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Old 09-12-10, 11:15 PM   #1
curb hash
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A trick to cheap rim truing?

I have an alloy framed Walmart cruiser that I bought as a fun beater and rain bike. I've had the bike a few months and just got around to taking some of the wobble out of the rims. I started the job as I do with my other and friend's bicycles by getting the spoke tension reasonably even with my Park tension meter.

After getting the spokes close to evenly tensioned both rims are now wildly laterally but not radially out of true. I spent hours trying to get these cheap alloy rims reasonably true and they are still a mess. I noticed that many of the pairs of spokes had very different tension readings before I started try to reasonably even out the tension.

This bike has only been ridden a few times and I weigh about 132 lbs so I don't believe the rims suffered any damage. I have had this happen once before trying to tighten and true a friend's big box store Schwinn mountain bike's rims- I finally had to take it to my LBS because I screwed them up so badly. I don't want to give up on getting this bike's rims back in shape- I want to learn how to true even crappy rims.

Is there a trick not normally done with reasonable quality rims?
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Old 09-13-10, 02:28 AM   #2
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Awh, I never use a tensiometer, but anyway ... I do it by heart, whatever leaves me good feeling. Rims aren't perfect that's why you are getting a wobble with perfect tension. The idea is that when you tighten a spoke next to the seam, the "opposite" spoke at the valve stem will get tighter too, as well as adjacent spokes on both sides.

Screw your nipples out evenly, start truing again and when you have it, just tighten all of the nipple for a given amount (be it a 1/4 or 1/2, but never go full turn).

My bike shops in the area are the worst wheel truers I ever found. They alway tighten spokes so much, they start to creak and cry. They are so tight that in a course of a year they will begin to break. After these experiences I said to myself if you're gentle with women, you'll start building good wheels someday too
After my third wheel, I graduated from wheelbuilding

On the funny note: when I laced my first wheel and took it to one of LBS in the area, he was tightening so much that every other spoke snapped and he was *****ing "what the heck is wrong with this wheel". I know what was wrong, I had used 12mm nipples instead of 16mm and spokes were a bit on the short side. I expected him to see that since he's a master wheelbuilder (so he says).

Last edited by constant mesh; 09-13-10 at 02:48 AM.
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Old 09-13-10, 03:06 AM   #3
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Originally Posted by curb hash View Post
I have an alloy framed Walmart cruiser ...and just got around to taking some of the wobble out of the rims. I started the job as I do with my other and friend's bicycles by getting the spoke tension reasonably even with my Park tension meter.

After getting the spokes close to evenly tensioned both rims are now wildly laterally but not radially out of true. I spent hours trying to get these cheap alloy rims reasonably true and they are still a mess. I noticed that many of the pairs of spokes had very different tension readings before I started try to reasonably even out the tension.
It is true that rims can be more or less round from the start, but what's the most probable cause here is that you're missing a solid reference point. Starting with a reasonable round rim, but with some spokes having more turns on their nipples will lead to an imbalance later on.
As suggested by Constant Mesh, back all nipples out until the threading is just visible, then work your way in from there.

After that, it's a three-way balancing act between lateral true, radial true, and tension balance. Giving priority to one way above the others is not the way to do it.
While there is considerable freedom in sequence of work, most would probably say work on true first, then see how far you can balance out the tension w/o unduly upsetting true.
Given the state of most road surfaces, a small radial hop, particularly for a bike that isn't seeing much speed is pretty much a non-issue.
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Old 09-13-10, 07:44 AM   #4
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Do as noted above, and go full rounds of turning each spoke the same as the others. When you reach the point of the spokes being reasonably tight if the rim is still way out of whack then you can safely assume that the wheel itself is physically bent.

I apologize for being blunt, but if you have to ask a question like this I would not recommend you work on your friends' bikes, and you need to learn that wheel truing takes more than a tension meter. You have to get the wheel in good shape, close to final tension first, then use the meter. Otherwise you are trying to tension one spoke in relationship to others that are way under tension.

The "trick" is understanding the purpose of a process and the interrelationship of parts in a system (like a wheel) not just the procedure.

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Old 09-13-10, 08:02 AM   #5
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When I first got my truing stand and tension meter, I trued up a wheel on my bike. I worked at getting the spoke tension even, working my way around the wheel. Funny thing happened though: I was trying to tension each spoke in turn instead of just doing little turns at a time (like constant mesh recommends) and the result was a severely tacoed wheel. I backed off the tension and started again, never tightening more than a 1/2 turn at a time and got the wheel trued up durn near perfect.
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Old 09-13-10, 08:32 AM   #6
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Originally Posted by constant mesh View Post
Awh, I never use a tensiometer, but anyway ... I do it by heart, whatever leaves me good feeling. Rims aren't perfect that's why you are getting a wobble with perfect tension. The idea is that when you tighten a spoke next to the seam, the "opposite" spoke at the valve stem will get tighter too, as well as adjacent spokes on both sides.

Screw your nipples out evenly, start truing again and when you have it, just tighten all of the nipple for a given amount (be it a 1/4 or 1/2, but never go full turn).

My bike shops in the area are the worst wheel truers I ever found. They alway tighten spokes so much, they start to creak and cry. They are so tight that in a course of a year they will begin to break. After these experiences I said to myself if you're gentle with women, you'll start building good wheels someday too
After my third wheel, I graduated from wheelbuilding

On the funny note: when I laced my first wheel and took it to one of LBS in the area, he was tightening so much that every other spoke snapped and he was *****ing "what the heck is wrong with this wheel". I know what was wrong, I had used 12mm nipples instead of 16mm and spokes were a bit on the short side. I expected him to see that since he's a master wheelbuilder (so he says).
As a wheelbuilder who has built thousands of wheels, this post, in my opinion, contains some bad info. Spokes generally don't break because they're too tight, but because they are too loose and fatigue. And unless the spoke was junk to start with, you can pull a nipple right through the rim before the spoke will let go. If someone starts truing a wheel and spokes begin snapping, don't confuse correlation with causation. The spokes were likely too loose to start with, are now fatigued, and break easily now that they are weakened. The poor tension put the spokes on the road to premature failure, not the later true job.

But then again, that's why people like me who rely on repeatability for customer satisfaction use tensiometers. We don't have to guess if the tension is OK or not.

Now, to the OP:

That Walmart wheel is built with hyper-cheap components. The rim is single wall and the spokes are junk. Could I true it? I could make it better-but wheels like that will turn into a potato chip if you try to put the spokes into a reasonable (for any decent wheel) tension range. Which is what yours is trying to do.

Good luck, OP.
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Old 09-13-10, 09:07 AM   #7
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Originally Posted by curb hash View Post
I have an alloy framed Walmart cruiser that I bought as a fun beater and rain bike. I've had the bike a few months and just got around to taking some of the wobble out of the rims. I started the job as I do with my other and friend's bicycles by getting the spoke tension reasonably even with my Park tension meter.

After getting the spokes close to evenly tensioned both rims are now wildly laterally but not radially out of true. I spent hours trying to get these cheap alloy rims reasonably true and they are still a mess. I noticed that many of the pairs of spokes had very different tension readings before I started try to reasonably even out the tension.

This bike has only been ridden a few times and I weigh about 132 lbs so I don't believe the rims suffered any damage. I have had this happen once before trying to tighten and true a friend's big box store Schwinn mountain bike's rims- I finally had to take it to my LBS because I screwed them up so badly. I don't want to give up on getting this bike's rims back in shape- I want to learn how to true even crappy rims.

Is there a trick not normally done with reasonable quality rims?
Yes. With even tension and the wheel in ROUND (this is the correct term for what you refer to as 'radially true') but out of TRUE (lateral), the cause is just a natively untrue rim, which leads to uneven spoke tension when they are true OR even tension and out-of-true. The correction for this is to un-bend it, and it takes a pretty good amount of (calibrated) force. I only do this on damaged or walmart level wheels because frankly, undamaged quality rims don't have this issue.

With tire/tube on and fully inflated to protect the rim edge, slam it on the ground at the highpoint for that side, preferably on a hard-rubber floor mat (like a fatigue mat) to further isolate the rim from potential damage. it'll take a good whallop. Check the true between each whollop and you may have to hit it a few times in different places around the rim. Continuing to attempt to true it via spoke tension alone will only result in frustration and super uneven tension which makes for a crappy wheel.

This is a similar idea but by slamming it on the ground, you can more carefully control how much force you put into it without fear of scratching/damaging the rim. http://2.bp.blogspot.com/_pX_MdfgBxg...elEmergEng.jpg

Just realize, you're polishing a turd and you can only expect so much.
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Old 09-13-10, 10:19 AM   #8
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If the rim is Physically Bent, Or cheap and never was round in the first place,
the spoke tension will go all over the place to bring it back into something
even within 0.125" from true .. lube the nips thoroughly ..

I've seen flat spots in rims come up by pulling the rim over a pole sticking out horizontally .

the 'pull' involves a sharp blow. think Hammer.
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Old 09-13-10, 10:32 AM   #9
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The rims being less than round and flat will actually not cause all that much of an issue with the spoke tension balancing unless the deformation is more of a kink than a smooth arcing type of bend. The forces of the tensioned spokes will easily pull a wobbly rim back to straight provided it's not dealing with a short radius kink. But having said that the single wall rimmed wheels that I've built ended up best when tuned to the lower end of acceptable tension. When I tried to bring the spokes to more like my normal tension the rims ended up pulling out of true with lots of little local wobbles. I played with that one for a while before I gave up and just eased the spokes back down a little. I don't use a tensionmeter so in my case it was more like two notes worth on a keyboard. At that point it trued up easily and nicely flat and I figured that I'd learned a lesson. YMMV but it has worked for the other few of sets of single wall wheels that I've either built or trued up
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Old 09-13-10, 12:29 PM   #10
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Thank you everyone for the information. I'm going to back off both rims and start from scratch with all of your tips. If I screw them up again I have a good quality spare front mtb wheel and I may just order a silver Alex coaster brake wheel with a Shimano hub ($32) from Niagara Bicycles. I don't like the "bad boy" black spokes/black anodized rims anyway.

Constant Mesh, that "Schwinn" I had to bring in to the LBS came back with wildly different readings on the spoke tension meter but, not wanting to open a fresh can of worms I gave the bike back to my friend. She is fairly lightweight and rides easily so I assumed she wouldn't be breaking spokes immediately. Cny- bikeman, I'm not that bad (I hope ) a bicycle mechanic and my riding buddies have no mechanical sympathy or knowledge and are too cheap to go to their LBS so I volunteer to keep their bicycles in reasonable shape.

I have several bicycle repair books- looks like I'll be adding a wheel building book to the bunch. Cheaper and more gratifying than a trip to the LBS.
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Old 09-13-10, 03:55 PM   #11
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Originally Posted by BikeWise1 View Post
As a wheelbuilder who has built thousands of wheels, this post, in my opinion, contains some bad info. Spokes generally don't break because they're too tight, but because they are too loose and fatigue. And unless the spoke was junk to start with, you can pull a nipple right through the rim before the spoke will let go. If someone starts truing a wheel and spokes begin snapping, don't confuse correlation with causation. The spokes were likely too loose to start with, are now fatigued, and break easily now that they are weakened. The poor tension put the spokes on the road to premature failure, not the later true job.

But then again, that's why people like me who rely on repeatability for customer satisfaction use tensiometers. We don't have to guess if the tension is OK or not.
I didn't mean to discredit any good wheelbuilder with what I have said, but to be honest, if I see spokes stripping nipples and one of them even broke on the elbow, but the spokes thread on the drive side is just half covered, you are in some trouble. I know it might be a bit dubious to explain that over the internet, but initially I asked the guy if he gave me the right nipples which were 12mm and old ones were 16mm. But he said it will be fine as long as I use same spoke lenght. Same spoke lenght?! We are talking 4mm difference here. I even brought old components to compare.

If you consider crediting your shop's work, you probably wouldn't want that guy in it. In return he got my dissatisfactory letter and I got a total refund, then bought new spokes at that very shop and my wheel still turns. So... still want my money?

Yeah, spoked wheel is a real brain massager ... I thought that too almost a month ago. It's not like welding and don't get it personal, man.
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