Alg

This one's for the Engineers amongst you.
I was cycling up a hill the other day. Big ring on the front and small on the back and pedalling hard.
I realise that by going down to the middle ring on the front chainset it makes things easier but does it wear all the chainset parts slower or quicker or the same?

Is the force exerted into the bottom bracket bearings and around the gear and on the bearing surfaces of the chain, greater if chugging up hill in a high gear or in a lower gear?
I know it feels easier but it has the same (not inconsiderate) weight to move up the hill.
Would I cut down on wear (£££) by using a smaller gear? Does the amount of times the peddles rotate come into it?
Anyone? (Yes it's a boring question)

AndyC_772

iTrader: (2)

If you're travelling at the same speed in either case, and all you do is change to a smaller sprocket at the front, then the forces on the back wheel remain the same - so no change in wear rate.

What you're doing by changing to a smaller chainring is using more lever action to pull on the chain. Work = force x distance, so for a given amount of work (ie. travelling at a given speed), you can either:

- move a greater force through a smaller distance (ie. large chainring, pedal slowly, feels like hard work), or
- move a smaller force through a larger distance (ie. smaller chainring, pedal faster but with less force).

Therefore, I don't think it makes any difference which gear you're in as to how fast the mechanism wears - or at least, the bits of the mechanism you're actually using. If you want to be sure of everything reaching the end of its useful life at the same time, ride in different gears to spread the load.

nixxon

Can't be much of a hill if you can cycle up it in the big ring! But yes, you will be placing extra loads on the cranks, BB, handlebars , frame and chain (not to mention your legs) if you carry on honking up hills like this. Try to keep to a cadence of 90 leg rotations per minute, or theabouts, to keep everything working sweetly. Carry on as you are, and you'll bust it sharpish.

Dark

iTrader: (1)

You're also putting a HUGE strain on your knees and these will likely knacker far quicker than the groupset on your bike!

AndyC_772

iTrader: (2)

Cost more to replace too...

ChrisB

You should avoid big/big and small/small chain combinations as the chain line is at it's extremes. These gear ratios are usually found elsewhere on a 3x9 setup.

Matteeboy

Spinning lower gears is more efficient - you need a highish "cadence" and need to "spin" rather than "push" the pedals.

I try and use my middle ring as often as I can - it's hardened steel, the rest are aluminium. Titanium next I reckon.