Road Fan

May I get an informal critique of the wheels on my 2005 Mondonico? They are gorgeous and classic - silver 700c Open Pro 32 hole clinchers on pre 2006 Campagnolo Record hubs. My conscience says I should overhaul the bearings. I've had the bike since about 2015 and the previous owner did not give them any attention, but they spin amazingly and are like buttah! But the bearings are not the question.

Really the spokes have no apparent problem. But the fronts are 32 hole 3x stainless, double butted 2.0 mm/1.5 mm/2.0 mm. I think they're DT. Now for a similar spoke, Sapim has a weight caution and one about "skill of the builder" on their website. I weigh about 190 now, as did the previous owner, and the wheels have remained true and even-tensioned. I assume I'm more porky than was expected. In any case I'm pleased but a little surprised! I suppose it illustrates the old Jobst Brandt point, that thinner spokes do not make a weaker wheel if they are all tensioned correctly.

The quality of the rears is also high, but ... the 16 sticks on the NDS are straight-gauge 2.0 mm, and the 16 on the Drive Side are butted 2.0 mm/1.8 mm/2.0 mm. The dish is not small but not extreme - the bicycle is set up fo 130 mm, 10 speed, the wheel is dished as it should be and the system alignment is good because the rear chainline and the front match at 42 mm. The weight distribution with lard (me) added is close to 60/40, so perhaps the need for more structure in the rear is real. But I don't have a good understanding of peak loading - drive torque, braking torque, bump loading, holes and other road nastiness. At the moment I'm running old Conti Ultra 4000 28 mm clinchers, which actually measure 24 mm wide. These are abut 15 years old, but my plan is to replace with tubulars if I want to upgrade tires, even though the Open Pros have no problems. This is also why I"m thinking about spoke choices.

Now the NDS diameter is 2.0, while the DS is 1.8. I think given the higher weight carried by the rear wheel, 1.8 mm seems a good choice given the 1.5 mm in the front - the ratio of the two spoke cross-sections is nearly equal to the ratio of the static wheel loading. But does the mismatch between the rear non-drive side and the drive side seem correct? I'm not a wheel builder, so intuitively it is not easy for me to see it.

Bottom line ... does this seem like an ok design?

Reynolds 

I'm no expert, but that setup looks like it should work OK. Only "odd" thing is the 2.0 NDS spokes, but I don' think that would cause any problems.

Road Fan

Thanks for your opinion, it pretty much agrees with mine. After about 15 years the wheels are in excellent condition, so they were built by a real good builder. They do work at least OK, and I don't see any problem but I wonder if any other good builder can think of why it might have been by design?

If I go ahead and change the rims out for tubulars, I would build the new front with the same spoke choice it has now. But, should I do that for the rear?

conspiratemus1

These sound like really nice wheels.

NDS spokes break in the elbows from repetitive flexing as the spokes load and unload as the wheel rolls. (Being under less tension if the wheel is asymmetric, the NDS spokes suffer more fatigue.). Because they don’t break in the shafts there is no reason why the NDS spokes cannot be DB also, just like the drive side. It is my understanding, as a piece of expert advice that I cannot independently appraise, that a smaller diameter spoke on the NDS will unload less in compression and will further protect the vulnerable elbow, and be more likely to stay tight. So by this reasoning, the wheelset could use 2.0/1.5/2.0 for the front and NDS rear, and the more robust 2.0/1,8/2.0 only for the drive-side rear. But if the wheel is good and not breaking spokes or going out of true from loosening on the NDS, I’d probably not mess with it.

But if your new rim does not allow you to use the existing spokes, my decision as an amateur without a spoke inventory would depend on whether I could buy the necessary odd lots of different spokes or being compelled to buy 100 the same. I wouldn’t use straight-gauge for anything unless money was tight.

This is the rationale I use for building successful tandem wheels in 36 spokes, albeit 140-145 mm OLD rear spacing. We weigh under 300 lb though, and for us I use 2.0/1.8/2.0 throughout.

repechage

130mm - 10 cog spacing... 2.0 drive side is ok- double check the clearance to the cage when in the largest cog- small ring.
you would be surprised how close it can get.
if worrisome go to 2.0/1.8/2.0 DB
double butted on non drive side ok- even 1.8/1.5 they get considerably less load.

for a guy pushing 200# you could make a case for 1.8 straight front and non drive side rear
depends on how you ride. Some folk seem to aim for potholes and do not raise their mass off the saddle when entering a driveway apron, undulation, etc.
my son is a work in progress, 140# but rides a bike like a 200# guy, I coach him, when we ride together, it is sinking in slowly.

Salamandrine 

I strongly suspect the builder used the spokes on hand. There's no need to make it that complicated by using different spoikes on DS vs NDS.

FWIW, I've been using off center (OC) A23 for a rear rim for a while now. If you want something asymmetrical and better, that's the way to go. It really is better for 130.

If they're holding up for you, don't worry about it. No big deal.

IME and IMO the question isn't gauge so much as straight vs double butted. Wheels built with DB last longer. 14/15/14 DB spokes would be my recommendation if you're looking for best. 14g straight for the back and 15g straight for the front is OK, if you're on a budget, but i feel that it is a false economy.

conspiratemus1

Especially for Campag hubs, with their “fatter” cassettes (-> more asymmetric wheel). Even on the tandem, we didn’t see the cracking around the spoke holes they are supposed to be prone to. Like ‘em a lot.

Russ Roth

My wife has used them for 10 years now and I have a pair I used on a cross bike for 2 seasons before repurposing them to my daughter's bike, not a crack yet.

OP, the spoke choice is an odd one and I'd assume based on the spokes available though perhaps they liked the 2.0 NDS since the thicker spoke felt stiffer. I've occasionally used a slightly thinner spoke on that side, 2.0/1.6 on my wife's wheels since they need a higher tension to do the same job as a thicker spoke which keeps them from loosening up more. Although with Campy I liked building straight pull nds with the heads out to move the spokes in, touch less bracing angle but better spoke tension, never liked those hubs due to how fat the cassette was. Course that's why they can now fit a 12sp cassette on the same hub with no modification and spoke tension isn't bad with a more modern 135 or 142 rear spacing. Can't image if you weight 200lbs that any wheel built 32h would have any trouble with quality spokes if built right. Although I'd never build with them myself for someone even close to my weight, the 1.8 straight gauge spokes that came stock on my mtb lasted almost 3 years before they started breaking and I hang out in the 270 range and am not gentle riding off road.

seedsbelize 

I've always read that you shouldn't mix butted and non-butted spokes. In your case it seems to be working fine. And, since it's working fine, why change it?
Of course they also say to never use a chrome nipple on a black spoke........