Bicycle Mechanics - Looking for some wheel rebuilding advice

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portsider
11-08-10, 03:31 PM
So I dented up my front wheel hitting a pot hole a few weeks ago. I tried repairing the dent by using an adjustable wrench, but no matter what I do the brakes grab, and I just don't trust the rim. I'd like to replace the rim.
If I buy a Velocity Deep V rim and new spokes, do you think it would be possible for me to rebuild this wheel using only my spoke wrench and my bike (for truing)? I don't want to invest in any other tools, because I don't have a desire to build additional wheels. Or, am I better off having a real wheel builder perform the work?
Thanks
Monster Pete
11-08-10, 03:35 PM
Try looking at sheldon brown's wheelbuilding guide. I used it to build up a wheel with a salvaged rim and 3-speed hub without any problems. It goes from start to finish, from initial 'lacing' of the wheel to trueing and tensioning. You can use the bike as a trueing stand with a ruler rubber band-ed to the chainstays as a guide. This gives you an indication of both roundness and true-ness. You can check the dishing by flipping the wheel over and comparing measurements.
cny-bikeman
11-08-10, 04:02 PM
Yes, one can build a wheel with nothing but a spoke wrench and a bike or fork to mount it on. Can YOU build a dependable wheel, round, true and properly tensioned, with only those items and no previous experience? Perhaps but the odds are against you.
That's not a challenge, just a fact. I think you are better off having a wheel built - unless you can find a quality prebuilt one that has the same hub as you already own.
wmodavis
11-08-10, 05:27 PM
... do you think it would be possible for me to rebuild this wheel using only my spoke wrench and my bike (for truing)? I don't want to invest in any other tools, because I don't have a desire to build additional wheels. Or, am I better off having a real wheel builder perform the work?
Thanks
It is possible to do what you want with a couple of my caveats thrown in for what its worth.
Most of the 'other tools' add convenience, cost and ease but are not really necessary to do a good job.
The spoke wrench should be a quality one or I can guarantee frustration and a likely botched job. Don't skimp here.
Whether you want to ever do it again or not, it is a good basic skill to at least have one real building/trueing under your belt so that you can understand and appreciate your bicycle wheel. They are really key to your bike riding experience though under appreciated by many.
Better off to have a 'real wheel builder' do it? Tha'ts debatable in my mind. Kind of depends whether time or learning are the mose important comodity here. If time is not, then you have the latitude of perhaps doing both. That is, try it yourself for that important learning experience and then if you either get too frustrated doing it yourself (some have) or simply want to have a pro check what you did and in the process relieve you of some of your money (and it may be well worth it) you doubly benefit (except for the $ part or maybe that is also a benefit - kind of depends on how you look at it).
I say try it. Read Sheldon and Park and Musson's 'The Professional Guide to Wheel Building' and any others recommended then go for it.
Jeff Wills
11-08-10, 09:25 PM
Yes, one can build a wheel with nothing but a spoke wrench and a bike or fork to mount it on. Can YOU build a dependable wheel, round, true and properly tensioned, with only those items and no previous experience? Perhaps but the odds are against you.
+1. I have built fine, long-lasting wheels with nothing more than a spoke wrench and a bike frame, but that was after building wheels for 10 years in a shop with a proper truing stand and tools. It takes time to learn how to build a wheel properly, and the correct tools shorten the learning curve immensely.
Doohickie
11-08-10, 09:33 PM
I recently replaced a broken rim on an otherwise good wheel. It was easy as anything, but I did have a truing stand and a spoke tension gage. The gage came in handy because when I was all done, the wheel was all straight and true, but the spoke tension was only a little more than half what it should have been. I probably would have been happy with the wheel at half tension but I bet it wouldn't have stayed true. Some people say you don't need to measure the tension, but getting it just right without a gage is a matter of experience.
davidad
11-08-10, 10:23 PM
If you can find the same rim you don't need to replace the spokes. As long as they are not kinked they are still good. With the same rim or one with the same ERD you can tape them together and removed one spoke from the old one and put it on the new one. I just finished one tonight. The rim was a piece of trash from IRD. It got replaced with a Mavic Open Pro.
You can then use the bike as a truing stand. To get the tension you will need ro keep adding tension a little at a time while stress relieving the wheel after each round. When the wheel comes out of true in a wave back off the tension 1/2 turn retrue and stress relieve and go.
Drew Eckhardt
11-08-10, 10:23 PM
Some people say you don't need to measure the tension, but getting it just right without a gage is a matter of experience.
Lighter (ex: Mavic Open Pro) box section rims with 28-36 spokes can be brought to proper tension by increasing tension 1/4 turn, then stress relieving, and repeating until the rim deforms in waves at which point you've reached its elastic limit, back-off half a turn, and re-true.
This is straight out of Jobst Brandt's _The Bicycle Wheel_.
The method doesn't work for deep section rims, low spoke counts, and/or heavy rim extrusions where the rim's elastic limit is not what's limiting spoke tension.
Drew Eckhardt
11-08-10, 10:35 PM
+1. I have built fine, long-lasting wheels with nothing more than a spoke wrench and a bike frame, but that was after building wheels for 10 years in a shop with a proper truing stand and tools. It takes time to learn how to build a wheel properly
Grade school boys can do it on their first try with written instructions and no additional help.
That's how Jobst Brandt tested _The Bicycle Wheel_
It'll take much less time with experience, it'll much more pleasant with a truing stand, I prefer my tension meter to Jobst's interactive approach, and a Masskrug lets me finish a wheel without returning to the fridge but you don't need those things.
Doohickie
11-08-10, 10:48 PM
The key point is this: Patience. The first time I did a major retruing of a wheel (loosened several spokes to slack and then tried to push out a flat spot from the other side), I tacoed the wheel. I backed off all the spokes again and finally got it to come in. So even if you think you've messed up, just try again.
rydaddy
11-08-10, 10:49 PM
Lighter (ex: Mavic Open Pro) box section rims with 28-36 spokes can be brought to proper tension by increasing tension 1/4 turn, then stress relieving, and repeating until the rim deforms in waves at which point you've reached its elastic limit, back-off half a turn, and re-true.
True, but how many people actually practice this? I'm guessing not many.
I built my first wheels more than twenty years ago, and I've never used a stand. A stand would be nice, but is anything but necessary.
For less than 28 spokes though, a tension meter is highly recommended... I built a 24h wheel once without one and nearly got squashed by a truck because I hugely underestimated the tension required; the wheel just washed out.
As for higher spoke counts, that Brandt move of cranking them up till the rim deforms then backing off just sounds like a bad idea. IMO your mechanical sympathy should stop you laying on the tension before you get that far. Just make your spokes as tight as you think the wheel can handle, and you should be pretty close if you have a clue (I initially built the 24h wheel with about the same tension I'd use for 36h - didn't put the brain in gear).
furballi
11-09-10, 07:57 AM
I prefer to build the wheel on the bike. Secure the frame and the front fork. Use the brake pads or attach two cable ties to the frame for side-to-side adjustment. Attach a cable tie to the seat tube for up-down adjustment. You should be able to achieve +/-0.005" tolerances with this technique. Make sure the rim is centered between the fork or the frame.
The Velocity V rim is very strong. It's also an easy rim to build. A good way to gauge spoke tension is to grease the spokes, nipples, and rim's holes prior to assembly. Lace the spokes so that all the threads are just covered by the nipples. Now increase tension of all spokes by 1/2 turn. Repeat until you feel a slight resistance from all spokes. Check for axial trueness. Side to side trueness can be +/-0.050" at this stage. Once you get axial trueness to better than +/-0.010", then you can work on side to side trueness. Once axial and radial trueness are up to par, then increase spoke tension on all the spokes by 1/4 turn at a time until you hear a squeaking sound when turning a spoke. This indicates that the tension is pretty close to optimum. Stress the spokes and check for axial and radial play.
portsider
11-09-10, 10:56 AM
Thanks for all the replies and helpful advice. Rebuilding sounds challenging, but I think I will give it a try (after reading closely re-reading your advice and directions from Sheldon's site and others). Instead of the Deep V I may try using the Velocity A23 rim instead. It seems to have an ERD within 1 of the Mavic Open Pro. If I choose this rim, I should be able to use the same spokes, right? I like the idea of taping the two rims together and transferring the spokes one by one.
I like the idea of taping the two rims together and transferring the spokes one by one.
I think it's easier to start from scratch. I like Jobst Brandt's instructions best.
It's easier to start from scratch when you're experienced enough not to make lacing mistakes.
But then again, experience has to come from somewhere...
Careful you don't scratch the new rim with the spokes. The advantage to using your old ones is that pre-stressing them will be far less necessary.
Drew Eckhardt
11-09-10, 08:58 PM
True, but how many people actually practice this? I'm guessing not many.
I built my first half dozen wheels the Jobst Brandt method. It worked great - my wheels stayed true after leaving the truing stand. The light rims that got bent/flattened didn't collapse (folding an under-tensioned led me to start building my own wheels) with the last failure being 220 pounds of rider + commuting cargo on a decade old Mavic Reflex clincher with a 23mm tire that was probably under inflated.
On the most recent one I decided that at just $50 a Park tension meter was worth the time savings and ordered one at the same time as the rim. Before de-tensioning I found 110kgf average (just like Mavic recommends) with a tolerance of +9,-5% outside the bent area (which took a 75kgf spoke that wouldn't stay tight and 136kgf on its neighbors to get things ridable with any attempts to balance tension failing to produce a true wheel).
If all my wheels were the same I might just get absolute tension by tone; although that wasn't practical where one set of 32 hole Open Pros has 2.0/1.5mm spokes except 1.8/1.6mm rear drive side, another is 1.8/1.6mm in all three groups, etc.
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