Ti forks...what is the true demand?

[rody]

MikeD, you are oh so wrong. When properly designed and integrated into a full surface area dropout and a butted tube, they track well and perform flawlessly. Unfortunately, I think you've experienced the poor examples of the past.

The choice of the 1.0 tubing was determined around the integrated design with the hooded dropout I was finally able to source through Paragon. The machined Ti dropout allows for full surface area contact with the terminal end of the blade, resisting the torsional forces that make so many plug and tab style Ti forks perform like spaghetti. Add in butted tubing that places material where you need it, and it's a combination that just plain functions; absorptive on the rough stuff yet tracks true.

The key to remember, it's still a rigid bike and no matter what material your fork is made of, it will not perform like a suspension model. An educated consumer makes a happy end user.

rody

 

[legrandefromage]

What about using existing fork crowns like a Switchblade or Pace or Manitou or RS and manufacturing a leg - my mate used to make 'stiffees' Tange Switchblade style but in Reynolds 531.

 

[MikeD]

no matter what material your fork is made of, it will not perform like a suspension model

Quite. A rigid fork that performs like a suspension fork in inappropriate axes is what I'm afraid of ;-) Whichever way you cut it (or indeed weld it), a 1in Ti tube ain't as stiff as a 1in steel tube. Although IIRC it was issues with steerer flex that killed off a lot of older Ti fork projects.

I like the Jones fork

Edit: The dropout stuff makes a lot of sense too

 

[utahdog2003]

I'd be interested, especially if there were some reasonable assurances that the thing could support a 200lb aggressive rider and not look like a battleship hanging off the front of the frame!

 

[Anthony]

Whichever way you cut it (or indeed weld it), a 1in Ti tube ain't as stiff as a 1in steel tube. Although IIRC it was issues with steerer flex that killed off a lot of older Ti fork projects.

It surely depends on the gauge as well as how fat the tube is. A triple-butted P2 is made out of 1.3-0.8-0.5 butted steel. Ti is usually plain-gauge and although Rody says he would use butted tubes for his ti fork, I'd be surprised if they would go down to 0.5mm, I thought 0.9mm was a more typical ti gauge.

I have to take my hat off to anyone who can induce steerer flex. Anyway if you have ti bars, a ti stem and ti fork legs, how can you tell the flex is in the steerer and not in any of them?

 

[scant]

say 1 1/4" as 1" would be too skinny for most fat-tubed ti frames

There're reasons beyond cost why these things never really took off BITD...

yeh, its call suspension

 

[JeRkY]

I'd be interested in 5 piece forks and the prices suggested above sound good too

Or what about some RC30 alikes (that's a thought, how about Ti legs for a Pace crown? would that be easier/cheaper to fabricate)?

I would very much be up for some of these!

 

[MikeD]

It surely depends on the gauge as well as how fat the tube is.

Yes. My rough back-of-a-spreadsheet calculations (keeping it simple with 1mm plain-gauge tubes) suggests that a 1in diameter tube with 1mm walls made of steel will be 1.75 times stiffer in bending than one made of Ti. As you say, one way around this is to make the walls thicker on the Ti tube. Bang 'em up to 2mm and the bending stiffness is essentially the same. But you're using twice the material. Ti is roughly half the density of steel, so you end up with a tube that's the same stiffness but weighs the same. Kinda pointless, unless corrosion is a big issue ;-)

More promising is to use a bigger diameter tube. Make your Ti tube 1-1/8in diameter and put it back to 1mm thickness and you've got a tube that's around 20% less stiff than the steel one and only 12% heavier. You can match the stiffness of that 1inx1mm steel tube with a 1-1/4inx1mm Ti one, but that'll be 25% heavier.

(Disclaimer: I'm not very good at sums, this might all be wrong ;-) )

 

[scant]

Kinda pointless, unless corrosion is a big issue ;-)

you've missed the point entirely. Ti is cooler


tho for the sake of your calculations, steel needs to be painted, ti doesnt, evens the weight out.

 

[MikeD]

Both fair points