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I wonder if any one can help me I have a trek road bike, I have had it several years and it has always worked really well gears changing well and never had a puncture.

A couple of weeks ago I went out for a ride and back wheel went bang and had a puncture. I took back wheel off and replaced inner tube and put back wheel back on.

I started cycling again and every thing seemed fine then I heard a strange snapping sound and when I tried to change gears right shifter would not work so could not change gears. I had to ride home with one gear.

When I got home I checked bike and found out gear cable had snapped.

Today I replace broken gear cable and other gear cable. I decided to change brake cables as well.

When I had finished every thing was working well all gears were changing smoothly, brakes working fine.

I decided to take it out for a ride to test. Every thing was going well then I heard a bang again another puncture. I took off back wheel replaced inner tube, pumped up and put wheel back on. I Started riding and every thing seemed fine gears changing fine. 2 minutes later right gear shifter stops working again.

I have checked over bike and gear cable has not snapped it is fine. gear shifter just does not seem to be working the levers for going up and down dont click when moved they just move around and do nothing.

Have I done some thing wrong when I changed the gear cable. Left shifter is working fine. and as I said after I changed gear cables both shifters were working fine and gears were changing smoothly until puncture.

Why do my gears suddenly keep stopping working each time I get a puncture. and any advice on what I can do to try and fix.

Im beginning to think im jinxed my last bike a carrera kept getting continual punctures every bike ride some times two or 3 times in one ride. I tried replacing inner tubes and tyres. but it made no difference so gave up in the end and bought the trek which has been great until now.

Sorry if this is long any advice would be much appreciated

thanks in advance

  • The gears and tube punctures should be unrelated - so its likely a technique thing. The first gear cable broke because it was old, and snapped under pressure. The second gear cable was new and stronger, so whatever you've done has likely pinched the cable somehow. Consider posting some clear photos of the rear wheel from the right (drive) side and we'll see what we can see. A Picture == 1000 Words. – Criggie Aug 29 '16 at 19:40
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    It's unusual for a shifter cable to break, unless very old or badly frayed from being removed/reinstalled several times, etc. I'm wondering if you're not installing the wheel correctly, perhaps getting the derailer on the wrong side of the cogs or some such. – Daniel R Hicks Aug 30 '16 at 1:02
  • As to the flats, I'd suspect that your tire pressure is too low. – Daniel R Hicks Aug 30 '16 at 1:02
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The lever not clicking when moving makes me think your shifter could be broken, but that does seem like an unlikely coincidence.

Shifter broken test: The way to test this is follow the cable down from the shifter and at the first place where the cable emerges from the housing, put your left hand under the bare cable and pull on it so there is tension on the cable. With your other hand, shift up and down. The clicks may get more audible, and hopefully you can feel the cable tighten and loosen with each shift. If you feel the clicks in the cable tension, your shifter is fine and you can move to the next steps.

Housing popped out of cable stops test: The way to find out is first "shift" your shifter into the hardest to pedal gear to release cable tension, then follow the cable from the shifter down to the derailleur. Check that the beginning and end of all the little plastic-covered pieces of housing are in their cable stops (the metal cylindrical pieces attached to the frame that hold the housing in place). If one of the housing pieces has popped out, pop it back in and it should shift again. You may need to manually push the rear derailleur cage towards the spokes to release the tension so you can get the housing back in.

Cable slipped test: Another possibility is the cable has slipped and pulled through the derailleur fixing bolt (the bolt that attaches the cable to the derailleur).
In this case, you would again "shift" the shifter to the hardest to pedal gear to reduce cable tension, loosen the bolt, pull on the end of the cable till there is no slack and re-tighten the cable. The shifting should begin to work again.

It should be one of those cases, although a piece of housing could have splintered and you'll see small wires popping out of it. If so, replace the housing.

Worst case, take it to a bike shop :)

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There are two things I would check:

First, was the rear wheel put back in the same position in the dropouts? If not, it could cause interference between the rear derailleur and the cassette, and prevent you from shifting to your easier gears. To fix it, change the position of the wheel or the b-tension screw adjustment on the derailleur.

Second, the cable housing that runs from the shifter to the derailleur may have gotten bent, pinched, or otherwise damaged while you were taking the wheel in and out. That could prevent the inner cable from being able to move and change gears. If this is the case, you could try bending the cable housing back, or you could replace it. (By the way, when you replaced the cable, did you replace the housing too?)

Since you mentioned that shifting does not work up or down, I would lean towards the second possibility. The first issue would only prevent you from shifting to your easiest gears.

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Two things to check spring to mind ...

You removed the rear wheel to fix the puncture - did you get it back in correctly? That would affect the rear mech. The gear cable sometimes gets knocked around and get unseated in their stops as you take the tension off the cable.

Also, I would check for a broken spoke ... as that can cause a puncture, and possible mess with your shifting, if it sticks out.

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  • A broken spoke will have no effect on shifting. It will put the wheel out of true and cause wobble and rim brake rub, but not shifting issues. The other part of your answer is correct and valid. – Criggie Aug 29 '16 at 19:34
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    @Criggie - Actually, a spoke broken at the hub and bent in just the right wrong way could theoretically interfere with the derailer. One would expect it to more likely lock up the wheel, though. – Daniel R Hicks Aug 30 '16 at 1:04
  • Welcome to Bicycles @kellbell. We recommend all new members take the tour to make best use of the site. I've made a small edit to your post. See How to Answer. A good start, keep it up – andy256 Aug 30 '16 at 1:44

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