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Old 06-08-09, 05:48 PM   #1
Kendeathwalker
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First Wheel Build- Slight Problem

Did a quick search and nothing turned up.

So here's my issue. Just built up my first rear wheel and took it out for a spin and noticed that the tire will slightly rub the left side of the frame when going through turns etc..

Here's a visual to show how tight the fit is.



Dont know if this is necessary but heres how much space the drive side has



(I looked at a couple other bikes and I can see this is very wrong.. but generally on the rear wheel the drive side has more room right?)


So I dont have a truing stand, dish stick or tensiometer so I built the wheel up in the rear triangle and trued it up by taping q-tips to the frame. Before I took it out for a ride I stopped by LBS and had a mechanic check it. He told me everything looked great, he checked the radial/lateral trueness and the tension with a tensiometer. Unfortuantely he did not check the dishing.. I think thats what my problem is? The dish is off? To correct this problem ill need to tighten the drive side spokes (say 1/2 turn) and slightly loosen the non drive spokes(say 1/8-1/4 turn)?

I tried to check the dishing when I was building it up by reversing the wheel in the frame and then seeing if it lined up in the same spot between my q-tip truing feelers but it was a little difficult to get the wheel out of the frame with out slightly knocking them askew..

Its not a fat tire as its just a 2.0 and I never had this issue with my last wheel.




On a different note Im having one hell of a time getting my front deralieur to shift between the first and middle chain ring properly. I can get it to shift smoothly in the stand but when im on the bike It wont shift back down to the first ring. I let up on the tension just a little and it is really sloppy climbing back up to the second ring. Not sure if any one here can offer me advice I haven't already read about, just putting it out there in case..


I appreciate any advice any one cares to give me. I felt really good about my first wheel build being "approved" by the LBS.. then felt like a dumb **** when the tire started rubbing the frame.. Very frustrating process.
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Old 06-08-09, 06:40 PM   #2
mobaar
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Yep. Dished incorrectly.

On a geared rear wheel, the drive side spokes need to be much tighter than the non drive side to get the correct dish.

I'd loosen all the spokes up and retension paying more attention to the dish. You can get it pretty close by eyeballing. Especially if your frame has a bridge on the seatstays with a hole in the center for a rack/reflector or the like.
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Old 06-08-09, 06:58 PM   #3
Kendeathwalker
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I have that bridge with the hole, are you saying that the center of the rim should line up that hole?



Whats confusing to me is that there is supposed to be more space on the drive side between the tire and the frame than the non drive. Or am I just looking at improperly dished wheels as a reference?

If I were to say clamp a ruler to my frame and mark where the two sides of the rim touch it exactly.. when I reverse the wheel in the frame is the rim supposed to line up exactly with those marks?

Last edited by Kendeathwalker; 06-08-09 at 07:18 PM.
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Old 06-08-09, 07:00 PM   #4
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Wtf. Is the wheel sitting properly in the rear dropouts.\? You want an even gap on both sides. That is

1) assuming the wheel is dished properly
2) the rear triangle is not out of alignnment

K.
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Old 06-08-09, 07:19 PM   #5
Kendeathwalker
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It is seated properly

.. And the problem is now becoming painfully clear to me that I completly ****ed up the dishing.

no issues with the rear triangle.

Last edited by Kendeathwalker; 06-08-09 at 07:36 PM.
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Old 06-08-09, 07:21 PM   #6
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Originally Posted by operator View Post
Is the wheel sitting properly in the rear dropouts.\? You want an even gap on both sides. That is

1) assuming the wheel is dished properly
2) the rear triangle is not out of alignnment

K.
+1
First make sure the axle is seated properly in the dropouts. It's usually necessary to have the bike with wheels on the ground with the full weight of the bike on the wheels when the quick release is closed or the axle nuts tightened.
To check for dish reverse the wheel on the bike or on a truing stand. If the rim moves over to the other side then it is out-of-dish. Proper dish means that the rim is centered between the dropouts, seat stays, and chain stays. In other words, the rim should be aligned with the center plane of the frame.

Al
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Old 06-08-09, 08:49 PM   #7
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Dishing... What a fun thing. You got the principle right - you want to loosen all non-drive-side spokes and perhaps tighten all drive-side spokes. The difference in tension between the drive-side and non-drive-side spokes is really high, especially if you have a 8+ speed cassette and a symmetric rim (as opposed to an asymmetric, or off-center rim).

The drive-side spokes will easily have twice as much tension as the non-drive-side spokes. I've seen figures as to the tension difference between drive-side and non-drive-side spokes but I can't seem to find them again - the difference is huge, though.

You're not looking at half-turn adjustments here. My guess is that you'll need to loosen your non-drive-side spokes by a couple of turns each. Assuming that your drive-side spokes are at the proper (quite high) tension already, you won't need to increase their tension.

Since you don't have a dishing tool, I suggest you do the redishing with the tire on. Eyeball it, and measure the chainstay-to-tire distance on both sides. Once the dishing seems good, which you'll achieve by relieving a lot of tension on the non-drive-side spokes, retrue the wheel in both lateral and radial aspects.

Once you're about done with the truing, don't forget to give all spokes a good stress relief, and don't be afraid to use a lot of force in that operation. Small and light bike mechanics put the wheel on the floor and walk on it, and the hit of a pothole is probably more than your hands can deliver - so put on gloves, grab the spokes four at a time, two pairs from each side, and squeeze them as hard as you can. You could also do the stress relief with a left-side crankarm, like Sheldon did. Stress relief is a critically important part of building a wheel that will stay true.

As for your front derailleur shifting issues, well... Triple chainrings are more capricious than doubles. You need to have the cable tension right, but more important that that, your low limit screw needs to be adjusted perfectly or you won't get good shifting performance.

Good luck!
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Old 06-09-09, 07:23 AM   #8
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Quote:
Originally Posted by hernick View Post
You're not looking at half-turn adjustments here. My guess is that you'll need to loosen your non-drive-side spokes by a couple of turns each. Assuming that your drive-side spokes are at the proper (quite high) tension already, you won't need to increase their tension.
If he's going to loosen up the NDS spokes, he'll need to add tension on the drive side. I can't say how many turns of the nipples he'll need to get the dishing correct but I would advise working around the wheel removing a half to a full turn at a time (less as the dishing gets close to correct) from the NDS and adding it on the DS. Check the trueness in between sets of adjustments to make sure you are doing things evenly.

And next time, check the dish while you are building the wheel

Quote:
Originally Posted by hernick View Post
As for your front derailleur shifting issues, well... Triple chainrings are more capricious than doubles. You need to have the cable tension right, but more important that that, your low limit screw needs to be adjusted perfectly or you won't get good shifting performance.
Yup, low limit screw. With the increased tension on the chain from pedalling, the FD needs to work a little harder to derail the chain while riding than when on the stand. Back the low limit screw out 1/4-1/2 turn and it should downshift just fine.
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