Dekes Posted October 19, 2005 Report Share Posted October 19, 2005 I've been looking at the monty 20" bikes. Their top bikes have Ti frames. Is it worth investing in it? Is it / does it ride so much better than alu models, which are 1000 euro cheaper. Or is it just more durable and lighter ? Quote Link to comment Share on other sites More sharing options...
Ali C Posted October 19, 2005 Report Share Posted October 19, 2005 sorry dude, monty arnt ti frames, the ti just stands for titanium bolts and spokes. Quote Link to comment Share on other sites More sharing options...
Tony Harrison Posted October 19, 2005 Report Share Posted October 19, 2005 The Monty Ti bikes have titanium bolts, and that's as far as it goes. The frames are aluminium. Raleigh made some prototype trials frames that Ian Cooper rode in 99-01 (see picture below), which were very good frames, although the geometry is somewhat 'old fashioned' compared to today's standards. Batch made titanium frames - Dimitri from Russia rode one for a while and it was half the weight of just about any other trials bike! Seriously lightweight! Having never ridden a titanium framed bike properly I'm not sure what it's like to ride. However, I do know someone whose just had a custom 26" ti frame produced and it's very nice... more on that soon... Quote Link to comment Share on other sites More sharing options...
Ali C Posted October 19, 2005 Report Share Posted October 19, 2005 I was riding for Global last year on their ti frames. Ti frames are very nice!! super light and they have a bit of "give" so they ride a bit softer than alu. That does become a problem with side to side flex though, which is why I am not riding the frame now. Quote Link to comment Share on other sites More sharing options...
Dekes Posted October 19, 2005 Author Report Share Posted October 19, 2005 then why are the 221Ti version bikes 1000 euro more expensive than the 221PR? Quote Link to comment Share on other sites More sharing options...
Si-man Posted October 19, 2005 Report Share Posted October 19, 2005 because monty take the piss when it comes to selling parts. they charge you extra just so you can have titanium bolts and spokes...whoopydo!! Quote Link to comment Share on other sites More sharing options...
chrishayton Posted October 19, 2005 Report Share Posted October 19, 2005 then why are the 221Ti version bikes 1000 euro more expensive than the 221PR? different frame, and spec Quote Link to comment Share on other sites More sharing options...
Mr Motivator Posted October 19, 2005 Report Share Posted October 19, 2005 Ti frames aren't lighter than Alu ones you know. Ti is just as light as Ally, but has the strength of steel. It just has a good weight to strength ratio. Quote Link to comment Share on other sites More sharing options...
Ali C Posted October 19, 2005 Report Share Posted October 19, 2005 ti frames are lighter than alloy, but titanium its self is heavier than alloy. Titanium is however stronger, so it takes less of it to build a frame of the same strength hence them being lighter cos theres less of it. Quote Link to comment Share on other sites More sharing options...
flipkickbs Posted October 19, 2005 Report Share Posted October 19, 2005 Correct me if im wrong, but titanim can be bent back far more times than alu so if you bend a component on the bike it could be bent back and still maintain its strength? Quote Link to comment Share on other sites More sharing options...
Ali C Posted October 19, 2005 Report Share Posted October 19, 2005 yep, alloy you can bend a couple of times, steel maybe 20 but titanium can be bent thousands of times Quote Link to comment Share on other sites More sharing options...
trialsguru Posted October 19, 2005 Report Share Posted October 19, 2005 ti mech hangers. why oh why are they still not made Quote Link to comment Share on other sites More sharing options...
Mark W Posted October 19, 2005 Report Share Posted October 19, 2005 'cos they'd cost a lot to make for what is, in essence, a sacrificial item :) Anyway, the funny thing about the Ti spokes and bolts is that the bolts used to snap fairly readily. Hence several of the team riders having to 5 sections in the worlds when they first rode the 221 Ti's. Ah well. Also, ti stuff rounds ridiculously easily? The ti brake bolts I had were shite ^_^ Quote Link to comment Share on other sites More sharing options...
Heatsink Posted October 20, 2005 Report Share Posted October 20, 2005 Here's some quality information for you :) I couldn't resist putting some proper figures on things to help see things clearly. Have a look at this comparison of typical material properties. I just had a search through www.matweb.com It should be noted that some steels used in bike frames such as the Reynolds and T45 stuff are upto 1/3 stronger than the 4130 listed. I've heard quoted that Titanium is typically 1/2 the stiffness of steel, although this wasn't what I found from the information I picked out, the Ti was 83% of the 4130 stiffness. Looking at the Strength to Weight ratio for this Titanium, it's 30% of that for the Alu and 59% of that for the Steel. Stiffness to Weight it's equal to that of Aluminium which is 44% more than that of the Steel quoted. I'd say that these two propeties above are the key things when thinking about Trials frame design (whilst keeping an eye on Fatigue too) So if you took an Aluminium frame such as an Onza T-rex and you wanted to make a version from Titanium in the same weight, you could use the same tube outer diameters with thinned walls (Titanium being 1.67x the density of Alu). The resulting frame would be equally stiff, less dent resistant and crucially, only 30% of the strength ^_^ Alternatively if you wanted it to be equally strong as the Alu version all over, by thickening the tubing walls, then the final weight would be 70% more to achieve this! The remark about being able to bend Titanium back loads of times before it breaks - You can see in the % elongation to break that it's possible to stretch a piece of this Titanium +54% before it breaks which is better than that for Alu and Steel, although I'd say this is a less important factor than being able to build a frame which has decent strength and stiffness. One final thing that seperates Aluminium from Steel and Titanium is the Fatigue Life. Steel and Ti have an Endurance limit whilst Alu doesn't. If you don't know what this means, have a look below: Fatigue & Endurance Limit Info (See page 5 and others) In summary Someone may be able to find some more representative figures for higher spec Titanium, but from my quick look the combination of material properties I can't see anything to endorse the huge price tags usually associated with Titanium frames & parts contary to what MBUK (who are trying to sell bikes for their advertisers) would have you believe. I'd like to be proved wrong though! Steve Quote Link to comment Share on other sites More sharing options...
Ali C Posted October 20, 2005 Report Share Posted October 20, 2005 I think the main reason why welded ti pares are so exspensive is because of the great difficulty. I was told how to weld ti, but I cant remembe, but all I know is its very hard, takes lots of equipment, so it all jacks the price up. Also, ti is just an exspensive matireal, so ti parts are always gonna cost more, not to mention its tool blunting properties. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 20, 2005 Report Share Posted October 20, 2005 Heres the science.... concentrate. All very well, but you'd need to compare 6061 and 4130 with something 6Al-4V for a proper comparison. As you know Steve, its the alloying agents that massive improve the properties of such materials! Edit: Quick Googling shows UTS of 6Al-4V to be more like 1100MPa (after heat treating), with Yield of 570MPa - http://www.key-to-metals.com/Article86.htm Thus making the Yield/Weight ratio 126, and therefore over 20% stronger than 6061-T6 (in theory)! Edit again: Density of this grade comes down to 4.0-4.2 as well, so the Yield/Weight is even better - 139MPa (using 4.1 as density) Quote Link to comment Share on other sites More sharing options...
Heatsink Posted October 20, 2005 Report Share Posted October 20, 2005 EDIT: Nice one for the higher end figures for the Titanium there ^_^ Any figures on stiffness too? All very well, but you'd need to compare 6061 and 4130 with something 6Al-4V for a proper comparison. As you know Steve, its the alloying agents that massive improve the properties of such materials! Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 20, 2005 Report Share Posted October 20, 2005 Couple of edits in case you haven't seen Steve ^_^ Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 20, 2005 Report Share Posted October 20, 2005 Any figures on stiffness too? Yeah, pretty much the same as un-alloyed - found a figure of 112GPa Adam ^_^ Quote Link to comment Share on other sites More sharing options...
Waynio Posted October 20, 2005 Report Share Posted October 20, 2005 christ this is way too scinetific for me..............il go out and ride my ultra 6 alloy steed..........hehe also ti is super hard to weld cos of all the gases it has to be surrounded by and stuff, it literally has to be inside a contained space and only certain particles can be in the air or it will go tits up. Waynio..................... just thort id throw my dab hand in on it as i was considering getting a ti frame made about 2/3 years ago when i had my 2 custom frames made. but it was too hard and expensive to do. id rather ride alu as its easier and much more reliable nower days than it was say 2/3 years ago. ultra 6 is probably one of THE best materials to use and i find that the feel of ultra 6 frames can give more spring and more comfort, iv had more frames than hot dinners and can truely say that i personally wouldnt like to ride much other material than ultra 6. id maybe go back to steel again as that gave loads and was very comfortable, just a night mare with the weight ratio. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 20, 2005 Report Share Posted October 20, 2005 christ this is way too scinetific for me..............il go out and ride my ultra 6 alloy steed..........hehe also ti is super hard to weld cos of all the gases it has to be surrounded by and stuff, it literally has to be inside a contained space and only certain particles can be in the air or it will go tits up. Hehe... U6 is a good material for sure. You need to weld Aluminiun in an 'inert' gas atmosphere too. The main expense with titanium (I believe) is extracting it from its ore. Its only really found naturally as Titanium Oxide (same with aluminium as Aluminium Oxide), and therefore the 'oxide' bit has to be removed. Its easier to 'extract' aluminium from its ore than titanium. Theres actually more Titanium Oxide on the earth than Aluminium Oxide! Quote Link to comment Share on other sites More sharing options...
Heatsink Posted October 20, 2005 Report Share Posted October 20, 2005 I've added the Titanium alloy mentioned by Adam and a higher spec Steel to the comparison table - Things are looking good for the titanium now ^_^ Titanium Alloy has an equal stiffness/weight ratio to the 6061-T6 Alu 56% higher UTS/weight ratio than the Reynolds 853 I found a Ti alloy with a higher yield strength again that the one mentioned in the web article, so this looks even more impressive in the table. The % elongation to break has dropped to a similar figure to the Alu, so maybe it will perform just as well but not better than the alu if bent back. For completeness all that remains is a higher spec Alu such as typically used for bike frames. Steve Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 20, 2005 Report Share Posted October 20, 2005 For completeness all that remains is a higher spec Alu such as typically used for bike frames I believe 7005-T6 is also on Matweb Steve ^_^ And I think U6 claims approx 20% higher yield/UTS than this! Quote Link to comment Share on other sites More sharing options...
Heatsink Posted October 20, 2005 Report Share Posted October 20, 2005 I believe 7005-T6 is also on Matweb Steve ^_^ And I think U6 claims approx 20% higher yield/UTS than this! Nice one :) Here's the final table then: Steve Quote Link to comment Share on other sites More sharing options...
Tony Harrison Posted October 20, 2005 Report Share Posted October 20, 2005 Plus you'd probably have to go to Russia to get a decent ti frame made. But even ti isn't immune from the effects of fatigue - two of the Raleigh prototypes developed hairline cracks near the BB (the third one just got snapped in half...). Interesting tables there, thanks for that. Takes me back to my Mechanics of Solids and Materials Science modules... Quote Link to comment Share on other sites More sharing options...
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