Shimano's current road lineup is Claris / Sora / Tiagra / 105 / Ultegra / Duraace

105 stands out as odd because its a number. Is there some special meaning ?

from https://bike.shimano.com/en-EU/product/component/105-5800.html


  • 105 was released in 1983 as a 6 speed groupset under the name "A105 Golden Arrow"
  • At the time Ultegra was known as "600" so some consistency in a 3 digit number. Dura Ace was always called Dura Ace, and Ultegra got its name in 1997
  • MTB groupsets have always had a name. There are no numbers for the groupset as a whole, though each year's revision has a model number.

Conjecture from the web

  • 105 is the reverse of 501, which came from Levi's Jeans, popular in the late 80s in Japan and matching the "workhorse reliable" nature of the 105.
  • 105 reads as "SOI" or "501" when rotated 180 degrees. But SOI is not a Japanese nor English word, like Dura-Ace ( Duralumin alloy + Ace 'best') or Ultegra = ( ultimate" + Integrity)
  • In the late 80s Shimano introduced SIS shifting and SLR braking. At this time many groupsets were stopped, like the 200GS, 300GS, 400GS, 500EX, and Exage. New groupsets with SIS/SLR replaced them over time.

So why has "105" persevered ?

  • 2
    Might be a good idea to forward this question to Shimano on Twitter or FB. I couldn't find any email contacts on Shimano website. Mar 2, 2019 at 4:23
  • 2
    I've contacted the PR person of my region, 'll give an update if they can redirect me to someone that could know more. Mar 2, 2019 at 12:17
  • 2
    My guess is like the fabled "Gorilla story", no one at Shimano has been squirted with a fire hose, but they still call it 105 - the reason why lost to the mists of time. That does not stop me hoping someone has the answer though.
    – mattnz
    Mar 3, 2019 at 4:11
  • 1
    @mattnz yep - there's plenty of different disagreeing opinions on the web, and no definitive answers.
    – Criggie
    Mar 3, 2019 at 6:11
  • Possibly related - I came across the "rule of 105" in a GCN video. The rule says "the rim must be at least 105% the width of the tire if you have any chance of re-capturing airflow from the tire and controlling it or smoothing it. " as mentioned in web.archive.org/web/20180428033729/https://silca.cc/blogs/… and bicycles.stackexchange.com/a/55483/19705 Probably a coincidence, but relevant.
    – Criggie
    Sep 7, 2019 at 0:19

1 Answer 1


This is a non-answer because I've been looking at Japanese bicycling sites and blogs and no one really knows. The closest answer is found here:



which google translate translate (with some clean-up) as:

What is the origin of the 105 name?

Finally, I will introduce my knowledge about the origin of each grade name [in the Shimano series]. The name of Dura Ace which was born in 1971 is a combination of Duralumin of the material and Durability meaning durability combined with "Ace" which wish of the world's best component. The birth of Ultegra in 1976 is a component that means Ultimate + Integrate. Concerning 105 which was born in 1982, it inherited the model number of the double lever SL-A 105 at that time and now it has become the grade name of 105.

So it's a non-answer answer. The author of this article, Kenji Hashimoto, is a sports journalist in Japan and so it's about as close as one might get unless you ask Shimano.

  • 2
    For historical interest: duralumin is the old name for what we would now call 2000-series aluminum alloys. That name appears to have been used in bicycle and bike component manufacturing from the 1930s to around the 80s. I don't know material properties, but I believe these alloys have been superseded by 6000 and 7000-series alloys in the bike industry. en.wikipedia.org/wiki/Duralumin
    – Weiwen Ng
    Nov 17, 2021 at 14:45
  • I can go with the journalist's origin story for the 105 name. "105 is one more than 104" was the best reason I could come up with. It makes me happy to know that I didn't waste your time with such a juvenile answer! To me, the Golden Arrow design remains stunning. In searching Shimano shifters as stylish key fobs & potential a draft beer levers (prototyping seems to be persistently ongoing.), I find the friction shifters that have any 'object' graphic somewhere on the levers are quite elegantly embellished. Oct 18, 2023 at 15:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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