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  #1891  
Old 11-10-2021, 10:56 AM
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David Kirk David Kirk is online now
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Quote:
Originally Posted by XXtwindad View Post
Hi Dave -

A question based off a thread awhile back here: https://forums.thepaceline.net/showt...=253242&page=2

I’ve often seen bigger guys (such as yourself and myself) on steel bikes with 1 1/8 head tubes but rarely on Ti bikes with standard 1 1/8 head tubes. Why is that? Is that because (as you seem to suggest) that, for bigger riders, Ti has to be “overbuilt” in order to be stiffer? I really do like the classic aesthetics of a standard 1 1/8 (particularly on a rim brake bike) better.

Thanks for your time.
I think there are two basic structural reasons for Ti bikes having larger head tubes -

- the main tubes on Ti bikes are typically larger than one would find on steel bikes because the material is more flexible. So to keep the frame stiff enough the top and down tubes will be large and those large tubes don't fit all that well on a smaller head tube.

- the larger driver today might be the carbon forks that one can buy today. The vast majority of carbon forks have tapered steerers and they require a larger head tube.



There's no compelling need to make the head tube on a Ti bike larger to make the head tube stiffer. A head tube is short and thick and plenty stiff even in old school diameters. I think the reason they are large are the reasons above combined with the fashion of having big head tubes brought about by carbon bikes that have big head tubes.

dave
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  #1892  
Old 11-10-2021, 10:59 AM
XXtwindad XXtwindad is offline
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Quote:
Originally Posted by David Kirk View Post
I think there are two basic structural reasons for Ti bikes having larger head tubes -

- the main tubes on Ti bikes are typically larger than one would find on steel bikes because the material is more flexible. So to keep the frame stiff enough the top and down tubes will be large and those large tubes don't fit all that well on a smaller head tube.

- the larger driver today might be the carbon forks that one can buy today. The vast majority of carbon forks have tapered steerers and they require a larger head tube.



There's no compelling need to make the head tube on a Ti bike larger to make the head tube stiffer. A head tube is short and thick and plenty stiff even in old school diameters. I think the reason they are large are the reasons above combined with the fashion of having big head tubes brought about by carbon bikes that have big head tubes.

dave
Thanks for the response. Much appreciated.
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  #1893  
Old 11-10-2021, 11:04 AM
robt57 robt57 is offline
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My 61 CM Ti Super Spectrum Extra Light with 1" fork/HT was one of the stiffer bikes I have ridden. Wound up fork steel steer tube helped I am guessing. Not that I could feel a 190mm tube flex I guess.
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  #1894  
Old 11-10-2021, 12:45 PM
truth truth is offline
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Hi Dave,

That's another great-looking bike coming together and 38s are awfully plump.

I was wondering what filler you use to fillet braze stainless?

Also, have you ever experimented with other wheel sizes like 650B? I know the rando crowd love those with wider tires.

Thanks, as always, for sharing.
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  #1895  
Old 11-10-2021, 01:02 PM
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David Kirk David Kirk is online now
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Quote:
Originally Posted by truth View Post
Hi Dave,

That's another great-looking bike coming together and 38s are awfully plump.

I was wondering what filler you use to fillet braze stainless?

Also, have you ever experimented with other wheel sizes like 650B? I know the rando crowd love those with wider tires.

Thanks, as always, for sharing.

Thank you. Yes then 38's are plump and that should be nice on dirt and gravel.

I use a special silver filler designed for fillet brazing stainless...it's good stuff.

I've played with them some and very briefly considered going that way on this bike but I'm a tall guy and my frames are large and they will fit a 700 wheel with a fat tire easily. So I opted for the larger diameter to help them roll over as rough surface easier.

Thanks for looking.


dave
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  #1896  
Old 11-19-2021, 12:59 PM
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I’ve been squeezing in work on a personal bike for myself in the moments I can between customer builds and the project is nearing completion…all I need now is for the 1x12 kit to show up early next week and I can build it up and take it out and freeze my butt off! The frame is a combo of Reynolds 953 and KVA stainless tubes and it’s all fillet brazed together with a special silver alloy designed for fillet brazing stainless. It’s built around a Velo Orange rim brake and the 38mm Rene Herse tire.

It’s funny - even though I built it and it’s taken so long to get it to come to fruition it feels a lot like UPS just dropped it off and I’m seeing it for the first time. It’s exciting. I love bikes and love trying new ideas and new combos of parts to get the ride I have in my mind to come out on the road. Next week, after the parts arrive, should be fun.

dave
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  #1897  
Old 11-19-2021, 02:55 PM
herb5998 herb5998 is offline
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WOW! looks great, excited to see the build.
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  #1898  
Old 11-19-2021, 03:11 PM
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David Kirk David Kirk is online now
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I was asked about the stand that the bike is in. My stepfather built this for me about 40 years ago during my pro BMX days. It breaks down flat and fit into the back of my tiny pickup truck and then pops together in the upright form to hold a bike. It's extremely well traveled and has been set up in countless hotel rooms, parking lots, BMX pits and my garage for 4 decades. It's a super clever design - Jim was super clever so that makes sense.

dave
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  #1899  
Old 11-19-2021, 05:04 PM
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donevwil donevwil is online now
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That's just beautiful Dave and right in line with what appeals to me most nowadays.

Is this frame 2x road crank compatible?
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  #1900  
Old 11-19-2021, 05:33 PM
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David Kirk David Kirk is online now
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Quote:
Originally Posted by donevwil View Post
That's just beautiful Dave and right in line with what appeals to me most nowadays.

Is this frame 2x road crank compatible?
Yep...1x or 2x....no problem.


dave
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  #1901  
Old 11-19-2021, 06:41 PM
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lavi lavi is offline
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This is truly something else. Wow.
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  #1902  
Old 11-19-2021, 07:18 PM
brewsmith brewsmith is offline
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As good as it gets Dave! Doesn't hurt that it's similar to what you just built for me, except I went with the trp brakes on that one.

Stay tuned for my side by side with it and the recently acquired lugged frame circa 2005 with the VO brakes.

Cheers to many happy miles/smiles
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  #1903  
Old 11-19-2021, 07:43 PM
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Quote:
Originally Posted by David Kirk View Post
The frame is a combo of Reynolds 953 and KVA stainless tubes and it’s all fillet brazed together with a special silver alloy designed for fillet brazing stainless. It’s built around a Velo Orange rim brake and the 38mm Rene Herse tire.

dave
This is so well done. Details, balanced stance, etc.

Are those different chain stays than what you normally use? They look more shaped than round. No doubt the RH is a plump “38”.
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  #1904  
Old 11-19-2021, 07:53 PM
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David Kirk David Kirk is online now
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Originally Posted by sparky33 View Post
This is so well done. Details, balanced stance, etc.

Are those different chain stays than what you normally use? They look more shaped than round. No doubt the RH is a plump “38”.
The c-stays are different....they need to have a single bend in them to snake between the tire and the chain rings. So they are oval with a single bend.

The tire measures 39 mm mounted tubeless and at 50 psi so that's pretty darn good. So many tires are so far off that you think that they must be mis-marked.

dave
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  #1905  
Old 11-22-2021, 12:12 PM
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David Kirk David Kirk is online now
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Five hundred thousand….half of a million. When I saw that number this morning it was a hard number to process honestly. The fact that since this thread started by William back in 2012 has been viewed 500,000+ times is just nuts. It feels like I would be remiss to not take advantage of the occasion and thank all of you for the interest in my work and for allowing me to hang out in this wonderful place for so long. I come to the Paceline nearly every day as part of my daily wake up to see what everyone is up to….and of course to enjoy all the bike photos posted. In the end I really just love bikes, cycling and the people who ride them.

Thank you for all the support and encouragement - it means more than you know.

dave
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