I'm very new to the world of bicycles, so apologies in advance. I have a second hand road bike built (by a professional) with spare parts of different components. The rear derailleur is Shimano Acera, the front derailleur is Shimano Tiagra. I have Shimano Tourney/TY SL-TX50 Thumb Shifter Plus - Silver, 7 Speed (or something like that). It also has caliper brakes of unknown brand/model. I am looking into slowly upgrading the components and was looking into upgrading the brakes and I am keen into changing the shifter and brakes for brake lever/shifters where it is all together. However, I am not sure which brakes or which brake lever/shifter I should choose to work on my bike. Should I change either the back derailleur (or front one) first or can I first change the caliper brakes for better ones as well as changing the brake level/shifters and at a later point change either the front or back derailleur? Could anyone suggest anything?

Thank you!

  • 1
    I suggest buying a better bike with components that you want, and sell this one to someone who can use it as-is. Replacing all these parts one at a time will take a lot of effort and money. You should also mention what model the bike is. Jul 19, 2020 at 1:37
  • Without tying to sound rude, do please note that Tourney is the second-bottom in the range of quality in Shimano's line up. The only thing below is non-groupset parts which aren't really intended to go far. Tiagra is a road groupset, and Acera is a MTB groupset, so its already a "bitser" bike. Instead of thinking "upgrades" simply wear it out by riding, and then look at your options for the parts that are worn.
    – Criggie
    Jul 19, 2020 at 3:20
  • Thanks for the comments. The component tourney right now is just the shifters on the handlebar (which is the part that I'm looking into changing since the front derailleur is Tiagra). The bike itself is an unbranded aluminium frame so has no model number or anything. I want to use the bike as a project to build it and change stuff myself (I know it will be expensive and time consuming). I just don't know what parts to change first. Thank you!
    – MRG
    Jul 19, 2020 at 14:47
  • I'm not sure why you want to change/"upgrade" components. For us that makes it hard to give suggestions. Your goal will drive your choices. For example, is there a performance issue like braking or shifting? Do you want a wider range of gear ratios? Many can be addressed with component changes, but things like frame geometry and wheel size-related issues pretty much require a different bike. Try riding your bike for 1000 miles and pay attention to what you like about it and what you don't. Try riding some other bikes as well during that time, for an even better perspective.
    – Armand
    Jul 19, 2020 at 19:01
  • I would suggest you look for a donor bike, and see what you can salvage off it. There's no point buying new parts for this bike. Or explore your area, look for a Bike Cooperative.
    – Criggie
    Jul 19, 2020 at 19:51

1 Answer 1


Shimano Tourney TY SL-TX50 shifters are 7 speed, so you must have a 7 speed cassette (or more likely freewheel) on the rear wheel. An Acera derailleur is from a 9 speed groupset (or possibly its an older 89 speed one.) The Tiagra front derailleur is from a road groupset and depending on age could be 3x10, 3x9 or 3x8.

You really cannot make any effective upgrades to a 7 speed drivetrain. You could replace either derailleur with better ones but it would make no difference. The 7 rear speeds and the Tourney shifters are the weak links.

You could consider upgrading to a 3x8 drivetrain, but you start to run into issues. If your rear wheel hub is a freewheel type you can't realistically upgrade to 8 speeds. If you have a freehub type hub with a cassette chances are it's a 7 speed cassette compatible that will not take an 8 speed cassette. In both cases you need a new rear wheel to accomodate a larger cassette. Additionally, to go to a 3x8 drivetrain you quite possibly need a new crank.

So you are looking at replacing about half entire the bike. At this point it's almost always better to look at buying a better bike with the upgrades you want.

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