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4in LIFT WITH 35s. NEED GEARS????

T

thejimmy

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Well I should get finished installing the lift tomorrow and then go get my 35-12.50-15s mounted up. Ive got 350 TBI 700r and 3.42s. I hooked up a tach and check it out before I started, at 65 it was 1800rpm at 70 it was 2000. I would like to stay in that range with 35s. I did some formulas on tire rack.com and came up with 3.96s. Some of the guys on here have suggested 4.56s butt this is a daily driver,mostly on the highway. a couple of guys said they had 4.10s and it still hunts between 3rd and4th. Im kind of leaning towards 4.11s. Any suggestions , experiences,or comments. Formulas were calculated with worn out 32-11.50s measuring 29.5 dia, 35 bfgs are 34.8 dia.:whistle: THANKS !
 
this has been covered to death.

basicly if 35" or more and overdrive tranny go as deep as you can . 5.13 are a good combo to keep the motor in the sweet spot and not let the tranny bog down and do the 3-4 hunt .
 
covered to death, yup, but i'm bored.......buy a membership for the lousey $25 and save yourself lots of money in the future too. use the "search" feature.

ok....lets make this simple........how do you like the performance and mileage now? could you live with the way it ran with 3.42 and 32"(29)? if so then get 4.10's.....

31/3.73=33/4.10=35/4.56......want more "power" get 4.88 or 5.13.
the lower the ratio the smaller the pinion gear, which could be bad depending how you drive.
i had both 4.10 and 4.56 with my 35's. i got better fuel economy on long highway trips with the 4.10's, but i liked the 4.56 better for all around driving (mostly NYC) and especially on roads with hills. 1800 rpms is good for a diesel, not so much so for a small block.

when you lift it and put heavier tires on it the mileage will tank somewhat. more drag and rolling resistance.....braking will suffer a tad too. go with 4.56's imo.
 
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I have 35's and 4.10's, minumum I would go would be 4.56's, the 4.10's work, but as mentioned, any little hill or slight acceleration of the pedal and it's dropping out of overdrive and back to 3rd, which most of the time for me personally is running alittle higher than I like at highway speeds.
 
My '91 6.2/4L80E Suburban 3/4t runs great with 35s and 4.10s. With 235/75-16s (31") being stock it figures to right about 3.73,which is fine with o/d. 3.42 is about the limit,to me,for running o/d. The website forums I like to visit seem to be a community of people with common interests where questions can be answered by those with similar experiences. The ones with more knowledge are more than willing to share what they know. For some,in this lousy economy,forking out $25 for every website they like to visit is hard to come by. I know that's true for me.
 
For some,in this lousy economy,forking out $25 for every website they like to visit is hard to come by. I know that's true for me.
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i didn't know people pay $25 for every site they visit. i just find it funny that folks will have the cash to lift, regear, buy tires, bottled water and think a membership here is expensive.......30 years ago, when i got started, we did things over and over till we got it right......cost lots of money too.

i'll maintain that spending a hard earned $25 to join here is an investment........there's TONS of info out there for free, go search for it.

also.....can you get into the classified section without a membership? i saved $50 this week by buying a perfect part from another member here. got to "meet" a great guy too. am i busting balls right now? i guess so. i'm just pretty sick of hearing people whine about helping to support a great resourse..............enjoy!
 
I'm no help since I'm running stock gears on 35's but the $25 has probably been one of the best K5 investments I've made. :thumb:
 
super k said:
My '91 6.2/4L80E Suburban 3/4t runs great with 35s and 4.10s. With 235/75-16s (31") being stock it figures to right about 3.73,which is fine with o/d. 3.42 is about the limit,to me,for running o/d. The website forums I like to visit seem to be a community of people with common interests where questions can be answered by those with similar experiences. The ones with more knowledge are more than willing to share what they know. For some,in this lousy economy,forking out $25 for every website they like to visit is hard to come by. I know that's true for me.
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Don't forget you have a diesel. Different gearing requirements than a small block.

CK5 is the best resource on the net for these trucks. Also highly traffic which costs money to run. You pay to play but the payoff is access to the best knowledge you'll find anywhere.

Hell, I own my Blazer because a member in Seattle, WA shopped, looked at, bought, and stored it for me.:waytogo:
 
I survived with 4 inch lift, 35's and 3.73's for a long time but a very healthy engine.
Yup 4.10's or 56's would have been better. and I would recomend a 4.56 for you, not knowing about your engine

the 3.42s IMO are only good for stock size tires and stock engines.
 
I also have 35"/4.10...but I also have a turbodiesel. For a smallblock I'd definitely go 4.56.
 
I have 35's and 3.42's with the same engine and tranny. I don't use overdrive at all anymore. It runs happily at 2300 rpm on the highway and gets better mileage than with the OD because it isn't hunting between OD and D and lugging anymore.

4.56's at a minimum if you want to use OD and not cause your tranny a lot of undue strain. If I could afford it I'd be running 4.56's or 4.88's myself right now.

Rene
 
Make sure to keep in mind that there is more to it then just matching the same rpm at a certain speed. The combination of the larger tires with more rolling resitance and the lift with more aerodynamic resistance require more power to move. For example, you have 30" tires and run 2,000 rpm @ 70 mph. Slap on those 35" mud tires and a 4" lift, then swap in gears that gets you back to 2,000 rpm @ 70 mph....you are not getting back to the same stock "seat of pants" power and fuel mileage because the gears are not compensating for the added power requirements.
 
thejimmy said:
Well I should get finished installing the lift tomorrow and then go get my 35-12.50-15s mounted up. Ive got 350 TBI 700r and 3.42s. I hooked up a tach and check it out before I started, at 65 it was 1800rpm at 70 it was 2000. I would like to stay in that range with 35s. I did some formulas on tire rack.com and came up with 3.96s. Some of the guys on here have suggested 4.56s butt this is a daily driver,mostly on the highway. a couple of guys said they had 4.10s and it still hunts between 3rd and4th. Im kind of leaning towards 4.11s. Any suggestions , experiences,or comments. Formulas were calculated with worn out 32-11.50s measuring 29.5 dia, 35 bfgs are 34.8 dia.:whistle: THANKS !
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best 25$ you will EVER spend...:waytogo:
 
The motor is a GM Goodwrench direct replacement 350 TBI with about 30k on it, still pretty healthy. I think Ive decided on 4.56s. I would like to be able to use OD without it shifting in and out at 65 or 70 and maybe gain a little power at slower speeds in 3rd and if I pull my boat. Seems like the majority says 4.56s except for the hard core off roaders,this is a highway vehicle.
 
thejimmy said:
The motor is a GM Goodwrench direct replacement 350 TBI with about 30k on it, still pretty healthy. I think Ive decided on 4.56s. I would like to be able to use OD without it shifting in and out at 65 or 70 and maybe gain a little power at slower speeds in 3rd and if I pull my boat. Seems like the majority says 4.56s except for the hard core off roaders,this is a highway vehicle.
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I plan on going 4.56 with my rig, when I redo it...I plan on using 35's...
 
My point was not about whether the site is worth $25. It was about offering info willingly to fellow members rather than telling them to subscribe and use search. I spend time on other sites that also cost money to get all the benefits. There's bound to be repeated questions. Not everyone comes on all the time or reads every post. The $25 is definitely worth it to support a place you can go and get more from than any magazine subscription,or three. Not evryone is out buying lift kits,tires,and bottled water these day. Some are parting one to build another and selling parts at swap meets to fund the passion they won't let a lousy economy take away from them. Some have it all on hold struggling to just keep their home,but won't give up on their dreams,and still come here to chat about it. Or better yet,offer the knowledge they've gained from as much as 40 or more years of playing with 4wds.
I know the diesels have different torque values. That's why I mentioned what motor I have,to help give some scope. I don't know what motor the OP has,but it makes a difference if it's a stock 305,400,LS6,or Ramjet 502. I'd say 4.10s are where the line is drawn with 35s,depending on what power you have. For me 3.42 is the line with stock sized tires and o/d. With anything 37" or over I don't even bother with o/d. It becomes self defeating,since tall tires raise your ratio as it is and gearing down to be able to use o/d is just spending money to end up where you started,IMO.
 
I just went with 4.10 but I have a th 350. I would go 4.56 if i had an overdrive trans.



Gas to jump to $5/gallon by Memorial Day. Obama said to get used to it and "trade your car in for an energy efficient car." With unemployment above 10% in many states, can YOU afford a trade-in!
 
My 88 K5 had 3.73 and 35's and OD was useless. I upgraded to 4.88 gears and it made a huge difference. 65mph is 2300-2400. It seems like high rpm, but before i was running at maybe 1700 in OD. I have a worn out original 350. The new engine will be a GM crate. Same power level.
 
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