Wednesday, December 01, 2010

Time For A Concept Bike! Part IV

Wow! I am getting a lot of responses to the idea for a gravel grinder specific bicycle both here on the blog and through e-mails. Seems that many of you have some ideas and suggestions to add in, and I appreciate them all. Actually, I am rather flattered that you all took the time to respond. Thanks!

Yesterday I took the opportunity to say why a couple of rigs I was considering didn't quite "do it" for me, and I think it is what sparked a lot of the commentary I received. It may be a misunderstood concept for many of the readers out there as to what I am trying to achieve, so let me just state my purposes again.

#1: I have a few bikes that are already "almost" what I want. I do not want to add, and don't need to add another bike with "compromises".

#2: I am zeroed in on a certain set of parameters, and while some of these bikes being suggested come within millimeters of what I want, they don't tick all the boxes.

So, if this idea for a concept is to be realized, it will be very specific and will be what I aim for, or I will not do it. I was hoping for another opportunity for a bike like this to materialize, but it went in another direction, and even though it would be "close", I am not interested anymore. So, if I seem a bit "grumpy" in my responses to comments, I do not mean to be that way. It's just that I have an idea that I am drawing a bead on, and hopefully I will not be distracted from it.

So, with that said, here is the next subject: Frame material. I am going to go with steel, mostly due to costs and ease of construction. I like fillet brazed construction and I have two bikes that utilize that joinery technique. It allows for odd frame tubing junction angles which lugs can not accomplish without being handmade at an extraordinary price. TIG welding would be okay, but I don't know if I will go that way. Could, but probably not.

Maybe in a more cash flush scenario I would opt for titanium, but that is far beyond my humble means to accomplish, so it is definitely not on the radar. Wish it was though. So, good ol steel it is!

Some of you will maybe point out that fillet brazing isn't the lightest way to go, and I would nod in agreement. However, I could be all wrong about this, but it seems to me to be a way to deaden vibrations to some degree over a TIG welded frame. Why is that important? Well, the less vibrations a rider has to absorb, the fresher, and more efficient, the rider will be. The Badger above is exemplary in this regard. It also is a good example of a higher trail figure bike and how that handles better on gravel than some of my other gravel grinder rigs.

Here is my other fillet brazed rig, the Pofahl. It is a great example of a slack seat angle bike and how that works in long, drawn out rides. I rode this 106miles in the 2009 Good Life Gravel Adventure around Lincoln, Nebraska, and it was set up with 180mm cranks, which put me low, and "down in" the bike. I liked that about this set up and these things are part of what I want incorporated into the "gravel rig".

These two bikes are "pretty close", but are too mountain bike-ish and have other things I don't care for in regards to this project. For one thing, I think both of these bikes are a bit over-built for the purposes of a gravel only rig. That's where I am coming from with my "lighter tube set" comments.

This is my Singular Gryphon from the same basic course that I ran the Pofahl on, (only this year it was called "Gravel Worlds"). This bike and the Fargo represent my favorite body positions and saddle to drop bar heights. The Singular in particular has a sweet riding, flexy-in-the-right-way CroMo tubeset. What neither the Fargo or the Gryphon have is proper front end geometry for bombing gravel hills on. Both get a wee bit sketchy and require what I deem as too much rider "herding" to keep them from getting too twitchy. Not what I want to have to be doing on multi-hour rides where 35-40mph down hills on loose gravel are happening one after another.

There are other finer details that I would want changed as well from these bikes. Obviously the biggest ones are getting away from huge tire clearances and such big tires and having top tubes more level since mountain biking won't be part of the repertoire. I will want less braze on madness than a Fargo, since I would want frame bags instead if it comes to that. Three water bottle bosses, minimum, and "maybe" rack mounts on the back. Possibly fender mounts, (if Ben Witt talks me into it), and a pump peg and chain hangar.

Well, there is more, but we'll cover that later.


Captain Bob said...

I must say that this might be a bike I want too. I personally want this bike to fit 45's with no toe overlap. I'd still like to ride singletrack without burning a hole in my shoes. Gt, are you set on the 40mm tire max? When are these frames going to be available? :-)

Guitar Ted said...

@Captain Bob: So far my personal preference has been to limit tire clearances at 42mm. Much bigger clearances than this and you may as well make it a mountain specific chain line, and if you have to do that you may as well make it a mountain bike. That's why I am sticking at the 42mm size. That is still up for debate too.

I figure you are giving me a hard time with the availability comment. :>) Just to be clear with everyone else: This is a personal frame project that Ben Witt may also use the concept of as well. Whether or not Ben and I have the same builder, different builders, or whether either of us has this done at all is all up for debate as well.

Unknown said...

If you make the bike have clearance for a 29x1.8" it will still fit a 35c and fenders, or a 42c with tight fender clearance. If you are set on the Racer brake, (which I agree with completely,) then I would think building the bike to fit the fullest tire that brake would accept would make sense. While not being MTB tire huge, I would think you would want to keep your options open. I would not build a bike like this that I could not put fenders on, period. That's just me though, I like to be clean. Ha! Chain line is not an issue with a 50c tire. Road components can easily be fitted if the chain stays are designed right.

This is exciting, I love projects like this. The point you make about the custom nature of this is easily taken care of as well. If a person wants something not currently made, and it is a bike that will easily last for 10-20 years, why not spend the extra $500 or so now to achieve that? 'Nuff said.

Captain Bob said...

It was a little joke but I do seriously want a frame like this. I loved my Peregrine but I was between sizes and toe overlap was an issue for me. And I want canti's.
I can't order a custom frame like this since I don't have the correct knowledge on what it takes to make it ride correctly. I do know what bikes are close to what I want. So, this topic is perfect, just what I have been wanting to read up on. Thanks!

Wally said...

Ben loves his fenders. Me, not so much. Might as well wear a skirt too :)
Having experienced a fresh gravel downhill at 35+ mph on a Fargo, I totally understand. I loved the ride but the "rush" reminded me of my moto racing/track days - and there I had more protection! I'd be real interested in what you two bang out. I have my own ideas and have been mulling this around for some time, hence my interest in what you come up with.

Guitar Ted said...

@Ben: Thanks for the feedback. I'll say this: I wouldn't at all be sorry if I could cram in an XR-1. My favorite gravel far! If 1.8's are all we get, then I'd be happy as well.

Fenders are cool and all, but unless I start riding in more rain, I don't see me needing them. I will say that your idea for the fender is super cool though, and may sway me in the end.

(Ya'all will just have to wait to see what Ben has in mind)

grannygear said...

Ok...the Badger has a non-setback post..pretty sure, and the seat is pushed back...not sure what the ST angle is, but I would say steeper.

Now the Popfhal...Poofall..Pohfalh...whatever that is...has a slack ST angle you say you like but the saddle slammed forward on the rails.

Hmmm. OK, GT...what gives bro?

Guitar Ted said...

@grannygear: Actually the Badger has a Salsa Shaft seat post which has a fair bit of set back, and the seat is back from dead center on the rails. The Pofahl has the saddle just barely forward of dead center on the rails in comparison to the clamp. Also, the Pofahl is a half an inch longer in the top tube than the Badger. (Could likely be an effect of the slacker seat angle and lower head tube on the Pofahl) Finally, I like the slacker rear of the Pofahl and the lower trail figure and hand position on the Badger. At least from a geometry standpoint.

MG said...

My Vaya doesn't overlap with 46s... But then it's got discs and doesn't do SS.

... but then I love discs and gears, so I have no beef with that. It's about the perfect gravel bike for me. If I could spring free the cash for a Ti Vaya, I'd probably do it, but I think a Ti Fargo is ahead of it on the list, currently.

grannygear said...

Hmmmm...ever do a plumb line drop to see how different they are...or how close they may be?


retroscool said...

How about:
with a setback seatpost?

Guitar Ted said...

@retroscool: Have you noticed the head tube on those? (If you can find it, that is. ;>) )

Nothing against that sort of set up, but having a stack-o-spacers isn't my cup of tea.

Doug said...

Hey GT.

On the chain hanger, if you aren't familiar with the Columbine Quickchainger you owe it to yourself to check them out. They are slick, don't have to touch the chain at all to remove/reinstall the wheel.

Neat project,