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Discussion Starter · #1 ·
I just got a new bike, a full suspension Felt. When the chain is on the small front sprocket and the smaller rear sprockets, it runs on the back of the front derailleur. This is with an unloaded suspension. Can this be normal or do I have the wrong front derailleur? It seems to me that the chain will saw through. Looking at another bike I have there is a lot of clearance between the chain and back side of the derailleur.
 

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Don't run it on the small front sprocket and the small back sprocket at the same time, that's called cross chaining and will wear out your chain and sprockets faster than not. Do a search on cross chaining and you'll find a lot more info than I'll type on the subject. Also don't run big front to big back either for the same reasons. Bottom line is that there are enough gear combinations that overlap that you have no real reason to need those particular combinations.
 

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how about with the suspension loaded? thats where it matters
every bike is different, but many suspension bikes will rub untill loaded, nothing unusual
 

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trboxman said:
Don't run it on the small front sprocket and the small back sprocket at the same time, that's called cross chaining and will wear out your chain and sprockets faster than not. Do a search on cross chaining and you'll find a lot more info than I'll type on the subject. Also don't run big front to big back either for the same reasons. Bottom line is that there are enough gear combinations that overlap that you have no real reason to need those particular combinations.
:yesnod:
 

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www.derbyrims.com
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That noise that happens is the alarm clock alerting a rider that it is time to shift into a bigger gear.
 

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Discussion Starter · #6 ·
Thanks for the input. This is my first suspension bike. With weight on the suspension, there is little rubbing. I can also see that the back of the front derailleur could not go lower because it would hit the swingarm at full compression. Is there a tutorial, intro or FAQ for those new to suspension bikes?
 

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This can also happen when it's time to replace the chain! It wears, stretches, and rubs on back of the front derailleur.

If this happens after installing a brand new chain, you probably need to take out another pair of links.

There's a chance that adjusting the derailleur body angle with the B-screw may increase the chain tension just enough to eliminate the front derailleur chain rubbing.
 

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Mtn-Rider said:
This can also happen when it's time to replace the chain! It wears, stretches, and rubs on back of the front derailleur.

If this happens after installing a brand new chain, you probably need to take out another pair of links.

There's a chance that adjusting the derailleur body angle with the B-screw may increase the chain tension just enough to eliminate the front derailleur chain rubbing.
I have never heard of, or seen, any of these causing or stopping the chain from rubbing the bottom of a FD.

trboxman's reply already covered the reasons.
 

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shiggy said:
I have never heard of, or seen, any of these causing or stopping the chain from rubbing the bottom of a FD.

trboxman's reply already covered the reasons.
I have recently seen exactly what I briefly mentioned. All resolved, as well as chain suck, by replacing the chain with a new one of proper length. Derailleur tensions will vary, your derailleur is not my derailleur.

True, the conditions described by trboxman tell you the chain is a gonner. Try it again with a new chain and it won't happen, but you really don't want to cross chain a new chain. I just always cross chain with minimal stress during chain relubes to check the drivetrain out.
 

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Mtn-Rider said:
I have recently seen exactly what I briefly mentioned. All resolved, as well as chain suck, by replacing the chain with a new one of proper length. Derailleur tensions will vary, your derailleur is not my derailleur.

True, the conditions described by trboxman tell you the chain is a gonner. Try it again with a new chain and it won't happen, but you really don't want to cross chain a new chain. I just always cross chain with minimal stress during chain relubes to check the drivetrain out.
A bad chain is one thing, but causing rubbing on the mech is another.
 

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Mtn-Rider said:
I have recently seen exactly what I briefly mentioned. All resolved, as well as chain suck, by replacing the chain with a new one of proper length. Derailleur tensions will vary, your derailleur is not my derailleur.

True, the conditions described by trboxman tell you the chain is a gonner. Try it again with a new chain and it won't happen, but you really don't want to cross chain a new chain. I just always cross chain with minimal stress during chain relubes to check the drivetrain out.
Sorry, the condition of the chain and/or the amount tension applied by the RD do nothing to keep the chain off the bottom of the FD as described by the OP. Not to mention that the OP has abrand new bike.
 

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shiggy said:
Sorry, the condition of the chain and/or the amount tension applied by the RD do nothing to keep the chain off the bottom of the FD as described by the OP. Not to mention that the OP has abrand new bike.
Exactly...Bad gear combo, Mech not @ the right height, or DS frame not 'squatted' while on the stand are the only reasons I can think of (also stated by others).
 

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Mtn-Rider said:
I have recently seen exactly what I briefly mentioned. All resolved, as well as chain suck, by replacing the chain with a new one of proper length. Derailleur tensions will vary, your derailleur is not my derailleur.

True, the conditions described by trboxman tell you the chain is a gonner. Try it again with a new chain and it won't happen, but you really don't want to cross chain a new chain. I just always cross chain with minimal stress during chain relubes to check the drivetrain out.
unless the chain has "stretched" beyond 1/2" and the springs are shot on the deraillier and the chain was too long to begin with.... you get my point?
the b adjuster also has nothing to do with it.
its pretty obvious that you dont understand bicycle drivetrains, you are mixing symptoms that the op didnt say he had, chain suck? usually a sign of worn chain and rings but the op said he had a new bike
who said the chain was a goner, they said dont cross chain, and if your chain is "stretched" to the point of sagging you have alot bigger issues to deal with
 

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Mtn-Rider said:
I have recently seen exactly what I briefly mentioned. All resolved, as well as chain suck, by replacing the chain with a new one of proper length. Derailleur tensions will vary, your derailleur is not my derailleur.

True, the conditions described by trboxman tell you the chain is a gonner. Try it again with a new chain and it won't happen, but you really don't want to cross chain a new chain. I just always cross chain with minimal stress during chain relubes to check the drivetrain out.
I didn't describe a gonner chain condition. I described a new rider who doesn't understand how to use the gears correctly..sometimes that describes a person who's been riding for years too... I also mentioned that the ultimate result of cross chaining was to wear the chain and the cogs faster than correct operation would. There wasn't enough info from the OP to determine if worn chain or cogs were likely.
 
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