8, 9, 10 and 11 speed chainring spacing.
10-18-14, 07:14 PM
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8, 9, 10 and 11 speed chainring spacing.
Does anyone know the lateral spacing (chainline) from one ring to the next, for doubles and triples, for 8, 9, 10 and 11 speed Shimano compatible indexed shifting?
I my short crank business I often run into situations like the following;
A customer in New Zealand has a 26" inseam. Her current bike has 8 speed STI brifters. But in the next year or so she hopes to upgrade to a newer, nicer bike. Said bike will probably have 10 speed drivetrain and shifters & her new 145mm cranks will follow her to the new bike. So I need to sell her a 10 speed crank and figure out what thickness chainring spacers I need to install to make it, temporarily, 8 speed indexed compatible.
FSA-USA have inexpensive 0.2mm (0.008") bronze chainring spacers for fiddling with this sort of thing. And Wheels Mfg. has 0.6mm aluminum spacers.
Another issue is that I never use indexed front shifting (IMHO worst cycling "innovation" ever.). Not sure if I've ever even been on a bike with "brifters". So I don't have a feel for just how fussy they are for chainring spacing.
I my short crank business I often run into situations like the following;
A customer in New Zealand has a 26" inseam. Her current bike has 8 speed STI brifters. But in the next year or so she hopes to upgrade to a newer, nicer bike. Said bike will probably have 10 speed drivetrain and shifters & her new 145mm cranks will follow her to the new bike. So I need to sell her a 10 speed crank and figure out what thickness chainring spacers I need to install to make it, temporarily, 8 speed indexed compatible.
FSA-USA have inexpensive 0.2mm (0.008") bronze chainring spacers for fiddling with this sort of thing. And Wheels Mfg. has 0.6mm aluminum spacers.
Another issue is that I never use indexed front shifting (IMHO worst cycling "innovation" ever.). Not sure if I've ever even been on a bike with "brifters". So I don't have a feel for just how fussy they are for chainring spacing.
10-18-14, 08:39 PM
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Offhand, I can't give you on center distances because i don't track that stuff, and have lousy memory for those kind of details.
However, what matters is the distance from the inner face of the outer ring to the tip on the adjacent ring's teeth. This is typically about 1-2mm less than the width of the chain which runs on it. Too wide, and the chajn can wedge between the rings, and too narrow and you'll have reduced clearance for the chain coming to the inner ring form the outer end of the cassette.
So, an indirect answer to your question is to fit the chain against the face of the larger ring and see where it meets the ring it'll engage on, and adjust according to that.
However, what matters is the distance from the inner face of the outer ring to the tip on the adjacent ring's teeth. This is typically about 1-2mm less than the width of the chain which runs on it. Too wide, and the chajn can wedge between the rings, and too narrow and you'll have reduced clearance for the chain coming to the inner ring form the outer end of the cassette.
So, an indirect answer to your question is to fit the chain against the face of the larger ring and see where it meets the ring it'll engage on, and adjust according to that.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
10-19-14, 07:37 AM
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Interesting subject, but google will end up being your best friend I bet, or searching right here at BF.
I easily found this thread and it heads in a direction that I wondered about setting here pondering the subject.
https://www.bikeforums.net/road-cycli...n-10s-11s.html
11 speed chain rings might actually be further apart than 10 speed. Reading deeper into the thread and there is some conjecture about the accuracy of that statement however.
I easily found this thread and it heads in a direction that I wondered about setting here pondering the subject.
https://www.bikeforums.net/road-cycli...n-10s-11s.html
11 speed chain rings might actually be further apart than 10 speed. Reading deeper into the thread and there is some conjecture about the accuracy of that statement however.
10-19-14, 08:59 AM
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Nothing beats actually measuring cranks. Go into your LBS, the one that you have a relationship with and bring a six pack, and with your caliper measure a number of cranks that are in the shop. If the staff have any critical thinking appreciation they will be more then willing. Offer to leave with them a copy of your findings too.
When I'm considering a crank set swap i'll place the two cranks next together so that the teeth of the rings line up tip to tip. This way it's easy to see if the c-c spacing is the same. Then consider the shift lever control (friction or index) and make a decision. Andy.
When I'm considering a crank set swap i'll place the two cranks next together so that the teeth of the rings line up tip to tip. This way it's easy to see if the c-c spacing is the same. Then consider the shift lever control (friction or index) and make a decision. Andy.
