TiTo Titanium Bike Crank Cover M20 Screw Titanium Alloy Bicycle Crank Arm Fixing Bolt Thread Cover Cap for Road Bike MTB

I didn't have the problem of the other reviewer. The cap I received fit perfectly and works with my Shimano tool. It's nearly identical to the GRX cap I replaced.

This cap doesn't fit flush as the oem cap on GRX hollow cranks. The out diameter is too large. You can screw it in but it sits proud.

This only threaded on with the tool provided. The stock Shimano tool is too large to fit the head of this bolt. Downside it the provided tool is plastic so its not going to last if you remove your cranks to service them. Looks pretty though

At least for the one I ordered, the inner size does not fit a normal Shimano HT fixing bolt tool. The only thing that fits is if you hammer in the soft plastic one that ships with the bolt. It fits in because it's soft, but then because it's so soft you can't actually tighten it. I returned the bolt because I couldn't get it on.

Acceptable replacement to improve strength of Shimano Deore HollowTech II cranks. Update 9/24/24, I have used these for several years on a Shimano cranks ranging from non-series Hollowtech to XT series. 10, 11 and 12 speed. I won't run a set of Shimano cranks without one, being a heavier rider (220lbs) I feel the TI fixing bolt keeps the end of the spindle from flexing. If you install the plastic tool a few times it will form itself to the fixing bolt for ease of installation. Your not supposed to cram the fixing bolt down with a lot of force anyways as it really is designed to set the bottom bracket bearing preload.