Martha has a hard ride through the London traffic and has broken two gear cables in six months, she and us think this is a bit excessive, so here is what we think she should do to find the cause and eliminate the problem. If you are breaking gear cables or want your cables to last longer? Read on
Question:
Gear cables:
Why have I managed to snap two gear cables in the last 6 months? I cycle about 50miles a week through London so there is some quite intensive gear changing. Is it just the level of use or something set up wrong on my bicycle?
Cheers,
Martha.
Hi Martha,
Two gear cables in two months is quite a lot at 50 miles a week! You don't say if it is on your rear or front derailleur? Also you don't say where they break, was it at the same point?
If you are doing commuting miles in heavy traffic in central London I would expect the brake cable to snap more often as it must be stop and go quite a lot of the time.
If they have broken at the same point then there is probably a reason for it, if it is at the end of a piece of outer cable or at a cable stop on the frame then there is probably some thing sharp on the inside at that point or you need to put grease where it must be rubbing and causing friction with either the end of the outer cable or on that point of the frame.
This can happen at the point where the cable leaves the gear changer, where the inner cable comes out of the first piece of outer cable, where the cable runs underneath the bottom bracket and then at the start and finish of the short piece of outer cable at the rear derailleur. With the front derailleur it will happen at the outer cable from the gear changer and again at the bottom bracket or if you have a MTB it could be on the top tube if the cables are top routed.
Frame Cable Stop
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Look for any points where you will get any friction on the inner cable, look for any sharp bits of outer cable, if there are any or if your outer cable is old then replace it. Regularly put grease under the bottom bracket where the cable run, this is usually on a small plastic cable guide or on some steel frames they can be on the metal.
You need to check that the running of the cable is smooth and free on its full length, spray oil to get into the difficult areas and grease where ever you can. We hope this cures your cable breakages.
Short Outer Cable
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Where is the cable braking?
Did the same cable break twice?
Something isn't right. I ride more than that in hilly areas and I haven't had a cable break in 5 years.
Mike Di Feo
could be you are using derailleur cables for brake cables, which are a small diameter cable.. and/or they are getting corroded from water salts etc. try putting a film of grease all along the cable every now and then and clean your bike often. hope this helps.