I have never looked online for rims.
I live near Minneapolis and there is a big
dealer there called Pioneer Rim and Wheel.
I just drove down there and they had the
15s in stock. They also have a branch in
Fargo ND. I suspect any good ag type tire
dealer could get them for you.
I have played around with tires on my
tractor quite a bit over the years. I also
ran these 6x14in implement rims and car
tires for a few years too.
These were very short.
You can get implement rims in 14, 15, 16
and 18in plus different widths. You can
also buy them in different 'offsets' which
means how much offset from the edge of the
rim the centers are welded in. The right
offset lets you run wider tires without
rubbing the spindles.
Right now I am running these 900-10 tires
which are a wee bit taller than the 14s
above. I like them a lot. They are 9in wide
and they don't rub the spindles. These are
10 ply tube type.
They came off a 1980s Ford golf course
tractor. They are a direct bolt-on for an
8N through the 1980s Fords all of which
shared the 6 on 6in bolt pattern. With the
added front weights and these tires I get
Zero scuffing on the lawn.
Hope I haven t 'tired' you out with all
this rambling.