Well, over the past day or so I've had responses from Exact Fit, Cycleworks and Bestorq about this and I've learnt quite a bit about belts. They've all been brilliant.
In summary of what I've been told (with a few quotes thrown in and names omitted) is that these belts are
"a couple thousands of an inch thicker tooth is all" (sic) than others so that the tooth is the correct shape when fitted and tensioned. The 2v belts are also
"the same strength as the 1198s" and they
"don't down spec the 2V models" so they are also a bit thicker as well, making them harder to get to the right tension. Apparently other belts may not allow for the tooth shape changing when they are tensioned.
So it seems that they are a bit bigger than the ones I took off, but they've been designed to be like that so that they perform better.
The bit I need to look at is where they say
"If your guy noticed this “on the drive” then I strongly suspect he is not tensioning the belts tight enough." so I'm off to wrestle the covers off again and re-check the tension... anyone recommend a good tensioner / app??
