Rim help needed please.

[Nody]

I've been riding my lads old (1995) mountain bike for about the past year, but, parts are getting worn and replacements hard to obtain.
The requirement is a wheel rim. The original marked Mavic 238 559x17 is cracked.
I assummed that 559mm was the inner diameter and the 17mm the width of the tyre well but although the measurements are close they don't tie up exactly and I suspect I'm measureing at the wrong place?
Please, is there anyone that can tell me where I should be measuring and, more importantly, how I go about getting a rim to replace the one that's damaged, I'd like to use the spokes again. I've rebuild wheels before but not for along time.
Thanks in anticipation.

 

[mattr]

559x17 is essentially the size of the tyre bead/rim interface.
So you can measure the 17 fairly easily (the inner width of the rim). The 559 is all but impossible to measure!

The ERD on the 238 rims is 545.5mm (from what I can Google) so any rim of the same basic size 559x16/17/18/19 with an ERD of about 544.5-546.5 should be good to go with original spokes.
As long as it's the same number of spokes and rim brake compatible.

In the other hand 25 year old spokes and nipples are probably going to be shits to take off, so might be worth either starting with a new rim and getting spokes to suit, it makes it easier to find a rim in the first place and easier to build.
Or pop a wanted ad up for a pair of period wheels.

 

[Nody]

Thanks for you swift reply.
Since my post I've found this site https://bike.bikegremlin.com/9266/effec ... iameter/#1 which explains a lot about measuring ERD, unfortunately, it needs a bare rim for accuracy.
My spokes are in surprisingly good condition and using them, taped in position, would allow the old rim to be fiddled off and the new on without the need to lace, set and straighten new ones.
I've not been able to find a site that specifies ERD and I've learnt that "rim sizes" are not an accurate representation of the actual dimension. My rims, between the clincher nibs, are 17.8mm somewhat bigger than 17mm and the diameter is, as you say, 545-point-something not the 559 indicted.
Where did you/how do you find the ERD of a rim, I've not found it cited on any site that I've visited?
I've no real idea of a suitable rim and Googling randomly hasn't been able to bring one to light yet. I was hoping that someone within the readership would have encountered this problem previously and been able to suggest a suitable, appropriate and experienced resolution.
Here's hoping....
Thanks in anticipation...

 

[mattr]

If you have a google for spoke length calculator (spocalc is one) they list ERDs (both measured and quoted) of hundreds of rims.
There is also a spoke calculator on the DT swiss website, and https://leonard.io/edd/ is quite useful.

545.5 is the ERD (where the spokes seat) 559 is the bead seat diameter, which is a different thing altogether......

And i've had a bit of a rummage, and i think you'll struggle to find a current rim with that shallow a section these days, unless it's disc only. Most of what would be a "shallow" rim now are in the 535-540mm ERD. Which will need new spokes.

Someone with more time might be able to find a shallower rim!

 

[fiendish feet]

The Mavic 237 UB control Rims Are 559x 17
I have a 32 hole rim in silver on Ebay
Its built up as a Front wheel . If you get stuck pm me :xmas-wink:

 

[Nody]

Super, thank you for your offer.
I didn't realise the wonderous world of cycle rims was as complicated as it is evolving to be. I'm determined to attempt to get to the bottom of the mystery, if at all possible. In the fullness of time, I'm sure, it'll all become abundantly clear... maybe?