Talk:ISO 5775

ERD really means Effective Rim Diameter
I have discovered an interesting point of confusion. "ERD" is used to mean two different things: European Rim Dimension, and Effective Rim Diameter. The latter is what it means most commonly in general use. The former is usually called "ISO," "European," or "ETRTO" size. This is an unfortunate confusion, because both of these are specified in mm, and usually they aren't any more than a few centimeters different. However, if you get them mixed up, you're going to have problems, as one refers to the tire bead size, and the other is most commonly associated with the spoke length. I think this article needs to mention this. What would be the best way to do this? AaronWL 23:25, 3 July 2006 (UTC)

Regarding the expansion of the ERD acronym, judging from the number of search hits, it looks like Effective Rim Diameter is the true expansion. And all of the bad hits are actually copies of the wikipedia page (*sob*). Trying to remember where I had got the wrong expansion from, I found this link in my bookmarks: One of the few rim manufacturers who actually give the ERD for their rims. At the top of that image is the bad expansion. I will replace it with Effective Rim Diameter.

Regarding the difference in measurements, again judging from a web search, the ERD appears to denote the rim diameter as used for spoke length calculation -- at the nipple seats, not the tire bead seat.

Opinions differ whether the ERD is measured at the nipple seat (eyelet surface, if the rim has eyelets) or the nipple head. Since the Effective Rim Diameter is by its name a property of the rim, I prefer the "nipple seat" definition. However, for some aerodynamic rims, the nipples must be mounted with the head pointing towards the hub, requiring the spokes to protude much further through the nipple seat. Conclusion: If given an ERD value, ask what it means exactly before using it.italso mean you cheatted everyone hahahaha

--RainerBlome 14:25, 29 July 2006 (UTC)


 * I'd favour the ERD section (added 7 Nov 2005 by RainerBlome) to be removed again. I wrote this originally as an article about the ISO 5775 standard, and ISO 5775 does not use the term ERD anywhere. This was not meant to be a generic article about all issues concerning rim and tire dimensions (but could be merged into such a broader article one day). The ISO 5775 standard is primarily concerned with the interface between rim and tire (and to some degree also with tire clearences). ISO 5775-2 does not talk in any way about rim dimensions related to spoke lengths. ISO 5775 does not mention that a rim might have spokes. Markus Kuhn 16:26, 29 July 2006 (UTC)


 * I think ERD should be kept until a broader article is created, as its related; if removed, it should be moved to its own article or part of some other article. However, I'm almost positive that ERD relates to the tire bead, not the nipple seat, as mentioned.  I beleive this partly because I've actually measured this distance on my rims, and partly because all rims that take a certain type of tire have the same ERD, yet do not have the same nipple seat diameter. AaronWL 10:21, 9 October 2006 (UTC)


 * ERD is a measure of the nipple seat diameter, as in where the nipples sit on the inside of the rim, not where they protrude from the rim. It is only of interest when building wheel and determining what length of spoke is needed.  Different rims with the same tire bead seat have different Effective Rim Diameter as can be seen by looking at the exelent website of DT swiss. Go here then click on spokes calculator on the right.  This gives access to their huge database of rim dimmentions, hub dimmentions, (both almost allways accurate) and calculates the leanth of spoke needed.  As can be seen, many different (by a few mm, enough to require different lengths of spoke) ERDs will be output by selecting different rims with the same tire seat.  Of course a 26" MTB wheel is much smaller than a 700C road wheel, and as such the ERD will be less.  That does not mean that the ERD is a function of tire seat.  As the ERD is independent of the rim/tire interface I do think the section should be moved, maybe to the bicycle wheel article.  —Preceding unsigned comment added by Keithonearth (talk • contribs) 09:50, 31 December 2008 (UTC)

Wired-edge vs Beaded-edge tires
I believe conventional Wired–on and Beaded-edge tires (often incorrectly referred to as clinchers in the US) are the same thing, commentaries please! –  Moebiusuibeom-en (talk) 03:31, 23 March 2010 (UTC)

No explanation of SS, C and HB characteristics
As far as I can see there is no explanation of what the three different rim types are: SS, C and HB. I believe that the best explanation would be an illustration of their profiles, with comments on their characteristics. Velle (talk) 09:13, 1 July 2010 (UTC)


 * I figured this out and added it. An open source for that information is the JIS standard D 9421.   Ccrrccrr (talk) 21:06, 10 October 2018 (UTC)

What's about ISO 35-622
Hi there, in the GDR there were tirres common with the size "28 x 1 3/8 x 1 5/8". I measured them, mounted and with full pressure they have a width of exactly 35 mm. First, this does match with the labeled 1 3/8 inches (1.375x2,54=3,49 cm). Anyway, the french size "700x35C" is used for these tires with a width of 35 mm. Suprisingly, "700x35C" is used for 37 mm-tires as well! (e.g. 37-622). Could it be more confusing? In case of getting new tires for the bike from the GDR, there was no other chance to measure the tires by myself according to ISO-standard. Result: The size is matching with 35-622er "Worldtour" (Michelin) or 35-622 "Marathon Racer" (Schwalbe). Some pictures of the mounted tires you can find here. So, ther're still new tires with this size, so this wrong labeling is not only a problem for fans of old bikes.

Questions according to the article: 1. Is the size 35-622 mentioned as an official size in the ISO-standard? 2. Shall we mention the problem that the french size "700x35C" can mean "35-622" as well as "37-622" ? 3. How can it be that, for examble, "28x1.75" = 47-622? Because, 47 mm are 1.85 inches, not 1.75! 4. Does anybody have a tire that is not from GDR (Pneumant/TSG/Kowalit) with the size of "28 x 1 3/8 x 1 5/8"? Would be interesting if it's 35 mm width as well. 5. Any other suggestions to this problems?

Thanks! --Max schwalbe (talk) 10:02, 9 September 2015 (UTC)

link to JIS D 9421
I noticed the link to a copy of the Japanese Industrial Standard was broken. Ordinarily, I would have tried to fix the link, for example one of the Internet archives, but I suspect the page was taken down because the hosting web site did not have permission for this copyrighted material. So, instead, I deleted the broken link. Anyone who knows better about the copyright status is welcome to fix the link. Condensinguponitself (talk) 16:26, 18 March 2021 (UTC)

Diagram needed for rim types
-- Beland (talk) 18:02, 28 July 2023 (UTC)

Update needed
The article is substantially based on previous versions of the standard, ISO 5775-1:2014 and ISO 5775-2:2015, and needs to be updated to reflect the changes and content of current versions ISO 5775-2:2021 and ISO 5775-1:2023. I will begin this work shortly.

-- Concentrate2 (talk) 09:26, 25 February 2024 (UTC)