Pesky noise!

Lycraboy_Andy

I was just after a bit of advice on how to stop my chain rubbing! I have a Giant Defy 4 which I have to say is a lovely bike but the chain is becoming mildly irritating!

I never touch the left hand shifters and just stay permanantly on the large ring at the front, but if I have to use the smaller rings on the back the chain starts rubbing against something. Having done a quick search of this forum it would appear I might just have to get used to it? Is this a characteristic of a 'compact' with crosschaining??

I prefer riding in higher gears anyway, however I can't keep avoiding the lower rings! :?

Grill

Sounds like you're cross-chaining (riding the big ring in the front as well as the biggest rings on the cassette). Without a front trim it's common that there's rubbing in this type of combination. If it's occurring when you're in the smallest cog then you just need to realign your front mech.

It's silly to crosschain. Most people do it because they think that staying in the bigger ring makes them "hard" or "manly", but the fact of the matter is you'll achieve the same ratio on the little ring.

antfly

The small rings on the back are the high gears, if you mean the big rings why don't you just use the small ring on the front ?

Lycraboy_Andy

Thanks for the replies guys, perhaps I'll try the smaller front ring later then. I'm relatively new to road bikes, I just assumed the bigger ring on the front provided more power.

Time for a bit of experimentation!

Grill

Check this out to see your ratios:
http://www.bikecalc.com/gear_ratios

Tom Dean

Lycraboy_Andy wrote:

I never touch the left hand shifters

This is your mistake - even if you stay on the big ring you can trim your front mech position (depending on which shifters you have)

goonz

Grill wrote:

Sounds like you're cross-chaining (riding the big ring in the front as well as the biggest rings on the cassette). Without a front trim it's common that there's rubbing in this type of combination. If it's occurring when you're in the smallest cog then you just need to realign your front mech.

It's silly to crosschain. Most people do it because they think that staying in the bigger ring makes them "hard" or "manly", but the fact of the matter is you'll achieve the same ratio on the little ring.

I tend to stay on the big ring because well mainly as its a pain to have to keep changing both rings as I tend to stay mainly on the biggest ring on the rear and only really use 2 or 3 extra gears.

I also did feel a little bit manly, but I guess I just didnt want to drop to the smaller front ring for hills unless really needed.

Still I dont really suffer from chain noise so just get the mech adjusted correctly, should be fine. I think chain rub is lessened on a compact as they crossover is not as pronounced as on a triple.

djm501

Crosschaining doesn't just cause rub though - it puts lateral tension across the chain links and eventually they will prematurely break - plus you're putting a lot more lateral wear on the sprockets than you need to as well.

Use the small ring - even pros will use the small ring on gradients. Look after your bike and it will look after both you and your wallet.

antfly

Exactly, not using it just makes no sense at all.

surfatwork

Also check if your front gear cable has loosened or frayed - that will pull the derailleur out of alignment and it will rub against the chain.

Mikey23

One of my bikes is a defy 4 and a nice beast it is too, presumably still with shimano 2300 groupset? As some have said, cross chaining is not a good idea and something you need to sort out ASAP. It's not very efficient and will reduce the life of your chain and possibly your cassette. I used to do it a lot but am trying hard not to. Try to hang in the middle rings and be more savvy with the use of your front rings. Persevere and it will make you a better rider. For what it's worth, I often have probs changing from small to big ring with the 2300, much easier with the 105s on the spesh

navrig

goonz wrote:

I tend to stay on the big ring because well mainly as its a pain to have to keep changing both rings as I tend to stay mainly on the biggest ring on the rear and only really use 2 or 3 extra gears.

No wonder men get a bad reputation for not being able to multi-task :twisted:

Also you are missing out on the extra calorie consumption as a result of having to stretch the fingers on your left hand and puuuuuussshhhhhhh!

goonz

Ok so I tried this on the way home, slipped into the small ring and had to shift immediately to the smallest rear cog. This bascially creates the same chain cross but in the opposite direction, small to big instead of big to small.

marcusjb

goonz wrote:

Ok so I tried this on the way home, slipped into the small ring and had to shift immediately to the smallest rear cog. This bascially creates the same chain cross but in the opposite direction, small to big instead of big to small.

Small->big or big->small is not cross chaining. (Though you say you were in small->small).

Big->big or small->small is cross chaining and, as others have said, it is not a good thing for the drivetrain (especially the chain, but can put a lot of stress on your rear derailleur as well). Regular cross chaining will almost certainly cause a premature ejaculation of rivets and side plates from your drivetrain. :shock:

As we see larger and larger rear cassettes, this will only become a bigger issue and, I would guess, that a setup with a 30t cog on the cassette (and I think we will start to see 32 before too long?), that it may well bind completely if you attempt big->big.

goonz

My bad yes I was using small-small, which to me would mean the same strain as big-big?

marcusjb

goonz wrote:

My bad yes I was using small-small, which to me would mean the same strain as big-big?

It's not good (small->small), but I would say it's not as bad a big->big overall (chain under lots of tension, rear mech cage being highly stressed etc.).

Steve236

I notice two types of noise when cross-chaining from big ring to bigger sprockets. One is an obvious and nasty noise from the rubbing of the chain on the front mech which tends to be an all or nothing noise and disappears when I trim the front in a click. The other noise is a quiter chattering that gets more obvious for every shift to a bigger sprocket. No amount of barrel adjuster tweaking can get rid of that one but luckily its not too annoying and can be lived with if I don't want to shift to the smaller ring for some reason.

keef66

Lycraboy_Andy wrote:

I just assumed the bigger ring on the front provided more power

I think you'll find it's the rider providing the power, and that's what determines how fast you go, not your gear selection.