biggest tires with the 2.9, gearing

[rusty70f100]

I'm running 235/75R15 tires (about 29") with 3.45 gears, and a M5OD. To tell the truth, that's probably too big of tire for those gears. Around town is fine, and highway is usually fine, depending on the steepness of the hill and the direction and speed of the wind. Freeway can really knock the speed back down in OD if the wind is wrong. Of course, 4th gear solves all these problems.

I keep telling people I'm going to put a big sail on top of it.

 

[TexCaliBII]

88BII,
That is neat. I run 30s/3.73/A4LD and the tach readings are pretty close from the formulae to what I see in the truck.

Jester,
I see your anti-lock light is on too, in the clouds even.... Cool :icon_cheers:

 

[feellnfroggy]

Its been my experience that 5th gear My tach usually moves about 200 rpms for a 15-20 mph change, (thats not exact just making a point how little it moves for big speed changes) You tires are alot larger than mine meaning your rpms should change less than mine for the same speed increase. Is it possible you tach needle is jumping, or your speedo needle is binding at some point, 2900 a 64 is believable, without a doubt. But it shouldnt jump that high in rpms for an 6 mph difference. I really think something is slipping.

 

[The Jester Race]

Its been my experience that 5th gear My tach usually moves about 200 rpms for a 15-20 mph change, (thats not exact just making a point how little it moves for big speed changes) You tires are alot larger than mine meaning your rpms should change less than mine for the same speed increase. Is it possible you tach needle is jumping, or your speedo needle is binding at some point, 2900 a 64 is believable, without a doubt. But it shouldnt jump that high in rpms for an 6 mph difference. I really think something is slipping.

Keep in mind my truck is not stock. Full width SAS, ~8" lift, 37" tires, and a tired old 2.9 with 186,xxx miles on it. A much larger profile. Wind resistance plays a big part.
It is possible something is slipping but I do think I'm closer to 4K @ 70 then you think I am.

My truck.

Back on topic, 5.13's with 37"s with the 2.9 is very drivable, just don't expect to be in a hurry anywhere.

-Jester

 

[Hahnsb2]

It is possible something is slipping but I do think I'm closer to 4K @ 70 then you think I am.

You'd be better off if you believed the basic math.
Run the number yourself.

http://pitbulltires.com/calculate.php

 

[The Jester Race]

You'd be better off if you believed the basic math.
Run the number yourself.

http://pitbulltires.com/calculate.php

I agree with you the numbers say I am full of shit. But in the real world the numbers are wrong. They do not account for an increase in weight, increase in rolling resistance, increase in wind profile, or the lack of power of the 2.9.

My offer still stands, come on down and drive my truck, and see for your self.

-Jester

 

[Hahnsb2]

I agree with you the numbers say I am full of shit. But in the real world the numbers are wrong. They do not account for an increase in weight, increase in rolling resistance, increase in wind profile, or the lack of power of the 2.9.

My offer still stands, come on down and drive my truck, and see for your self.

-Jester

Dude, wind resistance, weight, ect have zero to do with how many gear teeth are meshing together with a solid connection (a non slipping clutch) or how big the tires are. These are constants, increased rolling resistance doesn't change gear ratios and tire size. If you wanna debate this with an automatic that doesn't have a lock-up converter you may have a leg to stand on.

 

[feellnfroggy]

Hes right, the weight and resistance all have to do with the efficiency of your cylinder burn, the mechanicals are still solid material physics. But like I said I in no way doubt that you hitting 4k at 70, Im just really curious as to why if your pushing 29k at 64.


Have we jacked this thread or what? LOL, I apologize for my part in that.
Come to think of it the OP jacked his own thread, now thats funny.

 

[The Jester Race]

Dude, wind resistance, weight, ect have zero to do with how many gear teeth are meshing together with a solid connection (a non slipping clutch) or how big the tires are. These are constants, increased rolling resistance doesn't change gear ratios and tire size. If you wanna debate this with an automatic that doesn't have a lock-up converter you may have a leg to stand on.

You are too far gone. You have it set in your mind that I am full of shit, and thats fine. I am done arguing.

-Jester

 

[Hahnsb2]

You are too far gone. You have it set in your mind that I am full of shit, and thats fine. I am done arguing.

-Jester

Damn me and how I'm set in my ways of physics, math, and facts :icon_confused:

Never said you were full of shit, but your tach is.

 

[The Jester Race]

Hes right, the weight and resistance all have to do with the efficiency of your cylinder burn, the mechanicals are still solid material physics. But like I said I in no way doubt that you hitting 4k at 70, Im just really curious as to why if your pushing 29k at 64.


Have we jacked this thread or what? LOL, I apologize for my part in that.
Come to think of it the OP jacked his own thread, now thats funny.

I think it has to do with the 2.9's performance. It doesn't develop that much more power between 3k and 4k, does it?

-Jester

 

[Camshaft]

Im running 37s with a built 2.9 and 4.56 i have plenty of power on the road. i would like to go lower by putting a 4.5/1 T-case in it though

 

[lethal-threat-b288]

I think it has to do with the 2.9's performance. It doesn't develop that much more power between 3k and 4k, does it?

-Jester

Yall are still fighting about this? Seriously? Why don't you just put a 4.0 in it and solve your power problem and drive slower to fix the rpm problems:icon_thumby:

 

[The Jester Race]

Yall are still fighting about this? Seriously? Why don't you just put a 4.0 in it and solve your power problem and drive slower to fix the rpm problems:icon_thumby:

No, we're done. Weren't we? I thought we were done. I mean that's why I said I'm done. Until you brought it up again

I don't have a power problem, or an RPM problem. I simply stated that how my truck is setup my engine is turning at ~4k in 5th gear to do 70MPH.

And I'll quote myself here.

Back on topic, 5.13's with 37"s with the 2.9 is very drivable, just don't expect to be in a hurry anywhere.

-Jester

:icon_cheers:

-Jester

 

[89DANGERANGER]

ok kids ok kids calm down, dont break a space bar now. seems like id be fine with stock gearing up to 35s, my ranger had 33s stock gears it pulled fine. i dont have an overdrive gear so i run 3000rpm going 60

 

[mhughes165]

lol......this thread is amusing, the 2.9 doesnt lack power between 3k and 4k at all, if it does it is because its the mechanice doing the work under the hood.

and because the truck isnt stock deosnt really mean anything at all, that MIGHT have mattered if u had changed out transmissions and engines...

basically tp the original poster, anything 33 and under aslong as u have 3.73's will be TOLERABLE, esp with 4 low, other then that, dont fear the gear...

me im runnin 3.73s and 35's lol but i also have a very healthy small block under my hood lol

 

[buell-eyed-devil]

What motor you running? 89 dangerranger

 

[89DANGERANGER]

2.9 efi

 

[larrybjr]

good thread heres my ques.

heres my problem. This is my daily driver and on the interstate at around 65mph it will shift into over drive but if it slows below 65 it downshifts. The truck seems to be working too hard to push my 33s down the road. Downshifts then upshifts. So I was thinking of changing gearing. Never done this before so I was looking at it and it looks like you have to have special tools and stuff to do this right. Who has done this and is it as difficult as they say it is?? I just put the lift and tires on this past summer and its kind of a pain to drive on the intersate. Any input would help. Thanx

 

[rusty70f100]

You could just leave it in drive until you can change gears.