jyl

Hey guys, I am having some trouble w/ my third wheel build, and wanted to check if you think I am on the right track.

Rims are used Mavic MA40s, lot of brake wear on the anodization but rims look straight when placed on glass counter, I greased the base of the eyelets (where the nipples seat) just in case there was corrosion but they looked fine down there.

Hubs are used Normandy high flange, this is from a '70's Peugeot. Daughter's UO-8 is getting the steel basketweave Rigidas replaced with inexpensive but sort-of-period alloy rims.

Spokes are new Wheelsmith 2.0mm straight everywhere, except I'm using Wheelsmith 2.0-1.7-2.0mm double butted for rear non-drive side.

Nipples are new DT brass.

Pattern is basic 3 cross.

The problem I'm having with the rear wheel is: I still have about 1/4" correction to make to dish, need to pull the rim toward the drive side, but the drive side nipples are getting worryingly hard to turn.

I did grease the spoke threads and have placed a drop of oil on the nipple-spoke and nipple-eyelet points too. Even so, some of the nipples feel like they are getting close to rounding over. (You know how you can feel that point coming.) I'm using a basic Park spoke wrench, size 0.

Drive side tension is about #26 on the Park TM-1 tool which translates to about 135 lb I think. On the non-drive side it is about #20 which translates to about 110 lb. Tension on each side is pretty darned even. Lateral true is pretty close by now, so is radial, its really the dish that I am struggling with - no, I don't know why I didn't get dish sorted out before things got to this point.

I stopped working on this wheel last night, to think about what to do before I broke something. My plan now is (1) to make further dish corrections (and further lateral/radial corrections) by loosening the non-drive side, not by tightening the drive side. (2) to get a "four-sided" spoke wrench, to use if I do need to tighten a drive side spoke a bit.

Make sense? Or, do you think I should back off the tension on both sides?

Doohickie

I would loosen the non-drive side spokes even further and see what happens.

Who calculated the spoke lengths? Are you getting to the ends of the threads on the drive side?

mrrabbit 

Way overtensioned for drive side...

Bring those down to 24 on the dial...with wheel dished.

=8-)

jyl

Thanks for the replies! I will back off tension.

I used 613 ERD for the rims, that was what all the online sources have. I measured the hubs myself, and cross-checked against online sources - the measurements were pretty consistent (e.g. center-to-flange was different by 1 mm). I don't have the numbers with me right now.

I plugged the numbers into two online calculators, the bikeschool one and I think the other is called "EDD"?. Got spoke lengths that were very close between the two calculators. I also checked the difference between my hub measurements and the online ones, and they didn't give meaningfully different spoke lengths.

Then I rounded up to the nearest whole mm, since the shop only has whole mm lengths. Previously I've always rounded down; in future I will go back to rounding down because rounding up seems to give me more spoke than I need.

However, I'm not running into the end of the thread on either drive or non-drive side.

One thing is, I'm not sure what tension to aim for. In the past I was told that if the drive side gets to around 130 lb that's fine, and to let the non-drive side be what it will.

The spokes are all straightened, stress relieved, and so on.

By the way, I !despise! my dishing tool (Park WAG5) and want to either find an old tool that is actually solid, or start dishing into the truing stand.

cbchess

I had some trouble with that before while lacing with wheel smith spokes. I was using a used rim with a hop at the rim joint.- I could not pull things into shape - then one othe spokes failed at the head - not where the problem was at on the rim. after a few more spokes failed I switched BACK to DT spokes and never have used wheelsmith again.

gyozadude

The 1/4 inch off on dish is a lot. I have to wonder if your axle spacing forces you to extreme asymmetric dish. Note: your tension is quite high. And the conversion should be to kg-force, not lbs-force (multiply by 2.2 to get pounds). Target tension on the drive side typically is around 23 - 24 on the meter as Mr. Rabbit says. That gets you roughly to 100 kg of force. That's 220 lbs of tension on a typical 14g spoke.. I get maybe 2/3rds or less tension on the non-drive side. But it really depends on the axle spacing and amount of dish offset. Old 126mm road hubs had really back asymmetrical dish, and that pretty much has forced me to go with adding spacers to get to 130mm on the non-drive side and messing with locknuts and spacing on the drive side to set the minimum clearance needed for the chain to clear the stay when shifting to the smallest cog, and any space I can give to the non-drive side, I do.

But it sounds like you might get some benefit from loosening, almost all the non-drive side spokes, almost completely, then measuring dish and drive-side tension (which should also be much looser) and then slowly tighten the non-drive side. If you can't put any significant tension on the non-drive side (more than half), then you may need to mess with the axle.

jyl

The rear spacing is 120mm I think (1975 Peugeot) and these are the original hubs to the bike, some unnamed Gauloise-smoking monsieur or madamoiselle was able to dish the wheel properly with the original Rigidas so I think I shouldn't have to resort to spacers.

I plan to swap a 6 speed freewheel in place of the original Maillard 5 speed, mostly so that I can someday put indexing on the bike, but it is a Suntour Ultra FW so only slightly wider than the original.

Sorry that I was misreading the Park chart and got confused between kg and lb.

mrrabbit 

So long as the distance from the freewheel stop to the end of the lock nut is at least 31mm, the Ultra 6 should work.

=8-)

jyl

Again, thanks to all! The wheels turned out nicely. On the bike, with 25 width tires at 120 psi, these wheels roll and stop so much better than the wobbly steel basket weave 27" Rigidas that were on there, on which I couldn't inflate a tire past 60 psi. Like night and day. We'll see how well I built them, if they stay true.

Kimmo

One approach with rears I've tried with good results is to crank the drive side tension right up with hardly anything on the NDS.

Then, getting the dish right is easy, since you do it by adding tension to the NDS. It's easier on the nipples.

jyl

Oh, decided not to put on the Ultra FW just yet, because it is a 23T while the current Maillard is a 28T, and daughter wants/needs the 28T to climb the local hill. When she's off a camp this summer, I'll replace steel cottered crankset with a compact drive, then swap in the 23T. Actually going to go through the whole bike this summer and surprise her when she returns. Gotta find a Maillard FW remover so I don't have to keep running to the bike shop.