Shimano’s old bleed cup is fine. Sure, it has a low volume and is unrimmed and the plunger is insubstantial and the “Road Bleed Cup” is actually just an adapter that seems like an afterthought… Ok, it’s not great. Fortunately Shimano has come out with new cups, and they address all of the old cup’s shortcomings!
The most notable update is that road groups get their own cup this time around. The cups themselves have a much greater volume, reducing the risk of accidental spills when using the same amount of fluid as the old one, or reducing the frequency that you have to top off the fluid for particularly oxygenated systems. They both feature longer necks, greatly increasing accessibility to road and brake reservoirs. The port at the end of the cups has also been widened to allow more fluid to enter the system while allowing air bubbles to pass more freely, which saves a considerable amount of time.
In addition to the cups themselves, Shimano has included detachable, rimmed lids. These allow the bars to be tilted while chasing those air bubbles, without the concern of spilling brake fluid on the project. The plunger has also received a welcome update, in addition to being longer, the flat grabbing surface is now much larger, making it easier to insert and remove.
Shimano also took the time to update the syringe for their bleed kit. The new syringe features a higher volume, a hose that threads on (replacing the press-fit of the old one), and a guide pin on the end of the hose that helps it stay in position on the caliper.
These quality-of-life improvements make this bleed kit well worth the upgrade if you’re unsatisfied with your current set up! Be sure to check them out.