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Heads Up FYI

Pridanc

Well-known Member
Joined
Dec 4, 2020
Total Posts
56
Total likes
9
Location
LIBERTY HILL, TX, USA
OK guys, I learned one today and thought I'd share it with everyone in an effort to save some potential aggravation but first some background on what transpired: As I work on bringing a 1962 CB72 back to life, it was evident that the rear wheel and spokes needed to be replaced.

The wheel had an obvious bend in it and oddly every single spoke had a bend in it. They were bowed and bent equally at the nipple. Being the bum I am I envisioned the owner jumping the Grand Canyon (fertile mind OK?) somewhere along the line but regardless replacing the rim and spokes would be cake.

I've not replaced many rims/spokes over my life time but I have done it successfully so wasn't even slightly concerned about replacing this one. Part to remember as I share this with you all is that I've never run into anything strange along the way. New Rim, New Spokes....lace 'em up, straighten the rim and torque the spokes BINGO, all done. However this time...

When taking the old rim and spokes off/out I noticed that the spokes in the hub were all the same which went against my prior experiences. Remember I said experiences as I'm no expert here got it? Once I'd pulled all the spokes I noticed that the mushroom head end (the part of the spoke that engages the hub) of the spokes all had the same bend angle on them. It had been my experience that when using a relatively wide hub the outer most spokes of the hub needed a greater bend in them to properly seat in the hub without inducing a bow along the length of the spoke when pulling the spoke in place at the wheel. My thoughts were ironically proven out when I received the replacement set of spokes. Half of them had a greater than 90 degree bend at the mushroom head end which were to be used on the outside of the hub. So far so good.

There was no intent to make this bike perfect so the replacement wheel was still chrome steel (like the original) but nothing special. Once the new hoop arrived along with a new set of spokes I was off and running. Lubed the spokes, lubed the nipple heads, laced the spokes up and began the laborious task of tightening them up whilst checking true. Almost done with the final torque of the spokes when I suddenly noticed that these spokes had the same freaking bend at the nipple as the set I'd removed. What? I was flummoxed and not at all sure why or how this could be.

Standing back I went over my steps. One of my concerns revolved around a lingering question: Did the wheel somehow shift whilst tightening the spokes causing the spokes to be out of alignment? I went over how I had been extremely careful bringing each spoke into tension equally so that couldn't be it and eventually I realized that my thoughts would be almost impossible to happen based on the obvious mechanics and geometry of the doggone thing in the first place. I then thought that perhaps I had laced the wheel up using the wrong spoke holes in the wheel but in this case that too was impossible. There were no other holes that were anywhere near close enough to use without it all coming to a screeching halt part way into the lace up. It had to be something else. (don't forget I've only ever done a handful of lace jobs so have no real knowledge of why things like this might happen.)

If you look closely you can see the bend of the spoke just before the go into the nipple. ( easily seen live but can be seen here too.)
20210326_134910.jpg

Prior to reaching out to the pros at Buchanan's Spoke & Rim (www.buchananspokes.com) my single brain cell was stuck on the possibility that the rim nipple holes were not quite at the correct angle for the nipples to seat in the rim and yet still pull the spokes dead straight. Time to ask the pro's and when Buchanan's replied I learned my guess was close. They felt that although all other dimensions of the rim were correct for my needs, this wheel had it's nipple holes bored for a slightly smaller diameter hub which would reduce the angle of the nipples coming out of the rim so would have been perfect in that case.

I don't blame anyone since most folks are like me not being aware that this Honda has a large enough hub needing consideration when boring the spoke holes. I was sold the wheel I asked for. ( 18 inch wheel with 36 spoke holes) The folks I purchased from knew what my bike is but still I feel all of we "non experts" wouldn't have a clue that this could happen.

So there you have it. Make sure that when looking for new wheels every dimension should be considered. Now it is off to find the correct wheel and see what I can do with the one I purchased.

Have a great weekend. I know I will as I'm off to tackle the next job on the bike.
Stay well, PC
 
You may be able to 'ease' the holes in the rim with a file to correct the hole angle towards correct. However this may expose bare steel which can oxidize...
 
Compare the spoke pattern/spoke length to the front wheel. Sounds like some early and late wheel pieces are being mixed. I wouldn't oversize the holes, that could be a safety issue.
 
Thanks guys.

Not sure there is a mixing of wheel parts so much as the incorrect wheel in the first place not to mention my own ignorance of how a wheel is made. As an FYI both front and rear on this bike share the same lacing pattern. There are witness marks under the spokes at each hub not to mention that the wheel itself would not take any other pattern so I'm doggone certain I've got that right as presented to me. I'd love to see a close up of an all OE CB72 to see if mine differs but I'm inclined to think it is as it should be based on the observations noted above.

For all practical purposes the front and rear hubs are very close in measure (I do not have the tools to measure either accurately while they are assembled.) However, and of some note, the spokes are different front and rear. I don't know how they differ but spoke part #'s are different front to rear.

Now that Buchanan's has pointed out some of the finer points of rim making, which was what I was really sharing above my ignorance, I will now pursue correcting the problem. However before I return anything I may try "easing" the holes a bit with the old wheel to see the outcome. This might just work although I am inclined to get the correct wheel.

Again, I want to thank each of you for jumping in. Your thoughts and suggestions add to my education as well as adding to the thought process making each of you irreplaceable in my mind.
TY, PC
 
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