clengman

I've been working on converting an old Takara mountain bike to fixed gear to use for the winter. I'm done with the chainring and crank and I got my rear axle respaced and my chainline is very good. Now I'm working on getting the rim moved over to the left about 1/4" to get it recentered.

I have a Park TS-8 truing stand and TM-1 tension gauge that I have used in the past to check and make small tweaks to several bike wheels in the past. I'm not great at truing, but I manage to get everything close enough for my brakes to work. I've never had to make any large adjustments like this.

I started out by going right around the wheel and tightening all left side spokes by a full turn, then went around again and loosened all right side spokes by a turn. Then tightened left side by half a turn and loosened right side by half a turn. Then took the wheel off, de-stressed it and checked it. It's pretty close to centered now on average. It's not particularly straight at this point, but it's not way way off either.

Then I started checking individual spoke tensions and they're kind of all over the place, from less than 70kgf up to 120 kgf. There doesn't seem to be much correlation between tight/loose spokes and proper position of the rim. What I mean to say is that it seems like in many places if I loosen a tight spoke or tighten a loose spoke it will pull the rim further out of true.

I'm just wondering what might be a good way to proceed from here. Does it make sense to forget about trueness for the time being and try to get all the spoke tensions close to equal and then see where that leaves me? Or should I pay more attention to straightening the rim and just try to keep individual spoke tensions as close to ideal as possible as I go? Or maybe just give up and take it to the shop. I'd rather stay away from the last option if I can. I have put exactly $25 into this project so far including the bike and all the parts. Paying someone to true my wheel would more than double my cash outlay at this point. That and I like learning about this stuff. No better way to learn than by doing right?

Anyway, I appreciate any tips anyone has to give me.

EDIT: BTW I did mark one side of all spokes to make sure I wasn't just twisting the spokes. When I make an adjustment I overshoot and then back off to keep the spokes straight as I go.

fietsbob

I'd have to see the wheel ,.. take it to a shop since you are in doubt.

you may be compensating for a damaged rim .. that would require high tensions in 1 part lower in others .

start with a round & flat rim and things can be brought up to tension more equally ..

Bill Kapaun

Your NDS tension will be somewhere between 50-70% of DS tension.

Since you apparently have a tension meter I would-
Loosen all spokes & start from scratch.
Shoot for about 110kgf on the DS.
NDS will be wherever it ends up to dish.
I'd get DS up about 100 kgf before I got serious on the NDS. Just keep th NDS pretty even although low to start.

BTW- Loosing the DS as much as you tighten the NDS will result in too low on the DS.

Retro Grouch 

How old is the wheel?

If you're starting with an old wheel that has a warped rim, you're going to have to choose between having a true wheel, having even spoke tensions or some compromise in between. If the differences aren't too great, I'd shoot for a compromise. If they're off by a lot, I'd get myself a new straight rim to start with.

nfmisso

+1

clengman

It's a 25-year-old wheel that was ridden on (but not very much) by a 300 lb man. I happen to know it was only ridden for a total of a couple hundred miles max and it's been sitting unused for the past, oh, 25 years, but still, considering the size of the original owner, I guess it's not that unlikely that the rim could be a little wonky. One pothole and 300lbs could really do a number.

After respacing the axle to get the chainline right for a single fixed cog, the wheel is almost, but not exactly symmetrical. Should I still expect that big a difference between DS and NDS tension?

Bill Kapaun

In that case, the NDS tension will be much closer to DS.
It's pretty much a linear ratio between the amount of offsets from each lock nut to the center of the rim.

ThermionicScott 

Might be worth taking the rest of the tension out of the spokes (but leaving the nipples threaded on a little to hold the wheel together) to see if the rim is warped. If it's straight enough, you can then bring up the tension evenly and build the desired symmetry into the wheel.

Bill Kapaun

IF your wheel is pretty symmetrical, I'd probably shoot for a total NDS + DS tension about 185-195kgf.

clengman

Thanks for this suggestion. It was a good exercise starting with a completely loose wheel, gradually tensioning it and paying attention to how the rim moved as I was going along. I eventually got everything fairly tight and started checking the tensions on the drive side. Set tension for all DS spokes at right around 110 and adjusted NDS to keep the rim true. Then checked the dish and had to loosen all the NDS spokes a bit to get the dish right.

My biggest problem was trying to adjust the dish by flipping the wheel in the TS-8. It's really difficult to get it to register in the same spot everytime. Nonetheless I have my wheel true to within about a mm and the dish within 2mm or so. It's the straightest wheel I've got now. I should find the time to do this with each of my wheels at some point. Thanks again.

Bill Kapaun

I started with a TS-8 and ran into the same problems.
Also, as I suggested about using an adjustable wrench as a gauge to see if the rim is "wallowed out", stems from using that stand.
Th e rim would touch the "finger" and one assumes that you need to add tension to the opposite side spoke. IF the opposite side is already "high", you just exacerbate a minor problem when you flip the wheel and the opposite side is now 2X as bad.
If you mark the problem areas with a felt tip, you have a better view of the "forest", instead of seeing a few "trees" up close.

I picked up a used Park TS-2 on CL for a good price and it makes things so much simpler.
Once I learned how to properly "center" it, it really made things easier.

clengman

I did a little check for wide spots as you suggested before I started tightening everything up. That checked out okay.

As I tried to do some reading about the TS-8 and issues others have using it, I did discover one thing I was definitely doing wrong. I knew I was having a problem getting the axle to sit at the same level as I flipped the wheel in the stand. To try to fix this I was really firmly forcing the axle into the "dropouts" (for lack of a better term) and tightening the axle nuts thinking that was the best way to force it into the same position and keep it there. I learned that perhaps a better way to use the stand is to adjust the moveable dropout to just the right spot, use some shims to ensure that it won't wiggle at all and NOT use a skewer or axle nuts to hold the axle in position. Just make sure that the "dropouts" can't move and that the axle is resting in the bottom of the V. I'll try it that way next time and see if I have any better luck.

cny-bikeman

One problem I've seen with the advent of tension meters and truing stands in general use is that people seem to get tunnel vision. They focus on the indicators on the truing stand or tension gauge and look at true and tension as individual characteristics all to themselves, when in fact they are related not only to each other but to the rim itself.

You can't assume that your rim was in good shape before you started working on it. Spokes never straighten a wheel, they merely serve to hold it in the correct position relative to the hub. If tension varies all over the place when the wheel is "true" or the rim is out of true when tension is equalized then the rim is physically bent, and it is the rim that needs attention.
Incidentally, unless you are needing to increase tension it's always best when redishing to loosen one side and then tighten the other rather than the reverse.

clengman

Following advice in this thread, I took all the tension out of the wheel and started from scratch. I checked the rim with zero spoke tension and there were no obvious major defects, kinks, bends etc. I brought the tension up gradually and evenly and got the dish and true pretty close and individual spoke tensions check out for the most part.

cny-bikeman

That is often the best procedure after one has done an unknown combination of things to a wheel. As the spokes act on the rim and each other one needs a fixed starting point to undo errors. Glad it turned out OK.