Building UST wheels / EX823 rims

barq

Hi

I'm quite familiar with wheel building, but a friend has asked me to fix (respoke + new rim) his UST rear wheel. Can someone explain about how the nipples work on mavic ex823 rims - obviously you can't just drop them in because its a UST rim and the holes don't go all the way through. From what I've seen it looks like the nipples fit into some sort of cup which is then screwed into the rim. Do these come with the rims? What tool should I use? Any special fitting instructions or thread preparation? I assume normal nipples fit into these?

I've lost the log in to the technical section of the Mavic website. Is there any help there and does anyone have the password?

Sorry for the deluge of questions, but I've never dealt with UST rims so this is all new to me.

Many thanks.

skyliner

OK, Here goes, the inserts should be suplied with the rims. You should use 16mm nipples, and threadlock the inserts in.
If you've not got a spoke length yet, try the DT website. (It automatically gives lengths for 16mm nipples IIRC)

barq

Thanks. I take it that Park's SW-13 is the correct tool to install the inserts?

Dangerous Dave

I'm not sure, the wheel it pictures is one of the off the shelf wheels, which use different inserts to the EX823/XM819's.

I actually find buidling them a bit easier than "normal" rims, if a bit of a faff.

Lace the hub up as normal, drop the insert over the spoke, then thread the nipple on as you normally would.

It is best to use threadlock, but I've got away with not using it. The Mavic tool is about £7/£8.

barq

Ok thanks. I think the Park tool is double ended for the two different types of insert, but I may be wrong so I'll check. Is the Mavic tool that vaguely star-shaped metal one?

Dangerous Dave wrote:

Lace the hub up as normal, drop the insert over the spoke, then thread the nipple on as you normally would.

What and then tighten up the inserts before truing as normal from the nipples? I assume that means you can't thread the nipples on very far before tightening the inserts? That's a pain, I normally use my homemade nipple driver to get them all threaded on the same amount before the truing starts.

It does sound like a bit of faff! So I'm interested to hear you say it's easier. I guess I'll discover for myself.

Cheers for the help - much appreciated. (And, yes, I'll be using threadlock. These wheels are going to be doing a month of downhilling in Canada so they need to be good.)

Dangerous Dave

They're good rims, mine have lasted a good few years of general and racing DH abuse.

The "inserts" are essentially screw in eyelets.
And the rims have a solid outer wall, which enables them to be tubeless.

It's a completely different process to normal, instead of dropping the nipples through the eyelets in the rim, you drop the eyelets/inserts over the spoke, then screw the nipples onto the spokes. THEN you get the eyelet, pull it to the top of the spoke and then screw the eyelets into the rim itself.

I've only found it easier to true, but a tad longer to lace.

You can tighten the nipples on as much as you like with your nipple driver, I do the same, get them tighten on the same amount before I start tensioning/truing.

barq

Excellent - thanks very much.

Dangerous Dave

No worries It'll all make sense when you come to do it.

Oh, RE the park tool, so long as it fits after market Mavic tubeless RIMS it'll be ok.

And yeah, the Mavic one is a silver 4 point star shaped thing.

http://www.chainreactioncycles.com/Mode ... elID=18081

http://www.chainreactioncycles.com/Mode ... delID=3842

The Park one looks the right size, though it will be a pain to use, as the good thing with the Mavic one is that it's a bit like a big spoke key and you can just pop it on the eyelet and turn it without fowling the neighbouring spoke!
Didn't know CRC did one until just now, will have to invest in one!

barq

I'm glad you think highly of the rims. The person I'm building for seems to destroy one rear wheel for every week of downhilling. That sounds insane to me because I'm an XCer, but I suspect the spoke tension on his previous wheels has been too low. I know accidents happen, DH is rough... but this isn't a clumsy or heavy rider so I suspect bike shops have sold him very true (in the sense of roundness) wheels - but little attention has been paid to the spoke tension. Could be wrong, maybe he was unlucky.

The Mavic tool looks uncomfortable to use. But you are right, it won't foul the neighbouring spokes so I'll get that one. Besides, I'm only doing one wheel (and I'm not paying for the tools since it's a favour for a mate).

Thanks Skyliner and especially Dangerous Dave - you've really helped me out.

Dangerous Dave

No worries.

Well I remember coming up really short on a double on a race (really hung up) and it was fine... didn't touch it afterwards and did a good few more months only needing a sort out after Fortwilliam....

The tool isn't TOO bad to use, but like the reviews said, it isn't the most comfy. Perhaps the Park one would be better to tighten them up? Usefull I guess if you want to make 100% they are all fully tight, and if you're just doing the odd one.

You could well be right with your mate here, spoke tension can wreck a wheel! It's not hard to get right....

I guess it's always worth bedding it in and then re-tensioning, something I don't think a lot of people do that!

Good luck with your wheelbuilding, and hope you mate stops destroying wheels!