MPH Question.

[Rodney51Cub]

I know the Standard Cub is rated for about 7 mph on a good day with no head wind.

Does anyone know how fast a high crop Cub will run in normal configuration ?

Just curious.

[Barnyard]

There are several speedometer apps for iPhone s that are very accurate. Down load one and take a ride.

[ricky racer]

There are several speedometer apps for iPhone s that are very accurate. Down load one and take a ride.

But hang on tight! I'd hate to see you get swept off of that thing in road gear...

[Rodney51Cub]

I do not own a high crop Cub, I was just curious.

[Crimson Tim]

Easy enough to calculate. What’s the rolling radius of the standard Cub wheel and the rolling radius of the hi crop?
Rolling radius is just measuring the height from the ground to the axle center on level ground. With properly inflated tires, of course.
TractorData.com lists a Cub at 7.3 mph at 2000 rpm. First of all, shouldn’t we be looking at 1800 rpm?

I have a Cub on pavement on 9.5x24 Ag tires. A narrower tire would probably be more typical, which may or may not affect the radius. My other clubs are parked in the grass at the moment, so it would be difficult to get a decent measurement. I do not have a hi crop, either. In any case, on these 9.5s, I think we can call the rolling radius 20 inches. Assuming that high crop tire is about the same thickness (which may or may not be a valid assumption) that means a high crop rolling radius would be 23 inches.

Adjusting the TractorData.com speed for 1800 rpm yields:

Screen Shot 2022-06-17 at 11.19.45 PM.png (6.52 KiB) Viewed 378 times

Then adjusting that for the larger hi crop wheels yields:

Screen Shot 2022-06-17 at 11.19.33 PM.png (5.68 KiB) Viewed 378 times

So you’ll get about an extra mph out of the bigger wheels, depending on specific tire choices. I bet that 1 mph difference feels like a lot more, though!

For argument’s sake, if you stuck with the 2000 rpm engine speed, that would be 8.4 mph road speed for the hi crop versus the 7.3 mph for the standard Cub.

[Jim Becker]

My cut at the distance/speed difference by tire size (without actually measuring anything) is to consider the effective radius to be tire width plus half the rim diameter. For example, 9 or 9.5 -24 would be 9+12=21. I doubt that old size vs. new size designation matters. Nor does it matter much how this calculation is done, as long as all sizes are done the same way. The various sizes come out this way (sorted smallest to largest).
6-24 18
7-24 19
8-24 20
9-24 21
6-30 21
7-30 22

Note that the latest standard size (9.5-24) is as tall as the smaller high-crop tire. Going from 9.5-24 to 7.2-30 is only 1 inch, less than 5%, about 1/3 of 1 mph. Not that big a deal. Comparing back to the original 6-24, you are looking at nearly a quarter again faster.

[SamsFarm]

Well.....

Where the rubber meets the road is in the circumfernce!

Actual tire circumference, distance that tire travels in one complete revolution!

Once that is known, then one needs the gear ratio between the trans output shaft and the rear wheel hub.
(On a Cub that would be the ring and pinion ratio x the ratio of the pinion gear and bull gear in the final drive!)

Armed with those two pieces of data, one can calculate mph at any engine rpm they like.

[Waif]

Probably as fast as a standard Cub.
I've had one standard up to 70 M.P.H. ...... On a trailer...

[Barnyard]

I've had Harley up to 13 mph in my back yard when it got a little bumpy.

[Ole Timey Farmin]

I've had Harley up to 13 mph in my back yard when it got a little bumpy.

I've had a Cub go way faster than that, but not sure how fast, probably only 20mph but it felt like 90. I took it out of gear on the road while going down a hill. Once she picked up speed I couldn't put her back in gear nor did the brakes seem to do anything. I knew better but it was a small hill with another hill up 100-200 ft away so I thought Jewish overdrive would be fine. Well Yahovah had some fun watching me (hope someone got a good laugh). I on the other hand will NEVER try that again.

[Barnyard]

I've had Harley up to 13 mph in my back yard when it got a little bumpy.

I've had a Cub go way faster than that, but not sure how fast, probably only 20mph but it felt like 90. I took it out of gear on the road while going down a hill. Once she picked up speed I couldn't put her back in gear nor did the brakes seem to do anything. I knew better but it was a small hill with another hill up 100-200 ft away so I thought Jewish overdrive would be fine. Well Yahovah had some fun watching me (hope someone got a good laugh). I on the other hand will NEVER try that again.

Mine was on level ground. I would try downhill out of gear.

[Gary Dotson]

I’ve seen 15 on Cubota, front wheels shimmy pretty good at that speed. A little pucker goin on there! I seldom run it full throttle.

[BullDAWG]

I found a listing of every tractor's max speed in EACH gear but no listing for the Cub high crop. Has cub, SA, SAV, C, C wide front high crop, H, HV, M, MV. Even info on Orchard's, Wheatland's
, Riceland, and forgot their name but look like a bulldozer without the front blade. Just nothing on Cub high crop. It was printed in 1949, when did they first make a cub high crop?

[Jim Becker]

The Cub, SA, SAV, C, C wide front high crop, H, HV, etc. were each different models with published specifications. The high-wide option on the Cub was a machine attachment, just like a hydraulic system or a padded seat. As such, there were no separate published specs.

The high-wide option was in a 1950 brochure. I have found no earlier reference to it.

[BullDAWG]

TY, Jim...
Nowhere in that "General Line Catalog" from 1949 does it ever mention the Cub high crop and I've read all 689 pages. But thanks for confirming what I thought as I too have never seen any litature not ever an original tractor pre-1950 Cub high crops.