Cruising speed of 1975 CJ5 with 258ci I6?

[billkiene]

With 373 drive ratio.....(373 with 427 option)

Specs say 81 top speed.

Wondered what the hwy cruising speed was?


Looking at building a 1972-1975 CJ5

Some hwy and some mild off-roading.


Thanks for any ideas.....

 

[jeepsarecool]

I'm not enough of a mathematician to figure out how fast any jeep CAN go. But, I can say that all three of the CJ7 's I've owned would go faster than I was comfortable driving them. I imagine a CJ5 would be even more white knuckled. Honestly, 60 mph is about my comfort zone, but I've used them as daily drivers and done 70 on the interstate.

If you're just wondering what kind of RPM's you'll be turning at various speeds and such, here's a cool calculator:

Grimm's Ratio Calcs

 

[Lumpy Grits]

Have no issues with mine at 70mph, if there ain't a strong cross-wind.
OLG

 

[HackFabrication]

Specs say 81 top speed.

Wondered what the hwy cruising speed was? Looking at building a 1972-1975 CJ5 . Some hwy and some mild off-roading.

Thanks for any ideas.....

How fast ya wanna go? 81 mph is pretty dang fast in a CJ5 . But there are a whole lot of variables. Tires being a very important one.

For reference, my 76 CJ5 with a Ford Racing 5.0L (~350hp, chip tuned, 'B' cam, 24# injectors, 65mm TB, and headers), T-18 and 4.56 gearing, turning 32" TSL/SX bias ply tires, will easily go over 80 mph. I've only done 65 mph, and I've got to tell you, there was a lot more left (even though the motor was turning well over 3000 rpms). Short wheelbase, light weight, narrow track, straight axle, leaf sprung (and lifted) vehicles, running large 'aggressive' tires, are going to start getting squirrely at those speeds. No matter how tight (well set up) the steering is. Toss in a gusting wind, and/or the passing semi truck, and it's not going to take much for a CJ5 to go airborne. These vehicles have all the aerodynamics of a cinder block... And then ya gotta think about stopping. Front disc brakes made their debut in CJ's in 1976 (as an option). Ya go fast - Ya wanna to stop fast....

Personally, at my age (I'll be 68 this year), 65-70 is about all I care to run my CJ5 . And 55-60 is a really comfortable and relaxing highway 'cruise' speed. That's what the right lane is for....

 

[Posi]

I can tell you Bill D and his 1980 CJ5 can cruise at 70-75 all day long!
He got tired of pulling over waiting for me so he just told me to lead.
....and for the record Colorado Springs to Moab is an 8-9 hour drive at 60-65.
Of course Bill D would have done it in 6 hours.

 

[billkiene]

Thanks for all the good feedback about cruising speeds of CJs.


From the Sacramento area for the short distances I will go to get into the mountains or over to the coast I think it will be OK.

In California max speed for towing a trailer is 55 mph in the right lane.

Cursing slower in the right lane is pretty common here.



Going across Nevada and Utah just saw Max speeds posted at 80 mph.

 

[Tommy]

I have an '81 CJ5 , AMC 258 i6 / 4.2l with 3.73 gears. I run about 62 on the highways between Fresno and the Rubicon and the Desolation Wilderness area. It will go faster, and I have, but it seems to like that speed. I run 31 10.50 15s with a mild lift and have had little trouble on the highways or off road. The 5s are great for maneuvering off road but they will make you pay attention on the highway. If you are not in a hurry you will be fine.

 

[billkiene]

Sound good Tommy........thanks.

I think that speed will be fine with me.