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Looking for some advice from experienced wheel builders. @107 hrs on my '18 150sx, I'm starting to break spoke nipples at an alarming rate. All of them at the same fail point; the head breaks clean off of the aluminum nipple.
Hubs are still in decent shape, so the best plan I have so for is to rebuild with DID Dirtstars and Bulldog spokes. Cost effectiveness is key, this failure is already blowing my budget to upgrade my sons 85sx to a big wheel.
I was about to hit the purchase button, when I started talking myself out of it. Why not just replace the nipples? Spokes seem fine. I'm sure my hoops aren't perfect, but no big bends or dents. Shit, it'd still save a healthy chunk of change if I just went with Bulldog spoke kit and reused the rims and hubs.
Is this a silly idea? Will I be chasing my tail getting the used rims trued back up? Do old spokes lose integrity?
Also, does anyone know of a replacement nipple, besides OEM, that will work witht he stock Excels and OEM hub?
Thanks in advance.
Call a wheel shop dub, get their opinion maybe look into stainless steel nipples.
I've never tried DID Dirtstar rims.
Bulldog stuff is high quality and as far as I'm aware it's as good as you can get.
If you want unbreakable wheels, I think your original plan is a very safe bet.
If you want to save some cash, buy a complete Tusk spoke set and re-lace your existing wheels.
I'll very likely do this to my GasGas MC350F rear wheel.
I've done a couple of wheel builds with new Excel rims and Tusk spokes that have taken a lot of abuse with 100% reliability.
The Tusk spokes haven't stretched and I've seen zero issues with the nipples.
About halfway down the first page, a set of wheels I assembled with Excel rims, Tusk spokes, and stock hubs for my KX500.
https://www.vitalmx.com/forums/Bike-Builds,46/1990-KX500-Classic-Looks-…
Here's the practical rundown. The stock KTM nipples are junk, as you've discovered. No, they are not compatible with other nipples (no aftermarket option that threads on the stock spokes). Yes, you can replace the stock spokes and nipples with a good set like Bulldog. But if you're that far in, it's not really logical to reuse a 107 hr rim when rebuilding. Now you're putting a new rim and spokes on a 107 hr hub. This sometimes works OK. The issue with KTM wheels, the hub flange on the rear rotor side is very thin cast aluminum. If you rebuild with stronger spokes and a good rim, you then find the next weak spot, which is the spoke pulling through the hole in the hub. Ask Collin at Faster-USA and he'll tell you the same thing.
So, at the end of the day, you're better off just buying a complete wheel. You can usually find people selling new or low hour take offs fairly cheap. I have rebuilt countless KTM wheels at this point and can do it easily but realize these limitations and know what is worth the time or not. I am pretty hard on wheels and have never gotten close to 107 hrs on any stock KTM rear. Since you have, you may be much easier on them and might decide you're OK just doing spokes or spokes and a rim, especially if you're pretty slick at building wheels and don't mind doing it.
Great perspective, thank you.
Was hoping the rebuild route was going to get me a stronger outcome than the easy way out (Tusk Impact Complete Wheelset), but I was unaware of the limitations of the stock hubs. Now I have some thinking to do. Been hawking FBMP, and not seeing anything in my area for take-offs either.
Three options remain:
1) Band-Aid it with spokes only as moto9 suggests.
2) Cross fingers with OEM hub and rebuild with quality parts.
3) Sell soul to the Devil and go with the complete Tusk Wheelset.
Anyone care to vote?
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Not a wheel expert but have laced up a few in my time. If your KTM stockers lasted over 100 hours, you did great on basic upkeep. However at this point, all the aluminum nipples have timed out and are due for replacement. I really like Excel spoke kits, and have used tons of the Notako (NS) series (apparently now branded the Excel One line). The NS part number interchanges with the XS of their higher priced kits (steel spoke, aluminum nipple), but comes with traditional steel nipples and not the crappy spline-drives of the XS series. I believe you would need PN: NS8-52197 for your 19" application. This is the cheapest/safest bet, reusing your stock hub and rim. Its more of pain when truing the assembly to reuse the old rim, but not unheard of with budget constraints. You may have to drill your rim to accept the steel nipples, but that's normal and varies application to application.
For the record, I really like D.I.D Dirstar rims and recommend them quite frequently. Same for Bulldog spokes, good stuff. Also to note, if going with new spokes/nipples only on your KTM, I would safety-wire the assembly once trued. Austria group does this on their race bikes, moto and off-road. Doing so could potentially minimize hub damage due to flex of the likely oversized aftermarket spokes as well...
Front and rear wired on one of Webb's KTMs...
Thanks for the recommendation on the Excel spokes. I haven't had many first hand reviews on them. Dubya and FasterUSA both use Bulldogs on their pre-built wheels.
One interesting note on the spoke kits, are that the Bulldogs come with aluminum nipples, where-as the Excels come with steel.
After talking with both Dubya and Collin at Faster, I'm really feeling like I need to do the whole package. But finding an economical path is what I'm still looking for. Not necessarily a pre-built set. FYI, I've been advised that the Takasago hoops are a better rim than the Dirtstar Originals.
One thing that crossed my mind, if I reuse my hubs, I will be doing bearings and spacers as well. Further adding to the cost and getting closer to a pre-built set.
The wire might reduce flex to some extent, but it definitely prevents the spoke from getting all wrapped around the hub and causing a bunch of damage when the nipple breaks or the head pulls through the hub.
For sure. I actually wired the crosses on mine in between motos, this summer, after I broke a nipple. The ones that broke after that stayed right in place and I actually didn’t catch them until I was washing.
What Torque is recommended for KTM spokes ? 25 350 sx the New bike came with loose spokes on rear, mostly sprocket side. Been torquing 4.6 to 6 N.m range and loose again after couple hard track day rides.
KTM specs 6Nm. Running them at 5 front and 5.5 rear seems to result in less broken nipples.
Thank you FGR01 I got the wheel aligned back pretty close and re torqued to 5N.m for now with tire still on. Will see what happens later. Using a BLACKWIDOW truing/build stand and RKexcel torque wrench.
Sent you a private message with a good used rear wheel option ... reply if interested.
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