|what should i pay to re-dish my wheel - or can i do it...||surf|
Jan 9, 2002 10:51 AM
|I am a pretty mechanical and a do it your self kinda guy, but new to bikes. What should i expect to pay? Any tips if i do the re-dish myself. Thanks alot|
|re: what should i pay to re-dish my wheel - or can i do it...||TJeanloz|
Jan 9, 2002 11:22 AM
|First of all, you probably don't have the right tools to dish a wheel yourself- it requires an inexpensive and not complicated tool.
At the bike shop, re-dishing should fall in the same category of truing, so $10-$15 should do it.
|re: what should i pay to re-dish my wheel - or can i do it...||JimP|
Jan 9, 2002 12:47 PM
|I second that the LBS would be best to do it. If you do get the dishing tool, you have to not only change the dish but retension the spokes. Getting the wheel flat isn't too much of a problem but the real issue is getting it round. I built a great set of wheels with campy hubs with radial front and radial non-drive and then found that the hubs didn't like the tension I ended up with to get everything flat and round. So much for those hubs. Since then I have had my spoked wheels built for me and they have lasted much longer than my efforts. Of course you start building from scratch and use a tensionometer you can do a great job. Good luck..|
|But if you still want to do it yourself...||guido|
Jan 9, 2002 1:39 PM
|You need a spoke wrench, a dishing gauge, and a long afternoon, all of which will probably cost more than your local bikeshop would charge.
The rim can be centered with the wheel on the bike, but how good is your eye? The dishing gauge tells you the often unpleasant truth, when it says you're off 2 mm after you've finally gotten the rim to run true. Those shorter spokes on the freewheel side also have a tendency to get too tight, and the longer left side spokes too loose, as you try to bring the rim into center, always in the direction of the shorter spokes.
Looking onto the inside of the rim, the spokes tighten clockwise, loosen counter clockwise. The idea is you take basically an isoceles triangle and tilt it over to the right slightly, by lengthening one side and shortening the other.
The dishing tool is a V shaped bar which sits on the same side of the rim at two places 180 degrees apart. It has a pointer in the middle, which is set to contact the end of the axle, when the dishing tool is held onto the rim. The rim is centered when both sides of the wheel fit the dishing tool exactly the same. The pointer will tell you within a millimeter if its off.
The wrong sized wrench will, trust me, round off at least two or three spokes nipples before you're done. When this happens, you're screwed. You have to replace a nipple, which means detensioning the spokes so the rim won't do a warp sideways when you take all the load off one spoke. The spoke wrench should fit snug onto the nipple flat. Any play will eventually round off the flat.
When you've gotten the wheel perfectly true and dished, if any of the spokes aren't "tensioned" that is, don't produce a musical tone when plucked, but a dull "thud," the wheel will go out of true sooner rather than later, often within a few hundred miles. If you can get all the spokes to make the same note (middle "C" has been suggested), the wheel will remain true for many years, or until your first hard crash.
Have fun. A spoked wheel, like a suspension bridge, is a wonder of technology.
Jan 9, 2002 1:52 PM
|The spokes on the freewheel side are shorter, so they'll make a higher note when tensioned. The left side spokes will make the middle "C. '|
Jan 9, 2002 5:37 PM
|It's the distance from the hub to the nipple that is shorter. It makes no difference what the length of the spoke is, only the length of the tensioned portion influences the pitch of the plucked spoke note. A common misconception.
Regards the broader issue of re-dishing (assuming you need more dish): 1) loosen every non-drive side spoke 1/2 turn, 2) tighten every drive side spoke 1 turn, 3) eliminate dish, wobble, and hop, 4) repeat if more dish is needed. You won't change the overall wheel tension much with this approach, so if the wheel is good to start, it should be pretty good when you're done. All of this assumes you have a good spoke wrench, and a good mechanical feel for what you are doing. Worst case: you don't like the result and you take it to the bike shop for sorting out.
Jan 9, 2002 8:35 PM
|Always release spoke tension first, tighten next. In fact, if some of the spokes are really tight and the nipples might round off, loosen all the spokes two or three turns, then get rid of hops, then true, with all the spokes relatively untensioned. When the wheel is round and true, then tension all the spokes methodically a half turn at first, then as the spokes get tighter, a quarter of a turn at a time. The rim will stay round. All you'll have to deal with is true.
Thanks, Kerry, for pointing out the spoke tension is from the hub flange to the nipple, like a guitar string and tuning peg.
Jan 9, 2002 2:05 PM
|If you do it yourself expect to pay someone more to straighten out the mess you make. It's not rocket science, but until you have some experience it's fairly easy to screw it up. then even if everyhting loks right your wheelwon't stay true and you may even break some spokes. then it really won't stay true. You then get to start all over again. While a wheel can be built, tured and dished with nothing more than a bike frame and a spoke wrench it's much easier with a trueing stand. This is one of those things where paying someone to do it right the first time is the much cheaper choice. |
Of course if you're bound and determined to do it yourself you can do it, but it is going to be a learning experience and will take some time. Read Jobst Brandt's book, The Bicycle Wheel, while your wheel is in the shop.