I currently have Q3s on my bike and like them overall better than the stock M5s. Turn in is much quicker, steering is lighter, which is what I want. However, one area that's not great is the wear. They've been installed 2050 miles, at most I have 400-500 miles on them at this point. The M5s in contrast, lasted 4400 miles before hitting the wear bars.
The Great 50 vs. 55 Debate
One of the thing that bothers me about how most people approach this issue is they switch from an OE 50 series sport touring tire to a 55 series performance tire and then exclaim how different things are. But there's a side of this debate that most people do not understand. All 190/50 17 (or whaever size) tires are not the same. Even if the tread width is 190mm, the profile of the tread area varies tire to tire. Sport tires like the Q3 have a different shape than something like M5s.
You've all seen this image. This image is so misleading it's ridiculous, and only represents the most generic concept of the difference in tire sizes. It's vital for you to understand that not every tire has the same shape unlike what is portrayed in this literal piece of garbage.
Most of you have not seen this image. This image represents the reality of how different tires of the same size can be different. This is an actual comparison between two same size tires with different tread profiles. This is where the rubber meets the road. In this case, this compares actual profiles of the M5 vs. M7RR. This is evidence, this is proof, this is information. 
Why do 55's make a difference then, Vic?
The reality is you're changing the steering geometry, it's not from the shape of the tire's tread profile. You're decreasing rake probably ~1 degree by going from a 50 to 55. Same thing as many people know as raising the forks 10mm or so. It's ever so slightly decreasing stability of the bike. The better solution is probably raising the forks though, as this also would slightly decrease the wheelbase (maybe .25").
M7 RR vs. Q3
So now that you all understand a little more about how actual tread profiles work, here's some pics of my two sets of tires. Note, they are not mounted/aired up. However I would say it's safe to make some comparison even if that's the case.
Overall both sets of tires have very similar shapes. These are both the same size, 120/70 17 (f) and 190/50 17 (r) I'm confident in terms of turn in and steering effort they will perform similarly. 
Front
M7 RR - Sitting side by side, it's clear although very similar the profile of the M7 RR front is slightly more oval than the Q3 front. I expect this tire could even seem a little more agile in terms of turn in and lightness. 
Q3 - what can I say? I like everything about it that everyone else does. But even in these pictures you can visually see the profile is slightly more round on the Q3 vs. M7 RR
Rear
M7 RR - Sitting side by side, it's clear although very similar the profile of the M7 RR rear is slightly less oval than the Q3. I suspect this is just to counter balance the slightly more radical profile of the front tire? 
Q3 - Even in these pics the difference visually stands out, the Q3's rear is slightly more oval. The profiles are very similar though and I think overall the set's will have very similar handling characteristics. Could an ultimate flickable set of tire's consist of the more radical M7 RR front and Q3 rear? 
* Last updated by: VicThing on 5/3/2015 @ 6:10 AM *
