Case Study: Ksyrium SL

[Old school]

R45 per spoke. PM me.

[GoLefty!!]

thats a good price!! you should buy the spokes from him..

 

recent quote = R120 per spoke!!! Bedawnnerd

[Wannabe]

R45 per spoke. PM me.

 

Jammer Mercx, klaar weer van jou vergeet (moet die ouderdom wees)

Sal dit sommer selfde tyd doen as die ceramic bearing conversion. Sal jou bel vir afspraak.

 

Dankie vir lekker gesels op pad Sondag oggend.

Wannabe2008-09-10 05:53:15

[Gman1834]

Will you put some anti-seize on the spokes and nipples for easy removal next time.

[Wannabe]

Will you put some anti-seize on the spokes and nipples for easy removal next time.

 

I'll take JB's advice, and play with my nipples at least once a month

[greatwhite]

1. Fulcrum (read Campagnolo) state in their operating and maintenence instructions for Fulcrum Zero wheels (which are similar in a great many ways to Ksyrium SLs) that you should put a certain grade of loctite on the aluminium spoke thread - this might be to help in part deal with galling/seizing.

 

2. Although I personally believe the aluminium spoke is not ideal engineering practice for a number of reasons, the Ksyrium SL isn't an especially bad wheel other than this - but they have so many on the road, the number of folks with failures is bound to be high - I speculate the Sys-R wheels will have similar rim failures and sooner as will most other aluminium rim wheels in the sub 1.6kg catagory - the lighter the more rapid the rim failure. I expect the XTR wheels JB holds in such high regard to also have rim failure eventually too. BTW GoLefty: I've killed 4 mavic open pro SUP rims with fatigue cracks just like these (along with many other rims), so don't get too excited about them either.

 

3. When I saw JB a few weeks back, he gave me a strange look when I said my view on most high performance parts was that they were sacraficial. Engineering obselensce into a product is common in many industries, not just mavic or cycling. Longevity if often sacrificed to achieve lighter/faster etc. Extreme eg FIA F1 engines have only to last 2 races (and even that only because the FIA were trying to stop the upward spiral of cost of new motor per race), but they are able to achieve huge power and minimal weight. Market pressure in many sector also means many manufacturers make smaller products running at higher speeds to make a more cost effective option, but they know it will fail sooner - it a achieves 2 things a) they get the initial sale & b) they get to sell more (spares or completer replacement units) later which is when they really score. The best case of true planned obselescence I've seen is printer cartridges that have a chip in them to tell the unit to stop working after 50000 prints or 3 years which ever comes 1st.

 

4. Propriatory parts and the captive market: also common. Again look at the motor industry - many parts can only be bought from the dealership and the are very expensive. I have no idea what the number is now, but about 10 years ago, if you built a car from spares it would cost you 8-10 time the price of the complete new car. My gut feel is that now that number is higher.

 

 

[Willehond]

The bottom line is you can build a wheel from stock non-proprietary (rather call it generic) components, which is easier serviceable using other high end components in the bicycle industry (Shimano, Campag, Chris King, DT Swiss, etc.).

 

Like I said, I think it is good business practice to lock customers in, I just think customers need to look at the bespoke option too (pardon the pun) rather than just buying into the expensive Mavic option.  Looks like a lot of people agree.

[Johan Bornman]

Galling, spalling and Seizing

 

To add to Lefty's explanation and to apply this to the wheel problem at hand.

 

Galling is as Lefty described and happens frequently in aluminium nipples. Aluminium (or alloy, as the Yanks have made us call it) loves to gall. Alu nipples do that all the time and at the time of the build or adjustment. Galling can only happen in the presence of movement under pressure, as when an aluminium nipple is thightened on a spoke under high tension. The nipple's thread and the spoke's thread grind against each other an a cold welding process seizes * the two components together. This also happens on steel on steel, like in bolts nuts etc. When you eventually get the two separated through some miracle and you examine the threads, they're a mess.  It looks like half-molten crystals were jammed in the threads. It is preventable in wheelbuilding by using brass nipples. Brass makes an excellent bearing and even under stress, doesn't gall very easily.

 

* seizing - the locking together of two parts that are suppposed to slide or rotate around each other.

 

That's why aluminium-nippled wheels are very rarely tensioned like they are supposed to be. Some wheelbuilders will use brass nipples on the rear wheel's right hand side and hope for the best on the other nipples. It often works.

 

Even if the wheelbuilder managed to not gall the nipples during the build, he's likely to gall them a year down the line when the wheel needs adjustment. In my experience galling doesn't happen from riding - there's no movement in the nipple in a properly tensioned wheel.

 

A seized nipple, like most of those on the Mavic wheel I described (some were galled, probably during the build) is another story although the symptoms are the same. Here dirt has entered the space between the nipple and spoke and settled in there like Lefty described. Frequent washes and rainy rides have packed the fine particles tightly into the threads and shaft cavity and literally clogged it up. Now they can't turn. Oil doesn't help because you can only moisten in there, not flush.

 

Spalling is what happens to bearings when their surface flakes off. Spalling is always associated with flaking. That's another story for another thread.

 

Mavic's spokes in question are painted. During building, the nipples are turned on the painted spokes, paint comes off and settles, you guessed right, in the threads. Now that the paint is scraped off, we're left with naked aluminium. Naked aluminium quickly oxidises into big white crystals about 100 times the size of the original alu grains and SEIZES the nipple against the spoke.

 

 

Here's the gap betwen spoke and nipple where bad stuff can enter. Helped on my the centripital force of riding, the grit packs tightly inside, no matter how clean you think you keep your bike.

 

 

 

Here's a close-up of the nipple end. You'll see that Mavic tried to solve the problem by putting a teflon bushing in there (green). Teflon will work under low tension but not in a case like a spoke where tension is the name of the game. The bushing disintegrated during the build and only helped to jam more junk into more cavities. Tha bushing should have been a brass washer and the spoke should have been steel and the nipple brass.

 

What is the solution? This is it.

 

 

This is Shimano's solution. The new XT and XTR wheels are made like this.

 

Note:

1) The steel spoke.

2) Anodised alu nipple (not painted).

3) Tiny brass pressure washer betwen spoke head and nipple to prevent galling.

4) The little flat area on the spoke to hold it and prevent turning.

 

Now this is engineering!

 

[Johan Bornman]

Will you put some anti-seize on the spokes and nipples for easy removal next time.

 

I doubt that will work. Anti-seize, like copper compound is greasy and will trap dirt like a white suit in a coal yard. I think over time it will increase the problem. Anti-seize works in things like head bolts on cars where very little dirt gets trapped and where there isn't much of an entrance for the dirt in the first place. Also, the difference in scale between big bolts and little nipples means that the same remedies don't work for both.

 

 It may prevent initial galling but assist with seizing as per my earlier definitions.

Johan Bornman2008-09-10 07:52:16

[Piernas Flacas]

If I may ask: what is the advantage of these Shimano XT and XTR spoke and nipple design over the conventional type?

[Dirtbreath]

Do any other spokes and nipples fit the Mavic wheels or have they got your proverbial in a vice?

[Johan Bornman]

If I may ask: what is the advantage of these Shimano XT and XTR spoke and nipple design over the conventional type?

 

This is an interesting question and if more people asked this when buying bikes I'm afraid the industry will go bancrupt. However, it is not all marketing speak.

 

A straight spoke is more durable than a j-bend since the latter has offset at the bend and that is generally where the spoke breaks. Further, a spoke should enter the rim at 90 degrees or very close to 90 in order to prevent a bend at the nipple where the spoke then also breaks.

 

Most slapped-together wheels such as any handbuild with a hub from one company, a spoke from another and a rim from another is a compromise of sorts. A good wheelbuilder can eliminate trouble spots at both ends but at the end of the day, a spoke that is straight and arrives at 90 degrees at the rim and isn't bent anywhere, is the most durable.

 

Mavic approached this problem first with something called the Helium wheel. This used a conventional Open Pro rim with a standard nipple at the rim but a hub that accepted a straight-pull spoke. Problem was that that the weakest part of this spoke is the mushroom head which pulled straight off. Further, the wheel couldn't be tensioned since the spoke could not be prevented from turning as tension started to come in. Hence undertensioned and weak wheels.

 

*****lots of history skipped******

 

Then Mavic eventually produced the Ksyrium. This was a straight spoke wheel with a flat blade. Therefore the spoke could be prevented from twisting. Unfortunately Mavic decided that alu is lighter than ssteel and make the spokes from the former. All the problems thereof were described early on on the thread.

 

Lots of other companies fiddled with all sorts of stupid designs so that their wheel can look different. Rolf Vector, Shimano, Campag - all stupid designs.

 

The problem still remained. How do you create a straight spoke without a mushroom head, which you can prevent from twisting as you tension it?

 

Shimano thus produced the XTR wheel. Instead of a mushroom head, the spoke was threaded on that side and a ferrule screwed on. This then hooked into a slot in the hub. The other end had a permanent nipple as illustrated.

 

It solves the problem. However, it isn't all that elegant. It is a bitch to clean these hubs with their silly flanges and quite frankly they look like a machine's innards. The large nipple may or not be aesthetically pleasing but mos people dig the large red nipple. I'll leave it at that. At least the engineering on this wheel is sound.

 

Easton did it far more elegantly in my view. Their spokes have threads on both sides. The one end just scews into a thick-flange hub and the other attaches with a standard nipple to the rim. This configuration produces a bland-looking wheel with limited sex appeal.

 

I like the engineering in these wheels but I bemoan the use of proprietary parts. I think a standard wheel with J-bend spokes has more going for it than the rest. Unfortunately market forces think otherwise.

 

 

 

 

 

[Johan Bornman]

Do any other spokes and nipples fit the Mavic wheels or have they got your proverbial in a vice?

 

Over a barrel. Proprietary size and thread.

[stringbean]

You can be lucky you not working here in CT Johan,every second mavic wheel that comes into the shop has that problem.Here by the sea that problem happens even faster and sometimes just replacing 1 spoke is a nightmare.I also think the mavic wheels are crap.crap expensive spokes,crap boddies,crap nipples.I have old school 32 hole normal spoke training wheels,cost me 1K,never had a problem with them.

[Red Zone]

A quick question, would anodizing the aluminium nipple prevent it seizing with a steel spoke?

[turtlek]

guys why do you think i have got a set of cosmic carbon rims with different spokes and nipples and hubs (because mavic is too expensive and they never have stock well not when i call them)turtlek2008-09-10 23:46:25