
  7. BranndonC

    BranndonC 3/4 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    i'd go with 4.88's

    i have 5.13's and 37's SSR's which look to be smaller than my yard stick (36) anyway i love them on the street, but highway speeds have to stay between 65-70... i've gone 80 for long periods of time but i'm up near 3000RPM's then... just FYI
     
  8. jjlaughner

    jjlaughner 3/4 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    I would say it depends on what your running now?

    In MY situation I'm going to run 4.10's. I'm currently running 3.08s and 32's. If you go to 4low.com and check.
    A 3.73 and a 31 (which is what I have in my plow truck and I really like it), its very close to 4.10's and 35's. Going from 3.08s and 32's to 4.56 and 35's would be almost a 600RPM increase from MY current setup

    tire<font color="white"> . </font>|gear <font color="white"> .. </font>|OD |208 |speed

    32 <font color="white"> ... </font>3.08 <font color="white"> .. </font>.7 <font color="white"> .. </font>1.0 <font color="white"> .. </font>70 <font color="white"> .. </font>1584.7 RPM's --MY current RPM's
    31 <font color="white"> ... </font>3.73 <font color="white"> .. </font>.7 <font color="white"> .. </font>1.0 <font color="white"> .. </font>70 <font color="white"> .. </font>1981.0 RPM's --usual stock RPM's
    35 <font color="white"> ... </font>4.10 <font color="white"> .. </font>.7 <font color="white"> .. </font>1.0 <font color="white"> .. </font>70 <font color="white"> .. </font>1928.6 RPM's --(adds 343.9RMPs to MY current) 17.8% higher
    35 <font color="white"> ... </font>4.56 <font color="white"> .. </font>.7 <font color="white"> .. </font>1.0 <font color="white"> .. </font>70 <font color="white"> .. </font>2145.0 RPM's --(560.3 more RPMs) 26.1% higher

    4.56's seem like to much of a jump in MY situation,
    even from 3.73/31 to 4.10/35 there are only few RPM's difference
     
  9. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    Re: official gear size for 35\'s with a 700R4, post

    [ QUOTE ]
    Anybody have an approximate weight?



    [/ QUOTE ]
    I have a 406/700r4/241 combo with 14boltFF rear 3/4 ton 10 bolt front,35x16 boggers,16.5x14welds and I am weighing in right at 5,260lbs.
    as for the gears, Some like the really low gears like 5.13's with small tires If you have OD,but they consider OD to be used as a substitute as 1to1 or 3rd gear. So basically they consider with a non OD tranny say 4.10's but with OD you can go with say 4.88's and run the same RPM's. That is great for power but makes OD worthless for using it as it's intended purpose...lowering the RPM's for better fuel mileage. At that point it would be like having a 3spd auto with a granny low.I would go 4.56 so you will be able to still stay at a good cruising RPM in OD for fuel mileage.
     
  10. 88jimmy4x4

    88jimmy4x4 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    I am installing a 6" lift on mine this weekend with 36x14.50's and I will be installing 4.56 gears in mine. This is a DD and I definately like to drive faster than 80mph /forums/images/graemlins/grin.gif
    I was leaning towards 4.88's in case I go to 38" tires but I dunno, 4.56 sounds good.
     
  11. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    So after the 10,867 discussion on this, there is still no unanimous consensus on what gearset to run............ /forums/images/graemlins/thinking.gif
     
  12. rodzzilla

    rodzzilla 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    5.13's

    In OD it would give you the equiv. of a 3.59 rear ratio. Would be real fun stoplight to stoplight, too.
     
  13. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Re: official gear size for 35\'s with a 700R4, post

    [ QUOTE ]
    So after the 10,867 discussion on this, there is still no unanimous consensus on what gearset to run............ /forums/images/graemlins/thinking.gif

    [/ QUOTE ]


    I'm about to post up the official "What does a pretty girl look like?" thread. Should be about as easy to get consensus on......
     
  14. Chris_T

    Chris_T 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    I run a 700R4 with 35s and 4.56s. Mild 350 rebuild in good shape. I wish I had 4.88s or 5.13s, both for offroad and for highway driving. Reason is at 65-70mph the engine is just on the lower edge of where it would like to be. The engine is happiest at 75-80mph, but driving my 31 year old truck at 80 mph can be a little scary. If the torque curve was a bit lower on my truck, 4.56s would be great. Offroad they work well.

    Mileage - I can get 15 out of an all highway tank, about 12 around town, but I'm pretty bare bones, not a lot of extra weight
     
  15. Chris_T

    Chris_T 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    [ QUOTE ]
    So after the 10,867 discussion on this, there is still no unanimous consensus on what gearset to run............ /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    Unanimous? Of course not! I'm just waiting for someone to point this out to zakk or to link to one of his 5.13s posts. /forums/images/graemlins/grin.gif
     
  16. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    [ QUOTE ]
    [ QUOTE ]
    So after the 10,867 discussion on this, there is still no unanimous consensus on what gearset to run............ /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    Unanimous? Of course not! I'm just waiting for someone to point this out to zakk or to link to one of his 5.13s posts. /forums/images/graemlins/grin.gif

    [/ QUOTE ] /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif
     
  17. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    Yeah, but the gear calculators do not take into account the added rolling resitance and weight of bigger tires /forums/images/graemlins/eek.gif. There's going to be quite a difference in seat of the pants performance between something like a 35x12.50 BFG all-terrain on an 8" aluminum wheel versus a 35x16 Bogger on a 12" steel wheel.........

    Overall there are just way too many variables to give a "one size fits all" answer.
     
  18. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    Re: official gear size for 35\'s with a 700R4, post

    there prolly never will be a consensus on this one... depends to much on personal pref/driving style. Personally, I dont want to go over 65 mph in my truck... ever... so I want 5.13s.. some people like going 90mph at 2000 rpm, so they want high gears. to each their own.

    j
     
  19. zakk

    zakk 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    once a month i remember why i put this down in Word.
    enjoy.

    [ QUOTE ]
    Zakk’s Dissertation on why 5.13’s are the best choice for a 700R

    Recently, I made the switch to 5.13’s in my D60/14B combo. I run a mildly build TH350 and 39.5” TSL’s. The 4.10’s I did have were killing everything: the motor, the trans, freeway “ get up” …all of it was terrible.

    So, after typing this up a few times, I will commit this document to the annals of time, and have a friend of mine host it.

    The problem with larger tires and a 700R and larger tires, is that you can’t seem to get enough RPM’s to get the OD to properly engage.

    Dr. Watson of ORD fame has this problem with the Art Carr 700R and his 42’s. There is just not enough RPM’s to shift in OD. So what little freeway driving he does do, is all done in Drive.

    When we mix this with tires in the 35-38” range, 5.13’s are a great choice.

    Assuming a true tire dimension of 35”, a vehicle with a small block motor mated to a 700R would spin 2241 RPM’s. Running with 4.88’s would have the engine humming along at 2132 RPM’s, only saving 109 revolutions of the motor per minute. All are calculated at 65 MPH.

    Assuming a true tire size of 37”, 5.13’s would net 2120 RPM’s at 65 MPH.

    Most small block motors are comfortable running between 1800 and 2800 RPM’s. 5.13’s with the addition of OD allow this number to be on the lower end of the spectrum, while allowing for maximum acceleration and off road performance. Gearing can make a motor that is slightly lighter on power really come alive, as I have found with my mild small block 350 with approximately 285HP at the flywheel.

    In closing, unless you bought your axles with 4.88’s already installed, there is no reason that this author sees to not go with 5.13’s from your present gear ratio.

    Let the flaming begin….


    [/ QUOTE ]
     
  20. zakk

    zakk 1/2 ton status

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    Re: official gear size for 35\'s with a 700R4, post

    [ QUOTE ]
    So after the 10,867 discussion on this, there is still no unanimous consensus on what gearset to run............ /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    no but I called Mrs. Cleo and she said 5.13's
     

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