.The OEM BT23's made it 9100 miles with plenty of tread left in the rear but the front was cupped quite a bit (I maintain pressures weekly for my commute) and it felt like riding on nobbies at the end.
Bridgestone is OEM. Any Bridgestone tire is OEM (Original Equipment Manufacturer
) to the FJR, even the T30 which never shipped on a new FJR. The BT023 is OE (Original Equipment). Please say OE if that is what you mean. OEM is a term coined by independent parts distributors who could not sell genuine branded vehicle manufacturer (“Yamaha”) parts, but could source parts from the manufacturer who made the OE (“Bridgestone”).
An interesting fact: The FJR front brakes and rear brakes are not made by the same manufacturer. There are two OEMs, but only one OE.
Secondly, “cup” is a fun word to say but it is always wrong when applied to motorcycle tires. Cupping is a divot spanning multiple tread blocks appearing one or a few places around the tire. Due to imbalance, bad bearings, loose suspension, a number of things far worse than one can ride a motorcycle.
Modern motorcycle tires feather and scallop. Scalloping is a form of feathering, both are ugly wear patterns repeating on every tread block.
All street motorcycle tires will scallop and/or feather, nothing you can do about it. Higher tire pressures can reduce (not eliminate) the scalloping by creating a narrower contact patch. Narrower reduces the difference in speed across the road contact patch.
Scalloping occurs because the tread is rounded, not flat like a car tire. The center of your tire has a larger rolling diameter than the tread to either side yet the road moves at the same speed under the contact patch. Continuously changing diameter across the contact patch means something has to slide. The tire flexes more in the tread grooves so the edges of the tread blocks wear fastest as the tread squirms.