Can I change group set of this bike from Tiagra to Ultegra 8XXX without changing wheel? If yes, does it depend on geometry of rear fork?

I am asking because I would like to know whether it is cheaper to buy a new bike like this and occasionally change group elements (with used) Ultegra and you will get after some months one pro bike :).

Thanks for your time

More about what I want to buy here

 CAAD Optimo, SmartForm C2 Alloy, SAVE

  • 6
    If you're trying to save money, don't bother with Ultegra and just get 105. They're pretty much functionally identical, and a full Ultegra groupset is probably only about 150g/5 oz lighter than a full 105 groupset anyway. And I'd bet the published weight for the groupsets probably uses something like an 11-25 cassette for Ultegra and a larger, heavier 11-32 cassette for 105... Nov 18, 2019 at 17:15
  • 3
    Whats not mentioned in the answers so far is a Tiagra equipped bike has a Tiagra quality everything. You could almost turn it into an Ultegra quality bike by upgrades, but then it becomes a (very expensive ) Ship of Theseus (aka grandfathers axe)
    – mattnz
    Nov 18, 2019 at 19:48
  • 1
    The CAAD Optimo frameset is a lower-spec version of the CAAD 12 frame. Cannondale's site isn't specific on what makes the Optimo cheaper than the CAAD 12. When we're talking about top end framesets vs. the second tier ones, the second tier ones are often very close to the top tier framesets. The gap may be larger at this level, however.
    – Weiwen Ng
    Nov 18, 2019 at 21:42
  • 2
    Upgrading the groupset won't get you a "pro bike". You'll still have a nothing-special frame and nothing-special wheels, and the various other components adding weight. Indeed, if you want to make a noticeable upgrade to your bike, buy new wheels. Nov 19, 2019 at 9:35
  • 2
    @EminHasanov Buying a new groupset won't make much difference except saving weight. Is weight a limiting factor in your cycling? If so, losing a kilo of bodyweight is probably a better move than even a second-hand higher-end groupset. (And, by the way, Shimano's top of the range is Dura Ace, not Ultegra.) Nov 19, 2019 at 10:57

5 Answers 5


You could perhaps consider (if you go for the upgrade instead of the different bike route) to only replace some (the most important) parts with ultegra(or 105 if you want to save some money) and leaving the rest of the drive train parts as is (spec wise) or replacing them with higher spec but lower than ultegra/105.

In my opinion the rear derailleur/shifter are the most important/first parts to upgrade since you shift a lot more with the rear derailleur and adjustment and such needs to be a lot more precise to produce clean shifts than in the front. Shifters will last you a very long time and shifting performance is very much related to proper shifters. Also make sure your shift cables are in good condition to get optimal shifting performance.

Example setup: Rear derailleur: ultegra Front derailleur: 105/tiagra Chain: 105/tiagra Shifters: ultegra

In my opinion this is a good compromise in terms of price/performance. You could change the example by replacing Integra by 105 and 105 by tiagra to get a cheaper but still adequate option. The modern tiagra parts are quite good imo.

Regarding ultegra being 11 speed and 105 being 10 speed: in my experience derailleurs are not speed specific and Shimano derailleurs with different 'rated' speeds can be used interchangably when using the correct shifter (same number of gears) for the casette/freewheel. So you could also consider 105 shifters, ultegra RD and 10 speed chain as an option

In regards to cutting costs: try finding the parts used but new (bought but never used) on eBay or another second hand marketplace. Good deals can occasionally be found :)

  • Thank you for comment! Can I upgrade only Rear derailleur and shifter to Ultegra? I found rear drl only 30 eurs, used one, and cables from new bike I think don't need to change?! Nov 19, 2019 at 8:49
  • 1
    Yes you should be able to but keep the following in mind: if the shimano shifters you will be using are 11 speed and your current casette is 10 speed you will also have to upgrade to an 11 speed casette if you upgrade to the 11 speed ultegra shifters. you could consider older 10speed ultegra shifters or going with 10 speed 105 shifters if you don't want to upgrade your casette to 11 speed. The cables should indeed not need changing. I'm quite sure the 10 speed chain will work on 11 speed casette, have not tested it but i have used 9 speed chains on 10 speed casettes and the likes without issue Nov 19, 2019 at 8:52
  • but it's a safer choice to also go with 11 speed chain when going the 11 speed route for best shifting performance. Nov 19, 2019 at 8:54
  • 1
    The bike is currently equipped with Tiagra, which is one level below 105. It's not possible to buy something that's higher-spec than Tiagra but lower-spec than 105, at least not from Shimano. Nov 19, 2019 at 9:31
  • 1
    @Maarten I'm quite sure the 10 speed chain will work on 11 speed casette, have not tested it but i have used 9 speed chains on 10 speed casettes and the likes without issue And my experience is exactly the opposite - an internet vendor ( cough Ribble cough) once slipped a 9-speed chain into an order of mine in place of one of the 10-speed chains I ordered. The 9-speed chain would not shift properly on a 10-speed bike. To this day it sits in my garage in a ziplock back with a big "9 SPEED" label on it. Nov 19, 2019 at 13:29

You can do it, but it will be much more expensive to buy the Tiagra-equipped bike and then buy Ultegra parts piece-by-piece. Bike manufacturers get the parts much more cheaply than you can, and that price difference is reflected in the price of the bike.

Also, consider this: Ultegra is an 11-speed group. Tiagra is 10-speed. This means that you will need to upgrade the cassette, rear derailleur, and shifters all at once anyhow.

  • rear wheel/disc also should be changed? Nov 18, 2019 at 14:32
  • 11-speed cassettes do not fit on 10-speed freehubs. I think you could just replace the freehub body (the part that carries the cassette) rather than replacing the entire hub.
    – Adam Rice
    Nov 18, 2019 at 20:40
  • 3
    @EminHasanov actually, I suspect the freehub on this bike is capable of taking 11s cassettes. 11s freehubs take a spacer to fit a 10s cassette. So, you might not need to change the freehub. This does not make piecemeal upgrades a good idea, however. Also consider that it takes time (and money, if you're paying a store) to replace each component.
    – Weiwen Ng
    Nov 18, 2019 at 21:45
  • Honestly, I don't think so it will be expensive, because, I will upgrade by myself, and secondly, I will by only used groupset components, for example Ultegra derailleur ebay.de/itm/… here costs 30 euro, it is not so much but difference CAAD ultegra and Tiagra is more than 700euros Yes I know I have to change every element from groupset, but I can collect it time by time, isnt it? Nov 19, 2019 at 8:44
  • 1
    It sounds like you already have the answer you want.
    – Adam Rice
    Nov 19, 2019 at 15:29

There is nothing about the wheel or frame that is incompatible with Ultegra R8000. You might need an adapter for the bottom bracket but that's about it.

However, as others have said, groupsets are much cheaper when they come on a bike than bought separately, so you will not be saving money by upgrading incrementally. Additionally you will still have 'Tiagra level' alloy frame, wheels and everything else, which will negate having a better groupset to a large degree.

  • I’d also like to point out that Tiagra already has solid quality and should shift and brake quite nicely, especially with new and properly installed cables. I’d at least keep the Tiagra components until it’s time to replace the cassette (i.e. ~3 chains, ~10Mm) and cables.
    – Michael
    Nov 19, 2019 at 11:41

The only way to make this viable (economically speaking) is to find the parts you're looking for on discount during things like Black Friday. It's not impossible as I have done so myself, however you'll still have to install everything by yourself or the savings will vanish when paying the shop to do it for you.

  • Used groupset elements are really cheap As I understood from above comments, I have to change rear and front (not urgent) derailleur + shifters + bottom bracket Nov 19, 2019 at 9:16
  • upgrade brakes and crack himself, I don't need Nov 19, 2019 at 9:17

Another point that could trip you up, is that tiagra 10 speed is unique and weird in its cable pull.

This means Tiagra 4300 is not compatible with any other 10 speed groupset parts. So its an all-or-nothing change for you, have to do the right brifter and rear derailleur together.

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