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  1. #1
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    Chain blocking with 52/36 and 11-25

    Hello guys,

    I just rented a Tarmac w/ a 105 groupset, 52/36 and 11-25, for 2 weeks in Italy.

    I know cross chaining should be avoided at all cost, but from my exprience when doing so under distraction it simply causes noise and accelerated wear.

    In this case, when cross chaining on the 2 largest cogs (52 in front, 25 in rear), the lower pully is extended beyong its boundaries, to the point where everything blocks. The pedals will no longer turn even under high wattage. I have to get off the bike and take the chain off manually by hand.

    The italian guy at the rental place litterally shouts after me and gets really upset when I tell him this is not normal and there is either a problem with the chain being too short, or something else. He yells that I should never ever cross chain, as if I was trying to kill somebody... I know we should not, but sometimes it does happen.

    Any experience?

    Thanks!!

  2. #2
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    Sounds like chain was too short. With modern 11-speed cross-chaining is not the end of the world if things are set up properly (although many will say there should be little/no reason to do it often, if ever).

    But I doubt they would put more links in your rental bike's chain, so once knowing the issue the best course of action would probably be to not cross-chain.

    I'm sure much more knowledgeable folks will follow my reply with better / more correct ones...

  3. #3
    tlg
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    Guy at the rental place is an idiot. Who in their right mind would rent out a bike like that to potentially inexperienced riders? And NOT tell them to avoid the big-big?
    I've never heard of someone sizing a chain intentionally too short for big-big. Just stupid stupid stupid.

    There's absolutely nothing wrong with riding in big-big. Yes it may cause "accelerated" wear, but only you use it constantly all the time. Even then, it may only increase wear 10%.

    That's a tiny price to pay to avoid having the chain too short, ripping off the read derailleur and possibly ruining the chain, frame, wheel, AND rider.
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  4. #4
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    If he ain't gonna lengthen the chain and you're concerned about issues while using the bike it may be worth it to buy a cheap chain and use that during the rental period. Put his back on when returning it.

    What's a couple more bucks in the overall cost of a vacation.
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  5. #5
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    The rental guy is old fashioned and stupid. Every modern drivetrain will work big/big if everything is in spec and the chain is properly sized. He probably became a mechanic in the 80's and hasn't learned anything since. I'd either put a chain on myself or return the bike and go somewhere else.

    To be sure...there is NO problem w/ big/big other than very slightly accelerated wear. It is NO PROBLEM to use it when needed. Zero need to avoid it.
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  6. #6
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    Quote Originally Posted by Xcessiv View Post
    In this case, when cross chaining on the 2 largest cogs (52 in front, 25 in rear), the lower pully is extended beyong its boundaries, to the point where everything blocks. The pedals will no longer turn even under high wattage. I have to get off the bike and take the chain off manually by hand.
    Is that even possible due to a chain being too short? Too short of a chain would either prevent you from getting to those gears or rip the hanger off but once your in a gear it should turn I'd think. b-tension screw f-up maybe?

    Either way, that guy doesn't belong in a bike shop. Not only should the cranks turn when cross chaining but there's really no problem with doing it.

  7. #7
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    Quote Originally Posted by Jay Strongbow View Post
    Is that even possible due to a chain being too short? Too short of a chain would either prevent you from getting to those gears or rip the hanger off but once your in a gear it should turn I'd think. b-tension screw f-up maybe?

    Either way, that guy doesn't belong in a bike shop. Not only should the cranks turn when cross chaining but there's really no problem with doing it.
    Chain too short will sometimes do that. It'll allow the shift to be made but the derailleur ends up so far forward that it locks up.
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  8. #8
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    Quote Originally Posted by cxwrench View Post
    Chain too short will sometimes do that. It'll allow the shift to be made but the derailleur ends up so far forward that it locks up.
    I see. Thanks.

    This mechanic must be a real beaut. I can see a mistake sizing a chain to short but letting it out the door with such an obvious symptom??? Or it sounds in the case of this guy thinking that's what should happen.

  9. #9
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    Quote Originally Posted by Jay Strongbow View Post
    I see. Thanks.

    This mechanic must be a real beaut. I can see a mistake sizing a chain to short but letting it out the door with such an obvious symptom??? Or it sounds in the case of this guy thinking that's what should happen.
    I think the prevailing feeling w/ a lot of older mechanics is size the chain short. Combined w/ the idea that cross chaining was definitely to be avoided you get a lot of guys that just size chains way too short. As I posted before they just haven't bothered learning about the new drivetrains and don't care to. I remember when I first got into the business all the old guys felt this way. We had 8 speed at that point, according to those old farts only 10 gear ratios that were useable.
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  10. #10
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    Quote Originally Posted by jetdog9 View Post
    Sounds like chain was too short. With modern 11-speed cross-chaining is not the end of the world if things are set up properly (although many will say there should be little/no reason to do it often, if ever).

    But I doubt they would put more links in your rental bike's chain, so once knowing the issue the best course of action would probably be to not cross-chain.

    I'm sure much more knowledgeable folks will follow my reply with better / more correct ones...
    Yes, no sense in cross chaining unless rider is lazy. On a 50/34 11-28, once rider gets to 50-28, he's in the exact same gear as 34-19 cog, the 4th gear out. By the time he's going that slow, he should be in the 19 so he can use the other 3 gears if he needs them. If not, he'll have to double shift and slide across 4 gears in back.

    Reading all the favorable opinions on cross chaining, I'm concluding that narrow 10 and 11 speed chains flex more easily sideways, so they shift better cross chained than the wider 8 speed chains those old farts dealt with back in 8, 7, 6 speed days.

    In the '80s, cross chaining would wear out the chain and rear cogs noticeably faster and made a nasty noise that would elicit comments from other riders, not to mention wear out the derailleur pulleys. So riders didn't cross chain.

    Then again, they were dealing with 52/42, a 10 tooth jump, not 52-39, 12 teeth, or worse, 50/34, a whopping 16 tooth jump. So riders shifted in front lots more on the fly. Today the two chain ring ranges have much less overlap, so rider has to cross chain to fill in the gaps.

    To avoid having to double shift, manufacturers are eliminating the inside chain ring, giving up 3 or 4 useful gears, and we're back to 11 speeds, one gear less than the old 12 speeds in the '80s.

  11. #11
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    I think this is correct, older mechanics use as little chain as possible, under the assumption that you wouldnít/shouldnít be using big/big in the first place. The method of determining chain length I learned was big/big with the rear derailer cage at a 45 degree angle.

    I would have been in my small ring earlier, but Iím old school and learns not to cross chain. Now Di2 doesnít let you anyway, so new school meats old school.

  12. #12
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    Quote Originally Posted by Fredrico View Post
    Yes, no sense in cross chaining unless rider is lazy. On a 50/34 11-28, once rider gets to 50-28, he's in the exact same gear as 34-19 cog, the 4th gear out. By the time he's going that slow, he should be in the 19 so he can use the other 3 gears if he needs them. If not, he'll have to double shift and slide across 4 gears in back.

    Reading all the favorable opinions on cross chaining, I'm concluding that narrow 10 and 11 speed chains flex more easily sideways, so they shift better cross chained than the wider 8 speed chains those old farts dealt with back in 8, 7, 6 speed days.

    In the '80s, cross chaining would wear out the chain and rear cogs noticeably faster and made a nasty noise that would elicit comments from other riders, not to mention wear out the derailleur pulleys. So riders didn't cross chain.

    Then again, they were dealing with 52/42, a 10 tooth jump, not 52-39, 12 teeth, or worse, 50/34, a whopping 16 tooth jump. So riders shifted in front lots more on the fly. Today the two chain ring ranges have much less overlap, so rider has to cross chain to fill in the gaps.

    To avoid having to double shift, manufacturers are eliminating the inside chain ring, giving up 3 or 4 useful gears, and we're back to 11 speeds, one gear less than the old 12 speeds in the '80s.
    Uhmmm...no. You're wrong again.
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  13. #13
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    Quote Originally Posted by cxwrench View Post
    Uhmmm...no. You're wrong again.
    Nope heís not and Iím going to agree with Federico. There are other gear combos available that eliminates the need to cross chain and as Fed stated, it gives the rider options to move up or down tha cogset.

  14. #14
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    Quote Originally Posted by cxwrench View Post
    I think the prevailing feeling w/ a lot of older mechanics is size the chain short. Combined w/ the idea that cross chaining was definitely to be avoided you get a lot of guys that just size chains way too short. As I posted before they just haven't bothered learning about the new drivetrains and don't care to. I remember when I first got into the business all the old guys felt this way. We had 8 speed at that point, according to those old farts only 10 gear ratios that were useable.
    Knowing the level of expertise in bike shops, I don't doubt a few mechs would make chains too short for cross chaining up to the climbing gears. But a simple remedy is to put the chain in the smallest cogs front and back, then adjust chain length so it just clears the rear derailleur cage. That's as long as possible. Racers used to add links claiming the longer chains shifted more freely and lasted longer.

  15. #15
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    Quote Originally Posted by Steve B. View Post
    Nope heís not and Iím going to agree with Federico. There are other gear combos available that eliminates the need to cross chain and as Fed stated, it gives the rider options to move up or down tha cogset.
    It doesn't matter whether you've got similar ratios in other gear combinations. The big/big should work, it's designed to work, and nothing you say will change that. It doesn't matter whether you think it's ok to do or not. Shimano, SRAM, and Campy all believe it's ok and they make sure it will work.
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  16. #16
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    Quote Originally Posted by Fredrico View Post
    Knowing the level of expertise in bike shops, I don't doubt a few mechs would make chains too short for cross chaining up to the climbing gears. But a simple remedy is to put the chain in the smallest cogs front and back, then adjust chain length so it just clears the rear derailleur cage. That's as long as possible. Racers used to add links claiming the longer chains shifted more freely and lasted longer.
    That's exactly the method of sizing chains that I've been posting on here for years, probably a decade. I'm glad we agree on something.
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  17. #17
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    I cross chain all the time on my 7800 bike........It all depends on the chain line. If your chainline is wacked, you'll get all sorts of bad noises........PS. the chain on your rental bike is too short.
    If your opinion differs from mine, ..........Too bad.
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  18. #18
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    Quote Originally Posted by cxwrench View Post
    That's exactly the method of sizing chains that I've been posting on here for years, probably a decade. I'm glad we agree on something.
    You da man, cx! I beat you by about 20 years wrenching, so can add a little perspective, but mainly enjoy hanging around, learn stuff and keep up with the technology. Haven't wrenched in a shop for 3 years.

  19. #19
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    Nothing wrong with big / big riding (or small small) - I do it when I've got a short punchy hill to hit and don't want to drop off the big ring only to have to return to it for the downhill behind it - I would be very dissatisfied with a bike set up that didn't allow for that. A rider shouldn't have to look down at his cassette to know where he is all the time to avoid a stupid forbidden zone in gearing combo.
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  20. #20
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    Quote Originally Posted by Steve B. View Post
    Nope heís not and Iím going to agree with Federico. There are other gear combos available that eliminates the need to cross chain and as Fed stated, it gives the rider options to move up or down tha cogset.
    I agree that in Fred's fantasy world of eating up any climb in 53x11 there is no sense in cross chaining.

    But for actual riding/racing when the time required for multiple shifts to get the same ratio in the other ring is the difference between falling off the back or not it makes a lot of sense. That, and it just does't matter.

  21. #21
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    Quote Originally Posted by cxwrench View Post
    It doesn't matter whether you've got similar ratios in other gear combinations. The big/big should work, it's designed to work, and nothing you say will change that. It doesn't matter whether you think it's ok to do or not. Shimano, SRAM, and Campy all believe it's ok and they make sure it will work.
    An actual recommendation from Shimano is:

    "The most efficient chain line occurs when the chain is running in a straight line. This minimises friction. When you run big-big you're pushing an uneven power transmission to the rollers, plates and bushings, especially at the points where the chain line alters (the points where the chain meets the sprocket and the chainring). This uneven load causes extra friction which increases the wear on the chain and longer term leads to less than optimum gear shifting.

    For these reasons Shimano recommends avoiding extreme gear positions. "

    Campy has this to say:

    "Cross-chaining is a practice to be avoided as it is less efficient than a straighter chainline (increased friction, less free motion of links etc).

    We all might find ourselves cross-chaining during the heat of the battle during a race. However, we shouldn't make a habit out of it as there is generally a similar metric development gearing position available on a larger/smaller chainring.

    Extreme chain crossing can add wear and tear on chainring and cassette teeth as the severe angle of the chain brings the external or internal part of the chain in direct contact with chainring/cassette teeth as opposed to a straight chainline which keeps friction to a minimum and limits contact to the rollers located on the axles of each chainlink."

    Cross-chaining: is it really all that bad? | road.cc

    I believe in all cases the methods that both manufacturers use to adjust chain length allows for big/big combos', though the Shimano Di2 does not allow a big/big combo unless you cheat the system by telling it you have a certain crank/cassette installed. Even then you cannot run in Synchro as that will lock out big/big.

    So I can understand the Italian shop guy wondering why such a stupid American (kidding) is running this combo, when it's not needed and not recommended.

  22. #22
    tlg
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    Quote Originally Posted by Srode View Post
    Nothing wrong with big / big riding (or small small) - I do it when I've got a short punchy hill to hit and don't want to drop off the big ring only to have to return to it for the downhill behind it - I would be very dissatisfied with a bike set up that didn't allow for that.
    THIS!
    If you live in an area with miles long 3-5% grades, sure it doesn't make much sense to go big big. But if you're in an area with lots of short steep punchy climbs, you'll be using big big. If you come around a corner, hit a steep climb, get out of the saddle... you're not going to back off, sit down and shift your chainring just to avoid big big. That's just insane.

    A rider shouldn't have to look down at his cassette to know where he is all the time to avoid a stupid forbidden zone in gearing combo.
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  23. #23
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    Quote Originally Posted by tlg View Post
    Guy at the rental place is an idiot. Who in their right mind would rent out a bike like that to potentially inexperienced riders? And NOT tell them to avoid the big-big?
    I've never heard of someone sizing a chain intentionally too short for big-big. Just stupid stupid stupid.
    This!!!

    Come to think if it, why would someone renting out a bike to the public do this at all? I really hope he has good insurance. The owner of the bike rental is lucky the OP didn't rip the derailleur clean off the bike. Worse yet, the OP AND the rental owner is VERY lucky the OP didn't jettison himself off the bike in the process!

    I do have an older triple crankset road bike that I sized the chain a little short in order to get the 6600 RD to work with an 11-32T cassette without making noise in the 32T cog. However, I am the only person who ever rides this bike and I never use the big/big combo on this bike and never have. For anybody to rent out a bike this way is DUMB, DUMB, DUMB!!!

    Just the attitude of this guy is enough that I would never give him my business EVER again.

    The argument on whether it is good practice to ride in big/big on a PROPERLY sized chain is irrelevant here.
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  24. #24
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    Quote Originally Posted by Steve B. View Post
    An actual recommendation from Shimano is:

    "The most efficient chain line occurs when the chain is running in a straight line. This minimises friction. When you run big-big you're pushing an uneven power transmission to the rollers, plates and bushings, especially at the points where the chain line alters (the points where the chain meets the sprocket and the chainring). This uneven load causes extra friction which increases the wear on the chain and longer term leads to less than optimum gear shifting.

    For these reasons Shimano recommends avoiding extreme gear positions. "

    Campy has this to say:

    "Cross-chaining is a practice to be avoided as it is less efficient than a straighter chainline (increased friction, less free motion of links etc).

    We all might find ourselves cross-chaining during the heat of the battle during a race. However, we shouldn't make a habit out of it as there is generally a similar metric development gearing position available on a larger/smaller chainring.

    Extreme chain crossing can add wear and tear on chainring and cassette teeth as the severe angle of the chain brings the external or internal part of the chain in direct contact with chainring/cassette teeth as opposed to a straight chainline which keeps friction to a minimum and limits contact to the rollers located on the axles of each chainlink."

    Cross-chaining: is it really all that bad? | road.cc

    I believe in all cases the methods that both manufacturers use to adjust chain length allows for big/big combos', though the Shimano Di2 does not allow a big/big combo unless you cheat the system by telling it you have a certain crank/cassette installed. Even then you cannot run in Synchro as that will lock out big/big.

    So I can understand the Italian shop guy wondering why such a stupid American (kidding) is running this combo, when it's not needed and not recommended.
    Of course they're going to recommend not spending a great deal of time in big/big but that does not change the face that as I have repeatedly stated ALL of the drivetrains available now were designed to allow cross chaining. If all parts are in spec/capacity of the rear derailleur, it works. It's supposed to work. Obviously if you spend a lot time in those gear combinations wear will be slightly accelerated.

    All I'm saying is that all 3 companies have made it possible to use big/big rather than make it impossible because it's 'wrong' in someone's mind and then have to deal w/ people ripping derailleurs off bikes. If the capacity is there it was obviously meant to work. Not everyone can or wants to remember which gears some old fart thinks they shouldn't use, thus the drivetrain will work in those situations.

    You certainly seem to be spending a bit of time digging up this info in an effort to make it sound like a rider should not ever cross chain...but all you have to do is look at the components and see that they do actually work when you go big/big. That's all the proof you need. Any gear combination that doesn't result in perfectly straight chain line is going to increase wear but we still use them.
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  25. #25
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    Quote Originally Posted by Steve B. View Post
    So I can understand the Italian shop guy wondering why such a stupid American (kidding) is running this combo, when it's not needed and not recommended.
    "Not recommended" is not the same as "Not allowed".

    The Italian shop guy is creating a situation that is not allowed (at the expence of catastrophic damage to the rider and bike).

    If it's not needed or recommended, they why does Shimano instructions size the chain for the big-big combo?
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