gears rubbing

jackmcd

Hi

Hope someone can help....

Took my sons GT aggressor to the LBS as the chain was rubbing on the front derailleur in certain gears. They said they got it almost perfect but the bottom bracket is a couple of mm's too long and it will need changing to be spot on. I therefore took it back to Halfords (only bought 2m ago) who have told me with 27 geared bikes there will always be some rubbing in certain gears due to the angle.

Are they correct? Or should I insist that it is fixed?

Hope someone can help!

wildeye

nope they are wrong and talking sh<u></u>it to cover their asses, 9/10 halfords will always be wrong insist a fix

My wee baby

gravityengine

<b>Wildeye</b> You're talking crap.

The chain will rub on the front mech in certain gear ratios, such as small chainring-small cassette cog & large chainring-large cassette cog.

Using these ratios will cause a higher wear rate of all the components too.

The best thing is to try to keep the chain as straight as possible eg in the small chainring use the top 1/3rd (biggest cogs) on the cassette, in the middle chainring, use the middle 1/3rd of the cassette & in the outer chainring use the bottom 1/3rd (smallest cogs on cassette)

http://www.parktool.com/repair/ is a good source of repair help too.



My Bikes howies© Orange Bikes

ride_whenever

Covering laziness, get them to fix it, if the BB is a "couple of mm out" then they should bl**dy well put in the right one. Just get a bit lairy, if you're not happy as a consumer then you make sure they satisfy your perfectly reasonable demands.

My Scott

My Single Speed

Always remember to pick your Uni according to the local trails or you'll be stuck with nowhere to ride for three years!

Drfabulous0

gravityengine is right, on a lot of bikes you will get some rubbing in the gears you don't usually use (or shouldn't use anyway). It can be avoided by careful selection of components but when budget comes into it then expect it a little. If it is rubbing in mst of the gears then it has been setup incorrectly, and a 2mm imperfection in the chainline shouldn't prevent a decent mechanic from doing it right. Unfortunately without inspecting the bike I can't say who is feeding you BS. Perhaps you should get a third shops opinion.

<center><font color="red"><b>My Scott</b></font id="red"></center>

themolland8

yer, just listen to gravityengine. and you don't get bb's "a few mm out" cos if it is, its' prob jst missing a spacer

MOLLAND!!!!

The Joe Show

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by themolland8</i>

yer, just listen to gravityengine. and you don't get bb's "a few mm out" cos if it is, <b>its' prob jst missing a spacer</b>

MOLLAND!!!!
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

More bollo<u></u>cks. Where are you going to put it? On the axle?

You can get BBs too long/short.

However, a couple MMs out is highly unlikely as if it's the standard unit it will have be the right one.

As already been said, it is perfectly normal for some gears to rub, not that you should be using these gears anyway, and there is more side to side adjustment availible in a front derailleur than the distance of all 3 chainrings.

To put short, Halfords is right, and your LBS is just being lazy and don't want to do the work.

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jackmcd

thanks all - not straightforward then...

the final score I think Halfords have this round [;)]

you never know with halfords - so many different staff some know their stuff and some just make it up...