Easier gears for climbing

pineapplehead said:
Not concerned. Just curious about the technical properties.
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I posted a link recently in another thread with similar question. Chainring size can affect suspension kinematics. Depending on your frame design and whether you want better climbing or descending will determine the best solution if you want the mechanically superior option.
 
creaky said:
You're asking what ? Half way through page 2 and you're now talking about load on the chain but your original issue (even thread title) was wanting an easier gear and asking if a smaller chainring or 42 tooth (cassette) cog is the bets way to go ....
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pretty much. As in, are there any opinions on the best way to go from a mechanical perspective.
Ratios, small cog, etc are irrelevant, as I'm all over that as far as what suits me goes.

creaky said:
Do you want to know if the chain will have a harder life one way or the other, or the effect on your suspension linkage ?
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It's a hardtail. I'm simply curious about the technical differences between going 30t ring/40t cog vs 32 ring/42t cog. I've heard there is a preferable way from an engineering point.
 
teK-- said:
I posted a link recently in another thread with similar question. Chainring size can affect suspension kinematics. Depending on your frame design and whether you want better climbing or descending will determine the best solution if you want the mechanically superior option.
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Now we're talking. Perhaps this was what I read but can no longer find...
What you're referring to seems to apply to duallies however so perhaps my question is redundant for a hardtail.
 
Same hard tail on same slope, I would think gear inches would be directly proportional to the load on the system. This being the case you could use gear inches to answer your question.
 
I'm no engineer, but it would seem to me that a chain will be stressed ever-so-slightly-more under tension around a smaller chainring than a bigger ring.
On a bigger ring surely more links sharing the load would equal less individual link stress?

I really don't think this will make much difference to me. I'll just get a smaller ring.

It's a topic of curiosity though.
 
pineapplehead said:
I'm no engineer, but it would seem to me that a chain will be stressed ever-so-slightly-more under tension around a smaller chainring than a bigger ring.
On a bigger ring surely more links sharing the load would equal less individual link stress?

I really don't think this will make much difference to me. I'll just get a smaller ring.

It's a topic of curiosity though.
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I was reading an article a little while back talking about a mechanical advantage loss from chain angle on the smallest cogs in cassettes, starts getting noticeable below 12 teeth so once you are getting down in the 9 tooth cogs there is a substantial power transfer loss. Not sure if this is what you're referring to but cant see it making much difference at 30.
 
evad said:
I was reading an article a little while back talking about a mechanical advantage loss from chain angle on the smallest cogs in cassettes, starts getting noticeable below 12 teeth so once you are getting down in the 9 tooth cogs there is a substantial power transfer loss. Not sure if this is what you're referring to but cant see it making much difference at 30.
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This is interesting. I have a bit of a climbing background, so I tend to wonder about things such as load, angles etc - not that I really have any detailed understanding of physics.

Real world implications in my case seem to be zilch
 
pineapplehead said:
This is interesting. I have a bit of a climbing background, so I tend to wonder about things such as load, angles etc - not that I really have any detailed understanding of physics.

Real world implications in my case seem to be zilch
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Did you read the article SlowManiac linked for you? It talks about the same principles and where the friction loss from cross chaining cancels out the advantage. Not much you can do about it with 1x but it might take the focus off your legs during your next big climb!
 
evad said:
Did you read the article SlowManiac linked for you? It talks about the same principles and where the friction loss from cross chaining cancels out the advantage. Not much you can do about it with 1x but it might take the focus off your legs during your next big climb!
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Yeah that was also interesting.
 
pineapplehead said:
This is interesting. I have a bit of a climbing background, so I tend to wonder about things such as load, angles etc - not that I really have any detailed understanding of physics.

Real world implications in my case seem to be zilch
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This might be the basis for those ridiculously expensive ceramic speed jockey wheels? Might even work but nobody will ever know at their pricing. My own irrelevant anecdotal experience with a 2x11 roadie on the trainer is the larger chainring feels smoother/more efficient with the same chainline at a given power level than the smaller one. But that's 52/36 vs 34/32 etc.

Practically speaking I prob wouldn't jump more than 2t on the chainring if you haven't run it before. I went from an 11-46 Shimano to 10-42 SRAM cassette and all was sweet, then went 32-34 recently and what a difference on the climbs, farking hell.
 
Bigger rings give better leaverage. Same as longer crank arms. And less wear.

Ever wondered why bmx racers run light gearing but huge rings?
 
Ultra Lord said:
Bigger rings give better leaverage. Same as longer crank arms. And less wear.

Ever wondered why bmx racers run light gearing but huge rings?
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I don't think that's true?
I think the only advantage of larger gears with the same ratio (say 40/16 instead of 30/12) is that the chain sees less tension, and the chain has to bend less, both reduce friction and wear.
Another small advantage is when fine tuning your single speed gearing, changing the rear sprocket be one tooth has a smaller change in ratio so you get more choice.
Fixie geeks talk about this all the time, also track cyclists.
 
andrew9 said:
I don't think that's true?
I think the only advantage of larger gears with the same ratio (say 40/16 instead of 30/12) is that the chain sees less tension, and the chain has to bend less, both reduce friction and wear.
Another small advantage is when fine tuning your single speed gearing, changing the rear sprocket be one tooth has a smaller change in ratio so you get more choice.
Fixie geeks talk about this all the time, also track cyclists.
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Turn your wheel by grabbing it at a spoke near the hub flange, then again up near the rim. Its grossly exageratted, but the same principle applies for the chain rings.
 
Ultra Lord said:
Turn your wheel by grabbing it at a spoke near the hub flange, then again up near the rim. Its grossly exageratted, but the same principle applies for the chain rings.
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That gives an example of the leverage applied to the chain, hence the reduction in chain tension. The crank length is unchanged so the leverage at the pedal is the same, the rider will not notice any difference.
There is only an arguably insignificant change in friction.

There are advantages like wear and gear selection, but leverage at the pedal isn't one of them
 
Ultra Lord said:
Turn your wheel by grabbing it at a spoke near the hub flange, then again up near the rim. Its grossly exageratted, but the same principle applies for the chain rings.
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No, not at all really. What would have an effect is the effective gear ratio. If you set a bike with 46front:46rear gears, and compare it to a bike set up with 20:20, there is absolutely ZERO difference in effort required, as the ratio for both is 1to1. As Andrew9 says, the smaller gears will have some extra tension, friction and wear due to the chain working around smaller cogs. But that's pretty minimal really.

Your example of the wheel holding point would only apply if you had a single ratio at rear, and changed chainring size (or vice versa). Basically holding it at the flange versus near the rim is the same as changing the gear ratio, and that naturally changes effort required.
 
andrew9 said:
That gives an example of the leverage applied to the chain, hence the reduction in chain tension. The crank length is unchanged so the leverage at the pedal is the same, the rider will not notice any difference.
There is only an arguably insignificant change in friction.

There are advantages like wear and gear selection, but leverage at the pedal isn't one of them
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This is correct.

BMX racers run large chain rings to get sufficient rollout with 20" wheels.
 
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Thought I'd just throw in a comment for pineapplehead. If you do go for an extended range cassette, remember to check that your derailleur can handle it.
 
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