Normally I run the OEM 020 and the front is usually good for 10k plus. Got a new 021 from another st rider who did not need it. Getting ready for a 4k plus ride thru Colorado and Utah from Seattle. Got a new 020 read and thought with only 2.5k on the front it should be ok. Nope to my horror as I was checking the bike out I find the 021 with only 2.5k miles is already down to the wear bar? Yikes no way it will make 4k plus ride. So new 020 on the way.