noisy middle gear?
 

hi, sorry for the stupid question.....
i am a newbie on bikes, and have 2 problems...
when i change to the middle chain ring on my mountain bike it rattles and struggles to get in...any ideas?
also on the back sprocket i cant select the biggest cog, it says i'm in first on the gearshift on the handlebars, but wont go in at all?
again sorry for the really basic questions
thanks in advance
bike is 21 speed mtb

Sounds like your shifters and/or derailleurs are out of adjustment. You'll need to adjust the left shifter and/or front derailleur so that it moves further outwards when shifting to the middle chainring. I think the problem you have with the rear derailleur is possibly the low gear limit stop.

This is all assuming you don't have a rusty/mucky chain etc

Sheldon Brown has a good article on gears, I can't access his webpage atm though. Once I can, I'll post a link.

There's no need to be apologetic, we all have to start somewhere, basic or not ;)

the mtb is 2 week old, chain is not rusty, i've tried the limit stop on the back gear system, still dosnt shift to the largest cog.
as for the middle chain ring, i dont know what you mean lol
thank you anyway, i feel so stupid!!!!

[/QUOTE]

No apologies. It's important, and something of a "black art".

Firstly, many front derailers do not like shifting under heavy, slow loads. Either back off, or try to pick the front ratio before you hit a hard-pedalling spot.

Do the back one first.

As HighlySelassie (hah! luv it! <G> Obviously more Selassie than the Rastafus! <G>) said, it may be an end stop problem at the back.

But here is my order of checking every time I do the gears. Self-taught but it works, and seems close to the accepted methods.

I am just getting back into biking these past 3 months, so I am re-learning. I have always found that
passing on stuff is the best way to learn and refresh, and to make myself think. I also love the sound
of my own voice! <G>

I did have a KMart coffin special road/tourer once that was simply unfixable from one end of the ride
to the other...however....

I don't know what sort of bike you have, or whether old or new, but....

FIRST
Until you have these bits out of the way, you will have a hard time getting the gears to work.
* Make sure the drive train, including chain, is clean and free from any bends or glitches. Lubricate
with bike chain lubricant, or WD40 if nothing else is to hand. WD40 is OK, but you should clean and
lubricate often if you use this. The wax-based ones (white lightning??) seem really good. I have
actually seen the effects of the claimed dirt-shedding properties on the sprockets. I can only assume
the wax melts under the pressure of riding and runs away slowly....however... it should feel and
sound nice and smooth when you "back pedal" by hand, in every gear. It's a lovely feeling, and you
will know it. With mal-adjusted gears, you _may_ get some noise until they are adjusted, but do the
hygiene anyway.
* Check both front and rear derailer setups for bending or misalignment. Got caught by this the other
day. Front cage had had a bash (wife's bike, not mine <G>) and was out of line.
- The front cage should be in line with the C/L of the bike. If it looks bent _carefully_
straighten it, with finger only. It should get no more force than that, IMO. If not then use the collar that
allows it to turn on its tube.
- rear derailer sprockets should be straight up and down, not loose, and also follow the C/L
of the bike. Most commonly they have been bent into the bike.Be careful about straightening.
* Check for excessive wear of any parts on an old bike. The front derailer cage can wear quite a bit.

Rear derailer cogs can get sloppy etc. The rear derailer cane get slop as well, in its overall
mechanism. If in doubt, sneak into a bike shop and fiddel with a new setup to see how much slop
there should be.

There is play (usually springy) and there is slop (sloppy).

* If you get this next one, you many have real trouble, but make sure all sprockets/rings etc are not
sloppy.

OK

The rear.

Turn the bike upside down. Place the rear setup in 4th gear for your 7 setup.

Probably on the handlebars, but maybe on the derailer itself, there will be a little thumbscrew to
adjust the cable for the rear gears - (with the bike upside down remember that you have swapped bar
ends...DAMHIKT...<G>).
** remember where you started. Count turns!
- Looking straight down at the chain, slowly turn the adjusting thumbscrew on the cable. You will see
the derailer mechanism move from side to side slowly. Remember which way you run the adjuster to
move the derailer in and out.
- return the adjuster to where it started.
- slowly rotating the pedals (you will need to grab the tyre now and again to slow things down, unless
you have help), shift the gears until you are at the second largest cog, but the shifter says "largest
cog" as you describe, which is where the trouble starts.
- now adjust the cable _tighter_ (in toward the bike's C/L and then rotate the pedals as if pedalling,
not backward. Make the wheel spin in other words. If it does not climb up to the large cog, try a little
more. Repeat. This may well work.
NOW
Try going right back down to the _smallest_ cog, using the shifter, without touching the cable and
slowly rotating ghe wheel by "pedalling".
- If everything works, you have come close to fixing the trouble.
- ride the bike and fine tune with "real world" pressures and chain tensions etc..
- if not, then try "fine tuning" the above.

In the end, in each gear, the chain should run nice and straight across each rear sprocket, and
around the derailer sprockets.

However, if still not, then HS's suggestion is next.

End stops.
Do these only if the above does not work, or the chain tries to fall of either the largest or smallest
cogs. Again alwasyu check for straight and unobstructed drivetrain first.
You will likely need to have the bike right way up for this. A work stand is nice, but of course
roadside repairs need just you and the bike.
There are two little screws on the derailer setup. One is to stop at the largest cog, and one at the
smallest. Again, _remember_ where you were. Place the bike in largest cog setup. Alter the screws,
and watch the derailers. One of the screws will make the derailer move in and out. Remember which
is which, and which screw it was (it _may_ be marked), and return that screw to its old position.
Repeat for the smallest cog.

If all is well, you should set up the stops so that the chain travels across the sprockets, and both
derailer cogs, in a nice straight line at either end of the cluster, when in 1 or 7 on the shifter.

Just remember to pick up the bike and pedal a bit as you make each shift, before you look for
anything.


FRONT
This a lot more crude.

However, bike back upside down. Again adjust the cable until, while "pedalling", the shift will work.

You need to me tightening the cable again (moving the shifter cage _way_ from the bike this time)
Then make sure it works to the largest chainwheel as well.
Under this small load, the shift should be _very_ smooth, in order to work in "real life"
Then make sure it changes back down again.
Road test and fine tune.
You may need to fiddle with endstops again, but only if needed.

With the front set in middle gear, you should be able to change the back from smallest to largest cog
without the chain touching the front derailer cage. You should also be able to use all but the two "most opposite" (smallest smallest, largest largest) rear cogs when in large front or small front, and maybe even the second in each case. This is "crossing" the chain, and is not reccommended, but bikes vary.

Hope this does more good than harm.

No apologies, again. You have the guts to ask, and that's not stupid at all.

You may not have done the limit stop properly.

"Chainring" is the name for the cogs/sprockets at the front. Not stupid. I in fact mistakenly called them "chain wheels" in my post. There are many bike-exclusive names that I am still picking up as I go. For instance, I had never heard of a "bottom bracket" on the bikes I used to ride. I thought it must be the saddlle! <G>

Google for "bicycle anatomy" etc, and see what you find. It helps a lot, when people start telling you stuff.

You aren't stupid. We've all been there at one point in our lives. Check out the Park Tools website if you ever have any other questions about bike repair. They have a bunch of great tutorials that are easilly found from their "interactive" picture of a bike. http://www.parktool.com/repair/

OldNick: You are my new hero.

To fix your cghain not going into the bottom (largest) cog at the back, unscrew the little knurled screw when the cable goes into the derailler at the back 1/4 or 1/2 turn. This will compensate for cable 'stretch' (settling in to the cable stops). This is normal in the first couple of weeks use. When you are riding in the middle chain ring look down to see if the chain is rubbing against the inside or outside of the cage. If it rubs on the inside, tighten the gearshift cable a bit. If it rubs on the outside, loosen the gearshift cable a bit.

You are correct.

In my enthusiasm, I did not read the "two weeks old" bit.

However, that is no guarantee that nothing is bent...DAMHIKT <G>....or full of sand/twigs etc.

Actually, the two Malvern (up)Star(t) bikes I bought as "starters" to get me back into biking and see if and my wife were interested did not even work when we got them home! Good refresher course.

As I say, I love the "sound of my own voice" (sight of my own keystrokes?). However, seeing these sites being posted, I realise I need to do a bit of looking about, because all of what I said has been said elsewhere, probably more accurately and better.

Here's the webpage I was looking for earlier:

Sheldon Brown's helpful hints

It's got everything covered here, but it's a bit easier to digest and more structured, it even has pictures ;)

wow, thank you all, i will attempt all the above info this weekend, its such a relief to get helpful advice and not get shunned as a "stupid newbie"
i think i will be in this site every day for tips!!
again, a BIG THANK YOU to you all
mik (uk)

Just don't ask any silly questions, and we will be happy to try to help! <GG>


Little allegory:
I know a guy who is really into kayaking of all sorts, up to 1400 Km sea journeys etc. The sheer _fuss_ and niit-picking about a 17' plastic shell with a couple of paddles is amazing! <G>

But like bikes, it's more complex than it looks. And both are very persoal things, so it's much more pleasant when it all comes together (and not so good when it comes apart).

ok, sorted the middle chainring, old nick was right, i did back off and it went in ok, still cant get in to the largest ring on the back cassette, only thing i havent done is fiddle with the cable, maybe thats it.
i noticed today that when the gripshift says i'm on the no.2 on the back cassette it will be on 3 ring and so on, always seems the back cassette is ahead of the grip shoft, any ideas?

Your shift cable tension is probably not right. Try this:

1. Shift into your smallest cog in the back. Make sure your shifter says "7" or whatever your biggest number is.
2. Take up any cable slack until the cable is just taut.
3. Shift one notch and see what happens. If it doesn't shift onto the next cog, unscrew the barrel adjuster where the cable enters the derailleur 1/4 turn. Repeat until it works.
4. Shift once more to the next cog, fiddle with the cable tension if necessary, etc. untill you get to the biggest cog.

1 question.... unscrew is anti clockwise is it?

Thank you all who gave me advice, i read through it all and put into practice what was said, and its all fixed now, no noise, i can get the largest cog on the cassette.
again, THANK YOU ALL
mik (happy)

I just witnessed the birth of a budding bike mechanic.