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I bought recently a second hand bike for my daily rides, and it seemed in good shape. I rode it for more than a month without any problems, but recently had issues with it and had to get it fixed (mostly about a twisted rear wheel)

Out from the shop everything was fine until this morning, when I heard a "clack" coming from the back wheel, and suddenly felt friction on it Upon inspection, it seems like the wheel is "wiggling" by like 1cm. Both screws on the side are well tightened and do not move. The axle is not moving in the rear dropouts.

What could cause a problem like this ?

(I'm fairly new to this, so if it is a common issue please let me know as well)

EDIT: The problem seems to be a broken axle, I'll close after checking the bike again.

EDIT 2 (SOLUTION) : Upon inspection (sorry, couldn't find the time earlier), it's definitely the axle. I looked carefully, and the ball-bearing seems busted, with some balls out of it. I guess I found the problem, thanks for all the answers

stk
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    Did you check if all spokes are still in place and in one piece? (a broken spoke would untrue the wheel). Is the wiggling in the sense that the rim is not a perfect circle in the middle of the bike, but some part of it goes left, another goes right? OR is something loose like you can grab the rim and push it left and right and notice that it has some play (like something around the axle in the hub broke). – pseyfert Feb 18 '19 at 09:49
  • I feel something is loose around the axle. The rim seems to be straight but would moving around the axle – stk Feb 18 '19 at 10:00
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    OK we might need to iterate over this a bit while defining the problem. We'll be using terms from the glossary at https://bicycles.stackexchange.com/questions/244/terminology-index-a-list-of-bike-part-names-and-cycling-concepts You can edit the answers into your question. – Criggie Feb 18 '19 at 10:15
  • Does the rear axle move in the dropouts, or does the rear hub move while the axle stays still? Note this is not the wheel rim's normal rotational movement, but when the rim moves side to side. – Criggie Feb 18 '19 at 10:17
  • I'm not sure what the fault was to take it to the shop "a twisted rear wheel" and whether or not that's related to the current problem. – Criggie Feb 18 '19 at 10:18
  • @Criggie I don't think it's related, I was just saying the bike came clear out of the shop, so it shouldn't be in a bad shape (and thanks for the glossary !) The rear axle is not moving in the dropouts as far as I saw, I would say the hub is moving. I will take a closer look at the bike in a couple hours, I was running a bit late while commuting earlier – stk Feb 18 '19 at 10:21
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    Sounds much like broken axle. These things happen, especially with threaded multi-speed freewheels. – ojs Feb 18 '19 at 10:33
  • I'd go for a broken axle, too. Had the same problem 3 months ago, just a "clonk" and suddenly the wheel didn't turn freely anymore, just like the wheel was utterly buckled and hit the brakepads every rotation. – Erik Feb 18 '19 at 10:40
  • Thank you for the tip ! @Erik, that's exactly how it felt indeed. – stk Feb 18 '19 at 10:49
  • In that case you need to get a new back wheel. Depending on the state of chain and cogs you might want to exchange them, too. This stuff happens with used bikes, and you can't really prevent it or check for it. – Erik Feb 18 '19 at 10:53
  • In reality those axles are common spare parts because they break often, and any competent shop should have them or at least be able to order one if needed. – ojs Feb 18 '19 at 12:35
  • @Erik - Except that that's the exact same symptoms you get from a broken spoke. – Daniel R Hicks Feb 18 '19 at 13:38
  • @DanielRHicks But I can see a broken spoke right away. Also, one broken spoke doesn't have this effect - in my experience. – Erik Feb 18 '19 at 13:59
  • @Erik - A broken spoke can be very hard to see in some cases, and it's quite common for the wheel to be thrown completely out of alignment. – Daniel R Hicks Feb 18 '19 at 14:01
  • @stk Check all spokes first. Sometimes they stay in place even if broken, because of how they are laced. If they are all fine, then you know to look towards the hub internals. – Gabriel Feb 18 '19 at 14:30
  • @community -- Why did you "bump" this one? The OP answered it in his edited question. – Daniel R Hicks Jun 24 '19 at 21:05

2 Answers2

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This could be due to the cones on the axle coming loose. The cones screw onto the axle and prevent play in the bearings. If they are too loose the hub will be able to move independently of the axle. If they are too tight the wheel may not turn freely and you may damage the bearings by crushing them. See here for more information on how to properly adjust the cones.

T_Bacon
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  • Loose cones might cause the wheel to move by a couple of millimetres either way but a centimetre seems a lot, to me. Or maybe I've never seen cones that loose. – David Richerby Jun 26 '19 at 12:41
  • A few mm at the hub makes for a considerable shift at the rim. – T_Bacon Jun 26 '19 at 14:09
  • I mean a couple of millimetres at the rim. – David Richerby Jun 26 '19 at 14:10
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    To be fair, I haven't seen a case of a 1cm+ shift at the rim but that's not to say it couldn't be the cause here. The 1 cm of movement claimed didn't sound like it had been measured and it's easy to round these things up/down to a common unit. I just thought it might be something to add here as it is an issue I've experienced in the past and could be useful to someone else with a similar problem. – T_Bacon Jun 26 '19 at 14:14
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For older bikes, wiggling can also come from a broken spoke(s). For example, you might hear a "clack" when the spoke breaks if you hit a pothole or sudden transition in the road. At that point the wheel feels misaligned and sometimes rubs against the bicycle brakes.

akyeung
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