Originally Posted by
rowebr
The Dura-2 brake pads are narrower, and so are a better choice for rims with a narrow brake track. (I used "brake track" to refer to the area on the rim available for the brake pad to contact, not sure I'm using the right terminology) . I used the original Dura pads with Velocity Synergy rims, which have a generous brake track, they worked nicely. Now I'm using Velocity A23 rims, which have a pretty narrow brake track, so I'm using the Dura-2 brake pads with very good results. Overall braking performance seemed the same with either version.
Very interesting information. i have 7 pairs of new Kool Stop Salmon inserts in my parts box waiting for the current ones on my bikes to wear out. I bought them in two groups when web store orders needed a couple of extra items to get above the free shipping threshold. I just looked and 4 are Dura and 3 are Dura 2. I never noticed they weren't identical until I read this thread. The rims they will go on have plenty of brake track width so I expect which I use won't matter.