Bicycle Mechanics - Wheel truing on a Nexus 8-Speed hub

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Hello everyone.
Here's a quick question asked from a friend concerning the Nexus 8-speed hub... do both sides of the spokes have the same tension (as in the front tire) or do you need to true the wheels with higher tensions just like a standard derailleur?
mrrabbit
09-10-12, 12:29 PM
It's an asymmetrical hub - there's actually roughly a .5mm - 1.0mm difference in spoke length.
So the drive side tension will be a little higher. Assuming the rim can handle it - I'll finish off in the 100-107 kgf range.
Remember to properly dish the wheel using a dishing tool or using the flip-flop method with axle rotation in a truing stand.
Also in many cases, I'm lacing these 2X instead of 3X.
=8-)
The rim is a Rigida X-Star 17 with around 500km on it and is only slightly un-true from normal mild use. Should my friend inform the LBS (which probably has never worked with a Nexus hub) to check the tension to the above mentioned specs (100-107 kgf)?
mrrabbit
09-10-12, 01:47 PM
While most brand name basic and replacement rims are typically on the heavier side and can handle 107-110 kgf on the drive side in your typical 7/8/9/10 speed rears, I am unfamiliar with that particular Rigida (Weinmann?) model.
So until the rim manufacturer can provide the info, or another wheel builder who has worked with that rim chimes in, for now, as others would say, focus on relatively even tension, proper stress relieving, and proper dishing of the wheel.
=8-)
(Dishing when building a wheel means centering the rims between the locknuts of the hub...or the end caps in some cases.)
=8-)
There's never a reason to tell someone how to dish your wheel. With a few extremely rare exceptions, all wheel's rims are centered between the hub lock nuts (inside of dropouts). When the hub is symmetrical, like typical front hubs, the rim will also be centered between the flanges with equal tension of both sides. If the hub isn't symmetrical, the spoke length and tension won't be either.
mrrabbit
09-11-12, 08:06 AM
There's never a reason to tell someone how to dish your wheel. With a few extremely rare exceptions, all wheel's rims are centered between the hub lock nuts (inside of dropouts). When the hub is symmetrical, like typical front hubs, the rim will also be centered between the flanges with equal tension of both sides. If the hub isn't symmetrical, the spoke length and tension won't be either.
1. Of course there are reasons to tell someone how to dish a wheel. And it is also standard fare wheel advice.
2. I've been stating exactly that as the "verb" type of wheel dish for as long as I've been here. Was that for me or the OP?
=8-)
1. Of course there are reasons to tell someone how to dish a wheel. And it is also standard fare wheel advice.
2. I've been stating exactly that as the "verb" type of wheel dish for as long as I've been here. Was that for me or the OP?
=8-)
My point about never having to tell someone how to dish a wheel was directed at the OPs question as to whether the LBS needs to be told. I consider this a catch-22. Since ALL wheels are built centered on the axle, whether and how much to dish a wheel is axiomatic and determined by the hub, so there's no need to restate the obvious. Furthermore, if a professional needs to be reminded, then one must wonder why you'd trust a wheel to that person in the first place.
When you bring a bike in for a gear adjustment, do you also have to remind someone that you expect the RD to center under each sprocket? When you go to the doctor, do you need to remind him that normal blood pressure is 110/70?
Don't make this into rocket science, The OP was bringing the wheel to a pro, and should expect him to know his job.
I don't get question #2, but in any case, in case you have thin skin, nothing in my earlier post was directed at you. If I want to direct a post a someone (anybody) I'll be clear about it.
mrrabbit
09-11-12, 08:42 AM
LBSes when providing mini tune up service frequently will true wheels without concern for dish.
Some will do the same for quick off the bike wheel true.
A customer who informs an LBS of their expectations achieves two things:
1. Put's the LBS on notice that they do know a thing or two.
2. Keeps the LBS honest.
Of course it can irritate an LBS, but business is business.
=8-)
Your points are valid, though they indicate an extremely low opinion of bike shops. That brings up the question of why anyone would pay a so-called professional if he so thoroughly distrusted his knowledge, skill or diligence.
I don't deny that there are crappy, ignorant mechanics out there, but if you hand your wheel to one, telling him how to do his job won't magically make him better at it. IMO if you feel the need to tell a professional how to do his/her job, you need to find somebody else.
mrrabbit
09-11-12, 09:09 AM
Your points are valid, though they indicate an extremely low opinion of bike shops. That brings up the question of why anyone would pay a so-called professional if he so thoroughly distrusted his knowledge, skill or diligence.
I don't deny that there are crappy, ignorant mechanics out there, but if you hand your wheel to one, telling him how to do his job won't magically make him better at it. IMO if you feel the need to tell a professional how to do his/her job, you need to find somebody else.
You are assuming the customer knows the LBS or mechanic is bad or dishonest to begin - especially a first time customer.
=8-)
I stated my opinion, you stated yours, we both clarified out opinions, and as of now you have the last word, so maybe we can move on.
fietsbob
09-11-12, 11:59 AM
Use the dishing stick to get it right.. for some , just flipping the wheel over in the stand suffices.
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