Should there be no chain contact with front derailleur no matter what gear?
10-12-23, 09:16 AM
#76
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I fully understand how the how chainstay length effects chainrub issues. Kontact, on the other hand, is just posting more of his worthless views of things.
10-12-23, 11:25 AM
#77
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Was just showing an example of the type of info Shimano sometimes makes available regarding recommended frame design configuration.
I fully understand how the how chainstay length effects chainrub issues. Kontact, on the other hand, is just posting more of his worthless views of things.
I fully understand how the how chainstay length effects chainrub issues. Kontact, on the other hand, is just posting more of his worthless views of things.
10-12-23, 11:44 AM
#78
Senior Member
I set up my wife's 10 speed Tiagra system last year. My recollection is that the dealer instructions actually said that the small front / small back combination might cause the chain to rub against the interior face of the larger chainring. On my wife's bike, it could be set up such that no rub occurred in the offending combination but I took the warning to imply that is not always the case.
I was particularly surprised to be able to achieve a rub-less condition given that my wife's bike is very small and, thus, has pretty short chain stays. My best guess as to why it works is that she also has a compact chainring setup. If the large chainring got smaller but the small chainring stayed the same size, I'd think that would help with the rubbing. I struggle to visualize if that's also the case when both rings are reduced in size. Here, I'm thinking of the difference between a 53/39 and a 50/34.
My experience with lower speed systems seems to mirror that of others. Whether or not higher speed systems can be made rub-less with enough skill, I've found that my 7 & 8 speed systems can be made rub-less almost effortlessly. And I like that. I'm actually building up a couple of 1x7 bikes partly for this reason.
I was particularly surprised to be able to achieve a rub-less condition given that my wife's bike is very small and, thus, has pretty short chain stays. My best guess as to why it works is that she also has a compact chainring setup. If the large chainring got smaller but the small chainring stayed the same size, I'd think that would help with the rubbing. I struggle to visualize if that's also the case when both rings are reduced in size. Here, I'm thinking of the difference between a 53/39 and a 50/34.
My experience with lower speed systems seems to mirror that of others. Whether or not higher speed systems can be made rub-less with enough skill, I've found that my 7 & 8 speed systems can be made rub-less almost effortlessly. And I like that. I'm actually building up a couple of 1x7 bikes partly for this reason.
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10-12-23, 12:47 PM
#79
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Thanks for spelling it all out. I was just getting sick and tired.
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10-12-23, 09:40 PM
#80
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edit: looked one up at random, 420mm for all sizes of Aspero, 415 on the Caledonian, 410 on the R5, 405 (as per an earlier comment) on the S5.
Last edited by choddo; 10-12-23 at 09:46 PM.
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10-12-23, 09:58 PM
#81
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Does chainstay length vary much with framesize? Not got a lot of clearance behind the seat tube to play with.
edit: looked one up at random, 420mm for all sizes of Aspero, 415 on the Caledonian, 410 on the R5, 405 (as per an earlier comment) on the S5.
edit: looked one up at random, 420mm for all sizes of Aspero, 415 on the Caledonian, 410 on the R5, 405 (as per an earlier comment) on the S5.
I have seen a lot of geo charts, and chainstay length does sometimes grow with larger sizes, though it sometimes gets longer for the very smallest sizes.
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10-12-23, 11:05 PM
#82
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Wife's bike is a 48 cm Norco Valence for what it's worth. Her stays are simply shorter than the stays on my bikes. Many of mine tend to be 58-63 cm, long TT / slack ST geometry frames. I was built for the "sport tourer" it seems.
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10-13-23, 05:39 AM
#83
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https://www.norco.com/bike-archives/...-aluminum-105/
10-16-23, 02:32 PM
#84
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I acknowledge your fundamental point though choddo. Chainstay length doesn't seem to vary anywhere near as much as the other proportions of frames do as one scales up. As you intimated, that surely has much to do with most of us using the same wheel size regardless of the bike frame size.
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10-18-23, 04:12 PM
#85
good cheap fun
Avoid cross-chaining, read the setup instructions (so easy to do), and check your shift cables and housing, even if the bike is new. I find a lot of bikes out of the box have plastic housing ends and the plastic sheathing shrinking at the ends, exposing the housing's wire strands and allowing your shift system to flex slightly instead of staying rigid, causing mushy, inconsistent shifting. This can really affect 10+ speed systems. Nine and below are much more forgiving. Trim those housing ends flush and use metal end caps. 
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