Chain tension

Duncan817

Don't know if this is the right forum but any help would be appreciated.

My better half and I have just bought new MBT and took them out for a couple of hours yesterday.(not only first time mountain biking but first time on a bike for a long time!).....towards the end of the ride my chain was clanking (?) angainst something and felt really loose?

how tight should it be and is tensioning the chain just as it used to be - loosen the wheel and pull back or does it depend on the set up? also the gears didn't always shift up/down when required i.e. they would change quite a bit later after the levers were pressed.

many thanks
Duncan

Twisterboy

Welcome to the Forum.

David

stu8975

Most modern bikes have vertical dropouts (bit where the wheel sits) so cant be pulled back like older style bikes. Your chain tension is taken up by your rear mech, however certain gears are not recommended to be used....big ring front+ big cog on the back and small ring front and small cog on the back (will weaken the chain), it will mention this somewhere in your owners manual. as its a new bike, your gears may need a fine tune/adjust as the cables can stretch slightly when first used and resulting in your gears not working correctly , wherever you bought it from should re-adjust them for you for free.
What bike is it by the way?
There is a workshop section on the forum for any future technical enquiries (will get more responses), and welcome.

rhext

The rear mech for derailleur gears automatically sorts out chain tension. Especially given your problems with shifting, it sounds like that could be the source of your trouble.

It's possible you got mud/water on it which either gummed it up or froze. It's also possible (as noted by stu8975), that you're using the gears in the wrong combination.

If all is clean and dry and still not working properly, I'd take it back to the shop.

As far as the chain tension is concerned, you say it 'felt loose'. Not quite sure what that means. You can see when a chain is poorly tensioned because it droops - it doesn't 'feel' any different when you're pedalling, as the pedalling forces pull the top of the chain tight against the cassette. If you're using a mountain bike offroad and going fairly fast on rough terrain, it's not uncommon for the chain to slap against the chainstays and that can make a disconcerting noise unless you use a protector.

But the bottom line is that you shouldn't need to muck around with chain tension on a new mountain bike. If it's not gummed up with mud, not shifting cleanly and doesn't feel right, take it back to the shop.

rhext

The rear mech for derailleur gears automatically sorts out chain tension. Especially given your problems with shifting, it sounds like that could be the source of your trouble.

It's possible you got mud/water on it which either gummed it up or froze. It's also possible (as noted by stu8975), that you're using the gears in the wrong combination.

If all is clean and dry and still not working properly, I'd take it back to the shop.

As far as the chain tension is concerned, you say it 'felt loose'. Not quite sure what that means. You can see when a chain is poorly tensioned because it droops - it doesn't 'feel' any different when you're pedalling, as the pedalling forces pull the top of the chain tight against the cassette. If you're using a mountain bike offroad and going fairly fast on rough terrain, it's not uncommon for the chain to slap against the chainstays and that can make a disconcerting noise unless you use a protector.

But the bottom line is that you shouldn't need to muck around with chain tension on a new mountain bike. If it's not gummed up with mud, not shifting cleanly and doesn't feel right, take it back to the shop.

Duncan817

Thanks for the speedy responses.

its starting to make sense (I think!!!)
when in said it felt loose i meant when i was touching it and not when riding - but i now understand that it can (by doing a little research - which is what I should have done in the first place))

would/could the gear issue be caused by using the wrong gear combination?

rhext

The poor shifting you describe could possibly be caused by the wrong gear combination. To me it sounds more like something is interfering with the correct function of the springs in the rear mech. Possibilities are

1) Dirt

2) Lack of lubrication

3) Poor set-up in the shop (perhaps a defective spring, or something's been overtightened)

If it's noticeably dirty, then clean it and give it a quick spray of lubricant (making sure to avoid the braking surfaces). Then, I'd advise you to take a bit of a spin round the block practising shifts. If you try to use the large chain ring (front) only on the smaller sprockets of the cassette, the middle chain ring on any sprocket, and the small chain ring only on the larger sprockets it should work fine. You don't need to get too paranoid about this - you only need to avoid the largest couple of sprockets if you're on the large chainring and similarly for the small. If you're doing this and the shifting is still sticking, or you're getting disconcerting noises which might be caused by the chain hitting the frame, I'd take it back to the shop and ask them to have a look at it. They're very unlikely to charge anything just to have a quick look to tell you what's wrong.

Duncan817

Thanks rhext, i'll give it a go tonight.

supersonic

Is the chain whacking against the chainstay? One cause of noise.