bianchi10

So now that I'm looking for a replacement CX Ray sapim double bladed spoke, stores are telling me that the CX sapim rims are actually fairly flexy because they are so thin. I dont know anything about wheel spokes. Anyone have some knowledge they can drop on me about what is a good stiff option and why vs. some to stay away from and why?

I'm 175lbs. Maybe I should look at a wheelset that has a 24f/28R? My boyds are 20f/24R which I have used now for a little over 2 years without any spoke issues till this weekend. I think the 20/24 setup has a weight limit recommendation of 185lbs

ericm979

If you are replacing a broken CXray, put on another CXray.

Spoke cross section affects wheel lateral stiffness but not radial stiffness. Thinner spokes allow a little more lateral flex. But hub flange spacing and rim stiffness matter more for lateral stiffness.

Spokes with thin center sections and 2mm elbows are less likely to break due to detensioning. They have to stretch more for a given tension, so the wheel has to flex more to detension them. If you are breaking NDS spokes at the elbows that's because the spokes are detensioning enough so that they bend at the elbows.

When I build training wheels I use Sapim Race on the DS and Lasers on the NDS. CXrays are made from Lasers by flattening the center section. The thicker Race (1.8mm center section) make for a slightly laterally stiffer wheel. But that's not something you do one spoke at a time.

BTW CXrays are used by downhill racers. They are strong.

Which spoke broke and where did it break?

bianchi10

ok good to know. The first LBS I went to did tell me that I needed to replace it with the same type spoke so it would have the same type of flex throughout the wheel. So I will be doing so, I'm just thinking about future purchases.

It broke on the front wheel and about 2 inches from the hub.

Grambo

Sapim CX Ray spokes are excellent / very high quality so I doubt they are causing issues for you. My weight is similar to yours and I have purchased several custom wheelsets from very reputable builders over the past several years. All 3 recommended I go with 24 / 28 spoke count. The additional weight (as compared to 20 / 24) is minimal and the wheelset stiffness and duarbility goes up dramatically with a higher spoke count.

ericm979

That's an unusual place for a spoke to break, and most broken spokes are on the rear wheel.

Did it break where the spoke necks down from 2mm to 1.6mm, or where the flat section starts? Or where spokes cross and one bends over another?

You might want to check the tension on those spokes.... it could be low.

bianchi10

Its all jacked up because I tried to wrap it around another spoke at first and then when that didn't work, I tried to bend it back and forth to just snap it off but that didn't work either.

after looking at it, it appears it broke closer to the hub.

pdedes

It broke at the j-bend

ericm979

Are the hub spoke holes chamfered more on the outside than the inside? I think Boyd uses Bitex hubs and it looks like the same hub I have a couple of. I laced the first one heads out like your wheel. After 8000 or so miles the spokes started breaking at the elbow. After research I figured out that that hub's spoke holes are chamfered on the outside and not much on the inside. You're supposed to lace wheels so the chamfer is at the elbow so the hub supports it. On the hubs I have, when laced heads out the J bend sticks out from the hub about 1-2mm is not supported by the hub. So it eventually breaks.

I relaced the wheel heads in (and 1x although that wasn't required) so the elbows are supported by the hub.

Clipped_in

I'm curious to know why the conventional wisdom is to wrap the broken spoke around an existing spoke. Why not just twist it out of the nipple and be done with it? At least on external nipples?

Psimet2001 

Because then you'd have the nipple rattling around in the rim.

Replace with a sapim cx ray.

Spokes can break. Break 1, replace. Break 2, replace. Break 3 - re-spoke.

I have used plenty of Bitex hubs and never had this issue so - not an issue with the hub. If you're stress relieving it heavy enough your embedding the spoke into the flange anyway. See the notch on the inside of that hole? Not an issue of chamfering.

nhluhr

So? You have a much bigger problem than a rattling nipple already.

ericm979

Most people don't carry a spoke wrench. And even if you do, it's easier to wrap the spoke around another than to unscrew it. If you do it right it'll stay in place. It's not like you need to save the spoke. But if removing it makes you happy, do it. You can get the nipple out of the rim later by removing the rim strip and shaking the rim.

Psimet- yes, the elbow does indent those hubs some when you lace it with the heads in the countersink. But at least on my hub, there was still some elbow not supported by the hub, and that's where my spokes were breaking. Now maybe I didn't stress relieve the wheel hard enough or the spoke tension wasn't high enough (90 kgf). But Jobst's book says to put the elbow in the counter sink to support the elbow, so I am following that.

Psimet2001 

+1

Psimet2001 

The nipple is hard to remove if you don't have a spoke wrench on you, and then when the nipple is rattling around you have a higher chance of it wedging itself somewhere it shouldn't and causing a flat.

Securely wrapping the spoke around an adjacent spoke is the easiest and most effective way to secure it when one breaks.

Looigi

Agree, and fail to see how it can't be done successfully, unless the stub is so short it can't reach an adjacent spoke with enough left to wrap around it. Absolutely no reason it couldn't be done with the OPs broken spoke.

Psimet2001 

I believe the OP stated that he did but the wheel was too far out of true to continue riding (hitting the fork).

Clipped_in

Ok, fair enough.

I guess my ignorance reflects my lack of experience with broken spokes. I do have enough experience riding with others to know that broken spokes suck, especially if you are miles from nowhere.

jimblairo

DT Aerospokes have more lateral stiffness in a wheel than CXRays. The CXRays do offer greater radial stiffness.