Wheelbuilding / Wheel Building / Wheel build help

Bought an old Zipp 440 carbon rim off eBay and should probably have had this checked before I had it rebuilt, but didn’t... Now regretting it. Previous owner has ‘expanded’ the valve hole.

What’s the verdict, safe or not safe?

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Lol. What the fuck were they thinking

@GoSteady and @M_V thanks for the advice. Want to try building a set for my mtb. Would like to think I won't be completely put off after that and might build more down the line. It's more a case of it being the only bit of bike maintenance I'm not familiar with and want to learn, so I'm not overly keen spend £300 tooling up just in case.

return it. you'll still be covered by eBay even if you didn't check it fully when you collected it

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http://www.wheelfanatyk.com/blog/z-spokes/

You can use your frame or forks and a couple of tie wraps to act as pointers for truing. Granted a stand is easier to work on, but for an experimental or infrequent build it's fine.

With caliper brakes you can replace the pads with a pair of bolts, which can be easier to use than tie wraps.

If your after the rim being centered, to check the dish, just flip the wheel in the stand.

It not inconsistant as if you read on there needs to be a correction. This is the formula i use for triplet and it works.

I'm soon going to be building some 22mm depth china-carbon rims to low flange mack hubs, 20h front and 24h back. Seems like a recipe for the flexiest wheels ever, will spokes make any difference to remedy this?

My gut says CX-rays would be the best bet but will I actually see any improvement? Spoke weight is a factor given these are some of the lightest track hubs around and the rims are both >400g. I weigh less than 65kg for reference

improvement?

compared to what?
cx rays are squashed laser spokes (2mm - 1.5mm - 2mm) so are light

What is the flange spacing on the hubs?

Not sure. Will there be any difference in stiffness between CX rays and lasers? Do spokes even effect stiffness? Id rather spend the extra on cx rays so i dont have to worry about spoke wind up

Will there be any difference in stiffness between CX rays and lasers?

not really

Do spokes even effect stiffness?

yes but I guess you want a lightweight build.

Is it a track hub rear? what is the flange spacing? Symmetrical?

standard answer: thicker spokes on rear drive side (/drivesides) maybe cx sprint, and then cx ray on the rest

DT Swiss 350 straight pull vs Novatec A291SB/F482SN J-Band

Price aside, I'd like to know what are the pros/cons of each option. Based on a bit of research it seems some wheelbuilders/mechanics aren't that keen on straight pull which puts me off a bit

Why not 350 j-bend?

Not available on the site I'm buying the wheels from unfortunately

If they're building you might as well go straightpull. It's just the spokes are usually a lot more expensive.

Double fixed rear hub so symetrical flange yes. Does this mean cx sprint on the rear both sides or just cx rays all round?

some will say straight pull eliminates the risk of failure at J-bend

Will there be any difference in stiffness between CX rays and lasers?

No. The stiffness of the spoke will depend on the Young's modulus of the material used and the cross-sectional area of the spoke. All steels have essentially the same Young's modulus (particularly as all steel spokes I'm aware of are made from 18/8 stainless steel or similar) so the only thing that will change in terms of spoke stiffness is the cross-sectional area. CX-Rays are just flattened Lasers, so will have the same area in cross section. If you want stiffer spokes then you're going to need either a different material (impractical) or a chunkier spoke (like a CX Sprint rather than CX-Rays).

Oh, and I'd recommend not lacing the front wheel radially if you're using Mack hubs. 2 cross front and rear.

If it's symmetrical I can't see any benefit in using different spokes on either side. Using CX-Rays on one side of a 24 hole rear wheel will only save you 12g compared to CX Sprints all round.

It not inconsistant as if you read on there needs to be a correction. This is the formula i use for triplet and it works.

There's a correction factor to use if you pretend the DS is part of a 48h 5x wheel. But the post says that if you can use fractional crossing values then calculating spoke lengths on the basis of a 32h 3.17x wheels works and that it doesn't.

Doesn't matter to me, as they both (32h 3.17x or 48h 5x * fudge factor) give almost identical results.

Yes was planning on 2x all round. For strength and I prefer the aesthetics. So do you think for a light rider I'll need stiffer spokes than cx rays on the rear for 24 holes?

Does this mean cx sprint on the rear both sides

yes I would do that :)

What would you recommend instead then? Bearing weight in mind. Or did you mean CX rays will be fine?

Not sure, TBH. I've never build a 24h rear wheel with a shallow rim - the shallowest rim I've used myself on a 24h rear wheel with CX-Rays is a Kinlin XR31T which is pretty stiff. I suspect you'd be fine with CX-Rays, but I'd defer to more experienced wheel builders.

I built @Cycliste a rear wheel using an XR200 rim, which is light and quite floppy, and used CX-Rays on that but I used 28 spokes on the rear despite @Cycliste's feathery lightweightness. That was fine until a 6'1" chap called Alan rode over it after @Cycliste had gone over the handlebars. Wasn't so happy after that.

The difference in weight between 24 CX Rays and 24 CX Sprints is like 20g. Unless you're going super-weenie I would just get the chunky spokes

Edit: I'm not much of a wheelbuilder but just wanted to point out that the weight difference is fairly minimal. I have no idea whether or not the wheel will be stiff enough with CX Sprints as opposed to CX Rays.