[tuscanybill]

I have a friend that has the SSC SL wheel set 2005 all silver (I have the same wheels) the issue is with the rear wheel, he has had the LBS retrue the wheel two times. We got to talking and I offered to take a look. I true with a dial indecator (i'm a machinest) and I have a tention meter (park) I use for referance, I true till spoke "tone" is same on all spokes, (yes it takes a bit but really works) we got the wheel to a total run-out of .004" (BTW spoke tention is the same compaired to my wheels with no air pressuer) after about 150 miles the thing went wacky again. I think that this is scarry, my rim has never moved and after a small adjustment on my front it has never moved in 2400 miles. The rider is a strong rec rider not heavy (165) very careful and does great maintance. Anyone else have something like this?

Thanks in advance -- Bill

 

[Kerry Irons]

Try this

we got the wheel to a total run-out of .004" (BTW spoke tention is the same compaired to my wheels with no air pressuer) after about 150 miles the thing went wacky again.

It sounds like inadequate spoke tension, but you say you have dealt with that. When you have to re-true, are the spokes still up to tension? Also, are you stress-relieving the spokes as you go? If they are loosening, then you need higher overall tension. If you use a marker to swipe each spoke/nipple interface, you could see if things are moving after you've done the truing.

 

[tuscanybill]

Kerry Irons, Thanks for the reply, since I have only trued once so far, I have-not remeasuered the tension, the tone is definatly lowering indecating one of two things the the spokes/wheel are streching or as you indecate loosening. Interesting on marking them that may shead more light. I have read many post on rims cracking at the threads on this wheel type so I'm cautious on increasing the tension. I have-not looked up Mavics spec's at this point I just went off my wheels. -- Bill

 

[Marc]

Kerry Irons, Thanks for the reply, since I have only trued once so far, I have-not remeasuered the tension, the tone is definatly lowering indecating one of two things the the spokes/wheel are streching or as you indecate loosening. Interesting on marking them that may shead more light. I have read many post on rims cracking at the threads on this wheel type so I'm cautious on increasing the tension. I have-not looked up Mavics spec's at this point I just went off my wheels. -- Bill

One thing to keep in mind-only when working with an ideal rim, laced with ideal spokes/nipples, laced to ideal hubs should the spoke pitch (tone) be the same. It is a good way of getting in the neaighborhood though (

Another thought-with the park meter & it's table, you did refer to the correct column on the table? OTTOMH, I can't remember if it's bladed alu columns matches the spec of the spokes on the Ks...

 

[rruff]

I have read many post on rims cracking at the threads on this wheel type so I'm cautious on increasing the tension.

"Stretching" means that the spokes, hubs, or rim are yielding... which would lead to cracking eventually. Examine the loosening spokes very carefully for any sign of this. Also mark them as Kerry said, to see if the nipples are unscrewing.

People claim that tire pressure measurably reduces spoke tension... but I've never measured it myself.

 

[tuscanybill]

rruff, I have measuered many times the decrease in tension with air Jobst Brandts the bicycle wheel the formulas are there if you like math, what I have found is that differant tires make a big differance my friend and I run differant tires, my tires make a big differance his do not, thats why when compairing two wheels I always let the air out.

Room 1201, the spokes are on the table, 5.3x1.8mm and we are at 120Kfg drive side and about 70Kfg on the non drive ( no air)

Has anyone saw the Mavic spec's ? --- Bill

 

[divve]

Press down on the rim with your hands at opposing sides with the axle resting on the floor (something relatively soft, not concrete or you'll damage the axle). Go all the way round and do both sides. Not need to go crazy. Just some firm upper body pressure is sufficient. Afterward, check whether the wheel remains true. If it doesn't, correct wheel and repeat the procedure until it stays true. The point of the test is to expose a wheel that won't remain true during riding.

 

[rruff]

Room 1201, the spokes are on the table, 5.3x1.8mm and we are at 120Kfg drive side and about 70Kfg on the non drive ( no air)

Don't know their spec... but it seems like that should be enough. You said you compared them to another set of SSCs and the tension was the same?

 

[tuscanybill]

rruff, Yes the tension was vertualy the same, the problem wheel having an average that might be just a very small amount higher.

divve, thanks for the stress releif idea, also to the others that mentioned that as a solution, I have not made a practice of stress releiving when making minor truing adjustments (I do know its required during builds and major adjustments), but it should as you mention tell us if its going to hold up, the original run-out was .030" and it went back to at least that much (we have yet to put it back on the stand)

I'm begining to think that our problem wheel has a bit too much tension, with riding air, the problem wheel has significantly higher tension, we may back it off a little and stess releive it and see what happens. I will post the final solution.

My thanks to everyone for the ideas -- Bill

 

[tuscanybill]

Ok all that maybe interested. Here is a follow up, the LBS had the next try (I went on Vacation) they stress relived the rim two times before the truing stayed put. The wheel owner marked the nipples and after a time found the wheel drifting out again and found an offending spoke that loosened, he turned this one back to the mark and the wheel is true once again. We are going to try to wick a drop of locktite #290 in and see what happens.

As you can see we got a lot of good input and just wanted to let you all know how we made out so far. Thanks -- Bill