I looked on their website, but the only things I found was the standard creepy crawler and the competition. They DO have a 37x12.50x15, but only in the standard creepy crawler.
Here's their website:
Competition: http://www.maxxis.com/products/automotive/product_detail.asp?id=2364
Standard Creepy Crawler: http://www.maxxis.com/products/automotive/product_detail.asp?id=64
Here's their website:
Competition: http://www.maxxis.com/products/automotive/product_detail.asp?id=2364
Standard Creepy Crawler: http://www.maxxis.com/products/automotive/product_detail.asp?id=64