Cycling UK Forum

It's a bit of a long shot for me but I thought I might try and replace a worn 36 hole CR18 700c rim. My choice of replacement is the Exal EX17. A quick Google seems to show that the CR18 700c is no longer available in the UK. I would aim to be using the same hub and spokes.

It will in any case be a learning experience for me but is there anything obvious I'm missing, mainly of course because the rims are not exactly the same make/model.

Tape the new rim to the old one and move the spokes across.
Snag is likely to be that you get spokes crossing where the valve is, because you need to line up the angle of the spoke nipples NOT the valve hole.

According to the checks I've just made, they have ERDs different by about 10mm, so you'd need different lengths of spoke (unless there are different versions around?)

The ERD of the Exal is 601 (Spa Cycles), the CR18 620 (https://www.bikeforums.net/bicycle-mech ... m-erd.html). So I presume you mean that is 10 mm on either side of the rim. That seems quite a lot for similar rims - does that make the Exal a rather shallow/weaker rim?

I'm presuming that while a small difference could have been taken up by the spokes, 10 mm is way out and will require new spokes.

I believe I got 601 and 611mm in the pages I found, hence my comment about different versions. But either way, the ERDs aren't the same, so swapping spokes across isn't going to work.

horizon wrote: ↑31 Jan 2024, 11:25pm The ERD of the Exal is 601 (Spa Cycles), the CR18 620 (https://www.bikeforums.net/bicycle-mech ... m-erd.html). So I presume you mean that is 10 mm on either side of the rim. That seems quite a lot for similar rims - does that make the Exal a rather shallow/weaker rim?

I'm presuming that while a small difference could have been taken up by the spokes, 10 mm is way out and will require new spokes.

Your link is talking about 27 inch rims and 620mm ERD .

531colin wrote: ↑1 Feb 2024, 8:15am Your link is talking about 27 inch rims and 620mm ERD .

Thanks Colin. This link appears to be giving 700c and is coming out at 611.8 which seems nearer the mark:

https://www.kstoerz.com/freespoke/rim/165

The rim height/depth is given as 15.5 compared to the Exal at 19.4 thus making the CR18 ERD larger which makes sense, although not quite matching the figures (3.9 + 3.9 = 7.8 mm compared to ERD 601 and 611.8, a difference of 10.8 mm).

In any case, if I am right it still means new spokes.

I've checked out the price of replacing the rim against buying a complete, new wheel from Spa to the same specification. Doing it myself with a new hub/rim/spokes would be £74.60 compared to their price of £100. That's a very good deal IMV for a hand-built wheel (though Spa of course will also make a margin on the bits).

My current hub is an LX which if still OK is worth saving and thus reducing the cost to £48. That's a good saving but of course everything is predicated on the joy of doing it myself - it will take hours! The good thing is that I learn a lot in the process and since I've trued wheels have some tool(s) and some experience.

If you find a suitable rim with near enough the same ERD, you may be able to reuse the spokes. According to the manufacturer, the ERD of the H PLUS SON TB14 rim is 610mm. If that is correct (there is no substitute for measuring the ERD yourself), it might be close enough. What is the fit of the spokes like in the current wheels, e.g. spot on, protruding in/above the nipple slot, or short of the nipple slot?

Thanks slowster. The Hope rim is double the price of the Exal so it makes getting new spokes OK with an Exal. I like the Exal because I've chosen the components to be as bog-standard as possible but fit for purpose.

In checking out the Hope, I've already learnt some more about sizing etc and rim quality so it's all good.

I'll be checking out the existing rim again soon to look at current spoke disposition as you suggest.

ERD of KinLin ADHN is 606, not expensive also...

horizon wrote:.....In any case, if I am right it still means new spokes.

Surely it just means shorter spokes? IME this is readily achieved if you have a spoke thread roller; maybe now is the right time to get one?

Brucey wrote: ↑1 Feb 2024, 3:52pm

horizon wrote:.....In any case, if I am right it still means new spokes.

Surely it just means shorter spokes? IME this is readily achieved if you have a spoke thread roller; maybe now is the right time to get one?

It's a great idea although it would be about £130 for the roller and cutting heads. I would still need to cut the spokes to length, would I not? I'm a bit concerned that all that cutting and rolling might be beyond the limits of what is acceptable in MrsH's kitchen. Ordering them from Spa would be a lot easier (But then so would ordering the complete wheel, horizon. Ed.).

horizon wrote: ↑2 Feb 2024, 4:01pm........I would still need to cut the spokes to length, would I not? ....

cutting spokes is not normally very difficult; if you can cut cables/housing then spokes ought not be a problem. Most pliers have wire cutting jaws on the side, and they are normally good enough for at least one set of spokes. Even a junior hacksaw can be used to cut spokes to length. Provided you have a drill that you can use the rolling head in, you just need some means of holding the spoke whilst it is being threaded, which is not too difficult to do. So you probably only really need the rolling head just now. From memory, the rolling head is made to fit a 3/8" arbor/shaft, which you can easily make by cutting down a long 3/8"caphead screw or bolt. Or it might be 10mm, in which case you will need a different screw to cut down.