Looking for the ERD of the 729 and the Dee Max rims (same as the 823?) Thanks....Can't find this info anywhere!
Mavic ERD help....
- Thread starter JohnnyBoyDH
- Start date
The EX823 ERD is 532 and the EX729 is 534.5. Hope this helps!
I thought your bike was finally built.JohnnyBoyDH said:
effective rim diameter. It is used for calculating spoke length.
Hmmm, DT swiss's calc says 538mm for the EX823, do they not take into accoutn the nipple cups or something? This would explain why my spokes have seemed too long when I've built these wheels before, I have to turn the nipple so many times I'm sure it must be cutting new threads on the spoke! Surprisingly those wheels are still going strong.
Anyway, can someone confirm that the DTSwiss calc is wrong, and the ERD is 532mm, not 538mm? Guess I'll be going back to the bikeshop to change some spokes :-(
Anyway, can someone confirm that the DTSwiss calc is wrong, and the ERD is 532mm, not 538mm? Guess I'll be going back to the bikeshop to change some spokes :-(
i used the spoke calc and it came up with 256 and 258 for the rear 135mm hadley hub and 256 for both sides on the front with my 20mm hadley hub. the spoke length is perfect, the end of the spoke just comes out the other side of the nipple. i saw this when i had to change a few rounded nipples.
Its 532, dt swiss is wrong, as I found out after lacing up a wheel.
I just built one (hope pro 2 and 823) up yesterday and the dt swiss one (as well as another one) gave me spoke lengths that were 8mm too long.
Wow, didn't even see this is a 2 year old thread (I bet he figured out his problem by now).
Wow, didn't even see this is a 2 year old thread (I bet he figured out his problem by now).
It turns out the DT spoke calc has two problems though.
1) it has the ERD as 538 instead of 532 (or I've seen 530 somewhere now too). So this makes the spoke lengths 3-4mm too long.
2) when you change from 12mm to 16mm nipples it shortens the spoke length by 4mm, even though the length of the nipple should make no difference. I've two lots of nipples here, 12mm and 16mm, and if I screw them all the way onto the spoke until they run out of threads, the amount of spoke sticking out of the end of the nipple is 0mm for the 16mm ones and 1mm for the 12mm ones. Nowhere near the 4mm difference that the DT calc suggests. This is because the extra length of the nipple is mainly just for gripping with your spoke-key, most of that extra 4mm isn't actually threaded.
So, in short, the two errors seem to cancel themselves out. I've just built my wheel using the lengths given to me using the wrong ERD (538mm) and each spoke has had about 9 turns of the nipples after the thread disappears into it. Testing a spoke I have left I can get a full 14 turns before the nipple runs out of thread.
1) it has the ERD as 538 instead of 532 (or I've seen 530 somewhere now too). So this makes the spoke lengths 3-4mm too long.
2) when you change from 12mm to 16mm nipples it shortens the spoke length by 4mm, even though the length of the nipple should make no difference. I've two lots of nipples here, 12mm and 16mm, and if I screw them all the way onto the spoke until they run out of threads, the amount of spoke sticking out of the end of the nipple is 0mm for the 16mm ones and 1mm for the 12mm ones. Nowhere near the 4mm difference that the DT calc suggests. This is because the extra length of the nipple is mainly just for gripping with your spoke-key, most of that extra 4mm isn't actually threaded.
So, in short, the two errors seem to cancel themselves out. I've just built my wheel using the lengths given to me using the wrong ERD (538mm) and each spoke has had about 9 turns of the nipples after the thread disappears into it. Testing a spoke I have left I can get a full 14 turns before the nipple runs out of thread.
Don't hold me to this but I believe I measured the ERD of the old
823's at 532mm.
The nipple length definitley affects spoke length when using DT nipples: http://www.ridemonkey.com/forums/showthread.php?t=55674&page=2
823's at 532mm.
The nipple length definitley affects spoke length when using DT nipples: http://www.ridemonkey.com/forums/showthread.php?t=55674&page=2
Resurrection!
I'm digging up the dead and seeing if there are any updates.
I just got my new Mavic 823's today at the shop.
Calling Mavic turned up yet a new ERD, 528mm according to them.
The DT swiss spoke calc turns up 532mm now in the spec chart.
I assume the ST spoke calculator takes into account nipple length.
I've got my hub specs nailed thanks to Hadley giving them with the hubs (thanks!)
I'm digging up the dead and seeing if there are any updates.
I just got my new Mavic 823's today at the shop.
Calling Mavic turned up yet a new ERD, 528mm according to them.
The DT swiss spoke calc turns up 532mm now in the spec chart.
I assume the ST spoke calculator takes into account nipple length.
I've got my hub specs nailed thanks to Hadley giving them with the hubs (thanks!)
Nipple length has nothing to do with spoke length (the threaded portion of the nipple is exactly the same), I have absolutely no idea why the DT site does this.
The measurement that Mavic gives is NOT erd...it is thier own proprietary french made up measurement called spoke bed diameter...and it is indeed 528. To get erd from sbd, you add the thickness of two nipple heads....so about 4-5mm
Use 532 or 533mmmmmmm and use try spocalc (downloadable excel calculator) http://www.sheldonbrown.com/rinard/spocalc.htm it is a great little tool!
The measurement that Mavic gives is NOT erd...it is thier own proprietary french made up measurement called spoke bed diameter...and it is indeed 528. To get erd from sbd, you add the thickness of two nipple heads....so about 4-5mm
Use 532 or 533mmmmmmm and use try spocalc (downloadable excel calculator) http://www.sheldonbrown.com/rinard/spocalc.htm it is a great little tool!
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Hadley Hubs and 823 rims use a 256mm spoke all around. Buying all 256s save money as you only need to get one box. 12 or 16mm nipples don't make a difference either. Just be sure to dish the rim accordingly (usually no threads showing on the short sides and two threads showing on the long sides of hubs: long front = non disc side, long rear = disc side) due to the same length spokes.
Why doesn't anyone measure their own ERD? Two spokes cut to 200mm with nipples on the ends, put them in opposite holes and measure the gap... 400mm + the gap = ERD. And try it at a few locations to be sure.
Thank you, you saved me from the doom of incorrect spoke length! The DT spoke calc is spitting out 252mm L and 253mm R when you enter 16mm spoke nipples.
Actually it's NOT exactly the same
all these spokes are correct length, ie. still have 1mm of thread left to tighten, yet they are different lengths.
pic from wheelpro book.
Attachments
For DT spokes and nipples this is incorrect.
Have you actually measured a 12mm versus 16mm nipple when threaded all the way onto a spoke? The 16mm nipple has the seat that contacts the eyelet 2-3mm farther out than a 12mm.
Everyone but DT seems to say otherwise but the spoke ruler does not lie.
Describe what you mean by 'all the way'. Rolled threads are larger diameter than the spoke itself. You can thread the spoke right through the nipple if you want to. If you thread the spoke to the top of the slotted end of the nipple (as you would for maximum thread engagement) the length of the spoke/nipple combo with be the exact same length end to end, as well as elbow to nipple seat. Look at the pictures posted, the heads are the exact same shape on all nipples (so they will seat on the rim in the same way), and all spokes can (should be IMO) be threaded all the up to the slot when fully tensioned. The configuration of the 16mm nipple in the photo leaves the nipple internally unsupported and creates a stress riser at the exact place where the rim places the highest force on the nipple. Ever seen a nipple head snap off? Ever seen one snap off that had the spoke threaded all the way through the rim plane and near flush with the nipple?
Obviously, if you want to thread your spokes partially in the nipples a varying amount depending on the nipple length, the total length will be different. I have never done this (and see no benefit or structural advantage, in fact I see a destinct structural disadvantage to using this method on the 16mm nipples) in the 25 years I since I build my first wheel...????
If you want to do this, then certainly you would want to buy shorter spokes for the longer nipples...
I find it a bit funny that Roger musson does not allow nipple length variations in his calculator, that by his own words is: "the calculator is perfect - if it wasn't I would change it! ".
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Surely you know that when you screw past the threads on a spoke you actually start cutting more (partial) thread into the spoke? it's not really ideal...
I try to read every wheel building thread that comes around, it's the only area that I lack knowledge when it comes to bikes. After numerous threads I still have no fricken clue what Im reading and my eyes hurt. Somebody has to offer classes on wheel building.
Noah, finally joining the 823 army! Did Orvan try to drag you to the fulcrum side?
Noah, finally joining the 823 army! Did Orvan try to drag you to the fulcrum side?
I just checked a few DT spokes and nipples I have none of the spokes will thread right through the nipple unless it is forced and the nipple trys to cut more threads on the spoke.
You seem to be missing the most important point. The length of threads is different on the different length DT nipples. Look at the picture above, the proof is right there. The length of threads is the same on all DT spokes. You will NOT be able to have the same amount of spoke in the top of the slotted end of the 16mm nipple unless you cut more threads on the spokes.
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The wheelpro book is a worthwhile investment in biking knowledge. After you read that you realize all the wheelbuilding 'mystic art' stuff is just crap. It all seems pretty simple after you read it, and well, it is.
Nope, no kool aid involved. I chose 823's for an easy tubeless setup and a little weight savings. The Fulcrums are too pricey and only take a campy cassette, yuck!
The calculator caters for all spoke/nipple manufacturers. Some nipples require compensation, some don't and I explain this on the Help page. If you use the calculator and select any hub matched to a Mavic UST rim (819, 823) and calculate the spoke lengths it gives you a prompt to modify the calculated lengths.
www.wheelpro.co.uk/spokecalc/
I've never seen any nipple heads pop off regardless of where the spoke lies in the nipple. If this were a potential problem I'm sure DT would not shorten the spoke lengths in their caculator (their shortening compensations are a little excessive).
Roger
so whats the new consensus on the 823's actual ERD? is in infact 532mm?
i went by sickline's measurement of 528 but that didnt work out at all for the spokes for a Hadley hub.
i went by sickline's measurement of 528 but that didnt work out at all for the spokes for a Hadley hub.
C/P:
The measurement that Mavic gives is NOT erd...it is thier own proprietary french made up measurement called spoke bed diameter...and it is indeed 528. To get erd from sbd, you add the thickness of two nipple heads....so about 4-5mm...
Use 532 or 533mmmmmmm
The measurement that Mavic gives is NOT erd...it is thier own proprietary french made up measurement called spoke bed diameter...and it is indeed 528. To get erd from sbd, you add the thickness of two nipple heads....so about 4-5mm...
Use 532 or 533mmmmmmm