Front derailleur losing cable tension
Discussion
Since changing my front derailleur (Sora triple) and cable, I seem to be losing cable tension after 30 mins or so of riding, meaning I have to wind the barrel adjuster half a turn, 2 or 3 times on a ride to stop the cage from rubbing the chain.
Does anyone have any ideas as to why it is doing this?
Does anyone have any ideas as to why it is doing this?
What you are describing (I think) is cross chaining, which just means learning to use gears better
On the smallest "granny" front chainring, use the 3 or 4 largest rear cassette sprockets. On the middle front chainring use the middle 3 or 4 rear sprockets and on the large front chainring use the 3 or 4 smallest rear sprockets.
This keeps the chain angle nice and straight and avoids premature wear on the cassette and the chain.
The front mech has a trimming function (I think it's present in Sora but haven't checked) so you have a hidden click on the left shifter to swing the front mech inwards and outwards to help with the overlap at the rear, but the front mech is only so wide and cannot accomodate all 9 or 10 rear sprockets on the rear using the same front chainring
Hope that helps
Crude photos but you get the idea http://coachlevi.com/cycling/proper-chainline-exam...
On the smallest "granny" front chainring, use the 3 or 4 largest rear cassette sprockets. On the middle front chainring use the middle 3 or 4 rear sprockets and on the large front chainring use the 3 or 4 smallest rear sprockets.
This keeps the chain angle nice and straight and avoids premature wear on the cassette and the chain.
The front mech has a trimming function (I think it's present in Sora but haven't checked) so you have a hidden click on the left shifter to swing the front mech inwards and outwards to help with the overlap at the rear, but the front mech is only so wide and cannot accomodate all 9 or 10 rear sprockets on the rear using the same front chainring
Hope that helps
Crude photos but you get the idea http://coachlevi.com/cycling/proper-chainline-exam...
Great tip, thanks. I have started to do this out of desperation, but didn't realise it was a technique!
I still feel like I'm losing tension though, as the cage will gradually start to rub the chain. In top gear it will start off fine but when I return to top 10 miles or so later, it's starting to rub.
I still feel like I'm losing tension though, as the cage will gradually start to rub the chain. In top gear it will start off fine but when I return to top 10 miles or so later, it's starting to rub.
To lose cable tension, one of the following must be true:
1) Your shifters are loose on the bars and are moving about
2) The bolt holding the cable tight, isn't tight enough
3) Cable has stretched (although this happens over months of use and not during a single ride)
Is the cable run from the bars to the front mech smooth, with no kinks in the outer sleeving or catching on anything else - i.e. other cables?
1) Your shifters are loose on the bars and are moving about
2) The bolt holding the cable tight, isn't tight enough
3) Cable has stretched (although this happens over months of use and not during a single ride)
Is the cable run from the bars to the front mech smooth, with no kinks in the outer sleeving or catching on anything else - i.e. other cables?
Evening
You may have poor quality gear outer (black thick stiff cable from shifter to frame) that tends to come with equally poor quality cable ends. The outer cable may well be "pulling through" the cable end (black or silver plastic or metal) causing a reduction in inner (silver) cable tension.
Have a close look to see if this is the case.
If it's not that, then the bolt that secures the inner cable may be damaged (after over tightening), and cannot hold the tension
Worst case senario, new outer+inner/cable clamp bolt (M5)
You may have poor quality gear outer (black thick stiff cable from shifter to frame) that tends to come with equally poor quality cable ends. The outer cable may well be "pulling through" the cable end (black or silver plastic or metal) causing a reduction in inner (silver) cable tension.
Have a close look to see if this is the case.
If it's not that, then the bolt that secures the inner cable may be damaged (after over tightening), and cannot hold the tension
Worst case senario, new outer+inner/cable clamp bolt (M5)
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