Brad, I have a 300T track machine with the 2 speed transmission. I've just had it a week or so.

From memory I thought the top speed was about 12.5 mph. However, checking the brochure to answer you, I find the 12.4 mph max speed is for the rubber tire 300 only. Not the 300T tracked machine. The 300T does have a top speed of 7.8 mph as you mention.  My mistake! No wonder it was taking longer on the road than I thought! 

Oh well, I still love the machine for handling large bales. It is stable and I can safely carry a large bale up high enough to see forward, underneath the bale. Also love the LH door access and the cab. Easy to get in and out to remove netwrap and/or plastic from bale.

I started out with demoing a 190T but it was definitely not large enough to handle my large 5x6 bales safely.  I Liked the rest of the machine but not its capacity for my applications - feeding large bales, handling manure and handling large logs.  I then did as a friend did last year and went to the larger 300T. This is a bale handling machine! I'll just have to live with the 7.8 mph top speed.

Here is a picture of the speed spec page from the brochure and also a picture of me loading a bale in one of my cradle feeders before the last snow.

Thank you for straightening me out on the top speed.

(JCB Brochure top speeds.jpg)

(IMG010 loading bales in cradle feeder with 300T 011418.jpg)

JCB Brochure top speeds.jpg (36KB - 60 downloads)

IMG010 loading bales in cradle feeder with 300T 011418.jpg (86KB - 48 downloads)