Ti crack

[rogerzilla]

The problem with Ti saddle rails is that they have to be the same size as steel ones, or you'd need a new saddle clamp standard. Titanium is much less stiff, so should really be larger in diameter to prevent excessive flexing leading to fatigue.

 

[cougie uk]

The problem with Ti saddle rails is that they have to be the same size as steel ones, or you'd need a new saddle clamp standard. Titanium is much less stiff, so should really be larger in diameter to prevent excessive flexing leading to fatigue.

That might explain it. I've had very standard saddles since and had no issues with further breakages.

 

[T4tomo]

The problem with Ti saddle rails is that they have to be the same size as steel ones, or you'd need a new saddle clamp standard. Titanium is much less stiff, so should really be larger in diameter to prevent excessive flexing leading to fatigue.

I think they (Ti rails) are more at risk off fatiguing / breaking if they are clamped well off centre (so loads are different at either end of the clamp) and /or with a clamp that has mismatched top and bottom jaws

 

[Ming the Merciless]

I have a GILLES BERTHOUD Aspin with titanium rails. Good after 9 years and about 100,000 miles.

 

[T4tomo]

I have a GILLES BERTHOUD Aspin with titanium rails. Good after 9 years and about 100,000 miles.

that give me hope for my Ti Rolls

 

[Ian H]

The bike is still going strong. The profile of the chainstays was a weakness, which Ted has corrected, so I'm reasonably confident that it will see me out.
Just in case I do have a provisional order with Richard Hallett.

 

[wafter]

Interesting thread.. this one source suggests that typically Ti has a fatigue limit much like ally, however it's less pronounced and potentially the stresses involved are far higher than ally and a good bit more than steel.

Apparently the 4340 it's compared to has a significantly higher UTS than 4130; which is typically what bike frames are made of and I'd expect to be somewhere between 4340 and 1045 on that chart. Not sure how heat treatment conditions affect the fatigue characteristics of steel although I'd imagine it probably improves mechanical properties in this regard).

Can't say as any of this makes me second guess my commitment to steel