Wheel Build Advice Thread

[T-Rex]

DT Swiss calculator spat out 292.1 & 291.7 .....Roger Musson's gave 291.9 & 291.2.
...so I was rounding up to 293 assuming every length was available.
Do you think 292's would be too close to the ERD ? Would it be safer to build both sides with 294's?....and still get good tension?

I'm currently surfing customcutspokes.co.uk.....cheers for the link.

EDIT: Just realised that company actually cuts any length required (it's actually in the name. I'm not always the tightest spoke in the wheel... )

Based on this, I would get 292s all round, as others have said.

If you want to post the relevant hub dimensions and rim ERD I’m happy to check the calculations.

 

[T-Rex]

Dunno about "safety".... Leaves you at too much risk of running out of thread before you reack proper tension, especially if using finer gauge spokes which stretch mare than you'd think. I always round off, either way, to the nearest even-numbered measurement, that way you're never more than 1mm out.

I use the same approach in terms of getting to even number length spokes. Hasn’t caused me a problem so far

 

[yuley95]

DT Swiss calculator has never failed me.

I have used this for my builds and have to agree it would dangerous to add 2mm. The build I just finished (EX511 rims on 350 hubs) had me very close to running out of thread by the time they were up to tension - and that was based on using the recommended spoke length

 

[Oddjob]

I have used this for my builds and have to agree it would dangerous to add 2mm. The build I just finished (EX511 rims on 350 hubs) had me very close to running out of thread by the time they were up to tension - and that was based on using the recommended spoke length

What's running out of thread? How far was the spoke sticking above the nipple on the top side with the flathead notch?

Keep in mind the cross section of the nipple has the thread closest to the flathead notch (or male sqourx bit). There's actually a lot of dead space where the spoke enters the nipple. So you're better off having 2mm sticking out of the top then coming up a bit short.

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[Oddjob]

Ps this is the spreadsheet I use. It makes it quite easy to keep a database of built wheels or possible wheels.

Damon Rinard's free spoke length calculator

Spocalc.xls, a free downloadable bicycle spoke length calculator by Damon Rinard.

www.sheldonbrown.com

As I said, I've found website erd not to match actual rims quite often. But its also possible that I'm not measuring the erd quite right either so I like to add that 2mm margin.

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[Flow-Rider]

try this one too, I have had good results.
https://www.prowheelbuilder.com/spokelengthcalculator

That's all I've ever used for multiple builds and never had problems, if the rim isn't listed I just use the manufactures noted ERD.

I've come across what Duck also said from a wheel that was built from someone else where the nipple had bottomed out ( 2.0/1.6 mm butted spokes ) Sometimes the holes elongate in the hub over time also.

 

[born-again-biker]

Based on this, I would get 292s all round, as others have said.

If you want to post the relevant hub dimensions and rim ERD I’m happy to check the calculations.

Cheers Rexy.
Rim ERD is 602 (manufacturers number, not measured in hand)
It's got a few minor flat spots, but I reckon it'll be OK to re-use.
Doesn't leak air or sealant.

Hub is DT350 Boost IS.
58 / 52 PCD flanges
36.6 / 23.3 offsets.
2.6mm holes.

Perfect scenario would be 293mm spokes, I think. But because I'm a rookie wheel builder I don't yet have the gut feeling / experience to confidently pick the next size up/down with these particular components.

 

[The Duckmeister]

I've found the Sheldon Brown spoke calc spreadsheet to be very accurate. Way more accurate then my measuring skills or the erd listed on most websites.

So this has almost left thread showing a few times on wheels builds, which in turn means that there isn't full engagement between spoke and nipple. So my rule of thumb is to round up and add 2mm. The worst that can happen is that the spokes are a tad long but I can always

1. add washers for extra strength or
2. cut extra thread into the spoke.

A slightly too short spoke can mean that more than 25% of the spoke thread isn't engaged, or I have to get 14mm nipples.

I also never use any spoke skinnier than 1.8mm so I don't see all that much stretch.

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That spreadsheet can't be that accurate if it's left you short on multiple occasions..... Also, never trust pre-loaded ERD in any online calculator - always do your own measurements!. Model specs can change over the years, so the filed figures are not always correct.

Different manufacturers' steel alloys can have different stretch properties, so even if you don't use super-fine gauges, stretch is a factor that needs to be considered. The three spoke brands I've built with most are DT Swiss, Pillar and Sapim. Across a range of spoke profiles I've found Sapim to consistently be the stretchiest; they take more work to get up to tension than the others, and the built wheel is never quite as stiff, but probably the most resilient under dynamically variable loads. Pillar are very rigid, so they build up to tension very easily, and give very good handling wheels, but suffer durability problems because they're less able to disippate dynamic stresses, therefore are more prone to breakage. DT Swiss fall somewhere in between. I don't know any of the calculators take spoke stretch into account - maybe that's something to look into while we're in lockdowns.... take the same rim & hub measurements & see if the calculated lengths vary with different spoke types......

 

[SummitFever]

The spreadsheet is accurate. The maths is simple so its not like any of the calculators get that wrong. If using spocalc your input ERD is important. Measure yourself using two spokes cut to say 200mm with nipples locktighted on at proper engagement eg. Spoke thread at the top of the nipple.

 

[Oddjob]

Like I said, the spreadsheet isn't the problem. I've just found that with my fairly reliable inaccuracy, its safer to be a little long.

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[T-Rex]

Cheers Rexy.
Rim ERD is 602 (manufacturers number, not measured in hand)
It's got a few minor flat spots, but I reckon it'll be OK to re-use.
Doesn't leak air or sealant.

Hub is DT350 Boost IS.
58 / 52 PCD flanges
36.6 / 23.3 offsets.
2.6mm holes.

Perfect scenario would be 293mm spokes, I think. But because I'm a rookie wheel builder I don't yet have the gut feeling / experience to confidently pick the next size up/down with these particular components.

I make it 292mm both sides, with the following assumptions:

1. 32 hole rim
2. 3 cross lacing pattern. If you want to build something other than 3x, good luck, you are on your own...
3. And this is the most important one..... 602 is the correct ERD. I never believe manufacturers, if it's a rim I have not built on before, I always measure with the two spoke method. Remember to add nipple washers if that's what's specified by the manufacturer, per the discussion above in this thread.

 

[born-again-biker]

I make it 292mm both sides, with the following assumptions:

1. 32 hole rim
2. 3 cross lacing pattern. If you want to build something other than 3x, good luck, you are on your own...
3. And this is the most important one..... 602 is the correct ERD. I never believe manufacturers, if it's a rim I have not built on before, I always measure with the two spoke method. Remember to add nipple washers if that's what's specified by the manufacturer, per the discussion above in this thread.

You are correct, 32 spokes and 3x (or whatever it is currently laced as, which I believe is conventional).

....and I think I'm going to take everyone's advice & measure the ERD myself, first.
I keep reading about how manufacturers ERD's are not to be trusted.
I don't have any shorter spokes on hand to make up a 2-spoke kit (yet)
So I'm going to try Roger Musson's method for a built wheel. If I get 602 then all good. If not, then I'll disassemble & try 2 spoke method.

 

[T-Rex]

You are correct, 32 spokes and 3x (or whatever it is currently laced as, which I believe is conventional).

....and I think I'm going to take everyone's advice & measure the ERD myself, first.
I keep reading about how manufacturers ERD's are not to be trusted.
I don't have any shorter spokes on hand to make up a 2-spoke kit (yet)
So I'm going to try Roger Musson's method for a built wheel. If I get 602 then all good. If not, then I'll disassemble & try 2 spoke method.

You don't need to use spokes to measure, any solid bit of wire you can get jam a nipple onto works fine. EG a length of welding filler rod, a straightened coathanger. My measuring gear consists of one spoke and one length of coathanger wire with a nipple glued to one end.

 

[Flow-Rider]

You blokes must be buying really poor quality rims because I've never had any issues with manufacturers ERD, you probably have more chance of fucking the measurement up because the spoke holes are never exactly opposed across the rim and wheel isn't under tension.

 

[yuley95]

What's running out of thread? How far was the spoke sticking above the nipple on the top side with the flathead notch?

Keep in mind the cross section of the nipple has the thread closest to the flathead notch (or male sqourx bit). There's actually a lot of dead space where the spoke enters the nipple. So you're better off having 2mm sticking out of the top then coming up a bit short.

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I was using 14mm nipples and when i would screw the spoke into the nipple while on the bench, it would stop threading in just as the spoke reached the very top of the nipple (probably like the middle picture in the 3 different length nipples above). I don’t have the tools to cut more thread as needed so i have to walk the fine line of engaging as much thread as possible without risking it topping out.

Anyway - it worked out fine. Was just close

 

[The Duckmeister]

Measure yourself using two spokes cut to say 200mm with nipples locktighted on at proper engagement eg. Spoke thread at the top of the nipple.

I do a slight variation... I use two longer spokes, screw a nipple all the way onto each one, and mark a line across both spokes in the section where they overlap. Remove the spokes, lay them out on a bench with the marks aligned and tape them down so they don't move, and measure from the undersides of the nipples. ERD is measured at the load-bearing point of the rim. Take measurements from at least two sectors of the rim, especially if rebuilding a used one that might have been crashed around a bit. Similarly, carbon rims can have variable wall thickness where individual bits of carbon mat have been overlapped during layup.

 

[born-again-biker]

I have another question...

Is it important to measure the dish on each side before I disassemble the wheel?....so that I can set the same dish on the new wheel?
Mr Musson's bible talks about it being a function of the hub flange design...

 

[T-Rex]

I have another question...

Is it important to measure the dish on each side before I disassemble the wheel?....so that I can set the same dish on the new wheel?
Mr Musson's bible talks about it being a function of the hub flange design...

No. wheel build is centred around the hub.

 

[born-again-biker]

No. wheel build is centred around the hub.

OK, cool. I just re-read it.
So when I'm nearing completion I use the dishing tool to check the hub is centred in the rim?
When it is centred, the wheel will have the dished appearance with different spoke angles & tensions.
I'm not building the amount of "dish" by measuring any pre-determined offset....?

 

[T-Rex]

OK, cool. I just re-read it.
So when I'm nearing completion I use the dishing tool to check the hub is centred in the rim?
When it is centred, the wheel will have the dished appearance with different spoke angles & tensions.
I'm not building the amount of "dish" by measuring any pre-determined offset....?

That's right, you want zero offset, otherwise the rim won't be centred in the frame, and you risk having a tyre rub. It's possible that there are frames somewhere that are designed to have an offset rim, but I've never encountered one.

You will want to set the dish before you put too much tension into the spokes, and you will want to continually recheck it as you eliminate lateral and vertical runout. At least that's what works for me

The term "dish" is a bit misleading BTW. Yes, you will see the the spokes go onto the hub different angles drive side vs non drive, but there's no dish shape as such.

EDIT: And if you have not yet purchased a dishing tool, don't waste your money. You can dish quicker in the truing stand, or you can use a pair of tea cups on a table and a stack of coins.