Ti build has begun!

[JReeves]

   This past summer I took my first bikepacking trips, and with that, I was hooked...  The trips were done with my GT Peace 9r single speed.  I then built up a nice light weight Tomac Flint that I raced Leadville and several other races on.  Getting back on the GT was hard after being spoiled on my Tomac, however I didn't want to put it through the abuse that comes with bikepacking.  So, a couple months ago I got the ball rolling on a new build.
  I'm going full titanium frame, fork, and matching rear rack.  The bike will have 5 water bottle mounts, two of which are on the fork.  The rack will be removable with threaded eyelets in the frame.  It has Paragon sliding drop outs, with the split for a belt drive option, clearance for large volume tires, all the cable guides to run it geared if I desire, and is able to be ran with a 100mm fork.  I looked around for a while and couldn't settle on one frame.  I had a few specific "wants", and nothing met the criteria. So, after some back and forth emails, I'm having this made completely to my specs, and thus far, it's been a great experience dealing with Dmitry from Triton Bikes. 

I will keep this thread updated with pictures as they come along!

[JerryW]

Nice!

While you're at it, add a third boss on each fork leg for the option of using the Salsa Anything Cages. The three bosses are evenly spaced with 65mm between them. Easier now than later.


Jerry

[JReeves]

I really debated that, and had them placed at an angle(45degrees) that would give me room to run the anything cages if I want to.  The anything cages will mount with only two holes of the three being utilized, so I can always do the hose clamp method on the third hole tab.  My, and the builder's, only small concern was that each hole in the fork could potentially "weaken" it.  How much realistically? who know's...  If I do run the cages, I can't foresee putting anything in them that would be heavy enough to necessitate the third hole being used.  My shelter and sleeping pads would fit nicely in the anything cages, and they each weigh a pound, which is less than a full 24oz water bottle, so I think if I take that route, it would probably be sturdy enough.  Related to the fork bosses, that is the only revision not shown on this drawing...  They have been moved 20mm higher up the fork, to better clear the caliper.

[jeremy11]

How much will drilled holes weaken the fork?  I'm so glad you asked.   
Disclaimer: I'm a sophomore mechanical engineering student with no frame building experience
Short answer: you'll probably be fine as long as the metal is thick enough.  go for it and get you some anything cage coolness up front.

Medium answer:
For tensile tested rectangular specimens (pulled slowly), a circular drilled hole introduces a stress concentration factor of 2 to 3 times the stress over the rest of the specimen.  This is 2 to 3 times past what the stress would be even considering the reduced cross sectional area.
Bike forks undergo much more complicated stresses than slow tensile specimens do, including fatigue cycling (pun intended), twisting, compression, and bending loads.  Its also a thin walled tube with welds in it and braze ons, all which further complicates the situation.  It also depends on the specific materials, as more ductile materials inhibit crack growth better than more brittle materials.
Here's a FEA I did for a Material Science project, followed by a theoretical stress concentration graph of the ratio of hole diameter vs specimen width vs. stress concentration factor.



Any metal suitable for bike frames should not have a problem with it, based purely on what exists and its track record.
Any properly designed fork would need thicker metal first for stiffness.  Once it is stiff enough, the minimum strength requirements should already be exceeded.  Drilling boss holes in frames and forks is nothing new.  So if you also wanted the thinnest walled Ti fork possible, I'd be concerned.  For this, get the drill out and Go.

Source for Figure 2:
Introduction to Mechanical Design.  T.B. Jefferson, Walter J. Brooking.  The Ronald Press Company, New York.  1951

[Damnitman]

would this same officially unofficial opinion of yours still apply if one were to drill and tap the legs (one hole per leg) of an already existing Ti fork w/o welding in a brazeon?  what about Ti nutserts?

[jeremy11]

sure, why not.

[bmike-vt]

All material weakens when you poke it full of holes. The trick is designing it to do what you want. Otherwise we would all be left with solid, regular shaped hunks of various metals, woods, and composites, instead of bridges, cars, bikes, and rockets.

[JReeves]

Well after quite some time, it's done! 
 I was about to head out on a ride yesterday morning as the mailman rang the doorbell.  The frame had arrived!  It took only 7 days to get here, which was much quicker than I could have hoped for.  I had all the parts collected to put it together, so my anticipation beat out my desire to go for a ride...

I cannot speak any higher of Triton and the service/product that I have gotten.  There was a delay in the construction, but I am beyond ecstatic with the results!!!  Everything I hoped for was accomplished with this build, and more. 

I wanted a do-it-all bike with a large emphasis on bike-packing.  I added a third water bottle mount on the bottom of the downtube, as well as one on each for leg(similar to the Fargo forks).  I also asked for large tire clearance, sliding dropouts with belt drive capability, a matching titanium rack(for carrying a packraft mostly, weighs only 362grams), and of course custom geometry.  Dmitry nailed every aspect of it!!!

I have some Salsa Anything cages that I'm going to mount up to the fork, and now have a new project of making a frame bag for this one.  I'll keep this thread updated as I get her setup for my first trip, which I'm hoping will be May 26th.  That will be a shake down run for the CTR...  This bike and I are going to go places!

Here she is....  21.87Lbs as shown, no carbon, with huge 2.4 tires and not yet tubeless....  I could easily get it sub 20lbs in "race form" with some smaller tubeless tires and lighter bars and grips.



The geometry inspiration with a few minor tweaks...


Tire clearance with 2.4"!!!!


First ride!!!!  Wouldn't change a thing!!!

[Cheyou]

Very very nice. Have fun with her


Thom

[cousinmosquito]

That's a very pretty rig. Functional to boot.

Well after quite some time, it's done!  
 I was about to head out on a ride yesterday morning as the mailman rang the doorbell.  The frame had arrived!  It took only 7 days to get here, which was much quicker than I could have hoped for.  I had all the parts collected to put it together, so my anticipation beat out my desire to go for a ride...

I cannot speak any higher of Triton and the service/product that I have gotten.  There was a delay in the construction, but I am beyond ecstatic with the results!!!  Everything I hoped for was accomplished with this build, and more.  

I wanted a do-it-all bike with a large emphasis on bike-packing.  I added a third water bottle mount on the bottom of the downtube, as well as one on each for leg(similar to the Fargo forks).  I also asked for large tire clearance, sliding dropouts with belt drive capability, a matching titanium rack(for carrying a packraft mostly, weighs only 362grams), and of course custom geometry.  Dmitry nailed every aspect of it!!!

I have some Salsa Anything cages that I'm going to mount up to the fork, and now have a new project of making a frame bag for this one.  I'll keep this thread updated as I get her setup for my first trip, which I'm hoping will be May 26th.  That will be a shake down run for the CTR...  This bike and I are going to go places!

Here she is....  21.87Lbs as shown, no carbon, with huge 2.4 tires and not yet tubeless....  I could easily get it sub 20lbs in "race form" with some smaller tubeless tires and lighter bars and grips.



The geometry inspiration with a few minor tweaks...


Tire clearance with 2.4"!!!!

First ride!!!!  Wouldn't change a thing!!!

[Blammo]

That is one beautiful bike!

BTW how tall are you?  The bike doesn't look as big as the schematic seems to indicate, but what can I tell by looking at a photo.

[JReeves]

I'm 5'10" with a pretty long inseam.  The Tomac that it's based on is a size Large.  I prefer a little more aggressive fit, so it's got a longer top tube than many might prefer.  Not that "aesthetics" should determine build geometry, but I'm really happy with both the fit, and how it looks.  Everything just looks proportional and "right"... haha
Just tested the Salsa Anything Cages on the fork, and they fit perfect and clear the tires and wheels nicely.  Going to try to find time to get the frame bag sewn up this week. 

[JReeves]

9 days till I get out on my first bikepacking trip with the new bike...  Just finishing up some of the last things to get prepped for it.  Finished the frame bag today.  Came out great!!!  Dual compartment, with a removable divider.  Two #5 waterproof zippers.  400x300 Mini Diamond Ripstop with waterproof Poly coating.  Didn't have time to get the seat bag and bar bag mounted just yet.  I'll post some pictures with it all loaded up!  Also found some great stuff sacks for the Salsa Anything cages that I might use on the fork. 

[Blammo]

Nice!  Where're you going?

[JReeves]

Doing kind of an exploratory 3 day trip along the Toiyabe Crest Trail...  It's pretty much the middle of nowhere, located in the center of Nevada, it's 75 miles of singletrack running the ridgeline of the Toiyabe range.  It climbs from 7,000 feet up to 11,700 feet.  Planning on doing an out and back ride.  There's also dozens of side trails to explore if time allows.  I hunted out in the area two years ago, and just last Fall got the idea to explore the whole length of it by bike.  It'll be a good shakedown run for the CTR.  Trail conditions should be similar, and elevation is up there as well, so the lungs will get their taste of the thin air.

[JReeves]

Here's a little update...
The first "mock loading" of the new bike... This is loaded with pretty much every bag(minus small top tube feed bag) that I could ever need.  Most trips won't see this much gear, but love the capability to load over 35 liters of gear onto the bike!  I'll be packing up for a trip next weekend, and will update my gear layout and details about what is where on the bike when I finalize it all...  I'm thinking I'll be able to get by with the frame bag, two bags in the Anything Cages(not bags shown, but same size OR Dry Bags), and the seat bag.  That should balance it out, and give me more than enough room for a 3 day load out.

[JReeves]

And here's the final load-out...
Packed and ready for a Saturday morning departure.  Bike weight fully loaded as shown is 37.85lbs.  This doesn't include water in the frame bag yet.  Backpack weight is 10.65lbs(confirmed with hanging scale), which also doesn't include water, with 2L it will be 15lbs even.  I'm pretty excited to have such a light load on my back, as my last big trip I was packing probably 30lbs on several occasions.  Should make for a comfy ride.  I have a ton of room in the Osprey Talon 22 still.  The fork bags are a little un-balanced(2.3lbs vs 4.2lbs), but just riding it around the block a bit, it isn't noticeable, and still tracks straight even with no hands on the bars... Although obviously the bag with food(Fork Bag R) will lighten as the trip gets underway.  So truly, it should be balanced by the end of day 1.
Here's pictures, as well as links to all my gear:



Frame Bag: http://www.geargrams.com/list?id=8093
Seat Bag:  http://www.geargrams.com/list?id=8096
Fork Bag L:  http://www.geargrams.com/list?id=8094
Fork Bag R:  http://www.geargrams.com/list?id=8095
Backpack:  http://www.geargrams.com/list?id=8097