position of chain & rear derailleur when in the small gears

Specialeyes

Veteran
Location
Essex
Well, technically it's not maxxed out.... I'd stick it in big-big and if the rear derailleur doesn't look overstretched, then take a link out :okay:
 

si_c

Veteran
Location
Wirral
Looks a bit marginal to me - almost like it could do with a link taking out. The angle of the first photograph doesn't help - when in the small-small how much slack is there in the chain on the bottom?
 

Ajax Bay

Guru
Location
East Devon
I'd leave it as you have it (assume first image is small/small). The return section of the chain isn't touching the chain round the guide jockey wheel, is it? You could probably take a link (one inch) out but then it'd be pretty tight large/large.
 
It is borderline - maybe just don't ride in little - little if it can be helped.
thank you. I can do that, but

I only have trouble w/small in front & big in back when the chain is dirty. it gets sucked up & jammed against the chainstay, stopping me cold in my track. that really stinks on a standing climb. probably need a new chain & chainrings
 

weareHKR

Senior Member
I would suggest taking a link out personally.
Not a direct answer to your question, but you're getting into the areas of extreme cross chaining, ie, small/small & large/large generally are not good combinations, this also can cause excessive wear on your drive chain. This doesn't mean you can never use those combinations but they're not ideal.
It also depends on the chain line of the bike, how the front
rings line up with the back in a straight line.
You could possibly increase peddling resistance too due to the extremes of cross chaining!
With a tripple or double chainrings I would suggest you can achieve nearly all the combinations of gears without actually
cross chaining!
 

Ajax Bay

Guru
Location
East Devon
I only have trouble w/small in front & big in back when the chain is dirty. it gets sucked up & jammed against the chainstay, stopping me cold in my track. that really stinks on a standing climb. probably need a new chain & chainrings
You have introduced new information (chain suck occasionally in lowest gear).
So 'yes' take a link out, provided the chain will still go large/large.
Replace the inner/small chain ring. The other ones should remain entirely suck-free. The chain only needs changing if its elongation is more than the rider's self-imposed threshold or it means it starts skating over one of the rear sprockets. A new chain will just increase chain-suck ceteris paribus.
Chain suck - I learnt this the hard way (knowing there's was a problem - new chain and suddenly suck) climbing east-west over Wrynose and Hardknott Passes.
This is a useful and comprehensible article: http://fagan.co.za/Bikes/Csuck/ (referenced from Sheldon Brown's site).
A mitigation I used (and actually have left it there) is a chunky ziptie round the right chainstay up where the chainstay joins the BB shell. The idea was that a chain about to suck would knock against the ziptie and 'un-suck'.
1607619600991.png
 
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Once a Wheeler

Senior Member
My rule of thumb is to put the chain on the biggest front chainwheel and the biggest rear sprocket and then shorten it to the minimum length which the arrangement allows. The problem with going to the limits at the other end of the range is that when the chain whips around during gear changes it tends to chip and damage the chain stay.
 
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