Tire wear will affect it, too, since tear wear changes the height of the tire and the resulting circumference. With a new tire, on most Honda's, you have +5.5% error. An average worn tire is about +6.7% off, while a bald tire gives you around +7.6% off.

Sprockets, of course, will make a huge difference. If you go -1 +2, it will kick it to about +19% error.

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"I'd rather sweat than bleed."
CBR954RR - Street
CBR600RR - Track
CMRA Provisional Novice #328