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Changing from a Standard to Compact Chainset

by Jon L
Mon, Jul 13, 2015 17:38
6

I have just been offered a cracking deal on a new bike fitted with Dura Ace 9000 with standard 53/39t chainring and 11/25 cassette.

Currently I ride on a compact Ultegra 50/34, 11/28 and so I'm concerned that this may be too much of a step up and I'll look like a complete numpty having to bail out on hills that I currently manage without too much of a problem.

If I get the standard set-up and decide that I'm not man-enough, am I right in thinking I can change to a compact chainring and 11/28 cassette? This is going to cost circa £250 and the saving I'm making is significantly more than that on the new bike, but just wanted to make sure that I wasn't missing something.

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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6 comments

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VeloPeo | 9 years ago
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There's not a massive difference between a standard with 11-28 and a compact with 12-27. Rather than change the chainset, try changing the cassette first - much cheaper. Could even go to a 11-32. Planning on going standard and 11-32 on my next bike - wider gaps between gears but very versatile

Have a play with this:
http://gear-calculator.com/?GR=DERS&KB=34,50&RZ=12,13,14,15,16,17,19,21,...

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sergius | 9 years ago
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I wimped out on my new bike, I originally ordered a standard chainset with a 11-32 cassette. I then spent moths worrying about it (long lead time on the order with Rose) before deciding that I spend more time climbing than spinning it out on the flat - and switching to a compact with an 11-32.

I've not particularly noticed the larger jumps between gears (going from a 12-28 on my other bike to a 11-32). I have found the lower gearing has improved my times on some hills which I can now spin up rather than having to get out of the saddle.

If you aren't a pro and don't always ride in a group, I'd stick to the compact. You could consider getting an ultegra chainset as well; cheaper, stiffer and only a little heavier.

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Martyn_K | 9 years ago
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Buy a new crankset in the size that you want before delivery. Then remove the original one before using it and sell it. You will probably make a small loss but i'm sure the 53/39 will sell.

Oh, if the LBS are not playing ball then buy your crankset online. Their loss.

Other more tech savvy chaps will be able to confirm if you will need to change the chain length too with a 53/39-11/25 switch to 50/34-11/28.

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Cardboard Box | 9 years ago
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As a numpty myself I was faced with a similar challenge on a second-hand bike that came with an Ultegra 53-39t chainring. I fitted a 12/32 rear cassette which gave comparable gearing to my usual compact set + 11/28 which a) was a significantly cheaper option at circa £25 and b) fortunately didn't require any other modifications to the running gear.

Maybe that could be an option worth investigating?

Edited: Ignore my crap advice, the biggest cog the rear derailleur can handle on Dura Ace is 28

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Simon E | 9 years ago
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If it's a shop they could probably sort a chainset swap without it costing you (much) money.

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Jon L replied to Simon E | 9 years ago
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Yes it's a shop, but they seemed reluctant to offer any assistance, which is probably a sign that I need to look elsewhere.

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