I have just bought a cheap cycle for regular use (Kross Bolt 26"), but it comes in single speed. Can I put a 1×6/7 gear set in it?....the same model (28") comes with 21 speed gear set-up. How much will a cheap gear set cost?

  • 3
    It's cheaper to buy another bike (preferably used). Commented Aug 11, 2017 at 16:36
  • 6 speed parts are garbage. I don't think you can even buy a 6 speed derailleur. To get one, you'd have to pull it off a made-in-China "department store bike". 6 speed cassette clusters are thread-on freewheels, not cassettes. They require a wheel hub with a 1.75" thread which takes that freewheel. That's, again, only seen on below-entry-level junk bicycles.
    – Kaz
    Commented Aug 12, 2017 at 15:14

3 Answers 3


Technically yes, economically no.

You obviously need to obtain a multi sprocket cassette, rear derailleur, shifter, and cable and housing. Additionally you need:

  • Singlespeed frames have dropouts designed to provide a mechanism for adjusting chain tension by moving the rear hub, so you would need dropout adapters to fit a rear derailleur.

  • Single speed frames lack shifter cable bosses, so you have to get bolt on ones.

Those might be difficult to obtain. The real problem is that many other major components would need to be replaced:

  • You would need a new rear wheel with a hub designed for a multi sprocket cassette.

  • Derailleur chains are narrower than single speed chains, so you would also need a new chain

  • Because you have a narrower chain you need to replace the chainrings, which as this price point are integral with the cranks and cannot be swapped out, so you need a new crank.

Basically, you have to replace too many of the bike's original major components to make it worthwhile.

  • 1
    You can avoid adding bosses by running a full length outer and zip ties
    – mattnz
    Commented Aug 12, 2017 at 0:22
  • Thanks a lot....U explained it really well, guess I have to stick to my single speed bike until I start earning money myself and buy what I want. :)
    – ApUrB oo7
    Commented Aug 12, 2017 at 9:30
  • The main reason you need a new chain is that it's too short. If you go for 6 speed junk parts (though highly inadvisable), the chain width is fine; but the chain has been shortened for the existing ring and sprocket with no slack for larger cogs.
    – Kaz
    Commented Aug 12, 2017 at 15:18

You could install a hub with internal gears. You would avoid the derailleur/chain tension issues this way. Your bike would still lack bosses for the shifter cable, but you could use zip-ties or cables clamps here for support instead.

I can think of three issues you might have however. First is price; internal hubs are not cheap. Is your current bike worth throwing money at? Second is dropout spacing. You would need to measure the rear dropouts and find a hub that fits. Third is chain line. With your existing cranks and a geared hub, would the chain line be acceptable, or would the bottom bracket need to be changed up front?

Good luck!

  • 1
    Three-speed hubs are quite cheap.
    – ojs
    Commented Aug 31, 2017 at 6:53
  • 1
    I converted a single-speed bike to a three-speed, by purchasing a used set of wheels which included a Nexus-3 internally geared hub. I ziptied the cable and housing along my bike frame, and this worked just fine. I was lucky, though, that the length of cable was right for my bike.
    – Bicifriend
    Commented Oct 30, 2021 at 18:17

Add chainring and chain tensioner. Done for under $40! A front derailleur, cable, and shift lever are all optional; you can stop and shift the chain manually.

  • 2
    Welcome to the site - OP doesn't say but there's a chance their bike is fixed gear or a coaster brake, so it might help to say that a chain tensioner prevents the use of rear wheel braking and they need to have working brakes on a bike.
    – Criggie
    Commented Oct 30, 2021 at 7:47

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