Alert I am unsure of the right terminology for gear-wheel but I mean the round things near pedals such as 3x9 or typically with 3x7 (3 front, 7 back) mix in commuting bikes.

My current gears are 3x9 (3 front, 9 back) but I plan to change to cheaper, the current gear-wheels are used (about 15k km, 4winters and 3 summer).

  1. Can I put other gears such as 1x7 or somehow reuse the old gears?
  2. What should I take into account when choosing other gear-wheels and gears?

There is nothing problem with my current ones, they work fine (a bit slower than as new but not a problem) but I cannot spend too much on upgrading the gears/gear-wheels. I need to know what to look for in second-hand stores or to find some sort of compromise i.e. perhaps to upgrade things slowly part-by-part.

  • When you say "3x7" you mean 3 round things up front and 7 in the back?
    – freiheit
    Commented Feb 6, 2011 at 1:47
  • freiheit: yes, I mean it.
    – user652
    Commented Feb 6, 2011 at 2:59
  • Was thinking of doing this - 9 speed chains are 3x the price of 7speed and don't last very long.
    – mgb
    Commented Feb 7, 2011 at 17:51

2 Answers 2


I think you'll find that the cost of switching to a different gear type will be more expensive in the long run. As technology progresses, the 7 speed stuff will get harder and harder to find, and more expensive. I've messed around with this sort of thing, but going the other direction: there are a lot of items you'll need to switch. A short (probably incomplete list):

  • cassette (obviously)
  • shifters (obviously)
  • brake levers (if they're attached to the shifters, as many are)
  • The freewheel in the rear, to be compatible with the different kind of cassette
    • May include a new rear hub
    • May include a new back wheel
    • May instead include rebuilding the back wheel yourself
  • Your crankset in the front, if gear ratios are wrong for your new cassette

It ends up being a pretty big change. That said, you can get 9 speed cassettes pretty inexpensively. If you're worried about cost, you can get a new cassette for about $20. You can get a new 9 speed chain for $15 - $20. If you keep your chain clean, dry it whenever you get it wet, and keep it well lubed, you should be able to get at least 2000 miles out of it. If you replace your chains when they start to wear out, you should be able to make a cassette last through at least 3 chains. That's 6000 miles for about $65; not bad. Considering how much money and time you'd spend on new shifters, hubs, freewheels, and all the rest, I don't think it's ever really worth downgrading equipment.

  • excellent experienced answer, really appreciate it, thank you. Your point about technology is without premises but I think you are on the right track (just a guess). I have investigated the issue I have found out that maintaining 9-speed chain-system does not need to be expensive. LBSs tried to frighten me with 110-250EUR and one even with 350EUR for repair but notice the asymmetry: they would profit from selling me a new bike, I won't. I have found out that I can get SRAM PC 951 for 18EUR (ebay.de) and cassette/small-wheels roughly to your estimates (no idea which yet). Not bad.
    – user652
    Commented Feb 12, 2011 at 0:16
  • Thanks! I'm not sure what you mean by "without premise", could you elaborate? BTW, all the prices I quoted were from the USA-facing version of amazon.com. I have no idea if they'll sell the same stuff to you in europe, but I imagine you've got pretty similar options.
    – Benson
    Commented Feb 12, 2011 at 7:14
  • yeah spot on, I did not read carefully. I think your point about technology is based on experience that is your premise. By without premises -term, that is now wrong, I tried to the attack your observation. Is it possible that the technology does not advance and we are stuck with more expensive 9-speed chains in the future? Haven't followed the history of the market that long so no idea what even the term technology means here. But to unknown souls, I do recommend to not mess up with your system, read the reply. K.I.S.S.
    – user652
    Commented Feb 12, 2011 at 18:54
  • I'm sorry I didn't quote my source on that -- I actually took a poll of experienced bike mechanics a couple of years ago, trying to learn more about the progression of technology. One was the head mechanic in a Seattle bike shop for several years, another is the head mechanic and manager of another bike shop, and the third is just a guy who goes through a lot of bike parts. They all said the same thing about "new" tech becoming the new standard, and old stuff getting hard to find. It's a trend that's continued for years.
    – Benson
    Commented Feb 12, 2011 at 20:34

When looking at components they do have to match. If you are moving to a 7-speed in the rear, you will need to get a 7-speed shifter to match. As long as you stick with the same brand shifter (Shimano or SRAM for instance) you can use the same rear deraileur (the thing that moves the chain.

In the front, for the most part they are all compatible.

Depending on how much you are willing to give up, you can change your bike over to a single speed setup, and not have to worry about shifters at all.

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