What’s up with this wheel build?
I’ve been building my own wheels for as long as I can remember now. I’ve got some fine example well over ten years old, all on Mavic rims.
I recently bought Roger’s e-book and I did pick up a few bits. I discovered that even though my wheels have been true and stayed that way, they were not very evenly tensioned.
So, I treated myself to some Flow rims and a Park spoke tensometer. So, I build these up true and even and stress relieved. However, few weeks later, a few loose spokes. Fair enough, have another go. I end up with a wheel that is lateral by 0.2mm, round by 0.7mm and dished so that I can’t actually measure the error! Spoke tension is plus or minus 5% of the average of 110 kgf as confirmed by Stans. When i first rode the wheel, there was no pinging. So, how come a couple of months later I find one very loose spoke and that the spoke tension is all over the chip shop.
What am I doing wrong? Should I go back to mavic? Would be a shame, I love the Flow rim when it’s running true.Posted 8 years ago
You are assuming your tensiometer is giving an accurate reading of tension. This is not the case. Even the very expensive tensiometers are only +/- 10% and comparing two identical tensiometers – mine and one at a wheelbuilding factory gave different results. I’m not sure what the Park accuracy is like, could even by faulty. I really look after my tensiometers, I never let anyone touch them and I handle them with great care.
Anyway, I get the feeling your spokes are not tight enough and not to the 110Kg you assume.
RegardsPosted 8 years ago
I’ve also been really carful with the park tool but like you say, I’ve got no way of knowing if it’s a true reading. The spokes do feel less tight than my Mavic wheels which have served well but I know Stans make a big thing of how much tension to use. Do you think they’re just being very “American” about and trying to cover themselves?
I’ll add a bit more tension all round then. Guess the worst that can happen is a cracked rim.Posted 8 years agorob1984pMember
We tested a cheaper one from a well know bike tools make and a very expensive one from a spoke manufacturer and found the to be pretty innacurate. The main benefit is that they allow less confident wheel builders to check their consistancy and allows experienced wheelbuilders to periodically check the wheels they are churning out are still consistant.Posted 8 years ago
I’ve just been by the local bike shop to check mine against theirs but they don’t use one. I did however use mine to measure the driveside tension on some Hope Hoops. They were conventional Pro II hubs with DT rims, the scale on my tool read 25~26. Assuming they use 1.8mm spokes then my tool is saying they’re built to 155 kgf.
So, it does look like the Park tool is a bit pants. Like you say Rob, useful for checking the range but not much cop for measuring the actual tension. Qualitive rather than quantative. The Hope Hoops also felt like my old wheels built by feel and a lot tighter than my measured Flow rims. More tension needed it seems.
I can go one of two ways now. I can just add tension half a turn at a time and see how I go or just build them good and tight like the mavics and ignore the lower tension suggestions from Stans.
Thoughts?Posted 8 years ago
I used Rogers book as well but not being particularly musical, I didn’t trust the plucking method. The consistance of tension isn’t the issue, I’ve got that nailed. It looks like the tensions was too low overall (caused by what it seems is a poorly calibrated park tool). Normally, mavics and the like would build to 130 kgf but Stans say 100 kgf. I’m just wondering if people go a bit easier on Stans rims as the manufacturer suggests or if they ignore the advice and build as normal.Posted 8 years ago
I ensure that wheels built with ZTR rims have spoke tensions lower than I would use on other rims. The actual tension is a little higher than the recommended tensions from NoTubes – based on the readings given out by my 2 tensiometers (soon to be 3).
Remember I supply wheels to paying customers, I want to ensure everything is as perfect as I can make it. The last thing I want is warranty claims on failed rims. This approach has served me well, I’ve built lots of ZTR rims and everything worked perfect and I’ve adopted the same strategy on my latest ZTR activity.
Your situation is different. If you get things wrong tension-wise the only thing that’s going to happen is that your rim may fail and you have to buy another rim.
Here’s what I would do in your situation. Crank up the tension a little more (but less than a normal build). Ride and see what happens, repeat as necessary. It’s part of your wheelbuilding learning and as a wheelbuilder you’ll find it interesting.
Flow is a strong rim so I don’t see much possibility of it going pear shaped. 355 and Olympic need more care.
The mode of failure is going to be fatigue and that depends on how many miles the wheels get, so people with super tight ZTR’s with no failure may not be riding them much. There wont be static failure because I’ve tightened a ZTR Olympic to 2000N (not ridden it, cosmetic second that I experimented on).
RogerPosted 8 years agosvMember
Once again Roger adds extra value to his customers purchase! If you are reading this and like the idea of building your own wheels get over to wheelpro and purchase the PDF. Best move I made – built three sets so far plus a couple of rebuilds for mates.
Advertisment over!!! (the book is brilliant)Posted 8 years agomartinxyzMember
This thread seems to be going into a lot of detail without considering the obvious.
I thought someone would mention that rims take a beating.ok, a flow might be tough but hey ho, so is a 321 disc rim and look what folk have done to those in the past!
you say you rode them for a few months and found the spokes loose.dont doubt the build, you probably made a brilliant job of it but remember wheels dont stay round.flat spots not visible to the eye could be the problem.they might be running over a distance of 2 or 3 inches (or more) and although small enough not to see out of a wheel jig, big enough to lose you the tension you once had in the spokes around that area.
Its not always the quality of the parts or the build of the wheel thats going to cause spoke tension to drop off.Posted 8 years ago
Fair point Martin. I think the big assumption I made was that as I was riding 317 rims previously without bother, then the Flow would be stronger. However, I’ve also swithced to tubeless when I switched rims. Could it be that rims take mreo of a beating tubeless or that the 317 is actually more robust that the Flow? (Or I’ve just had some unlucky hits on this rim).Posted 8 years agosamuriMember
All sounds very anal to me. Pluck the spoke, if it sounds right it probably is. Never had a problem with spokes coming undone on wheels I’ve built myself, or indeed, wheels built at a decent shop. This doing them up as tight as you can business sounds a bit dodgy to me, never come across that one before, but it’s your lookout.Posted 8 years agobombermanMember
i don’t know anything about wheel building but i’ve read the thread. Could you just measure the tension on your rock-solid wheel builds using your park tensiometer and then knock a bit off for the stans? the meter might be out but it should be consistently out. if you know what i meanPosted 8 years agoAdamMMember
For what it’s worth, I don’t use my tensiometer to indicate absolute spoke tension, but to measure relative tension around a wheel or between wheels. Probably the most useful thing to do, as Bomberman says, is to measure the spoke tension on a wheel set that hasn’t got spokes working loose, then aim for that on your wheel builds. That way you can largely ignore the issue of calibration because you aren’t interested in whether ’23’ on the tensiometer means 130 or 160 kgf.Posted 8 years ago
Hi Roger, thanks for the offer. I’m in Nottingham so not close but not a million miles away. I keep checking your site to see if you’re running any more courses. The good news is, I’ve had a response from the shop I bought the tool from and they’re willing to have a look at it even though it’s ove a year old which i think is pretty good of them.Posted 8 years ago
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