Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

4.88 gears + 700r4 + 36 tires = ????

Discussion in 'The Garage' started by UseYourBlinker, Jun 19, 2003.

  1. UseYourBlinker

    UseYourBlinker 1 ton status

    Joined:
    Jun 7, 2000
    Posts:
    11,117
    Likes Received:
    0
    Location:
    .
    Hey fella's...and ladies. Haven't really been on in awhile just been a lurker. Anyone running 4.88's,700r4,and 36 tires with a 350 engine?? Any input would be great. Since I am gonna order the gears by next week. Also where did you guy's buy them from? It's for a 10 bolt/12 bolt combo. THanks!
     
  2. yunit

    yunit 1/2 ton status

    Joined:
    Feb 24, 2000
    Posts:
    3,068
    Likes Received:
    0
    Location:
    Oakland, NJ
    This is the setup that Steve Fox was running for a while and it worked for him.
     
  3. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

    Joined:
    May 24, 2002
    Posts:
    2,923
    Likes Received:
    0
    Location:
    Wilmington, NC
    i have 4.56's with 35" BFG M/T's and i really think i should have gone with a 4.10. it'll pull and take off like a mug, but the highway RPM's kinda worry me. so i think 4.88's would be kinda hard on it, unless it's going to be a trail only rig.
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,063
    Likes Received:
    70
    Location:
    Pleasanton, CA.
    Eric has the 700R4 with overdrive. I am running 700R4 with 4.56's and 35's and it is great at freeway speeds but I wish I had gone with 4.88's instead, it seems to want to search for overdrive when a slight hill is in sight.
     
  5. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    With a true 36 inch tall tire, the engine would spin about 2230 RPM at 70 MPH with 4.88's. For comparison, with 3.73's and 29 inch weenie factory tires, it would spin about 2120 RPM. 4.56's with your 36's would drop it back to 2085 RPM.
     
  6. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,031
    Likes Received:
    366
    Location:
    Vancouver, WA, USA
    i agree with 4x4H... I have 4.56s and 35s with a 7004r behind a mild 350. I wish I had gone 4.88s too... rpms are just a lil low while in OD at my normal interstate speed. RPMs could be a lil higher there, and a lil more low gear never hurt! Someday I'll prolly go to 4.88s for this reason... but its waaaay down the priority list right now...

    j
     
  7. zcarczar

    zcarczar 1/2 ton status

    Joined:
    Feb 10, 2002
    Posts:
    2,495
    Likes Received:
    0
    Location:
    Apple Valley California
    I have 4.88's and 35's. I can cruise all day at 70 too.
     
  8. 4GUNZ4X4Z

    4GUNZ4X4Z 1/2 ton status

    Joined:
    Aug 10, 2000
    Posts:
    3,459
    Likes Received:
    0
    Location:
    Mustang, Oklahoma
    Got 36's and 4.56's. Wish I had 5.13's.
     
  9. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

    Joined:
    Jul 18, 2001
    Posts:
    5,693
    Likes Received:
    0
    Location:
    CA
    Whad up Eric? HOLLA! /forums/images/graemlins/wink.gif

    I gots 3.73's/35's/th350... I will be going 4:56's in my 1 tons and 37's. /forums/images/graemlins/thumb.gif

    See you at blazerfest! /forums/images/graemlins/k5.gif
     
  10. outlaw612

    outlaw612 1/2 ton status

    Joined:
    Feb 11, 2001
    Posts:
    2,342
    Likes Received:
    0
    Location:
    Springfield, Illinois
    Ive got 4.56's and 36" TSL's and Im now looking for 5.13's.
     
  11. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    Y'all know, just a couple of months ago 4.56 for 35's were the ticket, what happened?
     
  12. zakk

    zakk 1/2 ton status

    Joined:
    Sep 21, 2001
    Posts:
    4,762
    Likes Received:
    0
    Location:
    San Jose CA
    i'm glad i saved this on my HD for you goof's that refuse to search

    [ 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 ]
     
  13. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

    Joined:
    May 19, 2001
    Posts:
    45,031
    Likes Received:
    366
    Location:
    Vancouver, WA, USA
    [ QUOTE ]
    Y'all know, just a couple of months ago 4.56 for 35's were the ticket, what happened?

    [/ QUOTE ]

    depends on the rig and the use. I dunno, i never really noticed until a recent road trip, but 4.56s + 700r4 + mild 350 + 35s = rpms just too low for OD. That said, i dont have a tach... and Im not an engine guru or anything... but it seemed to me anyway that the gearing could have been just a lil lower.. and the rpms therefore just a lil higher. I think 4.88s would be juuuuust right for me. Others opinions/experiences can/will/do/should be different.

    j
     
  14. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

    Joined:
    Dec 26, 2002
    Posts:
    7,603
    Likes Received:
    555
    Location:
    Wasilla AK,
    I run a small block with a 700r4, 44frt,12blt rear, 4.88 gears and 37" mtr's I like my setup works very well overdrive is nice to have
     
  15. TXsizeK5

    TXsizeK5 1/2 ton status

    Joined:
    Aug 26, 2001
    Posts:
    2,518
    Likes Received:
    0
    Location:
    College Station, TX
    I've got a buddy with 10bolts, 4.88's, rebuilt 700r4, and 36x14.50 Radial Swampers. He loves the setup, hasnt broken anything, and he drives maniac-like. He did break some axleshafts in a pulloff contest (on pavement lol) but other than that he's been loving it
     
  16. Stephen

    Stephen 1/2 ton status Moderator Vendor

    Joined:
    Sep 15, 2000
    Posts:
    4,227
    Likes Received:
    142
    Location:
    Carbondale Colorado
    Got the 4.56/TH700/35" combo in my burb and it's not worth changing (I'll do motor mods first) but if you're buying, get at least a 4.88 and consider 5.13's. I have a hard time thinking you can spin a motor too fast in overdrive, especially when most of my driving is done at 3K+ RPMs due to the overdrive kicking down.
    There's room to err here with motor build specs, etc but that's my recommendation.
     
  17. UseYourBlinker

    UseYourBlinker 1 ton status

    Joined:
    Jun 7, 2000
    Posts:
    11,117
    Likes Received:
    0
    Location:
    .
    Thanks for all the input! /forums/images/graemlins/thumb.gif
     
  18. Tshane

    Tshane 1/2 ton status

    Joined:
    Nov 26, 2002
    Posts:
    144
    Likes Received:
    0
    Location:
    Peoria, Illinois
    I dont know if this is true but i heard after you go past 4:56 in the front with a 10bolt or 44 that the pinion starts to get very small and weak is there any truth to this??
     
  19. zakk

    zakk 1/2 ton status

    Joined:
    Sep 21, 2001
    Posts:
    4,762
    Likes Received:
    0
    Location:
    San Jose CA
    small yes, weak is a matter of opinion. I saw a D44 get beaten to snot with 5.13's and the R&P didn't go. Usually a u-jpint will go first on those little axles
     
  20. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    Edit.......................

    So which one is correct, Randy's or 4lo.com??????????????????????????

    I am thinking that Randy's is more on since it has calculations for all trannys while 4lo seems to be calculated for a manual tranny...................

    Ah WTF cares anyway????? /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

    Now I'm edumacated on why people are saying 4.88s.............
     

Share This Page