Topped Out at 65 mph

tires are NOT what they say they are. they could be a 31" tire but depending on the rim width it can change A LOT in size. and also some tires are bigger than they say and some are smaller than they say they are. you really need to measure while they are mounted and installed on the jeep to get a good measurement

 

You also need to use the "Early Jeep Seat of the Pants Speedometer Calculator" which is double it and subract 30. So if you are driving an early CJ5 at 65 mph, you double that, 130, and subtract 30, so you end up with 100 mph. So even if the traffic next to you is doing 65, in an early Jeep it will feel like 100 mph (my apologies to Bob and Doug McKenzie and their metric conversion, double it and add thirty).

 

I go by the comfortability factor. I am comfortable driving 50 or 55 in my non-overdrive equipped CJ5. I am not comfortable driving it at 60+. 55 mph is MY top end in my JEEP. And I still have pedal left!

 

The computation of RPM at a given speed really has little to do with the stated diameter of the tire it does how ever have to do with the circumference of the tire which does not change no matter what wheel you have it on. The Speed calculator used the diameter of the tire to determine what the circumference of the tire is. How far forward the vehicle travels each time the tire is rotated against the road surface.

Those of you who are relating what your comfortable with as to the speed you drive has little if anything to do with the conversation about rpm/mph/gear ratios etc.

I grew up driving a 48 Willys CJ2A with a canvas top. I still have a hard time driving a car with the drivers window rolled up. (I'm 58) If you are used to driving the kiddies to soccer practice in your Mini Van or listening to the stereo in your BMW then yes driving in a vintage Jeep is going to FEEL like its about to blow apart BUT ITS NOT.

A Willys or Kaiser 134 can easily run at 3000+ RPM on long trips. The 134 has the same stroke as a Dodge 218 or 230 Flat head that they used to and still do make all sorts of speed equipment. My 40 Dodge 5 window Coupe had no problem doing 100mph with the stock engine and stock 3.90 rear end gears.

I'm not trying to talk anyone who thinks they are driving a fast tractor into going faster. I am trying to correct some ones math problem that isn't coming up with the correct answer based on the variables.

 

One of these days I will learn to just pass this discussion up. It never does any good. When I was younger this was so much easier to figure out. Some one dropped a flag and at the end of the 1/4 mile the guy who knew what he was talking about was handed the money the other one went home broke.

 

Done.

 

Looks like a really started something here. Beers for everyone!!! Seriously thanks for the help and opinions. I have learned a lot to consider. I have a set of tires that are slightly smaller in diameter, mounted on true mag wheels. I will try them out when I get a chance and see if anything different.

 

--Looking schmart on "paper"--https://www.youtube.com/watch?v=yWBiefjBkfs