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Post by Deleted on Sept 7, 2013 12:43:37 GMT
I'm loving my new triban 3. But when on the largest gear at yhe front and smallest at the back, the chain rubs on the front derailleur. Can I tweak this without mucking up the gears completely? I don't want to take it 20 miles back to the shop.
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Post by Deleted on Sept 7, 2013 12:50:44 GMT
First thing to check before doing any adjusting is to have a look at the limit screw, might be preventing it from moving that little bit further over to stop the rubbing.
If that is fine then the tension on the front will need adjusting slightly, if you do it 1/4-1/8 of a turn at a time then check you shouldn't messing anything.
Though I don't know if the barrel adjuster needs tightening or loosening
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Post by Deleted on Sept 7, 2013 18:45:52 GMT
You can get it to work without rubbing with some very cafeful and precise adjusting I found. Watch some youtube vids to learn all the little adjustments if you do not know. The problem is the 7/8 speed chain with the 9 speed deralliur and 9/10 speed chainset.
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Post by cbrdeano on Sept 7, 2013 19:11:30 GMT
Make sure the front derailleur cage is in line with the front chainrings before you attack the cable adjustments.
Many a T3 has arrived with the front derailleur not aligned properly ( usually with the rear in too much )
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Post by ianmoss on Sept 7, 2013 19:32:03 GMT
That's called cross chaining. You will find that it always rubs that way. You can get the same gear ratio by moving the the middle chainring and further down to the middle of the cassette (cogs at the back) cross chaining puts a lot of stress on the gearing components and increases wear.
Generally the small chainring (sometimes called the granny ring) is best used withe the 4 or 5 largest gears. The middle chainring should be good for all the cogs ( you may get rub on the very biggest or very smallest cogs. The large chainring usually best with the 4 or 5 smaller cogs for really getting a move on!
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Post by Deleted on Sept 7, 2013 19:44:25 GMT
the largest gear at the front and smallest at the back, the chain rubs The large chainring usually best with the 4 or 5 smaller cogs for really getting a move on! Wouldn't disagree with you on that, but bobdigi isn't cross chaining if you read carefully
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Post by ianmoss on Sept 7, 2013 19:54:12 GMT
the largest gear at the front and smallest at the back, the chain rubs The large chainring usually best with the 4 or 5 smaller cogs for really getting a move on! Wouldn't disagree with you on that, but bobdigi isn't cross chaining if you read carefully Sorry, yes indeed, read smallest gear as 'easiest' in this case the high limit screw should be adjusted.
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Post by Deleted on Sept 7, 2013 22:23:22 GMT
Mine does the same since day one. Even took it to the shop to see if they coul solve the issue but they did only partially and Icame with all kind of blah blah like triples are this way, and so.
I firmly belive it's caused by having a 9 speed front derailleur with a 8 speed much wider chain, they just don't match and results in rubbing. Mine does it with big front/small-second small rear and with middle front with 2 or 3 bigger rear cogs, small chainring isn't an issue because it's trimmable.
Gonna give a chance to the 9 speed chain but they're out of stock at tht moment, I promise won't pay for it though since the bike should be working without this annoyances but I'm not willing to lose my time with their shop service or hearing their poor excuses.
Oh, forgot to comment my front der wont reach it's high limit no matter how high cable tension is set (so high low limit starts to not engage), don't know if it's a shifter issue or what but if I operate the lever when on big front/small rear the rubbing dissappears, it's sad I can't ride pushing the lever all the time, silly me, hopefully I don't use than gear combination that often...
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Post by Deleted on Sept 7, 2013 22:29:11 GMT
Mine does the same since day one. Even took it to the shop to see if they coul solve the issue but they did only partially and Icame with all kind of blah blah like triples are this way, and so. I firmly belive it's caused by having a 9 speed front derailleur with a 8 speed much wider chain, they just don't match and results in rubbing. Mine does it with big front/small-second small rear and with middle front with 2 or 3 bigger rear cogs, small chainring isn't an issue because it's trimmable. Gonna give a chance to the 9 speed chain but they're out of stock at tht moment, I promise won't pay for it though since the bike should be working without this annoyances but I'm not willing to lose my time with their shop service or hearing their poor excuses. Oh, forgot to comment my front der wont reach it's high limit no matter how high cable tension is set (so high low limit starts to not engage), don't know if it's a shifter issue or what but if I operate the lever when on big front/small rear the rubbing dissappears, it's sad I can't ride pushing the lever all the time, silly me, hopefully I don't use than gear combination that often... 9 speed chain does not work with the 8 speed cassette. I tried it. I then bought a 8/9 speed Sram PC971 and that worked almost perfect. But eventually just swapped out everything to 9 speed after that.
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Post by Deleted on Sept 7, 2013 22:34:07 GMT
So you're able to push the rear dérailleur outwards slightly further? Have you tried undoing the cable so there is no tension on it, pushing the dérailleur out all the way, pulling the cable tight and doing it up?
Actually, if it will change into the smallest cog then surely you wouldn't want it to shift out any further? Sounds more like the limit screw isn't long enough or something
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Post by Radchenister on Sept 7, 2013 22:43:10 GMT
You're after solving cross chain issues with a fraction of a mm chain width difference as the main issue?
Also suggesting Decathlon are making things up, despite selling thousands of bikes and the majority of people learning what gearing combinations work, getting good at trimming their own gears etc. and acknowledging the limitations; then also lump in there may be shifter and derailleur limit issues in conjunction?
Strikes me it's time to work through which issue's which, as it's not hanging together logically at the mo' IMO.
There are sometimes issues with these gears of course, as on many triples but sussing how to manage them is half the battle / fun.
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Post by Deleted on Sept 7, 2013 23:38:31 GMT
But this isn't an issue about cross chaining, this is an issue about the top gear cannot be used without the chain rubbing - I would expect the highest gear to be usable straight from decathlon.
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Post by Deleted on Sept 8, 2013 0:31:10 GMT
Gotten confusing real quickly this thread, But the .somthings of mm add up, up and down the gears as the shifters only shift a specific number of mm.somthing on each shift.
To the original op, you can try adjusting the front dr very very very slightly more outboard, using the high limit screw.
If that does not work, maybe the dr is not parralell to chainring. Lastly the cable tension might need a very very slight increase, but be careful with this as it might then mess up shifting down.
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Post by Deleted on Sept 8, 2013 0:43:22 GMT
Yes the shifters will move a certain mm each time, but this should be matched by the cassette spacing, regardless of chain width the dérailleur should line up with each gear.
Actually, what does chain width effect? Needs to be a certain size to fit on the gears without rubbing against the next one along, but other than than would having a thinner chain that still fits on the cogs result in any difference to shifting other than possibly less chain rubbing when cross chained?
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Post by Deleted on Sept 8, 2013 1:07:16 GMT
On the cassette it's to do with how the chain is shifted using the ramps/ cutouts etc. If it's too narrow chain it will not use them properly. When it manages to shift up it would be further over to one side of the cog, so then it even slightly further away from the ramps for the next shifts. Too wide and it starts touching the ramps trying to shift prematurely. The FD should match speeds as it needs to be in contact with the chain for a certain amount of throw to shift smoothly and have tolerance for a range of slight chain angles for diff cogs. I'm sure theres more reasons but zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
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