Can 4.88 gears be a daily driver

[661buster1963]

My buddy here in SC has a 72 bronco. He wants to know if 4.88 gears are good for a daily driver. I know often times they are not but I think his set up is pretty prime for a daily driver.

He has a modestly warmed up 302, more than a stock cam but no thumper at idle. I can get spec if needed but tend to think it’s not. He runs bfg 35” act’s and it looks like about 33.5” effective diameter. He has no 3550 transmission and the aforementioned 4.88 gears. He just did rears for now. Front is still 4.11 and obviously not using 4wd right now.

This thing will use first gear to start, does decent with second gear start. He can run 70 mph on hwy at about 2700 rpm

You can tell gears and purring along but it sure seems to feel like daily driver. He installed disc brakes, power steering and has about 5 degree of caster so it doesn’t seem to wander.

Is there something else to be concerned about? Or does this sound reasonable close to daily driver material?

 

[bigmuddy]

Sounds spot on to me. 2700 is nothing for a 302 as far as RPM goes.

No worries that I can see.

 

[Apogee]

Anything can be a daily-driver if you choose to drive it daily...that said, your friends setup seems pretty comfy all things considered. I'd daily it.

 

[Broncobowsher]

Sounds like a good gear to me.

 

[snipes243]

I daily drove a very similar setup but with a (NV4500) for about 3 months and drove nice no issues, so I would say go for it.

 

[DirtDonk]

What's the concern your friend has about it being drivable? Have they driven other Broncos?
Sounds like they're driving it now, so should be able to decide for himself/herself if it's got the right stuff. But it sure sounds like it from here.

With stock 4.11 gearing and transmission (no overdrive and a piss-poor 1st-2nd selection) and 31" tires, it's not uncommon to be doing 3100-ish rpm at 70mph. The combination with the 3550 and overdrive makes it a super combo it sounds like.
If you go much below 2500 I'm thinking it won't feel very peppy. Maybe 4.56 would be "better" but I'm not sure how.

What all is the Bronco going to be used for? City only, or any trail riding?

Paul

 

[73azbronco]

you can beat a corvette across the intersection with 4.88

 

[Soylent]

My $0.02. Maybe not apples to apples. I have a 306 with ax15, BFG33 and 4.10. Wish I went with 4.56.

 

[661buster1963]

Thanks all. He is a younger guy, meaning younger than me at 60. He is 41, has limited time in the saddle with older cars. He wants maybe 10-15% trail rider but not on any Jeep trail where side are always pushing brush out of the way. I think he has friends that are how do we say, young and clueless who think 4.11 gears are too high with no understanding of mechanical things. I know one of them has way too tall tires on a tundra and now that truck about can’t get out of the way, tall and super wide tires on a mall crawler. He doesn’t have a tach, just when we drove around I used a dwell meter to get rpm. That 2700 rpm might sound like 3500, but meters don’t lie it’s only 2700.

I strongly suggest he upgrade distributor, it still has points and condenser.

 

[bigmuddy]

Thanks all. He is a younger guy, meaning younger than me at 60. He is 41, has limited time in the saddle with older cars. He wants maybe 10-15% trail rider but not on any Jeep trail where side are always pushing brush out of the way. I think he has friends that are how do we say, young and clueless who think 4.11 gears are too high with no understanding of mechanical things. I know one of them has way too tall tires on a tundra and now that truck about can’t get out of the way, tall and super wide tires on a mall crawler. He doesn’t have a tach, just when we drove around I used a dwell meter to get rpm. That 2700 rpm might sound like 3500, but meters don’t lie it’s only 2700.

I strongly suggest he upgrade distributor, it still has points and condenser.

There is part of the problem. He is used to newer cars and 6-10 speed transmissions with heavy insulation. Freaking out because his engine RPM isn't in the 2,300 range I bet.
the 302 was built for high sustainable RPM.

 

[Speedrdr]

I’m going with .488s unless I drop size of tires from 35s to 31s. I’d rather have a few higher sounding RPMs than prematurely replacing a clutch.

R

 

[ZOSO]

I drive my bronco regularly. At hwy speeds up to 80. With 5.13's and 35's. 4r70w it cruises great at 65+. Infact it gets smoother when you run it past 75. 70mph for me is 2850rpm or so.

 

[ntsqd]

I put ~120k miles on a truck with 4.88's and 33's. It did have an OD manual trans, but it also only had a 22R for power. I see no reason to not do it.

 

[bigmuddy]

Hell I am worried about my new 4r70w install with 35's and 4.56 gears! Really thinking I wish I had 4.88 or lower. We shall see.

 

[1969]

I plan to daily mine with 5.38s and 37s.

 

[DirtDonk]

Hell I am worried about my new 4r70w install with 35's and 4.56 gears! Really thinking I wish I had 4.88 or lower. We shall see.

What engine setup, and what planned driving?
I bet I could run 35’s no problem with my 4.56s and 4R70. But that’s because it’s a mostly stock Explorer engine and tune.
Works really well, pulls really hard, has good throttle response.

 

[onpier55]

I have 488 gears. Zf5 and 35’s. I’m glad I went with 4.88’s.

 

[lilthom]

Sorry for hackiing this thread but I have a matching front and rear 4:88 set up with lockers for sale in Wisconsin.

 

[bigmuddy]

What engine setup, and what planned driving?
I bet I could run 35’s no problem with my 4.56s and 4R70. But that’s because it’s a mostly stock Explorer engine and tune.
Works really well, pulls really hard, has good throttle response.

Good intel and is appreciated. I have a fresh 351 with gt40 heads and efi so I think I will be ok but got to worry about something.

 

[DirtDonk]

…I think I will be ok but got to worry about something.

Wouldn’t be a normal day without it!

And the answer to gearing is always the same.
Don’t jump the gun. Wait until the rig is put together and driving, see what tire size you end up with, see how much torque is generated off idle and low through mid-range, see what speeds you like to run at, figure what RPM you would like to run at those speeds, and THEN choose your gear.
The most important tool you’ll need during that process, his patience!