Splined hub strength?

The Profile setup has a 48-spline hub and the new KH unicycles have 8-spline hubs. Can anybody please tell me the difference? Which one would be stronger? I would have thaught that the 48-spline would be stronger because it’d have more surface area in contact with the cranks - is this right?

On another topic, it seems like when you’re trying to get a frame made that fits a 3" wide tyre, it’d be better to have a rectangular shaped frame (cross-section). Is this any weaker than an oval-shaped one if you use a long rectangular shape? I also think it looks better.


Re: Splined hub strength?

40 :smiley:

Sorry. The strength of any metal part will have a lot to do with the quality of the metal (heat treating, hardening, etc.) and less to do with the shape. But assuming equal axle diameter and identical quality of steel, the profile should have the edge in strength because of a larger effective diameter. The fewer splines, the deeper the cuts between them and the smaller effective diameter.

The strength of the new axles is as yet unknown, but in general it’s safe to assume that any splined axle is going to be a lot tougher than a cotterless axle.

Also, I will note that the Profile axles are famous for creaking, while my DM splined axle doesn’t make any noise at all. I consider that a plus, and expect the new KH axles will be quiet as well.

On another topic, it seems like when you’re trying to get a frame made that fits a 3" wide tyre, it’d be better to have a rectangular shaped frame (cross-section). Is this any weaker than an oval-shaped one if you use a long rectangular shape? I also think it looks better.

Andrew [/B]

Which one is 40? the profile is most certainly a 48!

It’s subtraction. What’s the difference between a 48 spline hub and an 8 spline hub? Answer: 40

See, this is why I suck in problem solving…

Do you think the new KH 24" mountain unicycle (thwe orange one) could withstand up to 6-7 foot drops without any bending or general damage at all? This unicycle seems like a really good deal to me because it’s pretty cheap.

Is the only bad thing about this noise the fact that it’s annoying or is it a sign of some sort of damage being done?


Are you planning on doing 6-7 foot drops to flat concrete or are you planning on landing on a transition? Landing on a transition makes a big difference because the wheel naturally rolls out and doesn’t put as much stress on the axle and cranks.

If the creaking from the Profile cranks is caused by the splines then it is just annoying and isn’t causing damage.

I think I’m planning to work my way up to about 5’ drops onto flat concrete. Are transitions when you land onto a slope? I’m not sure about transitions because I’ve never tried them. I’d probably hopefully work my way up to about 6-7’ drops with a soft landing (ie. grass and that soft stuff in playgrounds, etc.).

not ideal on a 24inch

Why not?

I’m holding out for the KH 20 inch, I like that seat, and it seems like a nice cheap alternative to the 600 dollar profile/yuni setup (which only comes with a miyata). I’ll wait till around christmas, hopefully there will be some good reviews of the KH20.


Yes, landing on a transition means landing on some sort of slope. The trick with landing on a transition is to make absolutely sure that your wheel is pointing straight down the slope when you land. If the wheel is not pointing directly down the slope then the uni will twist as you land. In the best case it will just cause you to fall off, in the worst case it would taco the wheel. Just keep that wheel pointing directly down the slope as you land and all is good.

I have a DM Vortex that has a splined hub that is similar to the splines used on the Norco KH muni. It’s a strong hub. I have done 4 foot drops to flat hard ground (no transition on the landing) and didn’t worry at all about breaking the hub or cranks. I land some of the drops pretty hard too (I don’t exactly have the best technique in landing drops). It could handle larger drops but I’m not up to doing anything bigger than 4 feet.

It’s hard to know what sort of limits to put on the new Norco KH hubs because no one has reported their experiences with that hub yet. I would guess that 6’ drops to flat ground would be OK as long as the rider is able to do drops like that without injury.

You really souldnt have any problems with a 24" wheel tacoing, and if you do it’ll be the first one iv ever heard about. In disorder II kris is doing some 8 or 9 footers on a 24", lots of 4-7 footers too. It should work just fine, and probably be more stable as well.

I disagree. I tacoed my 24 inch Torker setup after 2 foot drops, and if you want a good uni, Kris tacoes a 24 inch in New World Disorder

A properly built 24" downhill wheel using a rim like the Alex DX32, Sun Doublewide, or Avro ZUM, will not taco. A 24" Torker does not have a strong downhill rim and is not what we have in mind when talking about a 24" muni wheel. A properly built 24" downhill wheel can take lots of abuse as long as it starts out with a good wheel build and is maintained so that it stays true and the spokes stay tight.

In New World Disorder Kris is using a 26" wheel. 26" wheels are not as strong as 24" wheels and can taco (as Kris, Dustin, and many others have demonstrated). I’m not aware of anyone turning a good 24" downhill wheel into a taco.

I am kind of paranoid when about to do a big drop, because i dont want to untrue the wheel, even though it is a sundoublewide, and it will not taco.
How easy is it to take it very badly out or true, as in barely still rideable?

Who built the wheel? Did they build it up strong? Do you regularly check the spokes to make sure they are all still tight?

The quality of the wheel build is the major factor in wheel strength.

If the wheel was built well then stop worrying about it.


It is a Kovachi wheel, so i guess it is about as strong as it will get. How do you check to see if the spokes are tight?

Do you meen by this that you have never tacoed said wheel, or that you have never heard of such, or that any wheel that tacos is not properly built?

If memmory serves me, Kris had refered to killing several durring that North Shore commercial shoot… could be wrong. Anybody else manage to taco any of the described wheels, and would like to chalange this assertion?

Not to be overly critical -but I put alot of stock in your opinions, John, and wonder if I need to readjust my set regarding wheel streangth.


I think kris taco’ed alot of 26" wheels, but iv never heard of him tacoing a 24".