Bike maintenance for dummies.

1 lurker | 101 watchers
Oct 2014
9:00am, 23 Oct 2014
18,203 posts
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Stepford Wife
'one of the design limitations for the frame is going to be making the frame work with commonly available kit or they won't sell many bikes!'

I love that as a concept. Sadly not how the beloved bike industry works. They are more along the lines of 'let's build something and have custom things made for it then our customers will struggle when whatever it is breaks or wears out'. And as for custom bearings... Is there time for a 27.5 mud tyre rant? Oh, no, there isn't - I need to go to work.

The problem with the angle of dangle of the front mech is also to do with gear ratios and how the chain clears the plate in the cage. And that's the bit that can vary quite a lot depending on age of bike. And can't really be bent into shape.
Oct 2014
9:29am, 23 Oct 2014
1,101 posts
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jacdaw
Ooh! Are we going to talk about chain line?

(Quote from the internet... "In its most basic definition chainline is the line of the chain...")
Oct 2014
10:27am, 23 Oct 2014
2,650 posts
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Winded
SW - as the owner if a bike with a non standard headset I hear what you say. But if I look at websites like chain reactoon, wiggle, evans etc I see that almost all of the bikes are made with standard parts or even exactly the same parts and only differ by the logo.

Re chainring size, well - yes of course if the size if the chainring is changed radically or if a bike is designed with a very big or very small chain ring in the first place this changes the angle the front mech engages the chain. (In any case it might make some designs of front mech foul on the frame).

It remains the case however that as far as chainstay angle is concerned almost all road bikes use front mechs with the same spec and almost all traditional 26inch mountain bikes uses a front mech that has a slightly different angle. 29ers either have an adaptor or use the road bike angle. So for practical purposes the answer to the OP is buy one that is generically correct for the type of bike and it will work almost all of the time.
Oct 2014
3:49pm, 23 Oct 2014
2,313 posts
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Irontubs
Proper bike technical numpty questions:

Bike one- doesn't shift from the big chain ring to the wee chain ring

Bike two- doesn't change gears or skips a gear both up and down

Can someone tell me in idiot proof instructions how to fix them?

Cheers
Oct 2014
4:20pm, 23 Oct 2014
19,728 posts
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eL Bee!
Irontubs - I'd go down the route of: give everything a damn good clean and lubricate, and replace the cables and outers.

Adjustment can be covered in another post :)
Oct 2014
4:37pm, 23 Oct 2014
12,359 posts
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Yorkshire Pie
A lack of ability to change gears at the front is our specialist subject at the moment...

Bike 1 - broken shifter. No feedback at all from the shifter when I tried to change, felt completely dead. A bit inside the shifter had broken off so it wasn't moving the cable at all. [nearly] fixed with *cough* an upgraded groupset.

Bike 2 - needed new cables. Felt a bit more responsive because the shifter was trying to move the cable then failing because the cable needed replacing. Fixed with a new cable.

Bike 3 - MM's seized front derailleur. His job for tonight...

Cables would be my starting point unless something else feels obviously wrong.
Oct 2014
4:58pm, 23 Oct 2014
18,204 posts
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Stepford Wife
Cables are the solution nearly all of the time. And buy nice ones. Shimano for preference.

Winded - noted. It's the 'almost' bit that bites us on the bum though. And again it's a lovely theory that you replace like for like, but how often has the stuff been upgraded to a newer model while you were spending a couple of years wearing out a mech? Then the trick is finding the new model number.
Oct 2014
6:50pm, 23 Oct 2014
3,692 posts
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CStar
Highly recommend the 'Bike repair ' app for iPhone. Follow the instructions and pictures (good pictures) and suddenly everything becomes possible.

Or Youtube. :-)
Oct 2014
7:39pm, 23 Oct 2014
2,656 posts
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Winded
SW - true enough.

Irontubs - there are lots of videos on youtube showing how to set up, adjust & index gears. The Arts Cyclery ones are often good but looking at a few is fun (if you are the kind of person who likes sheds and tools anyway).

One thing I would say is don't mess about with the stop screws until you have tried adjusting the cable tension as 9 times out of 10 the problem is cable tension.
Oct 2014
10:57am, 29 Oct 2014
178 posts
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Tonybv9
Irontubs:
Bike 1. When you click the gear lever, does the cable go slack and the front mech not move? Problem with the mech: clean and lube.
Does the cable not move, but you can push the mech into place? Cable sticking: clean and lube.

Bike 2: Probably cables.

How to lube your rear gear cables:
Shift gear to largest sprocket.
Click gears down as far as possible WITHOUT TURNING PEDALS. This gives lots of slack in the cables, so you can unclip the cable outers from the cable stops on the frame. You can now slide the outers back and forth to reach and lube the inner cable.

Ultimately, new cables become necessary, but a good lube can work wonders.

About This Thread

Maintained by DeeGee
A thread for your questions about fixing common bike problems.

Need help naming a part? jimlangley.net

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