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I have a 2007 Specialized Tarmac Pro Double and I need some better gearing. I am doing more hill climbs and I feel that I need at least two lower gears than I already have. What would be the most efficient way to upgrade my bike. Would it be easy to get a triple chainring? Will I have to get a new derailleur? What else would I need to change?

  • 1
    Having looked at the bike, but knowing nothing about you, you get two hill gears by losing weight and pedaling harder :-) – andy256 Jun 3 '15 at 5:14
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    @andy256 That is harsh. Many strong riders have gone compact. – paparazzo Jun 3 '15 at 5:47
  • @Blam yes, both are true :-) – andy256 Jun 3 '15 at 8:45
  • @andy256 I wouldn't mind losing some weight, but I cannot handle 11%+ grade hills with the current setup. – Zlatty Jun 17 '15 at 23:14
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    Yes, I was being flippant, and do endorse the answer by @Kibbee. – andy256 Jun 17 '15 at 23:38
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You have a couple different options. I think the cheapest would be to switch to a compact crankset which would change the front chainrings from 52-39 to 50-34. I'm pretty sure you could do this while still using the same shifter. Changing the front shifter is required if you want to go from a double to a triple, as is changing the front derailleur. If you switch to a compact I'm pretty sure you can keep the same derailleur and shifter.

Another thing you'll want to look out for is the rear derailleur. You currently have a short cage derailleur, and you may need a medium or long cage derailleur when you go with a compact crankset.

I don't think a triple should really be necessary on a 10 speed system. I have triple, but I have an 8 speed cassette. I find in that case the triple is nice because you can still get lots of gear range while still keeping the gears close together, However, on a 10 or 11 speed cassette, this isn't really necessary. I think that switch to a compact crankset is a much better option.

Also, according to This post, the maximum cog size of a short cage Shimano short cage is 27 and the total drivetrain capacity is 29. To use a larger cassette, you would have to switch out the rear derailleur. If you used a compact crankset, you should be probably also replace your rear derailler for a medium cage, as your total capacity would be (50-34) + (27-12) = 31. However, if you changed the cassette to a 12-25, you could get away with not replacing the rear derailleur and still getting a little bit lower gearing, although possibly not enough for your needs.

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    good suggestion going to a compact crank. having helped a friend make that shift, the front der will still work, just need to lower it a smidge – Paul H Jun 2 '15 at 19:30
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    Also worth noting that a short cage rear mech wouldn't accommodate a triple chainset, so that would have to be changed as well. – Will Vousden Jun 3 '15 at 9:04
  • Thans on the thorough response. It seems that my best option would be to swap the rear cassette but to get any gains from it, getting a medium arm derailleur would make the most sense? – Zlatty Jun 17 '15 at 23:13
  • Why don't you change just the chainrings on the crank? It's really cheap, you shouldn't have to change anything else and you can go as small as you want. For example: jensonusa.com/Chainrings/SRAM-ForceRivalApex-10-Speed-Chainring. Just be careful to get something whose inner diameter matches your crankset, but your shop or online support can help you. – super Jun 17 '15 at 23:52
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You'll need to swap out your left (front) shifter and front derailleur to utilize all three chainrings of a triple.

Between the cost of that and the cranks, I think a better option would be to swap out your rear cassette for something with more range. Since you've already got a 12-27 on there, a 12-32 would give you I believe the range you need.

My hunch is that you'd be able to fudge it with your current short cage rear derailleur, but a medium cage mechanism will probably be less hassle in the long run.

Since cassettes are consumables and need to be replaced periodically, this cost of the just rear mechanism is likely significantly less than the shifter, front mechanism, and the crankset.

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    He would also need a longer cage rear mech to reliably accommodate a triple chainset. – Will Vousden Jun 3 '15 at 9:03
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When you say two lower gears, you presumably have 25 and 27 as the largest gears in your cassette. Does that mean 39/31 would be low enough? If so, the compact with a 34 will get you there, but 34/25 will be too high. Shimano makes a 12/30 10speed cassette in the CS4600 line, which I have coupled to a 50/34 compact. You will be in for a new rear derailleur that way. They also make a 11/32 11speed, but that needs new shifter as well. This might avoid the crankset change, however.

  • I see how going from a 52x39T to a 50x34 would also work. However it seems to be quite expensive. In any case, what brand, model do you recommend? – Zlatty Jun 17 '15 at 23:19
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    I don't have a brand recommendation. I was focused on what gear ratio you can achieve. A triple can give you very low gears, but forces changing a lot of equipment. You need to define how low a gear you feel you need, then you can explore your options. The compact has a two more tooth difference than your current chainring set, so you have to look at the capacity of your rear derailleur. – Ross Millikan Jun 17 '15 at 23:24
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I wouldn't get a triple crankset, there's a reason why those are dying off of the market. Consider instead changing your cassette and maybe your rings, if you're climbing a lot of steep hills and want a lower gear ratio, then what I would suggest trying first is swapping out your cassette with a mountain bike cassette, this may require you to also change your rear derailleur to a long arm derailleur, and you'll need a new chain, but you should change that whenever you change your cassette anyways. If you need a little bit more, then try swapping your small ring with something smaller. You'll save money this way too, because you won't have to change out your crank or your shifter.

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    "I wouldn't get a triple chain ring, there's a reason why those are dying off of the market." And that reason would be...? – David Richerby Jun 2 '15 at 22:42
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    @DavidRicherby 10 and 11 speed cassettes. Even when 3x9 speed bikes came out, out of 27 gears, there were only 14 usable gear ratios. They're heavier, redundant, and a pain to maintain and tune compared to doubles. 1x11 is far superior in my opinion. You only sacrifice 3 gear ratios, but you shed the weight of your front shifter and derailleur, and all but one chain ring. – ShemSeger Jun 2 '15 at 23:48
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    Even MTB is dropping the triple, and many going to 1x11. – mattnz Jun 3 '15 at 3:38
  • Its the final gear ratio that matters; how you get it is immaterial. Example - a triple at 26/26 gear ratio would require a 34/34 to achieve on a compact, or a 39/39 on a standard road double. If you need lower gearing, you need a bigger cassette or a smaller granny. – Criggie Aug 26 '16 at 22:21
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When I made this change 15 years ago, as well as the new triple chain rings I needed to change the bottom bracket - cotterless square taper type - (which needed to be longer to correct the chain line), front derallieur (needs to be able to cope with extra travel and larger difference in chainring sizes) and rear derallieur (needs to be able to cope with larger total difference in teeth).

You will also need to change your shifter to use the new range on the front.

  • +1 for answer the question asked, rather than diverging off into related but tangential answers like everyone else. – Criggie Aug 26 '16 at 22:22
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While there are many good answers from the community, it all depends on the rider. As being the rider for this scenario, the correct answer is to tough it out and just build up muscle to go up hill. Since posting this question more than a month ago I was able to train enough to be comfortable going steeper hills in higher gears thereby not needing a change in my components. Thanks everyone for your help, a vote up for everyone!

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