October 1, 2019 at 6:18 am #271114
About four months ago I decided to get back into riding. I bought an Apollo Gradient mountain bike. I know this is quite a cheap/basic bike but didn’t want to spend a lot if I didn’t stick with it. I have stuck with it and will eventually upgrade to something better but can’t afford to right now.
Now onto the problem, the gear changes have never been particularly smooth but over the last month they have got worse. The gear changes themselves, while clunky, aren’t a particular issue. What is an issue is that it sometimes misses a gear especially 3rd and 6th gears (so when I change from 2nd it will go straight to 4th or from 5th straight to 7th). This is more of an issue as you will think you are in the right gear and then it will snap back into the correct gear later on. This is a particular issue when cycling up hill as it throws my feet off the pedals. I’ve got massive bruises on both knees from where they have hit the handlebars at these times. This happens when riding on relatively smooth roads so isn’t even anything to do with the type of terrain that I am riding on.
I have taken the bike to a shop to be serviced and they seemed to think it was ok but it is still happening. So with that information and the fact that I can’t afford to upgrade my bike straight away what can I do to try and solve this issue with gear changes being clunky and gears being missed (or being missed then snapping back into them as I am riding)?
October 1, 2019 at 10:11 am #271127
I’m just a home mechanic (with a stained copy of Zinn’s book), so my advice isn’t going to be too detailed. But it sounds like your derailleur needs to be adjusted. I had similar issues when I replaced my shifter cable; the new cable would sometimes cause the gear to suddenly switch on me, especially when climbing.
I would try, in this order:
– Tighten the shifter cable at the derailleur
– Adjust the derailleur limit screws
– Fine-tune with the shifter barrel adjuster
Hope that helps!
October 1, 2019 at 11:16 am #271135
If you have been to your mechanic, they have probably ruled out the easy culprits, such as bent derailleur hanger and minor adjustments to the derailleur.
I am guessing it works fine on the stand but when you put the power down is when you have trouble. Some less obvious problems that they mechanic may not have checked could be: bent frame or bent axle. You could have too much frame flex as well.
But my money is on worn gears (cassette or multi-speed free wheel). If you are on a cheap bike, these are cheap to replace. You just need a tool(s) and a new cassette/freewheel. A freewheel can be very challenging to remove because it screws on as you pedal but with enough leverage it will come off. I’ve found new take offs for cheap.
October 1, 2019 at 2:35 pm #271167
If I am correct, it has a 7 speed Shimano derailleur and cassette. 7 speed is older tech, and has not really been updated in quality in a long time. They are prone to lots of little issues. Worn cassette, worn chain, just a sticky dirty chain or sticky dirty shift cable can cause strange shifting problems. My wife’s 8 speed (still older tech) got hit by a stick and it bent the derailleur hanger. Me and the shop mechanic tried to straighten it and it still shifted funny, I finally just replaced the hanger and that made things better. Still her bike, even with regular cleaning, needs to be adjusted more often than even my 9 speed trail bike or it starts sticking or skipping shifts, (9 speed is still fairly old tech). My new 12 speed enduro shifts way smoother then either of our other bikes and has only needed to be adjusted twice in two years.
October 2, 2019 at 4:01 am #271184
Thanks everyone. It does have the shimano 7 speed.
Is there a way to easily tell if the gears or chain are worn? And do you have a good guide for changing the cassette/free wheel? I’ll also have a look at the derailleur hangar to see if thats the issue.
October 2, 2019 at 11:00 am #271205
A link from post to post on a chain should be one inch, measure 12 links and if it is over 12 and 1/8 inches it is about time to replace. If it is up to 12 and 1/4 inch, that is very worn and if you changed cassette and/or gears without changing it, it would wear the new ones out quickly.
Park Tools website has tons of free how to videos for almost everything bike related.
October 2, 2019 at 11:11 am #271220
You can check if your chain is worn/stretched with one of these…
I would hazard to guess your derailleur hanger is slightly bent but not enough to be easily seen, the cassette is generally worn (though your bike mechanic certainly would’ve caught this I’d think), or maybe you have a tooth or two in one of your cassette gear wheels that is slightly bent. This happened to me and every time I’d shift into that gear, the chain would hit the bent tooth and sometimes immediately be pushed to the next gear or back to the gear I was shifting from if I was pedaling hard. It caused me so many problems on quick and short ups and downs until I just replaced the cassette. But it took a while to find because the tooth was just slightly off and there are a lot of teeth in there.
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