AEO

there is a technique to bend badly warped rims so that they become straighter.

I think it involved delacing it and working it against a door frame. There is a thread in here somewhere that elaborates it better and DannoXYZ made the post.

mrrabbit 

Before we go to that extreme, it would be nice if the OP can dig up a DV Camcorder that can do 720p or 1080p or just 720x480 / 640-480 up close in focus and without blur and spin the wheel.

Would like to see what the OP sees...

=8-)

ultraman6970

The one i have used is just a hammer and wood pieces, if the rim is V profile you cant hammer up for example. The other thing is that the darn rims are stupidly hard to bend with a hammer if you hit them like an old lady.

Is not hard to do and is just common sense. In the case of the OP i would try to get the wheel right one more time and if the same spots are giving problem just 2 pieces of wood and a wooden working table will do the trick.

In a race got an accident back in the day, half of the rim was wobbling like 2 cm to the left, the rear 2.5... were a pair of gp4s, took it to my team mechanic and I saw him loosing the whole wheels taking a hammer and some pieces of wood with the rim shape from a draw. I told him.. "are u f... kidding me right? you will dent the rims"... -no, u can't imagine how hard this rims in specific are, and started wacking the GP4 rims big time that was just unbelievable for me (at 15 y/o is hard to believe). 30 mins later the darn wheels were almost perfect, saved a lot of cash and daddy super happy

Personally i have worked out some rims too, sometimes is the only way to get close to total roundess. 2 mm i think is too much, 1 mm for me at least is not like a big deal.

canam73

It shouldn't be possible, but any chance you mixed up a couple of drive side/nds spokes? What is your lacing pattern, anyway?

This shouldn't cause the un-evenness among spokes on the same side, but that hub does seem to have a large difference in flange offset. Your listed tensions average to around 95 drive side to 50 non-drive side. What is your drive side target tension and have you cranked them any higher to see if things even out? I have a set of those rims and the rear is laced 3x with DT comps on both sides to a WI hub and my tension with a tire mounted and inflated is 120ds/63nds =/-5 with proper dish.

mrrabbit 

That mix-up possibility did slip into my mind...maybe there's a slight chance that a non-drive spoke or two ended up on the drive side - and have already run out of threads? But I think the OP would notice wind-up in the spoke?

Still a non-blurred close-up video would be nice....

=8-)

mrrabbit 

Just curious OP, a couple questions:

1. I get 290.3749 and 285.2720 - when rounded down plus -.035 for hole diameter slack:

289.50 and 284.50 for spoke lengths...

What did you use?


2. Did you use 10mm standard profile brass nipples on the drive, or are they 12mm standard profile brass nipples?

(I'm assuming the alloy non-drive nipples were 10mm...)

=8-)

cny-bikeman

Again, your ease in getting the other wheel OK reinforces the likelihood of a rim defect. The trueness is irrelevent, just a side effect of the rim defect causing the out of round/tension problem. Rather than waste your time further, if purchased new and recently I would contact the seller of the rim and show them this thread.

blaronn

I'll try to get some video tonight or tomorrow night. It won't be HD - just from an old digicam, but it should be clear enough to show what's up.


I suppose it's possible but I was pretty careful. Besides, DS is Competition and NDS is Revolution. It'd be hard to mix those up and not notice. More likely would be that there were a couple odd-sized spokes mixed in with one of the spoke batches. Still, I did check and they all looked to be the same length.


I'm doing 2x lacing in back.


I'm shooting for 120-130 kgf but haven't gotten any higher than listed in my first post. I backed them all off and am starting over.


DS = 286
NDS = 290

Online calculators consistently told me 285.2 or 285.3 DS and 290.3 or 290.4 NDS. I went with 286 DS and 290 NDS due to availability. These spokes worked great on rear wheel #2.


Isn't 12mm standard length for nips? All the nipples I'm using are 2mm x 12mm.


I'm learning a lot from trying different things with this rim so I'll give it another go or two and post video. If the next couple attempts don't work and the video convinces you guys that it's a bad rim I'll take it back to the LBS (ordered through QBP).

eddy m

3 thousands is way more than "pretty true". The Park website says 1 mm true and 0.5 mm round is acceptable. that's 40 and 20 thousands. My Racelite manual says 16 thousands. I need a dial to see anything less than about 15 thousands, and a properly tensioned wheel may have a 3 thousands dip at each spoke hole. If you need to correct large tension errors, chances are you will settle for something up to around 50 thousands, which is still straighter than even the best tires.

em

ultraman6970

No matter from where u got the rim, rims are not perfect, never seen a perfect rim thats why u have to play with the spoke tension but in some cases u just have to live with the problem or hammer the rim a tiny bit to bring some spoke tension closer to what it suppose to be.

For example ...70.......88 <-- two spokes adjacent to the seam , this doesnt surprise me at all. The seam is always weird, sometimes u get super tight spokes sometimes you get the opposite. But then u moved off the seam and u have spokes that are lose too, to me the rim is not that good. But wonder if the tension tool is reading right. Remember too that the non driver side always have less tension than the driver side, so if you are around 70% in the non driver side that's kind'a right.

Where are u located blaronn??

dbg

I've done it before. (had a couple of spokes mis-laced and didn't realize it for the longest time) Maybe I'm just a dufus but you might triple-check your lacing one last time. (Symptoms fit: a couple of spokes that are way off normal tension.)
Sorry for suggesting it again. Just trying to be thorough.

blaronn

From my obviously limited experience it seems that just a round of stress-relieving (or mounting a tire, or riding around the block) will take the wheel out of true WAY more than 0.003".


On rear wheel #2 (the one that built up fairly easily) I had DS tension around 120-130 and NDS tension near the mid-60's. Like someone said earlier, this hub has pretty narrow DS spacing.


In the mecca of cycling , Kansas City.

Retro Grouch 

If it's round 2.9mm of lateral runout is a piece of cake.

I identify opposing pairs of spokes, tighten one and loosen the other by the same amount - probably 1/4 turn initially and 1/8 turn if subsequent adjustments are necessary.

cyccommute 

Even worse is that Mr. Rabbit says that 3 thousandths is 'sacrificing' some trueness.

blaronn

Yeah, I don't have any problem getting it true; the problem is keeping even spoke tension at the same time.

mrrabbit 

Assuming the hub you specified...

289.50 non-drive
284.50 drive

Assuming the Velocity A23 ERD was aiming for the screwdriver flat of a 12mm nipple - that's what I get. Yet you are indicating that you are using 286.00 as one of your spoke lengths...

Did you test the spoke thread and nipple behavior to see how far into the nipple head the spokes poke through? Because I think there's that possibility that you may have run out of threads on a few of the spokes on the drive side.

You said you have backed off on all the spokes - might be a good time to do a test...if the drive side spokes are semi-tensioned right now and the drive side spokes are already a thread or two past the flat - that's a warning sign itself...

https://www.youtube.com/watch?v=gCXFK...H7Boe2oBRcEd-L


=8-)

mrrabbit 

This is a finished wheel AFTER stress relieving....

+/- .002 (that's .004 total...)


https://www.youtube.com/watch?v=szd8a...ZtC6NZEIgjD4Qr


=8-)

mrrabbit 

Of course! I don't want to be too generous!

=8-)

mrrabbit 

If you are referring to Bontrager Racelite which I assume are the paired spoke type - then of course there's a lot more allowance...

=8-)

well biked

Off topic, but those are some of the most ridiculous wheels ever, IMO. It's such a routine thing to see cracks in those Bontrager paired spoke rims that when we get a bike in for a tuneup that's equipped with them, before we even get started we inspect the rims closely for cracks at the spoke holes. There's a high probability that we will find some. Such a ridiculous design IMO. When we do find cracks, we inform the customer and they usually choose to go take it up with their Trek dealer......if not, we usually sell them a wheelset..

blaronn

+1. Coincidentally, I'm building this wheelset specifically to replace a Bontrager Race wheelset. Not my fave either.

ultraman6970

I was asking you where u live because if you where close to me just to see the wheel in person and give you a hand.

Another option nobody mentioned is that the hub holes are giving up or that the holes are not even distributed around the flanges or u have some holes in that hole that are upper than other ones for a bit.

Or the spokes u picked were used or are so bad that they stretched from look at them.

mrrabbit 

spoke length...nipples...threads...visual check...test....

Check the 286.00 side especially....

=8-)

reddog3

OP- If you are a relative noob to wheelbuilding, as I am, you learn something from every wheel you build. And if you only build for yourself it's hard to get enough experience to learn much. When I started I was lacing and relacing everything I could get my hands on, and that included friends bikes with factory built wheels. So there is everything to gain by starting over totally on wheel #1.

One conclusion I've come to is that a perfectly round and true wheel may not have equal spoke tension, and vice versa. Some rims are better than others to acheive this, even within the same brand and model. Some rims have a greater dip at the seam, or spokehole than others. If it's greater than .040-.050" I consider it a rim problem and may can it, trade it or whatever. I also don't feel it's worth worrying about a bit of a dip, cuz I ain't figgered a way to get it out totally. If I'm satisfied with everything else about the wheel, I mount the tire and find the high spot (there usually is one) then remount the tire with the high spot at the dip in the rim.

One thing I do if I can't achieve easily, what I consider my standard for trueness, is to tear it down and flop the rim over (assuming it's not offset). It may be my imagination but it seems that some rims are easier to move in one direction than the other. Or... maybe it's just the experience gained from doing it one more time.

A couple other little things I think I've learned have really helped to produce a wheel that is more equal in spoke tension while being very true. One is spoke stressing during the tensioning/trueing process. When you think you've stressed the spokes to the point of bending or breaking them- give 'em one more tweak. Another is "hugging" the flange on the outside spokes. I manually adjust the bend on an old hub to tighten it up.

I also don't check tension until the very end when I'm satisfied that it's up there and the wheel is true. And then it's only to confirm that I'm really-really close. I may or may not tweak it a bit more, depending. If it's +/- 5% I leave it.

Now... Mr. Rabbit comes along and sets the bar a little higher (thanks bud!) with regards to trueness, or so I thought at first glance. I have fixed indicators on my homebuilt stand, and set them to rub the rims for final truing. If the variation is looser than the thickness of a piece of paper, I work it out if I can. So... that's .004" or so. So, Mr. Rabbit's standard is doable after all.

Keep after it. I think you'll get it.

ultraman6970

Agree with the previous poster, one of the things I do with rear wheels is work out the driver side 1st and then when im satisfied and the wheel is round and true I do the non driver side.