smontanaro 

I have Specialized sealed bearing hubs on my Griffon (126 rear spacing) with Sachs LY95 seven-speed freewheel and Sapim Laser spokes (2.0/1.8/2.0). Non-drive side spokes have loosened up on me a couple times. The other day I trued the wheel for the second time. I noticed that I was really right at the limit of the rims (Ambrosio Montreal Durex tubular) with the drive side spoke tension. I could definitely see the rim starting to bulge around the eyelets (but no cracks).

Still, when I got the wheel true, I was really over tension on the drive side and under tension on the non-drive side. I didn't have a ton of space between the small cog and the dropout, so moving a washer/spacer over to the non-drive side seemed questionable (even if there was a thin one to move - I didn't remove the freewheel to check). Instead, I just added a 2mm washer between the cone nut and lock nut on the non-drive side and redished the wheel. That brought the tension down on the right and up on the left. The wheel still slips into the dropouts without any problem. I did not realign the axle (should do that), so the exposure on the left is a couple mm less than before. I will go back and do that.

Does that seem like a reasonable approach to the problem? Is there something I might have missed doing this?

guy153

It seems like an innovative solution. You will lose a bit of stiffness because of the reduced bracing angle. I would use less tension on both sides and threadlock.
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conspiratemus1

Sounds perfectly reasonable . I’m supposing that the wheel was a little loose in the dropouts before you added the spacer on the left. If so, it is now optimized.

icemilkcoffee 

Did you move the axle to the left to re-center the axle?

plonz 

This one is making me think

What is the new OLD? I’m thinking maybe it was something less than 126 prior to adding the 2mm spacer? If it was 126 and is now 128, I think your solution works but it feels like a workaround to a root cause that still exists. Wondering if spoke length might be contributing to the tension issue...

smontanaro 

I mentioned in my previous post that I've not done that yet. Will take care of it tomorrow.

79pmooney

That shouldn't cause any issues except perhaps making putting the wheel in a little slower. Did you check the dish? (How centered the rim is between the locknuts?) Easy way to check - loosen the brake nut a touch and push it over to just touching the rim. Flip the wheel around. If the dish is correct, it will again just touch. If not, loosen the spokes of one side a touch and tighten the other.

If you really want to make this a better wheel, take out the non-drive side 2.0-1.8 spokes and replace them with 2.0-1.6 of 1.8-1.6 spokes. That will go a long ways in improving the balance of tensions. (All my rear wheels are built that way.)

Ben

Edit: Re-centering the axle is a nice touch for you but the bike doesn't care. Once the wheel is lined up and the quick-release is tight, the axle beyond the locknuts is doing nothing and doesn't even have to be there.

smontanaro 

OLD is within the margin of error, I think. It's tough to get an exact measurement of OLD on a built wheel, at least with my calipers. The dropout spacing actually measured slightly less than 125mm. "126" is only a nominal measurement anyway. I'll try and make more accurate measurements tomorrow.

Not sure how spoke length affects tension. If they are not too short or long (engage enough threads, but don't interfere with the base tape) and you can dish the wheel properly, the tension with be the same if a spoke is 298mm or 299mm.

conspiratemus1

No need to recentre the axle as long as you've got a couple of millimetres of axle exposed past the left (and right, but you didn't touch the right) locknut. It's a lot of work, loosening up both sets of locknuts/cones just to walk the works 1 millimetre over (half the width of the spacer) and totally unnecessary. You also risk getting dirt in the bearings while you have slack in them on both sides. Nothing says the ends of the axle have to protrude the same distance on both ends. Your photo, with the spacer in situ, shows you have ample axle showing to guide the wheel into the dropout. So much that I wonder if the spacer was supposed to be there from the get-go and somehow got omitted somewhere along the way. Leave it as is.


But I'd be curious as to whether the dropout spacing is > 126 mm, or the OLD was < 126 pre-spacer. Academic interest only, since your addition of the spacer has fixed the problem: OLD seems to equal drop-out spacing, whatever it is.


Now, if you wanted to convert your Sachs freewheel to a 6-sp, and make your wheel even less asymmetric and reduce the risk of bent -> broken axles in the bargain, then you would need to re-centre the axle, as it would stick out much too far on the right and the QR wouldn't work. But don't do this just for one millimetre.

Edit: If this is something you were contemplating doing, I have the necessary "EY" smallest sprockets you need, in 13 or 14 teeth, to replace the LY + IY pair mounted on there now. This is all you need -- you just run six sprockets on a seven-speed freewheel. The spacing will be seven-speed of course, making the whole package even slimmer than a Sachs 6-speed would be, without the expense of sourcing a whole six-speed freewheel from scratch. I can send you one of whichever you need for just the cost of postage. Send me a PM....or invite me to e-mail you.

smontanaro 

Yes, that was kind of the point of the exercise. Adding a couple mm to the left side of the axle required the rim to be moved left wrt the locknuts to center the rim between the dropouts. That reduced tension on the right and increased it on the left.

Salamandrine 

Not sure what the issue is here but many millions of miles have been ridden on 126 rear wheels without those problems occurring, or requiring any special spacing tricks. Drive side spokes are always going to be tighter. If they are bulging around the ferrules, they are too tight and the rim will fail eventually.

As 79pmooney mentioned, it is important to check dish with a dishing tool, DIY or otherwise. Truing stand not good enough. Brake blocks definitely not good enough. Bad dish will cause the problems you have. The only other thing I can think of offhand is perhaps the spoke threads were overlubed? If you use any kind of teflon lube on spoke threads, they won't stay tight. Better off not lubing them. I use linseed oil.

smontanaro 

Dishing tool was used. The wheel is nicely centered under the brake center bolt.

My concern about the tension was that the drive side tension clearly seemed too high (bulging rim - I realize the issue of failure) and I'd already seen the non-drive side spokes loosen twice, indicating the tension was too low. Tension meter confirmed both extremes. After the insertion of the spacer and redishing, the tension meter confirmed that both sides' tension moved in the right direction.

Salamandrine 

I wonder if your hub was missing a spacer, and you simply restored it? I guess you could verify this by measuring the hub OLD and looking up factory locknut to flange distances, if you can find factory reference, or compare to another 126 hub. I still think you shouldn't be having this problem if there isn't some other underlying issue.

FWIW, BITD they'd use this trick on tandems sometimes. Space out the rear hub to reduce dish.

Modern 130 10/11 speed wheels have more severe dish issues. I'm now sold on OC rims. Way better. Not exactly period correct for you.

Aladin

Makes no difference in this scenario... ---> reduced bracing angle. Just irrelevant.

What your doing is done all the time... I'll move the gears close as can be done to the frame... making sure rotating clearance is sufficient. Buys even more NDS tension.. which also can be increased by 'cheating' center a mite left.. .1" hurts nothing. So a rim w a 110 kgf limit can make 65-70+ left.. that range where spokes should stay put given reasonable rider weight. A drop of nail polish is my finish top of the nip head... left side.

Bulging holes: rather than the flimsy spoke washers pimped by some makers.. go the hardware store and get M4 metric washers. Usually those pass in most double wall rim access holes as a nip seat. Makes a nice nip seat.

All I run rear is triplet 16/8 (24H rim) .. built several 18/9's (18H drilled left or 36H). Generally an avenue for one's own use.. the novice/average user can't grasp the concept. But generally those finish at 100-90 ratio for tension.. ideal range overall for a rear.. for most riding.

I have.. built a rear wheel w lock washers left side. Yes one mm or so longer for the spoke.. which was one reason the experiment went down. Yet they never shook loose......... another 'real hardware' store item.

SurferRosa

Good post, great pics, and good solution. I don't have a problem going 2mm wider than the dropout spacing on a hub with this issue, given I have 3mm of axle length on each side. Maybe you don't need that much, but I do. And it's no problem at all to recenter the axle. I always loosen both sides of the hub when overhauling them, so the cones, washers and nuts aren't seized.

plonz 

This is an interesting tip I think I’ll try.

Still thinking OP’s hub may have been centered on less than 126 OLD and the 2mm spacer corrected it.

fietsbob

#1 , wider frame width.. a 120 or 126 wheel 5 or 6 speed, in a 130 wide frame with its longer axle & added spacer on the left end..
recentering the rim involves de dishing it..
been there , did that..

smontanaro 

Spent more time with the wheel this morning. Removed the freewheel and measured the drive side spacer, ~12.5mm. I pulled out my drawer of spacers (which had recently been augmented by a set from Boulder Bike) and found one that was more like 11.7mm. Installed it, evened out the axle exposure and redished the wheel, again, slightly improving the tension values. With the freewheel off, I could get better access with my calipers and measured the OLD as 126.5. On the frame, the dropout spacing measured 124.7. Slipped right in despite the ~1.8mm difference.

The chain just clears the dropout by maybe a gnat's whisker. As I rarely use that cog, it shouldn't be a problem. Still, I might keep my eye open for a slightly wider spacer(s) for the drive side. I thought perhaps a 9sp chain would work, but though the outer width is less and the cogs will fit, the chainrings are too wide.

ThermionicScott 

I see a target tension of 60-70 kgf NDS thrown around a lot in wheelbuilding threads, but I've never been able to get that much in my 7-speed 126mm wheels. It's usually half of the 110 kgf I've put into my DS spokes. So I am often doing the same thing -- seeing if I can remove any DS spacers and add them to the NDS. A few of my wheels are 127mm just because I wanted to move a little more tension from the DS to the NDS.

FBinNY was always big on using really skinny spokes on the NDS, too. I miss his posts.

SurferRosa

And a 9-speed chain might run noisily along the derailleur wheels when shifting low to a wide cogset like I've seen on my old '70s-'80s Campy stuff.

Aladin

You do NOT change the spoke tension left if all spacing is same w light spokes. You DO stretch the 1.6 middle section more.. which means the nip head is much less likely to detension/move as that elogation keeps the nip seat firm.

I .. used to really like using Sapim Lasers.. 1.5 I think mid-land dia. The wind up.. especially after some use/oxidation is a PITA. 2-1.8's now.. few grams what the H.

Funny thing.. the 'real know it alls' (so some think) on another 'marketing' forum.. "everything wheels" subforum ranted per triplet rears.. bracing angle and all that regurgitated keyboard sh*t. Come to find.. a guy who ACTUALLY runs real tests ran them vs the market flavors of today. Guess what flavor won out?

See Tour de 'Chemical' .. see all the G3 rear Campy's. 14-7s. Those dudes obviously push a wheel........

126's.. move all the spacing possible to the left.. cheat .1 left.. use lighter butted spokes if one wants to mess w that.. freeze the threading
however one wants. Yet Triplet is easiest route.. espechially on light rims.

ThermionicScott 

Yep, we agree on that. My lightest wheel set has 1.8-1.6-1.8 spokes on the NDS at about 50-55 kgf, so far so good at almost 5000 miles. Either I'm a very smooth and careful rider, or this stuff works!

I really like triplet on paper, look forward to trying it some day.

noglider 

I used to reduce dish by adding a spacer in the 80s. It's a known and legitimate thing to do.

smontanaro 

Aladin ThermionicScott What is this Triplet thing of which you speak?

ThermionicScott 

In a nutshell, you build a wheel with half as many spokes on the NDS as on the DS, allowing you to bring the NDS tensions nearly up to those on the DS. So you no longer need to use high tensions on the DS to keep everything stable, and spokes and rims are much happier. It works best with hubs and rims that are specifically drilled for it. Campagnolo's G3 wheels use the concept.

In looking for the old threads I learned from, I was alarmed that a lot of pictures and blog posts are already gone.

https://www.bikeforums.net/bicycle-m...el-lacing.html
https://web.archive.org/web/20100817173724/https://www.wheelworks.co.nz/blog/triplet-lacing-pattern/
https://kstoerz.com/freespoke/triplet.php
https://www.campagnolo.com/WW/en/Tec...es/g3_geometry (ignore all the marketing fluff about "improved energy transfer" and whatnot )