Fyi

[Jack Brunk]

If anybody was thinking about getting a 6/4 ti frame from Moots, you better do so stat. The tubing is being discontinued due to very high costs by Reynolds. Moots says they have enough tubing to last through the beginning of April.

Jack

[SoCalSteve]

Jack,

You own a couple of Moots frames, yes? Are they the 6/4 SL versions?

Besides weight, can you tell me the difference between the 2 Ti tubing materials (if you know)?

Thanks,

Steve

[RPS]

6/4 is stronger, but the materials are very similar in density and modulus of elasticity.

[Jack Brunk]

RPS is correct. The frame is stronger and about 1/4 lb lighter in the 56 size. It has a very stiff BB and has more snap than the 3/2.5 frames that I've test ridden.

[SoCalSteve]

RPS is correct. The frame is stronger and about 1/4 lb lighter in the 56 size. It has a very stiff BB and has more snap than the 3/2.5 frames that I've test ridden.

Moots 3/2.5 frames that you've ridden or other frame companies?

Also, please tell me what you mean by "snap".

Thanks again,

Steve

[RPS]

RPS is correct. The frame is stronger and about 1/4 lb lighter in the 56 size. It has a very stiff BB and has more snap than the 3/2.5 frames that I've test ridden.Jack, any real difference in frame stiffness is due mostly to differences in tube sizes, not in the material differences themselves. It's very likely that if the lighter frame is also stiffer, it's due to larger diameter tubes.

[michael white]

Yeah, as I understand it, what the 6/4 does is allow for different configurations due to its greater yield strenth, thinner walls @ greater diameter tubes, and that's what makes the difference in performance or "snap." The downside is that it's even harder to weld than the hard to weld 3/2.5. Therefore some companies mix the two tubes when the advantages can be gained, e.g. the Litespeed Ultimate.

[wooly]

I have a Compact SL. The main triangle tubing is 6/4 but the seat and chain stays are 3/2.5. I found this out when talking to Moots when buying my frame last year. Great frame. I don't think I'll sell this one, especially now since it will be "rare".

Wooly

[AgilisMerlin]

I have a Compact SL. The main triangle tubing is 6/4 but the seat and chain stays are 3/2.5. I found this out when talking to Moots when buying my frame last year. Great frame. I don't think I'll sell this one, especially now since it will be "rare".

Wooly


FARKIN' SCHWWWWWWWWWWWWWWWWEEEET :banana:


YOU DONE DID RIGHT ON THAT ONE, AND I AM YELLING WHEN I WRITE THIS :D



AMERLIn

[coylifut]

Ti bikes with stealthy black components look great. That one in particular. Next winter I think I'll have the paint stripped off my Spectrum. Ti done right can be very light (2.5 lbs or so), crazy durable and has that magic carpet ride feel to it.

[pdxmech13]

Another poke at the hornets' nest ...

Tensile strength: 6/4- 170,000 3/2.5- 134,000
Yield strength: 6/4- 160,000 - 183,000 3/2.5- 116,000
Elongation: 6/4- 10% 3/2.5- 15%
Elas. Mod. (10^6 PSI): 6/4- 16.5 3/2.5- 15
Shear Mod (10^6 PSI): 6/4- 6.38 3/2.5- 6.5
(Ti-3/2.5 - CWSR, Ti-6/4 - CW)

Ok, I'll try to keep it brief. A few points:
6/4's higher tensile strength (~21%) is irrelevant since Ti frame tubes simply don't break in tension. So forget tensile strength.

Yield strength- this can be a pretty big deal since ultra thin tubes need higher yield strength to keep from either "beer canning" or being dented in a crash (or by running into a garage door frame.) In the real world, cold worked 6/4 tubes are pretty close to impossible to buckle while 3/2.5 tubes are only super tough compared to ANY other material.

Elongation, the amount of stretch a material will allow before failure. Again, pretty much irrelevant in the case of Titanium.

Elasticity Modulus, or bending stiffness; 6/4 is about 15% stiffer than 3/2.5 in bending, all other things being equal. Rarely are ANY of the variables equal though. Since only a few frame tubes are actually stressed in bending, 6/4, while very cool, does not add a lot of value.

Shear Modulus, or torsional stiffness; 3/2.5 is at best about 2% stiffer than 6/4 in torsion. In the real world, bubkis, nada, zilch, zip ...

So, where are we? If you had one frame of each with the same diameters and gauges, I very much doubt that ANYONE could feel any difference. Yes, the 6/4 frame would be considerably tougher in a "get off," but the 3/2.5 would be so tough anyway, that it is pretty much silly to talk much about it.

6/4, as a frame material, does give a designer more latitude if they are trying to make hyper light bikes because of that very high yield number. Larger diameter / thinner wall tubes can be very reliable when made out of 6/4. BUT, boy does the stuff cost a bunch to get in the sizes and wall thickness that make it all worth it. The production 6/4 tubing out there really does not take advantage of what can be achieved, and therefore does not offer enough advantage over your typical 3/2.5 tubing.

When it comes to dropouts, it is a different story. 6/4 strip is relatively inexpensive, and with its super high yield strength, it makes a bomb proof dropout. Kind of useful for those who insist on shifting into their spokes or picking up big sticks in their chains. As it turns out, 6/4 welding wire is the ticket too. It welds easier than most other alloys.

So warm up the spit balls and have at it...

JSGOT

[SoCalSteve]

So, in the "real world" (according to Mr Kellogg), it sounds like more marketing than any real world differences.

[wooly]

Regarding Tom Kellogg's comments: That's pretty much what I heard from Moots - a bit lighter but should ride identically to a similarly sized and spec'd 3/2.5 frame. But, I'm a sucker for this stuff so I bought it.

Wooly

[SoCalSteve]

Regarding Tom Kellogg's comments: That's pretty much what I heard from Moots - a bit lighter but should ride identically to a similarly sized and spec'd 3/2.5 frame. But, I'm a sucker for this stuff so I bought it.
Wooly

I have a bridge in Brooklyn for sale.

I looked for you in PS. Didnt see one Moots the whole ride. Next year, I will be riding my Vamoots. Just back from Moots, beautifully refinished. They did a superb job. Cannot tell from new. I finished building it last night and tomorrow is her maiden voyage.

From what I love about my Kirk's geo, the Moots is almost identical in many ways. I am sure I am going to love it (even if it is ONLY 3/2.5).

Steve

[wooly]

Bridge in Brooklyn? I just bought the San Vincente bridge over Long Beach harbor so I'm low on capital.

I couldn't make PS. Work has been tough so riding's been limited lately.

Sorry about your 3/2.5... :D

[RPS]

Higher yield should help some in preventing dents, but I’m not sure that it would do much to prevent localized buckling of tubing when failure is due to excessively high diameter-to-wall-thickness ratios.

IMO when dealing with thin wall round tubing like we see in super-light-weight frames, it is very likely that buckling starts much before yield stress is reached, and at that point it’s generally over with unless the load is reduced instantly.