I was looking at my Trials uni the other day, and I though I had a vision problem but my KH 09(?) Ti hub looks twisted. I took a picture with the cranks on so you can see how twisted it is, it’s not super bad, but for a Ti hub I dont know how it’s possible. I’ll take the cranks off, I’ll see if there’s any cracks or if I can see the hub is twisted somewhere…
Anyway, here’s 2 pictures, I’ll take some other with the sun and the cranks off if I can see anything on the hub.
Twisted Sister!
This was Ti also, alot stronger? Maybe, but really lighter. I’m glad we’re over square taper.
My Profile hub/cranks are sort of like that, not quite as bad as in the photo, but it is noticeable. As far as I know, it’s been like that since I got it. Been riding for years and never had a problem with the hub, except for the usual creaking.
I don’t think this is unpredictable. Titanium is not stronger than steel, it’s just lighter for near the same strength. You could make a titanium part stronger than steel for the same weight if you made it larger. As long as the part stays the same size it will be weaker than the hardened Chrome-Moly counterpart.
Well, I took my cranks off and the hub is slightly bent… for real… I’m going to e-mail Kris now, see what he can do, I bought this hub from UDC this winter:(
Titanium is about equal in strength to low grade steel. As noted it is weaker than 4130.
Nice and to the point. Sometimes I get too wordy.
Ti spindles would be fine for a road uni, and maybe for an ultralight XC rig. I don’t know if I would want to sacrifice the strength on my MUni, and if I had a trials uni I would want the strongest spindle I could get regardless of weight.
Warranty it.
Aww dude that sucks, hope you get it replaced. I hope mine doesn’t do that.
I emailed Kris yesterday, I hope I’ll get it replaced. I’m pretty sure Kris will do something for me. I’ll have to go back to my old crappy Cr-mo hub for a while probably.
I emailed Kris yesterday but he didn’t replied yet, I wonder if I should email Pete at municycle.ca too? That’s where I bought my hub from.
I can’t wait until I get a new hub.
I went to unicycle.com just a few days ago and i got a tour of the place and i forget the ladies name that helps run the place but she showed me that there is only one real original Ti hub left that they have
I don’t get why riders get Ti hubs but keep using plain gauge spokes. It’s a known fact that DB spokes are far superior and beneficial than straight thickness spokes, since they are allowed to flex more in the centre and put less stress on the heads of the spokes, meaning less snappage and is friendlier for the hub flanges and rim as well. Whilst overall providing a stronger wheelbuild. Hey, it’s also lighter!
Ti hub + plain gauge spokes vs. CrMo hub + DB spokes. There is a clear winner in the strength+value for money department. Only get a ti hub if you know it’s made well in a good place.
Well, Kris told me it shouldn’t be on warranty… But, he wants too see this hub and he’s sending me his MomenTi spare hub and I sent him my hub so he can look at it.
Thanks Kris!
I’m glad this is working out well. Still, you should be a bit more gentle on a Ti spindle than you would on CrMo. Hopefully you’ll get years of service out of the new hub.
Thats awsome! Thats sooo generous of him.
I wasn’t too hard on my Ti hub even though I thought it could take anything I’d throw at it, I dont know how it could’ve twist like that. I’ll be sure to not do anything too big on my new hub though! I hope I’ll get years of service with my new hub:) But if I get any problems with the splines again I’ll just go back to CrMo.
Yeah, he also sent me a pair of Pulse gloves to help with the hassle:D Kris is a really cool guy:)
sweet that’s awesome, good to hear
The picture of your Ti ISIS splined hub looks fine, are you sure it’s twisted?
The real way to tell is to put those cranks on another hub or swap cranks side to side and see how they look. More than likely, the splines slipped. I guess it’s possible, but the only thing that comes to mind is if the material thickness was no sufficent, but after looking at mine last night I don’t see that they are not super burly.
I do not think a chromoly hub is any stronger, possibly weaker, take a look at these materials comparisons:
First number is Yield Strength
Second number is Ultimate Strength
Third number is Denisity
Material Yield strength
(MPa) Ultimate strength
(MPa) Density
(g/cm³)
Steel, high strength alloy ASTM A514 690 760 7.8
Stainless steel AISI 302 - Cold-rolled 520 860 8.19
Titanium alloy (6% Al, 4% V) 830 900 4.51
Aluminium alloy [6] 2014-T6 414 483 2.8
Source: http://en.wikipedia.org/wiki/Tensile_strength
Some more interesting tidbits comparing the three materials:
Steel vs Titanium
Look at the chart again. You’ll see that identical steel vs titanium frames would be about equal in strength, but that the titanium frame would be about half the weight and half the stiffness.
Such a frame would likely have a whippy feel due to the reduced stiffness, especially in loaded touring applications. To compensate, builders of titanium frames use somewhat larger diameter tubes to bring the stiffness more into line with what riders like. This tends to increase the weight a bit, but by making the walls of the larger tubes a bit thinner, they can compensate to some extent, and come up with a frame that is still lighter than a normal steel frame.
Steel vs Aluminum
The situation with aluminum is even more pronounced. the “identical” aluminum frame would be 1/3 as stiff as steel, roughly half as strong, and 1/3 the weight. Such a frame would be quite unsatisfactory. That’s why aluminum frames generally have noticeably larger tubing diameters and thicker-walled tubing. This generally results with frames of quite adequate stiffness, still lighter than comparable steel ones.
If you concentrate a little bit on the picture you can see that it is twisted a little bit, you can see that the splines aren’t fully straight. I’ve been told by a few other riders(as you can see in the thread) that Ti is only as strong as Low-grade Cr-mo, Kris did told me this too when I talked to him about my hub.
I just feel safer going Cr-mo anyway, I dont really mind if my uni is super light weight anymore.
