Monday, December 27, 2010

Tsunami - 2.0 Ultrasound

As you probably know I've put in my order for my second Tsunami frame from Tsunami Bikes. I've come to refer to the frame as "Tsunami 2.0" so that's what it is. Recently I had some developments on the frame so of course I have to let you all know about them.

First, although I hinted that I was thinking about this frameset long and hard, I wanted to give you an idea of what that means to me.


Rough sketches.

Some really rough sketches. I was fiddling around with cable routing.
This was during the summer of 2010. Note the bottom of the downtube.

More rough sketches, this on the way to Interbike (fall 2010).
The notes include thinner seat stays ("aero" works), lighter top tube, aero downtube, attempt to use only a CamelBak in races, and a possible aero seat tube.

The main issues for me had to do with cable routing. I wanted internal cables to keep things clean and to keep the cables, well, aero.

Brakes, they're pretty straightforward. I knew how to do the top tube so I felt set with the rear brake. The front brake, well, that's kind of set too because either I buy a new brake caliper or I route the cable the same way. Since I won't buy a new caliper just yet, it's just a regular set up.

That leaves the derailleur cables.


I knew that I'd have some exit room at the bottom of the downtube (see sketches above). The opening at BB end of the downtube would be perfect for directing the bare cables into the under-BB cable guides.

The problem was how to get the cables in there.

After fruitless sketches (unaided by the fact that I couldn't just machine a part and mail it to Joseph to weld in), I gave up. I asked Joseph (Wells, the guy behind Tsunami Bikes) how to get bare cables inside the downtube. He replied he had a way.

I decided that "the way" would be "my way".

When I got over that hurdle, I placed the order for my frame.

The other day I checked my email and found one from Joseph. He'd attached a picture of the frame in progress. He did this for me before, and once again I got to see the frame before it was even welded up.

This is a really cool part of buying a Tsunami Bike - you get to see it as it gets built. It's your frame, not just any frame, and you get to see it from start to finish.

With the tubes cut and tacked together, the frame already looks like a frame. All my race bike philosophies become plain to see here, open to anyone and everyone to examine and then copy or reject it. It's not really like Formula One where the aerodynamic intricacies stay hidden from view. In F1 you can pick out the large pieces, the outside ones, but not the way a lot of the internal channels work; a lot of stuff remains a mystery.

In bike racing, at least with aluminum frames, what you see is what you get.

What I am getting, sort of.
Obviously an aero road frame concept.

I'd said in an earlier post that I'm looking to make some changes to the bike. Along with the sketches I made (and that Joseph never saw or even heard of), you can see how this frame took shape.

The most obvious thing, to me anyway, is the aero seat tube. It's got to be aero because it's so long, and I certainly am not going to be sporting a 54.2 mm seat post. The cut out in front of the rear wheel area gives it away. You can see just how much the rear tire will intrude into the seat tube area. Note that the tire will clear the tube by only a little bit, perhaps half a centimeter.

Chainstay length?

390 mm.

Oh yeah!

The frame bears some Sharpie marks where Joseph will put some housing guides. You can see the downtube is "aero", although, to be honest, it doesn't look much more aero than my downtube right now. It's okay, I figure it will psych me up to look down while I'm riding and not see it.


The seat stays look much longer too, another oval profile tube.

Now one thing that I denied planning, and my sketches back this up, is that I'd have an integrated seatpost (ISP), one of those seat tubes that extend upwards and replace much of the seat post. The problem with them is that you can't really adjust much once you've cut, and it's also much more difficult to pack a bike when the seat tube sticks up really far.

Therefore I decide not to get an ISP.

That was the plan.

Joseph asked how the frame looked because I could request changes at this point. I replied that I liked it. He then asked if I wanted him to cut down the seat tube or if I'd want to have it end so I'd have about, oh, perhaps an inch of my seatpost exposed.

Of course, now that I had the option of an ISP, I decided to think about it. I've been debating whether or not I should buy a super aero seat post and adjusting the frame to fit its aero height. That would involve precisely measuring where the round bit turns aero and exactly now much post I'd need. Since in all my travels I have yet to find a zero setback aero top 27.2 mm seat post, I decided against the aero post for now. If I find one then my next frame may have a regular seat tube height designed to have a particular post sitting so that its profile narrows as soon as it juts above the seat tube.

Anyway, with the thoughts of an ISP frame dancing around in my head, I went downstairs to measure my current Tsunami. Trusty tape measure in hand, I measured from the bottom bracket (center of the shell) to the point about an inch below the top of the usable bit of seat post.

580 mm.

(Okay, go ahead, laugh. Continue reading when you're done.)

I also measured my bike bag to see what 58 cm of seat tube would look like sticking up from the BB clamp thing built into the bike bag.

Not bad.

In fact, if you think about it (and I did, then measured to verify), a 700c wheel is a bit taller than 580 mm. The bead diameter is 622 mm, so it's maybe 80 mm taller overall when you include the tire. Figuring in the BB mount's height, the top of the tires should be about even with the top of the seat tube.

I ran upstairs and told Joseph to cut the seat tube at 580 mm.

Okay, I didn't do it that quickly. I thought about how I'd mount a blinkie light back there. I'm still not sure, but it'd involve using the very top of the post, the one inch exposed bit.

I thought about holding a little seat bag for a couple tubes, multi tool, levers, and some money. I decided that I need to "smallify" the bag I have now and do with just a little tighter packaging.

Finally I thought a potential camera mount back there for a potential rearward facing camera. I decided that I didn't have an idea on what to do. That means that for now I still need to think about how to mount a potential rear-facing cam.

I can deal with those problems when they come up.

But for now, it is what it is. I can't wait.


kubuqi said...

Hey, since you have such a huge seat post/tube, why don't full it with stuff?

One thing I can imaging is a blinkie light INSIDE the tube with only light comes out from holes... would be cool.

The other thing might include the spare tube/toolset hidden in, but I'm not sure if it is easy for you to pick it out by hand. LOL.

bernside said...

Hey CDR,

I am impressed with your willingness to innovate and your hands on involvement in the design of your frame.

Question about your plans to forego bottles for a camelback: from my limited knowledge of tt and tri stuff, I thought the prevailing wisdom was that a bottle on the seat tube was actually more aero than none if you are using a spoked rear wheel.

The idea being that the bottle splits the air stream and pushes it out away from the wheel instead of feeding it directly into the aerodynamic disaster of a spoked wheel. Thoughts?

(Plus some roadie types might say that even integrated into clothing, a camelback is still a camelback and should be left to the bearded, dope-smoking mtb crowd.)

Good luck with the frame. Love the blog.

Aki said...

I think the bottle on seat tube is a valid concept. I'm not sure if it's been tested with aero wheels (super tall or disk), nor if it's been tested at various yaw angles. Since the frame will offer me the option of mounting cages, I'll try both ways.

Part of keeping things off the bike is that it feels better. Less weight to move around when rocking the bike. Taking a few lbs of water off will make it feel more responsive, esp in my Abdu-like sprinting throes. A lighter saddle helps with this too.

I like to tinker and stuff but unfortunately I'm not trained formally. But when I've checked random ideas/concepts with folks who know how to prove or disprove it, the results were usually accurate.

For example, I can't prove mathematically that a tire is stationary at some point in every revolution it takes while it's on a bike going 30 mph, but I know it's true (else it would skid on the stationary pavement). A mathematician proved it for himself and relayed that information to me.

Some aero stuff I understand. Some others I don't. I'm hoping that the seat tube with an aero rear wheel will make for a "longer airfoil" overall. I'm not sure on the legality of disk wheels in crits but since they are faired wheels (for the most part) they should be mass start legal. That would be optimal.

I think the BMW designed frameset (under a surfer guy's brand) is very interesting - they use carbon to shape the tubing to "build in" such fairings.

Of course all this is mainly theoretical because I'm not that strong - 205w (now) to 250w (summer) FTP, typically 1200w peak power in a sprint. I have no delusions of suddenly becoming a 500w FTP rider or having a 2000w jump. So I'm splitting hairs here. 10 or 20 watts would be significant for FTP.

I am hoping for another mph top speed but that may be fantasy. I was told a well designed frame is supposed to give me about 1 kph or 0.6 mph at top speed (40-ish mph).

Aki said...

btw a blinkie inside the top of that seat tube is a possibility. That would be interesting.