Sunday, January 20, 2019

Measuring motorcycle chain wear

According to my service records, I installed a new Regina 520 Z-Ring chain on my WR250R in March 2017 at 21,000 km. My odometer now reads about 38,000km on the same chain. In that distance I've completed many muddy backwoods rides, long highway rides, and a 7,500km ride down the Continental Divide--all with a loaded bike.


Nevertheless, after 17,000 kms, this chain hardly shows any wear other than some cosmetic polishing. It has no stiff links, and there's a consistent mild resistance when bending the chain (as in a new chain), indicating that the Z-ring seals are all still good. Here's the outside after cleaning with mineral spirits:


And here's the inside (left) and outside (right).


My maintenance ritual has been a daily brushing with a nylon motorcycle chain brush ($10 online) to remove trail grit, then spraying with a paraffin-based chain lube while the chain is still warm from riding. The paraffin builds a tenacious Cosmoline-like layer on the chain that repels water-blasting even in heavy rain. This routine has rewarded me with no significant wear of chain or rear sprocket (a Dirt Tricks sprocket--awesome quality), although I've had to replace several front sprockets which is to be expected. Previously I used Dirt Tricks front sprockets, but when I was not able to get a replacement in time, I thought I'd try Renthal sprockets at half the price, and was pleased to see a good 8,000+ km out of one before it needed replacing. I'll probably stick with the Renthal counter sprockets from now on, as they are cheaper and more easily available, and I don't see a significant wear or running advantage over Dirt Tricks.

Dirt Tricks has a great guide to measure your chain wear. I didn't want to disconnect my master link, so I measured 50 spaces between pins and got exactly 31.25", which is exactly half of the 62.5" you should measure for 100 spaces on a brand new 520 (5/8" pitch) chain.

I was surprised by the lack of chain wear and at this rate will likely get another good season out of it before it needs replacement.

No comments:

Post a Comment