Bike Forums - Rear end clanking when hitting bumps

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- - Rear end clanking when hitting bumps (https://www.bikeforums.net/bicycle-mechanics/1008481-rear-end-clanking-when-hitting-bumps.html)

It's probably just me not attributing enough importance to the "without binding" part, but yeah, that quoted part is copied and pasted straight from Singlespeed Bicycle Conversions

Update: Wheel put back together with a new axle, and good torque on the freehub body retaining screw as well as on the cassette lockring. Quiet as any bike! Much thanks to everyone for the help :thumb:

Also, I'm being careful with chain tension from now on!

I'm mostly in a discussion with myself right now, but I still figured I'd post an update for the future googlers.

So I blew another axle yesterday, but I think I figured out what's happening. My chainline with the cassette cog was pretty close, but not 100%. Plus, I'm running a biopace ring, which makes chain tension a bit tricky: for the tension to not be too tight when I hit the tightest spot (around vertical cranks), it has to be quite a bit loose when it's the loosest (around horizontal). Not loose enough to jump off the chainring, but apparently loose enough to jump up on the next bigger cassette cog when I'm coasting with the cranks horizontal and hit a pothole or something. The next pedal step would inevitably bind the chain (bigger cog, so chain goes too tight), pull on the axle, and either bend it, pull the wheel out of the dropout, or both.

Fortunately yesterday's ride was to the LBS to pick up the spacer kit, so I just installed that, carefully set the chainline and tension, and now off to a test ride.

Quote:

Originally Posted by auxym (Post 17825545)

Haha, no kickstand :)

So I took apart the hub. The freehub body retaining screw was still tight-ish, but I unscrewed it and torqued it back down as tight as I could with a 6" wrench (I know, I should get a torque wrench).

With that out of the way, I found out my rear axle and skewer are bent :( And they were brand new a week ago! Ridden something like 30 km. Off to the lbs to get new ones, but what could have caused this?

If you could loosen it with a 6" hex wrench, it was definitely too loose before, and I would be surprised if you got adequate torque when you tightened it back down. Get a real torque wrench and some hex heads -- they're cheap. :)

As for the chain tension thing, it's unfortunate that Sheldon used the word "tight" at all. Get rid of the Biopace ring until you've gotten the hang of setting the chain slack properly. It's subtle enough with round parts. You should know if the chain is going to bind before taking it off the stand, let alone riding it.

Quote:

Originally Posted by ThermionicScott (Post 17841958)

About the torque wrench -- I know. It's on my "to buy when I find one on sale" list.

As for the chainring, I don't have any other 110 rings lying around, and news ones are too expensive for this project. I'm aware biopace isn't great for SS, I'm watching kijiji/craigslist to find a cheap crankset/chainring.

Assuming your cassette hub/freewheeler is tight and the frame is good, I would probably check the axle bolt. I

'tis fine, no more clanking since I tightened the freehub and cassette :)