Chain rubbing against the front mech

odessouky

I remember reading somewhere that you shouldn't use the smallest size gear (ring) on the cassette with the large ring on the chainset...or something like that?

Reason I'm asking is today i noticed that when the chain is on the 50T chainring, when going up gears to the smallest ring on the cassette...the chain was rubbing on the front mech..

is that normal...or my front mech needs adjusting?

Also, is it normally sooo difficult and tricky to shift from the smaller 34T ring to the 50T ring...?

I find it a pain, and have to keep my hand on the left hand shifter all the way in, keep pedaling until the chain finally gets on the 50T ring? (more often than not, it doesn't, and stays on the 34T, and once it just fell off!)

Does my front mech need adjustment?

Bike is only 4 weeks old, done about 100 miles only so far... (online purchase, so I'm on my own)

Front and rear mechs: 105 5700
Cassette: Shimano non series 11-28T
Shifters: 105 5700
Crankset: Compact 50-34T, bikes in house brand...not shimano..
Chain: KMC...i think

thanks

napoleond

Yep, mech needs adjusting. New cables 'bed in' so most shops offer a free tune up after 1-2 months. Or look at YouTube clips online, far more satisfying when you do it yourself and it's REALLY easy!

blackpoolkev

As well as considering the adjustments offered by tweaking the screws on the mech, look at rotating the mech. Tiny adjustments with a bit of trial and error often works.

odessouky

Thanks for the response.

Is it something i can attempt on my own?

Is there an online guide that can help me fine tune the front mech?

chrisgal

As mentioned the cables/mechs have lost tension and need tweaked. This is probably something you should learn to do yourself by using the barrel adjusters (presuming the limit screws have already been set up correctly). There are multiple videos on YouTube which give you a step by step guides.
You also mentioned cross chaining which is small to small (smallest ring to smallest cog) and large to large. This should be avoided to reduce wear and tear.

wishitwasallflat

odessouky wrote:

Thanks for the response.

Is it something i can attempt on my own?

Is there an online guide that can help me fine tune the front mech?

Yes and yes ....

As NapD already said

wongataa

odessouky wrote:

Thanks for the response.

Is it something i can attempt on my own?

Is there an online guide that can help me fine tune the front mech?

Go to the Shimano website and find the technical documents section. There you will be able to find all the documents for your parts. These include fitting and set up instructions. Print them off and adjust the bike. Gear set up is very simple.

Matthewfalle

Cross chaining shouldn't be encouraged but its not really a biggie so long as you don't ride like that for hundreds of miles at a go - short bursts are fine.

Re encouraging wear - hey, we're talking minimal here - no dramas at all so long as you follow what I have said above.

arlowood

Have a read through this and you will get some basics on front mech set up.

http://www.parktool.com/blog/repair-hel ... djustments

After that just trawl the YouTube clips 'til you find one that covers what you need.

eg http://www.youtube.com/watch?v=tfBiXgf8JxI

Front mechs can be a bit more challenging to set up and adjust than rear mechs but that doesn't mean you should shy away from it.

belgium

If you bought the bike online and have no mechanical knowledge of fixing a bike then take the bike to a decent bike shop and ask them to service it for you.
once the bike is given the all clear and is safe to use get yourself a workshop manual(park do a great one) and learn as you go along

steve6690

I have a 105 setup on my bike and it has a trim feature to stop rubbing. Does your have it ?

odessouky

steve6690 wrote:

I have a 105 setup on my bike and it has a trim feature to stop rubbing. Does your have it ?

I have no idea what a trim feature is?

How can I find out if I have one?

dj58

It will have the trim function, read this Shimano service instruction sheet:
http://techdocs.shimano.com/media/techd ... 696762.pdf

Watch these:
https://www.youtube.com/watch?annotatio ... 2_tKpE6PhI

http://www.youtube.com/watch?v=vLQk29enhRQ

andrewc3142

Front mechs are like the devil incarnate until you get it. Then you can laugh at the devil.

I'd suggest the bold approach.

Find yourself an hour or so. Undo the gear cable, take the FD off the down tube. Then look at some youtube vids (sorting out the brilliant, good, OK and downright crap) and download the tech specs for your brand/model.

Make some tea, put on the radio.

Then set it up from scratch. Probably won't work first time, but don't worry.

Have a ponder about what each part does, what each adjustment screw does.

Once it's almost right only very incremental tweaks are needed.

If you have a workshop stand then great. If not, seriously consider getting one, or hanging the bike on a beam or similar is almost as good.

The final frustration is that what works on the stand may not work on the road. Once you think it's done, do a test ride and there will probably be some further tweaks needed.

Derailleurs are really very basic things. Tension a cable to pull a part that shoves the chain over.

Treated badly they are a total PITA.

However, keep them cleaned, lubed and adjusted and they are truly engineering genius.

Maintaining and keeping them sweet is part of bonding with your bike.

trekvet

All the above are correct, but I expect you'll find it could be as simple as the H limit screw and/or the lack of cable tension. To sort it you will need these (or similar),
http://www.ebay.co.uk/itm/like/11134089 ... 0&ff14=108
Watch the spoke clearance here, as I had to saw a bit off, wrap a bit of tape where it touches the bike paint,
and this to sit on
http://www.ebay.co.uk/itm/like/32122406 ... 0&ff14=108
Do not loan them out, label them as your bike tools.

davidof

odessouky wrote:

Reason I'm asking is today i noticed that when the chain is on the 50T chainring, when going up gears to the smallest ring on the cassette...the chain was rubbing on the front mech..

Biggest to biggest or smallest to smallest might rub, I wouldn't worry about that. At what point do you get rubbing? Largest rear cog or someway down? 10sp front mechs are fairly narrow so there isn't a lot of room for extreme chain alignments. Things will vary from frame to frame, wheel to wheel somewhat too.

tuneskyline

You could have a small mouse in your down tube

simonhead

tuneskyline wrote:

You could have a small mouse in your down tube

Serious Cat

simonhead wrote:

tuneskyline wrote:

You could have a small mouse in your down tube

Agree 100% simonhead, he has used that hilarious response in about 3 threads now and is probably sitting going hur hur hur in hysterical laughter whilst we all feel sorry for him.