Over the past several years I have had several different Dunlop rear tires on my scoot. I have to admit that I am pretty abbusive to the rear tire because I really like to twist my right wrist
Anyway, my 2000 883C came with a D401 130/90-16 on the back and a D402 MH90-21 on the front.
When I got a screw in my rear tire, and was stranded, my local HD dealer replaced the factory D401 with a D402. When I questioned him about it, they claimed it was just a better tire and that all the 'big' bikes come with the 402 stock. I figured he was right. The tires are identical in appearance (tread pattern, side wall, etc). The bike seemed to perform fine with this tire on it, but it just didn't seem to last nearly as long or have the accelerating grip of the stock one.
After that one wore out very quickly and the front was finally ready to replace, I went out on the web to find a good deal. And that I found. I posted a while back int eh good vendors section all the details abotu this tire distributor. In that research, I kept coming across everyone recommending the D401 for the rear, so that is what I ordered and installed not even thinking about what the differneces were between the 401 and 402. Honestly I just figured since the big bikes had the 402 and the Sportster has had the 401, that the 402 much just be capable of handling more weight.
This tire is lasting quite a bit longer again and I haven't changed my riding style at all. So that got me to thinking....what is the REAL difference between the D401 and D402? I am just barely into my research on this, but thought I would pass along the initial findings. The size of the two is different!!!!! Yep, that's right the D402 (REAR) only comes in a MT90 B16 and the D401 is a 130/90 B16.
401 = 25.40" diameter, 5.18" width, 12/32"
tread depth, 805#@41psi weight capacity.
402 = 25.70" diameter, 5.20" width, 9/32"
tread depth, 827#@40psi weight capacity.
As you can see, the 401 comes with deeper tread from day one. AND your speedo will be slightly off with the 402 from the slightly larger diameter.
I'll keep researching and will post whatever I find, but as a word of advice, unless you are really in a pinch, try to make sure that a 401 remains on the back of your scoot.