Front chainring climbing

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Front chainring climbing

Postby gururug » Mon Mar 05, 2007 4:15 pm

It seems like its "easier" for mew to power climb on the front large chainring. This is for smaller hills. The small chainring doesn't seem to give me enough leverage to pull the torque on the upswing (if you catch my drift).

Does anyone else do this on small (-.5km) hills. Is there a chance of doing some damage like this?


I shift to the large chainring, then let the calves / up swing drive (pull) me up the hill (out of the saddle), I don't really have much choice anyway as the small chainring and the lightest gear become too heavy when I try to spin :cry: I guess I should add i'm pretty light (65kgs), this may be a factor!
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by BNA » Mon Mar 05, 2007 4:27 pm

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Postby mikesbytes » Mon Mar 05, 2007 4:27 pm

For a small hill, I usually either stand up and power over in what ever gear I'm in or drop just one gear on the rear deralier and spin a little. All depends on the hill of course.

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Postby sogood » Mon Mar 05, 2007 6:20 pm

From a strict mechanical point of view, this practice does not make sense. For the same gearing, the lost mechanical advantage using a smaller chainring is fully balanced by the use of a smaller cog at the rear.

Above is the theory but I have read people stating that larger chainrings are smoother, whatever that means.

But realistically, you are more likely to run out of cogs on a tough climb. And you'll be straining your joints and muscles with each decrease in cadence.
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Postby gsdkain » Mon Mar 05, 2007 7:43 pm

hi I really have no idea but i find when climbing a short climb particularly one that is steep I too find it easier initially to use a larger gear to get to the top but I know there is no way I could maintain that for long on climbs over 500m(length).

If I use a smaller gear but still big enough to need to stand up I find that I just dont have the core strength (and probably cardio) to maintain a good consistent rythm, so I find it easier(perceived) to use a bigger gear that is more resistent to my weight, I just keep going up gears until it feels as though my pedalling becomes "smoother" when in reality I'm really gassing rapidly and there is no way I could keep up that sort of power for long.
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Postby europa » Mon Mar 05, 2007 8:28 pm

Might be related to my experience the first time I stood on the pedals on the Black Beast. I was in the bottom granny gear at the time and mate, that gear is so low that rather than pedalling while standing, I just fell :shock: I have to go up at least two gears to be able to stand which, quite frankly, makes the whole exercise a complete waste of time. Changing onto the middle chainring would probably be a smart move for me ... so I'll try to remember to try it next time I'm on a big hill (funny how you get these revelations at odd times :wink:

Standing on the pedals isn't as instinctive as we'd like to think. It's a learned technique and until you start to get a good rhythm, with the bike moving from side to side underneath you, is a waste of effort. It's worth learning though, especially if you don't have a granny ... or if you ride a fixie :roll:

Personally, for a very short climb (and methinks you don't really realise how long half a km actually is), I'll often just stand and power up it. It's easier and gives you a break from sitting. Longer climbs though, I spin, but I've got the advantage of a granny gear.

Be also aware that there is a lot of overlap in gearing between the chainrings and this may be why it seems to make sense going onto the big ring - you may have only changed two or three gears. I'd recommend feeding the numbers in Sheldon Brown's gear calculator and seeing how your own bike's gears do overlap. Sometimes this is just meaningless, at others, it can explain some otherwise weird effects.

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Postby 531db » Mon Mar 05, 2007 8:45 pm

gurufug wrote:

"It seems like its "easier" for mew to power climb on the front large chainring. This is for smaller hills. The small chainring doesn't seem to give me enough leverage to pull the torque on the upswing (if you catch my drift)."

Trying riding hilly Time Trial races on a fixed or single gear. You'll soon find out about 'power climbing' and 'power spinning. :shock:

But seriously, too big a gear can do nasty things to your knees later on.
Use the appropriate gear ratio for the climb. Racing on the Repco SL, people have commented on my 'big ring' climbing but I was in 50x19 or 50x21, which are about the same as the 42x16 and 42x18 that they might be using.
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Postby sogood » Mon Mar 05, 2007 9:08 pm

Are you guys comparing apples to apples?

For the same gearing/gear ratio or whatever you care to call it, how can it be different? Or the whole field of Newtonian mechanics will have to be re-theorized. :shock:
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Postby gururug » Mon Mar 05, 2007 9:37 pm

I'll go to sheldon brown.

Big chainring + three or four cogs from left and lots of upward pull

vs

Small chainring + large rear cog (struggle to maintain any cadence up a small hill)

Go figure, doesn't feel like it hurting my knees as I change my pedaling style to focus on pull up and push with calves

Font chainrings are: 36-50T
Rear cogs are: 11-25T

I think physique has more to do with this than physics. I am a stocky person, thus find it easier to lay down torque and lift up hills.

Larger chainring at front give more less revs thus better torque transfer from stand (thats my theory anyway)
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Postby sogood » Mon Mar 05, 2007 9:52 pm

gururug wrote:Big chainring + three or four cogs from left and lots of upward pull

vs

Small chainring + large rear cog (struggle to maintain any cadence up a small hill)

Wait on, the above two scenarios does not give you the same gear ratio.

To really talk about large vs small chainring effect, surely you need to at least make sure they are both set at the same gear ratio eg. 53-23 (60.6 gear inches) vs 39-17 (60.3 gear inches). Or it's not a comparison... Gosh!
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Postby europa » Mon Mar 05, 2007 10:26 pm

I can buy the argument about being able to put down more torque on a larger ring (the force is applied further from the spindle), but in reality, it's not going to make a lot of difference ... well, I can't see that it is. I have noticed variations in how the same gear ratios 'feel' but can't say I'd get excited about it, especially as that is only doing the big jump between the middle and the tiny chainring - it's not noticeable going from middle to large (yes, lots of overlap in my set up).

You need to sit down with Sheldon's gear calculator and see how your gears overlap. Really. That means counting the teeth on every cog (unless you can find where they're stamped) because not all cassettes have the same spread or distribution of gears. As sogood is trying to point out, you can not compare efforts until you are comparing the same gear ratios and I for one would not be surprised to learn that you're not fully appreciating the overlap in the gearing between the large chainring and the small. A gear calculator is the only way to figure that out.

But one thing you can be sure of - high force on the pedals is not good for your knees. High enough force for a long time, will damage your knees and if kept at it long enough, the damage is irreversible. That isn't to say 'change what works best for you', it's trying to explain why low gearing and spinning is so popular.

It's up to you to work out what's best for you on THAT bike, and it won't be the same as me because I'm a lot heavier, have thigh muscles like tree stumps and ride a bike with a huge range of gears (just across the cassette, let alone with the chainrings as well), and it won't be the same as sogood because although he's closer to your size and rides a racer, he may have a very different set of gears and his skills are quite different to yours (he's mastered this standing and climbing routine).

Gawd it's late, and this post is getting a tad heavy. But I'm not going to delete it. Run the gears through the calculator mate, it'll be interesting, even if it doesn't prove to be helpful.

Now, I have to go and retape my bars ... and it's 11 o'clock :(

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Postby sogood » Tue Mar 06, 2007 5:26 am

europa wrote:That isn't to say 'change what works best for you', it's trying to explain why low gearing and spinning is so popular.

The other commonly quoted reason for spinning up a climb is that it's easier to accelerate at a higher cadence. That's a technique Lance A used quite effectively in many of his attacks on the mountains, so I read.
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Postby gsdkain » Wed Mar 07, 2007 7:57 pm

sogood wrote:
europa wrote:That isn't to say 'change what works best for you', it's trying to explain why low gearing and spinning is so popular.

The other commonly quoted reason for spinning up a climb is that it's easier to accelerate at a higher cadence. That's a technique Lance A used quite effectively in many of his attacks on the mountains, so I read.


So true, I agree its Armstrong who revolutionised the sport in regard to high cadence climbing, however if he didnt return to cycling after cancer we'd probably be talking about how bigger gear lower cadence climbing is more affective.
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