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Titanium Hub?
Hey everyone, I have a question about the Ti hub. What is the weight difference between it and the regular KH hub (08)? Also, how much stronger is it? Is it worth it to get it if your not breaking your normal hub? -- hungry4uni ŤŔϊãĻş ЦИΪĈҰĆĻέ my sponsor' SixSixOne' (http://www.sixsixone.com) ------------------------------------------------------------------------ hungry4uni's Profile: http://www.unicyclist.com/profile/16147 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
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#2
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Titanium Hub?
Saves about 180g-190g, dont know the exact amount sry. I may be wrong, but i think i heard Kris saying that its as strong as the normal hub. If you have the money and want a lightweight and strong uni, then get it! Weightweenies FTW hahaha -- Smilymarco 'Municycle.com' (http://www.municycle.com) Lesen - Denken - Posten ------------------------------------------------------------------------ Smilymarco's Profile: http://www.unicyclist.com/profile/4110 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#3
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Titanium Hub?
hungry4uni;1168406 wrote: I have a question about the Ti hub. What is the weight difference between it and the regular KH hub (08)? According to Unicycle.co.uk Kris Holm Titanium ISIS Hub Weight: 425g. Weighs 200g less than the 2008 KH ISIS hub with CrMo axle. Kris Holm ISIS Moment Hub 2008 Weighs (including bolts and spacers): 644g Nimbus ISIS Hub Weighs: 600g (635g including bolts and spacers) Onza ISIS Hub Weighs: 600g (635g including bolts and spacers) Kris Holm/Onza splined 36-hole hub- 2005 model Hub Weight: 680g (with bearings & bolts) Qu-Ax ISIS Hub (red) Weighs (including bolts, bearings and spacers): 815g Suzue Unicycle cotterless hub Weight - 530 / 525g with bearings, spacers & nuts. According to Unicycle.co.nz KH Moment Titanium Hub Weighs a miniscule 426g including bolts, bearings and spacers! KH Moment ISIS Hub Weight (including bolts and spacers): 644g KH-Onza 36-hole hub- 2005 model Weight: 500 g (bare), 650 g (including bearings, bolts and spacers) According to Unicycle.com (USA) Kris Holm Titanium Hub Weight: 1 lb w/hub bolts & spacers (453g) Nimbus ISIS Hub (36-Hole) Weighs: 1.4 lbs (including bolts and spacers) (635g) Poznanter/Profile Hub Weight 2 pounds (907g) It weighs less than a suzue (half a kilogram) and the old best hub weighs nearly 1kg. It would be nice to have but with a price like that not everyone can afford one. -- Rowan ------------------------------------------------------------------------ Rowan's Profile: http://www.unicyclist.com/profile/3772 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#4
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Titanium Hub?
For the record, titanium is weaker than steel, and unless there is something funny about the heat-treatment process on the hubs, the ti hub should be weaker than the steel hub (possibly by a significant difference). Also, strong welds in titanium are much harder to do than in steel (much less tolerant of contaminants), so the welded flanges have a much bigger risk of breaking at the welds than the steel hubs do. I believe Tony Melton already broke a hub in this fashion. -- gerblefranklin (just ride) ------------------------------------------------------------------------ gerblefranklin's Profile: http://www.unicyclist.com/profile/4295 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#5
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Titanium Hub?
gerblefranklin;1168445 wrote: . I believe Tony Melton already broke a hub in this fashion. Tony too? You might be talking about 'Joe Dyson' (http://www.unicycle.org.nz/bb/viewtopic.php?t=2172). [image: http://i7.photobucket.com/albums/y28.../IMG_1933.jpg] -- Rowan ------------------------------------------------------------------------ Rowan's Profile: http://www.unicyclist.com/profile/3772 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#6
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Titanium Hub?
gerblefranklin;1168445 wrote: For the record, titanium is weaker than steel, and unless there is something funny about the heat-treatment process on the hubs, the ti hub should be weaker than the steel hub (possibly by a significant difference). Also, strong welds in titanium are much harder to do than in steel (much less tolerant of contaminants), so the welded flanges have a much bigger risk of breaking at the welds than the steel hubs do. I believe Tony Melton already broke a hub in this fashion. Thank you. Was about to say something along these lines. -- agentQ --- 'Uneed Films' (http://www.uneedfilms.com) ------------------------------------------------------------------------ agentQ's Profile: http://www.unicyclist.com/profile/13021 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#7
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Titanium Hub?
how is titanium weaker than steel? everything i've ever heard says that titanium is far stronger than steel by weight/strength ratios unless titanium is far less dense...but that makes no sense, i want to see some background to what you're saying. show me where you are getting this from. -- skrobo Unicycle For Christ 'MY VIDEOS' (http://www.youtube.com/profile?user=skroboskim) 'World Record' (http://www.youtube.com/watch?v=oig5IEq-v4Y) 94cm Highest Hop (rolling) 308cm Longest Hop (10 feet) 210cm Static Flat Gap ------------------------------------------------------------------------ skrobo's Profile: http://www.unicyclist.com/profile/12272 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#8
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Titanium Hub?
I wish I had my old text books handy with all the properties of common metals and alloys but I seem to remember carbon steel and titanium having similar strength but titanium weighing about 60% as much as the steels. A google search could probably verify this. -- saskatchewanian ------------------------------------------------------------------------ saskatchewanian's Profile: http://www.unicyclist.com/profile/14180 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#9
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Titanium Hub?
skrobo;1169130 wrote: how is titanium weaker than steel? everything i've ever heard says that titanium is far stronger than steel by weight/strength ratios unless titanium is far less dense...but that makes no sense, i want to see some background to what you're saying. show me where you are getting this from. If weight doesn't matter Ti is stronger, but on bikes and unicycles, weight matters and Titanium is used to save weight. Is impossible to say if it's strong or not. Depends of the weld quality and design. Ti is lighter cause it's strong than ALUMINIUM and you can use really thin walls. But if the walls are to thin it may breaks, like any other materials brakes. Also Ti is really rigid and don't flex! -- pedrotejada '*Kris Holm Unicycles*' (http://www.krisholm.com) '*Unicycle.com.br*' (http://www.unicycle.com.br/) *Brazilian Unicycling Team* ------------------------------------------------------------------------ pedrotejada's Profile: http://www.unicyclist.com/profile/14471 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
#10
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Titanium Hub?
The amount of misinformation in the cycling/RC anything/Motosports communities is ridiculous. Any thread like this is a fine example. pedrotejada, Titanium is NOT rigid. It has a significantly lower modulous of elasticity than steel ( http://tinyurl.com/8qxp49 ), making it far flexier. I seem to remember talking to Kris about this issue when discussing whether titanium muni frames are worth the trouble. Also, since the design of the steel and titanium hubs is essentially identical, we can compare strength and make reasonable predictions. But you are right to say good design work should account for material choice therein. Skorbro, your post makes it sound like you've never picked up a big chunk of titanium while expecting it to be steel. It is a dramatic experience to notice how light it is. And my source for the density and strengths of materials is _Machinery's_Handbook,_27th_Edition_. Go buy yourself a copy if you don't believe me. The density of titanium is, according to my copy of _Machinery's_Handbook,_27th_Edition_, 0.163 lb/in^3, while steel is 0.25 lb/in^3. So titanium is about 35% less dense. In a situation where strength is the ultimate issue, and the dimensions of the part are fixed (we can't make bigger ISIS splines), what matters are the strength to volume ratios. 6Al-4V titanium, the alloy which I believe Kris uses in the hubs, has a (0.5% ?) yield strength ranging from 120-160 ksi, depending on heat treatment. While 4130/4140 steel, depending on heat treat, has a 0.2% yield strength of 100-155 ksi. 4130 steel can be made much harder than 6Al-4V titanium. So if the titanium hub is fabricated perfectly, it can be of comparable strength to the steel hub, but it is unlikely to ever exceed the steel hub's strength. I am ignoring spline hardness, by the way, since I assume no rider is regularly changing cranks. Now, factor in the issues with the difficulty of welding titanium, and quality control thereof, and the titanium hub's strength is an issue. Hence the fact that a much smaller sample of riders has already broken a titanium hub, while I, at least, have never seen a broken steel hub. If the titanium hub were machined from solid (prohibitively expensive), I would have more faith in its durability. You would not be wrong to argue that the softer titanium hub builds a stronger wheel by conforming to the spokes better, but I don't think that's where a hub will be failing. I hope this clears things up. And the answer to the original question is, the titanium hub is ONLY worth getting if you aren't breaking the steel hub. If you are, you should either switch to profile, or get a custom built hub/crankset with a larger splined interface. P.S. Rowan, you are right. I did mean Joe Dyson. -- gerblefranklin (just ride) ------------------------------------------------------------------------ gerblefranklin's Profile: http://www.unicyclist.com/profile/4295 View this thread: http://www.unicyclist.com/thread/75414 Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- http://www.usenet.com |
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