# What does 1.50 refer to on Spec GX26 rims?



## singletrackmack (Oct 18, 2012)

Does anyone know what measurement 1.50 refers to on the yellow sticker that says "26X1.50 Japan" on this specialized GX26 rim?


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## mik_git (Feb 4, 2004)

1.5 inches wide?


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## singletrackmack (Oct 18, 2012)

That's what I originally thought, but the rim's outer width is exactly 1" wide.


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## mik_git (Feb 4, 2004)

the tyre?


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## shiggy (Dec 19, 1998)

singletrackmack said:


> Does anyone know what measurement 1.50 refers to on the yellow sticker that says "26X1.50 Japan" on this specialized GX26 rim?
> 
> View attachment 938712


The tire size the rim width was originally designed for. It is an obsolete designation used on single wall rims. The "26" in the model name is the rim's actual width in mm.


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## thickfog (Oct 29, 2010)

Y'all are wrong. 
It's a multiplier in dollar amount. To get the rims price you multiple that number by the number of spoke holes. So 1.5 x 32, 1.5 x 36. Etc. 

Amazing how much knowledge has been lost over the years. C'mon gents.


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## singletrackmack (Oct 18, 2012)

The bike came stock with spec hardpack 26x2.2 tires.

It wasn't just specialized who had this measurement. Trek also had a 26X1.5" rim on their 1991 850, but I don't think that the 1.5" on their house brand rim referred to the rim width either. A 38mm wide rim would be extremely wide for the early 90's or late 80's. That's even pretty wide for today.

I have no idea what manufactures were referring to with the 1.5 measurement for their rims.


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## singletrackmack (Oct 18, 2012)

shiggy said:


> The tire size the rim width was originally designed for. It is an obsolete designation used on single wall rims. The "26" in the model name is the rim's actual width in mm.


Hmm, interesting since specialized stocked 2.2" tires on these rims. That seems to make the most sense tho. The only other thing I could think of was that the total diameter is 26" with 1.5" tires, but that seemed pretty weird.



thickfog said:


> Y'all are wrong.
> It's a multiplier in dollar amount. To get the rims price you multiple that number by the number of spoke holes. So 1.5 x 32, 1.5 x 36. Etc.
> 
> Amazing how much knowledge has been lost over the years. C'mon gents.


I assume your joking, right?


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## mainlyfats (Oct 1, 2005)

singletrackmack said:


> That's what I originally thought, but the rim's outer width is exactly 1" wide.


What is it when you add the braking surfaces?


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## shiggy (Dec 19, 1998)

singletrackmack said:


> Hmm, interesting since specialized stocked 2.2" tires on these rims. That seems to make the most sense tho. The only other thing I could think of was that the total diameter is 26" with 1.5" tires, but that seemed pretty weird.


_*OBSOLETE*_ rim size designation. 1.5" was the width of the tire originally intended for use on this width rim. Many (Many, MANY) years later wider tires were and are commonly used.


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## singletrackmack (Oct 18, 2012)

shiggy said:


> The tire size the rim width was originally designed for. It is an obsolete designation used on single wall rims. The "26" in the model name is the rim's actual width in mm.


Just took a closer look and these rims are double wall, not single. Not sure if that maters since you say it's the rim width of 26mm that was designed to use 1.5" tires. You should be able to see the two walls inside the valve hole in this pic.

So thanks to the info you've given what I think I figured out is going on here is that if a rim says it is a 26x1.5 that means it's actual measurements are 559mm in diameter X 26mm in width. Is that right?

View attachment 938870


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## shiggy (Dec 19, 1998)

singletrackmack said:


> Just took a closer look and these rims are double wall, not single. Not sure if that maters since you say it's the rim width of 26mm that was designed to use 1.5" tires. You should be able to see the two walls inside the valve hole in this pic.
> 
> So thanks to the info you've given what I think I figured out is going on here is that if a rim says it is a 26x1.5 that means it's actual measurements are 559mm X 26mm. Is that right?
> 
> View attachment 938870


No.
The rim bead seat diameter is 559, but the ISO width is not 26mm. ISO size is the BSD and internal width.

The size label on this rim is pre-ISO. That labeling method was closely tied to tire width _*at the time it was created*_ but that was a long time before MTBs came on the market. _It has not had a direct meaning to the range of intended/usable tire widths for decades._


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## singletrackmack (Oct 18, 2012)

shiggy said:


> No.
> The rim bead seat diameter is 559, but the ISO width is not 26mm. ISO size is the BSD and internal width.
> 
> The size label on this rim is pre-ISO. That labeling method was closely tied to tire width _*at the time it was created*_ but that was a long time before MTBs came on the market. _It has not had a direct meaning to the range of intended/usable tire widths for decades._


I actually didn't mean the inner width was 26mm, but the outer rim width. So does a rim that says 26x1.5 mean 559mm bsd x 26mm outer rim width? I am curious because I would like to get another set of wheels with the same rim width as the gx26. These run about 21mm inner rim width which is great for 2.35-2.5" wide tires.

So I am wondering if another set of rims from a different company, say the trek matrix 26x1.5 would have the same size rim width as the GX26.

Thanks for your help.


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## whatisaidwas (Apr 26, 2014)

26 x 1.5 was used to distinguish this cruiser/mtn rim diameter (559mm) from the old Schwinn 26 x 1 3/8 size (590mm) or the English 26 x 1 3/8 597mm rims.

GX26 = 26mm rim width

That the tire size is 26" and the rim width is 26mm is confusing, but one of those 26's is not really related to the other one.

There is also a GX23 used in later models, 23mm wide.


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## singletrackmack (Oct 18, 2012)

Got it. I found a picture on google of some GX23 rims and they also had the same 26X1.50 Japan sticker on it. So the 1.50 does not seem to have anything to do with rim width.

But still not clear as to what that second number indicates. For example trek matrix mtb rims come in a 26x1.5" and a 26x1.25". I am pretty sure both have a bsd of 559. What difference in the rims would the 1.5" vs the 1.25" indicate?


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## laffeaux (Jan 4, 2004)

Shiggy is correct. The 1.5 refers to the size of the tire intended to go on the rim when the rim was visit developed (likely pre-mtb). It would have been narrower than a 2.125 rim which was intended for balloon tires.

Sheldon Brown has a good article on rim sizes: Tire Sizing Systems
The whole thing is worth reading, but the "Traditional Sizing Systems" section explains the differences between a 2.125 and 1.5 rim 26-inch rim (which is not 26 inches).

It gets even weirder with French sizing (650b, 700c, etc). The "C" in 700c refers to a wide tire, yet today a 700c tire is often though of as being 23-25mm road bike tire (which is not what the "C" originally meant). Likewise, "the "B" in 650b refers to a tire that is narrower than a "C" tire, yet today 650b is most often wider than a 700c tire (unless the 700c tire is on a mountain bike, at which point we call it a 29er tire). :|


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