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The drive-side dropout and rear axle have broken twice. It's an old-style freewheel, not a freehub+cassette. (I weigh around 100kg, and ride a lot, and have been touring on hilly, gravel roads, with 15kg camping gear on the rack.)

The bike is an old (20-25 yo) hybrid Malvern Star (model "Elite"), steel frame, with 5 cogs on the back, and a freewheel. About 2-3 years ago, the drive side dropout broke, along with the rear axle (QR). I got new dropouts welded in, and the QR axle replaced with a solid bolt up (for $172 AUD). They told me the axle "wouldn't beak". After a year or so, the rear axle broke again (which the LBS replaced). Then, about 6 months after that, the drive-side dropout broke again (EDIT near the chain stay) - not the weld, but the dropout itself, next to the weld.

I ride everywhere, and did several wilderness touring trips during that time. They were "on-road", but hilly, gravel roads (Bunyip State Park), and sometimes they're corrugated, sometimes water eroded, and ther were some tree roots on a rail-trail once, which I (mostly) manage to avoid. I wouldn't think they'd stress the bike that much, and wheel rims are perfectly OK - even though single-walled.

The LBS said it's because the freewheel stresses the axle, and when it breaks, the angle of the axle stresses the dropout, causing it to break in turn. They said it's the only cause of the break, and would not happen with a freehub and cassette. Researching online, I see the freewheel design does stress the axle. The guy now maintaining Sheldon's site agrees that that's how dropouts break; a couple of source only say it "can" break dropouts - but most don't mention an effect on dropouts at all.

Is the freewheel why my drive-side dropout keeps breaking?

Would a freehub + cassette really "solve" this problem, or would it keep happening? I want to go on longer tours, and don't want to get stranded!

Is there another solution?

Many thanks for reading all this! :-)

tyres: Schwalbe endurance, 26x1.50, inflated to 100psi (which they are rated to). Supposedly somewhat puncture resistant; but I got one on every tour.

dropouts: The replacements were forged dropouts (originals were pressed dropouts). It looks pretty strong to me, it's about 4mm where it broke, and about 7mm where the bolt goes.

hubs: after second broken axle, LBS noted slight pitting on the hub where the ball bearings run. Wheels are "Joytech", new about 5 years ago. They were the cheapest ones ($80 AUD, IIRC), single alloy rims. They look very well made (to me). The rear was a QR.

  • As additional (local) info, I would say that Malvern Star are reasonably solid medium quality bikes, and while the kind of riding @hyperpallium is doing might be better suited to a Cyclocross bike, the steel frame should handle it. – andy256 Apr 10 '15 at 11:48
  • What tires are you using, and at what pressures? – andy256 Apr 10 '15 at 11:49
  • I weigh around 105Kg and I've never had an axle break. The rear hub uses a freewheel. – Daniel R Hicks Apr 10 '15 at 12:06
  • @andy256 Schwalbe endurance, 26x1.50, 100psi, on both (I got a puncture on every tour) – hyperpallium Apr 10 '15 at 12:34
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    100psi is very high for a 26x1.5" tyre. Pressure only helps prevent pinch/impact punctures, and the "enough" level for a 100kg rider is probably a lot lower. I'd suggest about 80psi. – Emyr Apr 14 '15 at 15:55
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You already more or less answered your own question.

The reason is that in a freewheel hub the drive side bearing is close to the center of the axle. This gives the forces from your weight and pedaling much more leverage to bend the axle than on a Shimano-style freehub where the drive side bearing is located at the end of the axle. When the axle bends, it twists the dropout, which can also break.

Some other brands of freehubs solve the axle bending problem with a thick oversized axle. This could work with a freewheel hub too, but I am not aware of anyone who makes that kind of hub.

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    Phil Wood used to make those kinds of hubs, and may still, REALLY beefy axles. The axles were basically diameter of the cones on a normal axle, then necked down to fit through the drop outs. – Eric Apr 10 '15 at 18:37
  • Looks like they are still available online. At above $400, ouch. – ojs Apr 10 '15 at 18:46
  • Maybe used on Ebay, probably already built as wheel would be your cheapest option to get a Phil Wood hub. – Eric Apr 10 '15 at 18:54
  • @Eric Would these beefy axles be less likely to break than a shimano-style freehub? Along these lines, I've heard a "through-axle" is also very strong (but requires a different frame...) – hyperpallium Apr 11 '15 at 1:08
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My guess is that the rear hub is defective, or (at least for the first incident) was improperly assembled.

If the cone lock nuts on the axle are not set tight enough, it's possible (especially with a slightly bad or poorly lubricated bearing) for the (probably right) cone nut to be pulled tighter and tighter until either the bearing seizes or the axle snaps from the strain. When this happens all heck will break loose, and it's easy to believe there could be some collateral damage.

Once this has happened the first time, the hub (if not defective before) has likely been distorted to the point that it's almost certain to happen again.

I would say you need to replace the hub. If not, it at least needs to be carefully inspected for damage, and the person assembling it needs to be doubly careful to get the lock nuts tight.

  • When the LBS replaced the axle the second time, they noted some slight pitting on the hub (where the ball bearings run). It seemed very slight, and they said it wouldn't have caused the axle to break (but probably was caused by it being broken). – hyperpallium Apr 11 '15 at 1:17
  • PS: The wheels are "Joytech", I bought them new, maybe 5 years ago. They were the cheapest ones ($80 AUD, IIRC), single alloy rims. They look very well made (to me). The rear was a QR (though I thought was getting solid bolt ups). – hyperpallium Apr 11 '15 at 1:32
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What kind of dropout did you have welded back in your frame when you had it repaired? A higher quality dropout might be in order.

  • It was a forged dropout (the original was a pressed dropout). It looks pretty strong to me, it's about 4mm where it broke, and about 7mm where the bolt goes. However, current bike I've checked out have extremely thick dropout, looks like 10mm or more. A stronger dropout was also my first thought, but what if the LBS is right? (And I realize that just now, even if a stronger dropout fixed it, I'd still be breaking axles is also a problem...) – hyperpallium Apr 11 '15 at 1:00

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