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When replacing the rear brake pads I noticed that 4 spokes were broken and the wheel wobbles. I phoned a local bike shop and was told that they recommend replacing the wheel if more than 3 spokes are broken.

I assume that this is a safety precaution but wonder if the recommendation is in line with common practice. I certainly have no desire to get thrown off the bike in traffic, but it also seems a waste to (probably) discard an entire wheel because it might be damaged and might fail at some point.

This is a 27" road bike, inexpensive, which I ride for transportation in the city (Tokyo).

The rear rim is a bit scored from waiting too long to replace the brake pad, which is another factor to consider.

To clarify slightly, it probably would be cheaper to replace the wheel as suggested below. My objection is more of an ethical one -- tossing something useful into a hole in the ground seems irresponsible. Difficult to avoid though, the way things work right now.

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    It depends. The wheel may have been poorly built or had some bum spokes in it from the factory, and it will be fine. Or it may be that the spokes are at end of life and you will have to keep replacing them, and it would be cheaper to just get a new wheel. Or it may be that all the spokes have been over-stressed (or perhaps subject to unusual corrosion) and they're all ready to pop. (I'd replace the four and watch it carefully. If any more break, especially more than one at a time, get a new wheel.) – Daniel R Hicks Oct 7 '15 at 2:56
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    Could simply be that the labour cost of replacing 3 spokes starts to get near to the cost of a cheap machine built wheel. – DWGKNZ Oct 7 '15 at 3:14
  • you shouldn't get broken spokes from city riding, they indicate a problem – JamesRyan Oct 7 '15 at 10:54
  • One thing that is worth knowing is that spokes commonly break because they're under tensioned, rather than over tensioned. Under tensioned spokes flex, which causes metal fatigue. – stib Oct 7 '15 at 12:54
  • @JamesRyan, city riding can include some pretty vicious potholes, which you can be forced to ride through by the traffic. And that's assuming you don't ride up/down curbs. – Chris H Oct 7 '15 at 13:09
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On a reasonably built and loaded bike (which is how I hear you describing your bike) with well built wheels I would expect the wheels to last a very long time. With that in mind, several broken spokes with no obvious cause are a red flag. My first thought would be inadequate tension leading to flexing and fatigue. If that is the case, other spokes will likely follow.

With a damaged rim, it might be worth biting the bullet and buying a new wheel – or if you have a good hub, having it rebuilt.

If you're inclined to do the work yourself, replacing spokes isn't too hard and the tools are reasonably inexpensive. There is a knack to truing wheels, but you'll be starting from a reasonable place and all you will likely need to do is to tension the new spokes.

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Its your call - depends on how you ride. I've replaced at least 15 spokes in a 26" MTB wheel, but always one or two at a time and I still ride that wheel today.

If you were a racer with fewer spokes on the wheel, then absolutely a new rim. Since its a city bike, much less of a problem should it degrade.

Wheel repairs are reasonably easy, but take time and bike tools and the knack to true the wheel.

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No one can give you a definitive answer that it is safe.

I find Japanese bike shops to generally be very conservative in terms of safety, which is why they're recommending replacement. No one wants to be responsible for any harm that comes to you (or your bike) if the wheel fails catastrophically.

That being said, if it were my own bike I would replace the four spokes, retension and retrue the wheel and see what happens. If it continued to break spokes, I'd junk it. But this is contingent on you being able to: 1) source spokes of the right length and type; and 2) rethread the new spokes, true your wheel, and retension everything correctly. At minimum you need the right spoke wrenches and this would also be much easier if you had a truing stand and tension meter.

In any case, since it's a lot of trouble, why not just plunk out the $100/¥10,000/100 euro for a new wheel? At least you'll be able to keep your old tire and tube. I've also found that if you can find a grimy old bike shop, they might sell you an old wheel for much less than a new one.

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You can replace unlimited spokes if the wheel is in good condition. It does require experience and special equipment, but for a bike shop it is straightforward. Spokes cost the equivalent of a few dollars each. With labor, it should be about $30-$40 at a good bike shop.

I'd be more concerned about the rim scoring.

BTW, it's not going into the ground. A bike wheel is easily recycled.

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It depends, and upon a number of things.

I blew three spokes on a 27" Weinmann wheel in April, and I think I commuted for 3 days on it before I realized that I'd blown the spokes. Weinmann wheels have an excellent reputation, including those from a 1986 Schwinn.

However, there is a rule that old wheels are no match for old bikes and old bicyclists.

In looking at the wheel and spokes, LBS mechanic [whom I know and trust] said that metal fatigue was the culprit. I could have paid to get the spokes replaced, but I'd be gambling that I'd blow another spoke in a week or two.

I decided instead to pull the 27" wheel from my wife's old road, a 1989 Schwinn, have it mounted, and the wheel trued. I rode on it until mid June--when I blew a spoke on that wheel and the rim bent badly enough that the tire rubbed on the chain stay.

Eventually, I bought a new wheel, and upgraded from a bolt-on to a quick release, which produced a bit of extra cost.

If the wheel is "older", get a new wheel.

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