17" vs 15" wheels pros and cons Options

[moggy]

I don't seem to see many 914 circuit racers with 17" wheels on. Everyone seems to stick to 15". Is there a reason for this? I'm less bothered about the looks of 17" vs 15", I'm more interested in this from a performance perspective. Who out there has tried both wheel sizes? what size did you decide on, and why?

I personally have 15" (Cookie cutters 7" wide all around)
(IMG:http://www.914world.com/bbs2/uploads_offsite/i31.photobucket.com-3285-1440357310.1.jpg)


and 17" (Cup1 7"front 9"back)

(IMG:http://www.914world.com/bbs2/uploads_offsite/i31.photobucket.com-3285-1440357310.2.jpg)

At the moment, I'm forced to use the 17" on tracks where I need the top speed, due to my low ratio gearbox (a hangup from when it was a rally car). The 17" wheels have a 26" overall diameter. Whereas the 15" wheels are used on slower, twisty tracks.

There is a huge weight difference between the wheels (including tyres) of 32kg (70.5lbs) total, which is an obvious benefit to sticking to the 15 "cookie cutters. But weight can't be the only reason why you circuit racers stick with the 15", so what are your reasons?