Changing gears under load.... Chain came off the front

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Boshk
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by Boshk

1st time, chain came off as I was changing from small to large chainring at top of the hill.... Couldn't believe it, shifting had worked really nice until then. I wasn't even changing under serious load, still sat on saddle.
I can shift rear derailleur out of the saddle but never dared tried front...

Can you guys all change gears under load whether it's mechanical, electronic, shimano sram or campy?

I know YouTube reviews on eTap, di2 etc etc are all paid promotional videos, they are all out of their saddles, loading the drive trains and stating... Perfect shifting of front derailleur small to big, big to small.....
True in general?

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silvalis
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by silvalis

Always been 50-50 for me depending on the drivetrain, some better than others, some working flawlessly (but sounding crunchy) and others never working well at all. The more expensive groupsets appear to be more tolerant of shitty shifting technique
Chasse patate

Zakalwe
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by Zakalwe

It's happened once or twice but never something I've had to worry about, 99.9% of the time it doesn't happen . Are your limit screws set properly?

hogehoge
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by hogehoge

Shift from small to large chainrings under maximum load all the while even on the largest rear sprocket, both standing and sitting. I normally back off the power when swithing from large to small chainrings to avoid dropping the chain ( especially when cross chaining). Shift the rear all the while under maximum power sitting or standing. I'm using 9150 groupset with 9100 chainset (SRM) 38-52 (not 36) .

TobinHatesYou
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by TobinHatesYou

If you are throwing a chain over your big ring, I don’t care if it’s under massive load or not...your FD is poorly set up. 50-50? No effin’ way. Maybe once every thousand miles on SRAM and pretty much never on Shimano.

As well when are you ever shifting from small to big at a low enough RPM (high enough stress) for this to be a problem? When cresting, I almost always shift up front before I upshift from cog 5 to cog 6. Usually this is accompanied by a synchro shift in the rear back down to cog 4.

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silvalis
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by silvalis

TobinHatesYou wrote:
Thu Apr 26, 2018 5:35 am
If you are throwing a chain over your big ring, I don’t care if it’s under massive load or not...your FD is poorly set up. 50-50? No effin’ way. Maybe once every thousand miles on SRAM and pretty much never on Shimano.

As well when are you ever shifting from small to big at a low enough RPM (high enough stress) for this to be a problem? When cresting, I almost always shift up front before I upshift from cog 5 to cog 6. Usually this is accompanied by a synchro shift in the rear back down to cog 4.
You referencing my post?
I never said I was throwing a chain over my big ring. I said it was 50-50 misshifting. Don't think I've ever chucked over the big ring under load before...
Typically the pickup pins slipping and dumping the chain back down, occasionally past my bendy chain catcher and onto the bb. Have it happen on a 4600, a rs500 and a centaur crank. maybe once on a force 22. never on a 6800 crank. A couple of times on an athena '14 crank and a SR15 crank, but interestingly these stopped doing it after 1000km or so.

Is the OP talking about chucking the chain over the big ring?
Chasse patate

TobinHatesYou
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by TobinHatesYou

Dunno, "came off the front" seemed to imply that, but maybe he meant it shifted up and then fell back down onto the small ring? That doesn't happen to me either. Sometimes the shift lags on my SRAM setup because the chainring has 6 ramps spaced as if there should be 8, but the chain doesn't "come off."

Boshk
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by Boshk

TobinHatesYou wrote:
Thu Apr 26, 2018 7:41 am
Dunno, "came off the front" seemed to imply that, but maybe he meant it shifted up and then fell back down onto the small ring? That doesn't happen to me either. Sometimes the shift lags on my SRAM setup because the chainring has 6 ramps spaced as if there should be 8, but the chain doesn't "come off."
Came off the front to outside of chainring onto crankarm.
I check FD with big chainring and smallest cog, there was only about 1mm gap....

TobinHatesYou
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by TobinHatesYou

Boshk wrote:
Thu Apr 26, 2018 9:57 am

Came off the front to outside of chainring onto crankarm.
I check FD with big chainring and smallest cog, there was only about 1mm gap....
Which groupset are you running?

SRAM Yaw FDs are probably the most susceptible to throwing the chain over the big ring and have the lowest tolerances for adjustment. Shimano and Campagnolo FDs are easier to set up.

Boshk
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by Boshk

Chorus 2015+, record chain, dura ace chainrings on Quarq pm

Zakalwe
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by Zakalwe

perhaps your derailer cage isn't set parallel with the chainring, if it's kicking slightly out at the bottom then it'll push the chain beyond the teeth.

Zakalwe
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by Zakalwe

Hold on, DA chainrings? wtf dude

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Mr.Gib
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by Mr.Gib

Boshk wrote:
Thu Apr 26, 2018 10:44 am
Chorus 2015+, record chain, dura ace chainrings on Quarq pm
Mixing and matching will make it pretty much impossible to diagnose a problem. It could always be the mix that is the problem.

I don't get the whole shifting under load thing. When I was racing I found that the only times I needed to shift under load was when I lost concentration and was caught unprepared - never happened if I had my head in the game. Out of racing never - even on hammerfests on crazy rolling terrain. Can't imagine why I would take the risk, particularly on the front (rear less of an issue of course). There is one guy in one of my regular groups who seems to think shifting under load is just what you do. His bike is always jumping and jerking, and every once in a while he misses a shift, drops a chain, etc. PIA to be behind at any time - not a popular dude.
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wheelbuilder
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by wheelbuilder

Mr.Gib wrote:
Thu Apr 26, 2018 4:10 pm
Boshk wrote:
Thu Apr 26, 2018 10:44 am
Chorus 2015+, record chain, dura ace chainrings on Quarq pm
Mixing and matching will make it pretty much impossible to diagnose a problem. It could always be the mix that is the problem.

I don't get the whole shifting under load thing. When I was racing I found that the only times I needed to shift under load was when I lost concentration and was caught unprepared - never happened if I had my head in the game. Out of racing never - even on hammerfests on crazy rolling terrain. Can't imagine why I would take the risk, particularly on the front (rear less of an issue of course). There is one guy in one of my regular groups who seems to think shifting under load is just what you do. His bike is always jumping and jerking, and every once in a while he misses a shift, drops a chain, etc. PIA to be behind at any time - not a popular dude.
So much this..........I've been around a lot of guys that do this too. Even worse are the guys that try to shift while pedaling at about 5rpm. I always lessen the power when shifting. Only takes a second. It's not like you are losing ground/time, or will be dropped because of it. Smooth pedal stroke is King.
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Calnago
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by Calnago

Totally concur with Mr. Gib and Wheelbuilder. A bad shift is a bad shift, whether it’s accomplished electrically or mechanically. Keep in mind that the chain and chainrings and the method of engaging them through a sideways push is exactly the same regardless of whether it’s electrically or mechanically actuated. It’s just that with electric, you become oblivious to the horrendous things that are happening when you make a bad shift (under load, low rpm, the list goes on). So, if you remember cringing when you tried to make a bad shift on your mechanical system and thinking “holy sh&t, I think I might break something doing this”, well... the same thing is happening with electrical, it’s just that it doesn’t care if it may be putting a lot of undue stress on your drivetrain versus had you shifted under more favorable conditions. Electric doesn’t “manage” the shift. It can’t, at least not at this point in time. It just does what it’s told regardless of whether it’s a good idea or not.

As for trying to diagnose the OP’s issue... he’s mixing and matching components not specifically designed to work together and probably has it set up poorly as well. Waste of time.
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