Running 18 mm front and 15 mm rear with Pirellis. Modded my fenders cutting 3 vanes on the left and one on the right to get rid of the rubbing.
You don't NEED to cut the vanes, it just makes noise with zero chance of damage. The tires will basically break off one side of the vanes when reversing close to full lock. The noise it makes is horrendous without the vanes completely removed.
Before
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You can see the vanes broken on the left side in the picture above.
After
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Results
Untitled
It is an aggressive setup, but when we mounted 15's at EAS I was pretty disappointed. The 18's are perfect to my eye with the front wheels flush with the fenders.