Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I was hoping that someone could provide me with the precise Shimano road-bike 8, 9, and 10 speed sizes for the following:

  1. Cassette Spacer Width
  2. Cog/Tooth Width
  3. Maximum Chain Width
share|improve this question
up vote 11 down vote accepted

I think these may be what you're looking for. FYI, a lot of this information is available with a little searching. Depending on what exactly you are looking for, you might want to look up a document for a specific cassette as the numbers might be slightly different.

Spacer widths (From Shimano tech docs)

  • 8 Spd: 3.00mm
  • 9 Spd: 2.56mm
  • 10 Spd: 2.35mm (1.0mm for lower spacer)

Cog/Tooth Width (From Sheldon Brown)

  • 8 Spd: 1.8mm
  • 9 Spd: 1.78mm
  • 10 Spd: 1.6mm

Chain widths (From wikipedia)*

  • 8 speed - 7.1mm (all brands)
  • 9 speed - 6.6 to 6.8mm (all brands)
  • 10 speed - 6.2mm (Shimano, Campagnolo)
  • 10 speed(Narrow, Direction) - 5.88mm (Shimano CN-5700,CN-6700,CN-7900)

*These chain widths are the standard widths, which I assume are recommended. I wouldn't go wider, but a narrower chain will probably work as some chains are cross-compatible.

share|improve this answer
+1 for being generous enough to provide an answer despite the fact that op could have easily have found the answer through Google. – PeteH Aug 12 '13 at 21:54
+1 for the same reason. – Carey Gregory Aug 14 '13 at 5:27
@PeteH Google won't have it nicely in one place like this. Well, it probably does now, if it points to this question! – Kaz 2 days ago
@Kaz People have maintained these lists on web pages for years! – PeteH 2 days ago
@PeteH, By the way, this morning I used a caliper gauge to measure, down to the micron, a KMC Z51 (which was labelled as a 6-7-8 speed), as well as a SRAM PC-850 (labeled as just 8 speed on the packaging). The both measured quite exactly 7.65 mm, not 7.1, at the widest girth. I wonder whose 8 speed chains actually measure 7.1. – Kaz 2 days ago

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.