Aspect Ratio

New to this forum (not new to VTXOA) and I'm thinking about the darkside as my Avon R is starting to wear out. I'm interested in what people think is the best aspect ratio for my ride ('02 1800 Retro w/cast wheels), which is largely 2-up with my wife on board. I was thinking (and might be over-thinking) based on many years of car racing experience that it would make sense to get quite a "sticky" car tire, meaning more "wet weather high ultra performance" (in cars this translates to poor tread wear but with good water clearing), and I notice that sizes for those kinds of tires seem to be in lower aspect ratios (205-50/16's mostly), like Toyo's for example. I'm kind of assuming that the lower tire load in general means the wear won't be bad on the bike vs on a car, hence better longevity - safe assumption or wrong? If I get a 50 ratio, aside from probably messing up the speedo further, by lowering by roughly 1.2 inches what happens to the handling? If bottoming out is a concern due to 2-up with bags etc. would adding 12.5" progressive springs solve that? I know a 1300 FD would help the speedo issue. Any recommendations for a tire match to my criteria that might work? Of course there's the GY TT that seems so popular - how would this compare to the logic I just laid out?

Sorry for the litany of questions, just trying to figure it all out - seems like the choices are somewhat limited by availability of the car tire sizes. I do know that while I was happy enough with the feel of the Avon R's (but I can't compare to darkside as I haven't tried it) the tire life is awful - about 5K miles so far and I reckon there's maybe another 1k in them at best and they're shot.

Thanks for your help!

the ct's are all softer than MT's anyway. gettin into the shorter sidewalls like that will make the handling worse on a scooter. Dig into a tire calculator like Tire Calc and you will be able to compare how much farther off your speedo and odo will be. That would be a pretty decent change and I would think it would raise your RPM's a bit, the 1300 final drive is only good for an adjustment of a couple hundred RPM from my experience and won't help much...

the Hydroedge or tripletread in a 205/60 or a 205/65 are proven performers for other members...

hope that helps...