Anyone ever heard/seen/ridden at 6/4 Douglas bike?

[bthomas515]

Was sent an interesting trade offer that I can’t find much of anything online about?

It’s a Douglas 6/4 titanium frame? Looks to be shaped like an litespeed vortex with shaped downtube. Have scoured the internet and here and am only seeking info about the 3/2.5 lower end models.

Anyone have experience with the 6/4 or know any details about them?

[Veloo]

Never touched one but think Colorado Cyclist sold those in the late 90s, early 2000s?

[bigbill]

Douglas was Colorado Cyclist store brand. I have some Douglas spacers. Their Ti bikes were a good value, and I've never heard anything bad about them. When I was stationed in Hawaii 04-07, I had two friends that rode them, one on a 6/4. He said it was a stiff ride, and it probably was, given the nature of 6/4. If that's your thing, I'd request photos of the bottom bracket area and head tube to check for cracks.

[Mark McM]

Originally Posted by bigbill

Douglas was Colorado Cyclist store brand. I have some Douglas spacers. Their Ti bikes were a good value, and I've never heard anything bad about them. When I was stationed in Hawaii 04-07, I had two friends that rode them, one on a 6/4. He said it was a stiff ride, and it probably was, given the nature of 6/4. If that's your thing, I'd request photos of the bottom bracket area and head tube to check for cracks.

What is the nature of 6/4 titanium that results in a stiff ride? 6/4 is stronger and harder than 3/2.5, but it has virtually the same modulus of elasticity.

[bthomas515]

Originally Posted by Mark McM

What is the nature of 6/4 titanium that results in a stiff ride? 6/4 is stronger and harder than 3/2.5, but it has virtually the same modulus of elasticity.

I wonder if they can use more material because it’s a lighter material with the same resulting frame weight?

[Mark McM]

Originally Posted by bthomas515

I wonder if they can use more material because it’s a lighter material with the same resulting frame weight?

6/4 and 3/2.5 titanium alloys have roughly the same density as well. Normally with stronger version of the same material you can use less of the material, making it both lighter and less stiff. The exception being if the extra strength allows you to use oversized diameters - in which case the extra stiffness comes from the larger diameter, not from the elastic modulus of the material.

[zennmotion]

I believe the Douglas brand was manufactured by Titanium Sports Technologies (TST) in Washington state, they made Ti frames branded for a number of "makers" including Mongoose, Dean, Diamondback and others. I have an unbranded road frame that I bought from the factory when they dropped out of building bike frames, it's made from straight gauge 3/2.5 Sandvik ti. Nice neutral geometry, flawless welds, but its dated now with an older 1inch head tube.

[bthomas515]

Originally Posted by Mark McM

6/4 and 3/2.5 titanium alloys have roughly the same density as well. Normally with stronger version of the same material you can use less of the material, making it both lighter and less stiff. The exception being if the extra strength allows you to use oversized diameters - in which case the extra stiffness comes from the larger diameter, not from the elastic modulus of the material.

Hmm interesting. I never really understood the difference but knew it just cost more. Sometimes, a lot more

[benb]

6/4 is harder to work.

Anecdotally it seemed like 6/4 got a slightly worse reputation (IMO) because:

- It was used on some of the more affordable/mainstream brands
- It was used for more manipulated frames

More manipulated with a harder material to work with seems to imply a frame that's harder to make and might increase the chances of a mistake.

I knew a couple people (very strong) who kept cracking shaped 6/4 bikes of a certain brand at the welds or seams and finally got a 3/2.5 oval/round frame from a different brand that wouldn't do 6/4 and never had another issue. Well known names but I'm not sure it matters. Never Douglas.

Realistically I don't think it matters at all compared to the quality of who is building/designing the frame but an awful lot of the really well regarded brands seem to have a good reason not to bother with 6/4, including Serotta IIRC.

[Mark McM]

Originally Posted by benb

6/4 is harder to work.

Anecdotally it seemed like 6/4 got a slightly worse reputation (IMO) because:

- It was used on some of the more affordable/mainstream brands
- It was used for more manipulated frames

More manipulated with a harder material to work with seems to imply a frame that's harder to make and might increase the chances of a mistake.

I knew a couple people (very strong) who kept cracking shaped 6/4 bikes of a certain brand at the welds or seams and finally got a 3/2.5 oval/round frame from a different brand that wouldn't do 6/4 and never had another issue. Well known names but I'm not sure it matters. Never Douglas.

Realistically I don't think it matters at all compared to the quality of who is building/designing the frame but an awful lot of the really well regarded brands seem to have a good reason not to bother with 6/4, including Serotta IIRC.

3/2.5 titanium is sometimes called "tubing 6/4", because it has some similar properties to 6/4, but is easier to manipulate into tubes (and other shapes). 6/4 is stronger than 3/2.5 (by unit volume), so theoretically you could use less 6/4 to make a frame of the same strength and stiffness as 3/2.5. But due to the difficulty in manipulating 6/4 into structurally efficient tube shapes, 6/4 frames often didn't end up much stiffer, lighter or stronger than frames made with well designed and selected 3/2.5 tubes. Lightspeed used to play up the distinction between 6/4 and 3/2.5 titanium, to justify the higher cost of their 6/4 frames. But when they came out with the Ghisallo, which at the time was the lightest production frame ever made (and Lightspeed's most expensive), they purposely didn't mention that it was actually made from 3/2.5, not 6/4.

[tellyho]

A 6/4 Litespeed mtb passed through my possession last year. That derailleur hanger was the hardest I've ever aligned. Had to put almost all my weight on the tool to get it to move. Stiff as hell.

Sadly, the frame was too small for me, but the buyer got a deal on the nutty collection of parts I put on the bike.

[rePhil]

No experience with a 6/4 but I had a 3/2.5 Douglas I purchased new from Colorado Cyclist. At least at that time they were made by TST, Titanium Sports in Kennewick WA. It was a very nice riding bike.

[bthomas515]

Originally Posted by rePhil

No experience with a 6/4 but I had a 3/2.5 Douglas I purchased new from Colorado Cyclist. At least at that time they were made by TST, Titanium Sports in Kennewick WA. It was a very nice riding bike.

Yeah, I know someone who rode a 3/2.5 and loved it! Might check this out and see if the guy and I can work something out.

[cdimattio]

Originally Posted by bthomas515

Was sent an interesting trade offer that I can’t find much of anything online about?

It’s a Douglas 6/4 titanium frame? Looks to be shaped like an litespeed vortex with shaped downtube. Have scoured the internet and here and am only seeking info about the 3/2.5 lower end models.

Anyone have experience with the 6/4 or know any details about them?

Some time ago I had a Douglas 6/4 and sounds like the bike you have described. House brand for Colorado Cyclist. Mine happened to be built by Litespeed, but I understood they used other fabricators.

Only moved on as it was a tiny bit small, but it rode well for me.

[the bottle ride]

Originally Posted by zennmotion

I believe the Douglas brand was manufactured by Titanium Sports Technologies (TST) .

Litespeed made the 6/4 Douglas frames.

These were essentially the poor man’s ultimate (which I had- kind of heavy, and stiff)

The reason the 6/4 was heavier/stiffer is that Litespeed created the tubes by folding sheets of metal- and then welded at the seams.
These are not traditionally drawn tubes.

The rode stiff because these were bigger tubes typically.

I think litespeed/lynskey were the only companies to make 6/4 bikes (others than drop outs etc).