Bottom Bracket Selection Guide
Shimano Crank Spindle Wear Problems on Bikes: A little wear is not so little
Spindle wear is a problem that can kill any crank, sometimes in record time. Shimano crank spindle wear problems on bikes are especially critical when it comes to cranks with integrated spindles, like a Shimano crank, rather than a modular system, like a Cannondale Si crank, because excessive spindle wear can destroy a crank permanently. Let's talk about how this happens, how to diagnose the problem, and how to prevent crank wear on bikes.
Now this is something that I like to do I mean when it's a really new bike or an old bike either way. I like to do it. It's just a good check and that is just to take our handy vernier caliper and make sure it's zeroed and calibrated and come in here and measure the spindle itself. Now of course these surfaces have been cleaned very thoroughly so we can get an accurate measurement and we want to see what kind of wear we're experiencing out here on this spindle over time, because you can definitely see where this has been what's called fretting right there. That is where the wear is occurring as this is operating. You can see it’s supposed to be 24mm, and you can also see it’s not 24mm everywhere. This one isn’t worn enough for me to even worry about because the polymer shield will take it up, but if this were in a bottom bracket that used what’s called a bearing, I think a 37-24, either way the one that’s 24mm in the ID that a lot of companies use, this could actually be a problem once it deviates from that 24mm dead on. To exacerbate that, the steel races in that setup will actually wear this further and cause the issue, which is why we use polymer inserts in our Shimano products, such as our Shimano MTB BB.
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