Last week my chainset was replaced (in warranty) and I just found out that the chainset is 10 speed (FSA Vero) but my rear cassette (+Claris gears and shifters) is 8 speed.

I want to know if I will be fine. The bike is Carerra TDF Limited Edition 2012 model.

  • 1
    no you're not. Regarding the width of the chain, 8 speed is different to 9-speed is different to 10-speed is different to 11-speed. People will say you can get away with mismatches, but coming straight out of a shop, you shouldn't have to "get away" with anything. There has to be a question on here that covers this, U'll have a quick look.
    – PeteH
    Aug 31, 2014 at 19:13
  • possible duplicate of What Are the Widths of Shimano 8, 9, and 10 Speed Cassettes?. Not an exact dup, but will give an idea of how the widths vary with number of gears.
    – PeteH
    Aug 31, 2014 at 19:15
  • This is in regards to a crankset, not a cassette, so it isn't a duplicate.
    – Batman
    Sep 1, 2014 at 17:21
  • Sorry for being offline. Some good replies. I am yet to test it after the gears were adjusted (due to work). I think I will just have to visit a different/better halfords store and complain about my experience and ask them to fit me an 8sp chainset.
    – MrVentzi
    Sep 3, 2014 at 22:14

3 Answers 3


In my experience this is a non-issue. The only difference between 8,9,10 speed chains is the exterior width not the interior. That matters a lot on the rear cassette, but not much if at all on the front. From this article the difference in the exterior width of 8spd chain vs 10 spd is 0.9mm. On the front that just doesn't make any signficant difference.

If you had a triple crankset and really short chainstays, you might run into some issues, but with a double and your bike, it should just work.

I'd say take the bike for a test ride and if you're happy with the way the front derailler shifts and it is capable of cross-chaining then I wouldn't worry about it. At this point insisting on an 8spd replacement will only get you a very low quality crankset.

  • As it looks in the article you linked to, the cog/tooth width differ between 8-10 by 0.2mm. Doesn't it mean, that interior of chain is also narrower?
    – Alexander
    Sep 2, 2014 at 0:30
  • No, they are all 3/32 inch width chains. You can run a 10 speed chain on ancient cogs if you want to. Think about how wide 0.2 mm actually is, that's two human hairs. Sep 2, 2014 at 1:28

The distinction of speeds especially in the front is primarily for marketing. You're fine with this '10 speed crankset'.

  • Nope, width at the front is important because an 8 speed front d will shift much further out than a 10 speed front d. Restricting the H screw will help but a struggle to get perfect and keep in trim. They could have also put a new 9 or 10 speed chain on because some 8 speed chains would be too wide on a 10 speed spaced crank.
    – DWGKNZ
    Aug 31, 2014 at 21:32
  • 1
    Look at the numbers, at best the difference between chainrings on 8 and 10 spd is 0.45 mm. That's well beyond the installation tolerance. Sep 2, 2014 at 0:09

Mostly, the different designations are there to encourage whole component group sales. As a general rule (not an absolute one), you can mix and match derailleurs and chainrings with other parts, but only with a one speed difference and with the other parts being the lesser speed.

In other words, 8 speed chain, shifter, and cassette (these three must match except for 6-8 speeds) are ok with 9 speed elsewhere, but not 10.

Realize that there is usually a difference in chain width, so there are potential exceptions to this rule.

  • No. Shifter must match rear derailleur number of cogs. Exception is 6, 7, 8 where the cable moves the same amount. 8, 9, 10, 11 are differ each from other.
    – Alexander
    Sep 2, 2014 at 17:56
  • that's what i meant. edited to reflect as such.
    – wxl
    Sep 2, 2014 at 19:10
  • the derailleurs & chainrings don't need to match the shifter, cassette or chain. is that clear?
    – wxl
    Sep 3, 2014 at 0:33

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