At the moment, on my road bike, I have Shimano Tiagra groupset. I would like to upgrade it to Sram Red, but I cannot afford to pay for the whole groupset at one time and would like to buy them in steps. I am wondering if this would be possible to do. If yes which components would I need to buy first?

Thank you.

  • 3
    This is a very expensive way to do this. A much better way to do this is to save up and buy a whole new bike.
    – alex
    Aug 12, 2014 at 14:08
  • Speaking for the gears only, the key thing is the chain width, which is driven by the number of cogs on the cassette. If the number of cogs on the new cassette equals the number of cogs on the old cassette (i.e. you don't need a wider/narrower chain), then a step-by-step upgrade is likely possible. Otherwise you will end up with a less-than-optimal arrangement - shifting may be possible but won't be as precise as it should be.
    – PeteH
    Aug 12, 2014 at 18:55
  • Shimano and SRAM cassettes with the same number of cogs may be interchanged and fit on the same freewheel.
    – Carel
    Aug 12, 2014 at 19:22

3 Answers 3


If you want to upgrade gradually you need to follow the compatibility of the groupsets.

If your Tiagra groupset is the 4600 series of 2012, the 10 speed components should be compatible with other Shimano 10 speed road components, so you can use Dura Ace 7800 and 7900, Ultegra 6600 and 6700, and "105" 5600 and 5700.

The amount of cable pull per gear is different between Shimano 10sp road and Shimano 10sp mtb. SRAM 10sp doesn't use the same cable pull as Shimano 10sp road or mtb.

  • Good answer. Also to note that the earlier Tiagra version was 9-speed, which would introduce further issues going to Sram Red. That upgrade would be difficult to do piecemeal.
    – PeteH
    Aug 12, 2014 at 18:58

I did something similar last year but waited until I had all the components before assembly. If you are patient and you buy only when you think the price is the best you've seen there are deals out there. It was time consuming (18 months) but the savings can be worth it. I got an Ultegra groupset for about $600 one component at a time. With the release of the 11 speed groups you may be able to pick up some lightly used 10 speed parts at reasonable prices. Also evaluate if Sram Red is what you need. The top shelf parts come at a big price. There can easily be a 30 to 40 percent price difference between the "Red" and the "Force" lines of components. The high end cost can make them lighter but not necessarily more durable. (See Bontragers Law /strong,light,cheap pick any two). Some people claim the top line stuff also needs more frequent adjustment to maintain the quality shifts they are famous for.

  • Yes, waiting a while can get you a good price. Though don't wait too long, otherwise parts may be discontinued, and become harder to find and more expensive.
    – vclaw
    Aug 13, 2014 at 11:59

If you're moving between Shimano and SRAM, the shifters and derailleurs all need to be purchased at the same time. The cassette and chain can stay provided they're the right number of speeds, but I do have a strong preference for SRAM chains whenever possible.

That being said, if your bike is equipped with Tiagra, a better option would likely be sell it and buy something which shipped with Red anyway (or possibly buy a cheap donor bike from Nashbar/BikesDirect or similar with the Red components and strip it out, since the parts are individually quite expensive).

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