Be honest, how often do you inspect the front sprocket? It has the fewest teeth and tightest radius. The teeth will start laying over well before the back starts showing wear. Even 10K miles is not acceptable mileage for a $300 setup that provides very little gain. Fine on a track bike.
I juggle gearing quite often so inspecting the front is a non-issue,the 520 front is steel and showed no signs of wear.
Teeth laying over from the tight radius? It's a 16t not a 14t or 15t; running a 16t on the street is basically common practice&one of the 1st mods any rider does as it's cheap&shows a seat of the pants improvement. If your bike is make 250-300rwhp and 125-175ft/lbs then yeah,I'd be concerned running a 530 16t let alone a 520.....
Again,I've run a 520 chain on a K5 1K ten years ago that made 200rwhp+,ran 8sec 1/4's,topped out well over 200mph blah blah blah and basically beat the snot out of it. Yet my set-up showed no extreme signs of wear as you describe you had with your 520 set-up&if the teeth on the CS were going to roll over
I'm sure they would have started to after the 7-8k miles
I had on the set-up before selling the bike.
$300? Pretty sure I paid $220ish from motomummy on my last 520 chain/sprocket conversion.
Also,disagree with your statement regarding changing gearing on a street bike: IMO, you should never change the gearing for a street bike either. The engineers spend a great deal of time coming up with the ideal ratio for street riding. If you don't leave town with it, by all means.
Why not? Speaking from experience a K5/6 1000 will top out at 100mph in 1st gear. Pretty tall for a street bike wouldn't you say? So switching the front from a 17t to a 16t for easier commuting is a huge no-no? Please explain...