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I just bought a Trek 7.1 fx bike off Facebook marketplace and took it in to get it looked at for a once over. What came back was a broken axel in my rear wheel which is the biggest problem, and why now I can’t ride it till it’s fixed. I started looking for options for a new wheel specifically used near me and found a 700c wheel set which I think may work but was hoping one of you could steer me if I should do it.

My current wheels have a 622x19 and the new ones I’m looking at (a set) are 622x18, question one, are these differences okay for my bike? Does that “18 vs 19” make a difference in how my bike will ride?

Secondly, my bike is a 7 speed on the rear hub and these new wheels are for an 8-9-10 speed hub. Will these actually fit to my bike? Is there any information that I should get to check if these will fit?

Both brands of wheels are bontrager the current ones on the bike are bontrager at-750 and the ones I’m looking at buying are bontrager Camino

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  • The camino wheels will work fine-- they are for the trek 520 touring bike. The rear axle dimensions will be fine too.
    – JoeK
    Mar 3 at 8:25
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    A bike shop should be able to replace a broken axle if the hub is not damaged.
    – Carel
    Mar 3 at 12:40
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The frame will take any 700c 135mm hybrid wheel, which can be either freewheel or cassette. You likely have a freewheel hub, which means you have a freewheel, which means if you buy a cassette wheel like you are talking about you will need a 7-speed cassette plus a 4.5mm spacer to go with it. And then you're putting a new cassette on a worn chain and chainrings, which could turn into needing to replace at least the chain and perhaps all of it, depending on how worn it is, which may seem cautionary but we're also talking about a bike that was heavily used enough to be riding around with a broken axle.

You could look for a used hybrid freewheel wheel, but without knowing what you're looking at, it would be easy to come up with one that's in poor shape. And, it sounds like you have no particular reason to replace the front anyway. The 18 vs 19 internal width doesn't matter.

7-speed cassette hubs almost never break axles, but if you did have one and the wheelset you're looking at was a good deal, then yes it would be fine.

Unless a project is what you want, there is a lot to be said for just having the shop install a new freewheel wheel and adjust everything for you.

If spending as little as possible is the goal and you're trying to do it all yourself, it is possible you could spend the least by replacing the axle. It's common for broken axles to result in the cups and cones getting too damaged for a shop to want to mess around with, but cheap axles are cheap and you may be able to get it rolling. If it wasn't ridden too much after breaking, it may even be fine, and it's falling apart anyway so it's easy to look at the condition of the cones. You would need a cone wrench and freewheel tool plus grease and bearings to do this.

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  • You know it doesn't necessarily take heavy use to break these axles, Nathan.
    – JoeK
    Mar 3 at 8:26
  • @JoeK That is true. What I was trying to get across is that it's not just a distant hypothetical that the rest of the drivetrain being worn could be a gotcha if a new cassette is dropped in. Mar 3 at 9:05

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