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Old 03-08-11, 01:36 PM   #1
bikerx68
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Problem truing Shimano WH-7850 C24 CL front wheel

I have a new set of Shimano WH-7850 C24 CL wheels and am having a problem truing up the front wheel. the wheel has 16 bladed spokes and is radially laced. What is happening is that when in the truing stand, I get the wheel trued almost perfect. But when spinning the wheel in the stand, the indicator rubs right where the spoke enters the rim. This happens on each side at every other spoke (due to the spokes going to alternating sides of the hub). I hope I explained that right. I also had the same problem with Shimano WH-RS80 (same rim and spoke count as the dura ace) front wheel. Anyone else have this problem? Any tips or tricks?

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Old 03-08-11, 03:21 PM   #2
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These are new and need to be trued? The shop you bought them from should be able to help you with them. What did you do to solve the problem with the last set?
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Old 03-08-11, 03:28 PM   #3
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Originally Posted by bikerx68 View Post
I have a new set of Shimano WH-7850 C24 CL wheels and am having a problem truing up the front wheel. the wheel has 16 bladed spokes and is radially laced. What is happening is that when in the truing stand, I get the wheel trued almost perfect. But when spinning the wheel in the stand, the indicator rubs right where the spoke enters the rim. This happens on each side at every other spoke (due to the spokes going to alternating sides of the hub). I hope I explained that right. I also had the same problem with Shimano WH-RS80 (same rim and spoke count as the dura ace) front wheel. Anyone else have this problem? Any tips or tricks?
Thanks
Are you using a spoke holder to prevent the spokes from twisting/windup? I have the C50, same spokes and never had any problems.
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Old 03-08-11, 03:33 PM   #4
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These are new and need to be trued? The shop you bought them from should be able to help you with them. What did you do to solve the problem with the last set?
How does this answer his question?

Sometimes, a wheel could go out of true from hitting an unexpected pothole, and maybe he bought it from a seller a thousand miles away.
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Old 03-08-11, 03:39 PM   #5
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How does this answer his question?

Sometimes, a wheel could go out of true from hitting an unexpected pothole, and maybe he bought it from a seller a thousand miles away.
1st question is just to ask why a brand new wheel needs truing and suggesting that the seller should be able to help/
2nd question is to suggest that the solution used on the previous wheelset with the same spoke pattern and problem might help on this one.
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Old 03-08-11, 03:39 PM   #6
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this is why i would only buy new
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Old 03-08-11, 03:42 PM   #7
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The OP doesn't know how to properly true and tension balance the wheel. Either that or the rims are bent, but to be bent in the symmetrical pattern the OP suggest is ridiculous.
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Old 03-08-11, 03:43 PM   #8
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1st question is just to ask why a brand new wheel needs truing
Sounds like you've never assembled or looked at any brand new wheel out of a box. Shipped directly from a supplier or distributor.
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Old 03-08-11, 03:46 PM   #9
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this is why i would only buy new
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I have a new set of Shimano WH-7850 C24 CL wheels
The OP says they are new.
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Old 03-08-11, 03:48 PM   #10
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Sounds like you've never assembled or looked at any brand new wheel out of a box. Shipped directly from a supplier or distributor.
Just lucky I guess. I have seen plenty needing more tension but rarely needing trueing. I might also expect a little more from a Dura-ace level wheelset than from a run of the mill low or even midrange set.

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Old 03-08-11, 03:55 PM   #11
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My bet is that the OP is not very adept at truing wheels (bladed spokes, especially).

He needs to use a holder to prevent the bladed spokes from twisting up. Also, I hated/loathed the spoke wrench Shimano supplied with my wheelset. The ParkTool blue handle spoke wrench is the correct size for those nipples. I bought one from E-bay for about $6. I recommend them.
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Old 03-08-11, 04:01 PM   #12
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Here is more info about the wheels:

-they were bought new from www.wiggle.com and arrived in factory boxes, were and still are within about .5 mm true
- I do know how to true a wheel, have been truing wheels for about 10 years on my personal bikes and friends bikes.
- they did come with the shimano spoke wrenches and I am using them properly to prevent twisting/windup on the spokes.

Let me elaborate on the issue: the wheels would be considered trued within spec by any shop that looked at them. I just have never seen this type of issue before on a wheel. It seems to me like the spoke tension is pulling the rim laterally out ever so slightly in the direction that the spoke is pulling. I don't have a tensionometer so I can't give a number on amount of tension, but using the "pluck the spoke" method, the spokes are all very close in tone, if not exact.
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Old 03-08-11, 04:06 PM   #13
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Here is more info about the wheels:

-they were bought new from www.wiggle.com and arrived in factory boxes, were and still are within about .5 mm true
- I do know how to true a wheel, have been truing wheels for about 10 years on my personal bikes and friends bikes.
- they did come with the shimano spoke wrenches and I am using them properly to prevent twisting/windup on the spokes.

Let me elaborate on the issue: the wheels would be considered trued within spec by any shop that looked at them. I just have never seen this type of issue before on a wheel. It seems to me like the spoke tension is pulling the rim laterally out ever so slightly in the direction that the spoke is pulling. I don't have a tensionometer so I can't give a number on amount of tension, but using the "pluck the spoke" method, the spokes are all very close in tone, if not exact.
Then, what is the issue? If the lateral trueness are within .5mm tolerance, then that is good. This tolerance is what I aim for in my wheelsets.
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Old 03-08-11, 10:49 PM   #14
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I am not sure, but it sounds like you are trying to fix something that isn't broken.
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Old 03-09-11, 06:54 AM   #15
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after thinking more about it, I am going to de-tension the the wheel a bit and then retrue to see if that makes a difference. they may have come from the factory with too high a tension which could be causing the rub with the truing indicators
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Old 03-09-11, 07:06 AM   #16
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I think you are on the right track in reducing spoke tension if the braking surface is being deformed at each spoke on a given side.
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Old 03-09-11, 07:19 AM   #17
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Is it even possible for a lightweight 16 spoke wheel to be perfectly true? It sounds to me like a normal amount of deformation considering the large gaps between same side spokes.
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Old 03-09-11, 12:11 PM   #18
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Both the rims you referenced are composite rims and its definately not what I would consider normal behavior. Haven`t any first hand experience myself but would suggest you contact Shimano tech support directly with an inquiry.
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Old 03-10-11, 08:17 PM   #19
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All, thanks for the great info. I am buying a Park tension meter so I know that I am within spec for the tension before I hit the road to test.
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Old 03-11-11, 02:40 AM   #20
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All, thanks for the great info. I am buying a Park tension meter so I know that I am within spec for the tension before I hit the road to test.
Let us know how things are resolved.
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