# PVD Bird of Prey. Building this week.



## pvd (Jan 4, 2006)

I finally pulled the trigger on the new road bike design. It's gonna be crazy sick. Here are some teasers. I can't wait to ride this bike!


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## scottzg (Sep 27, 2006)

I can hardly wait


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## Thylacine (Feb 29, 2004)

You're almost as excited as your stem.


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## dbohemian (Mar 25, 2007)

the pictures are wicked cool! What you using to make them?

Um, looks like a road bike. What are the features that make it special? I can see that you will be making one of your integrated head tubes and the fork crown/blade area look cools.

Road bikes are pretty simple in concept so hard to do something outrageous. My feedback? Personally, I hate this new crop of tall but narrow chainstays. Depending on the application I almost always go for round ones as they are laterally stiffer than other types. Really depends though.

And the stem is hideous. Sorry Pete. Why not add just a touch of height on the head tube above the top tube (or make your intersection point higher) along with 1cm of stack plus maybe off set the stem intersection just a tad and mellow the rise on that thing. I know they accomplish the same thing and this is a more efficient way of doing it but damn, you are going to look like one hell of a goober with that on your bike.

Look forward to seeing it.

Dave B
Bohemian


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## pvd (Jan 4, 2006)

I'm using SolidWorks for all that. I use BikeCAD for rough sketching, then I bring the design into CAD to get the fussy things dialed in. Things like chainstay/seatstay bends can be done much better once you have a 3D model. I can maximize tire clearance and ensure chainring clearance before I start cutting tubes. Fork crowns are much easier to mitre with 3D models.

This bike is pretty cool. It's designed around improving weight distribution on the wheels and still being comfortable. 71 degree seat tube angle. Tire clearance for 32c tires w/49mm brakes. On a normal frame, I ride a 56cm effective top tube. This bike has a nearly 59cm top tube. The Shimano press fit bb spreads the chainstays out huge. Integrated head tube improves front end feel. Notice also that the fork and stem are integrated.

I prefer rise stems to the goofball alternatives. A long time ago, there was this guy named Pythagoras. He's got my back with the rise stem. This stem is pretty cool. To get extreme rises and keep the binder length down, the 1.250x0.035 tube busts a 2" radius bend into the binder. The steerer binder is integrated and acts as the headset top cap. Once the bike is painted, it's all going to look like one peice.

Personally, I look at folks with 3" of spacers under their stems as goobers. Really? That's prefered over a rise stem? Stupid.


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## dbohemian (Mar 25, 2007)

Good job on the rendering.

I see now some of the special features. Makes sense. So I am going to play devils advocate for a moment.

So in essence the geo is late 60- early 70 relaxed and capable of large tire clearances? These bikes were useful for roadracing and winter cyclocross and I think its great.

I am not at all sold on integrated headsets "feeling" any different although it is a cool look and take this with a grain of salt because my sensibilities are old school but you could just lengthen the HT and bag that stem which is going to be a PIA to make anyways. The integrated thing is cool. Ala Bruce Gordon? that look is great.

So, even though I am doing it at the very moment with Uber bike the slope on the TT is not very neccesary as road riding is such a static exercise. If moving the TT and lengthening the ST and HT minimize the stem at all then is that such a bad thing?

Pete, I know you know these things but I am just bringing them up for discussion as not everyone on this list is as knowledgeable about these things and the aesthetic of road bikes is morphing into MTB bikes with skinny tires with no real reasons at times. Just thoughts.

Dave B


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## C Dunlop (Sep 26, 2008)

30mm or so of spacers above and 10mm below are better in that it gives adjustment. If you do any number of hours on a road bike you build more flexibility in your position. At the start of a season I feel sore with 40mm of spacers below the stem, by the end I have 10mm. If you ride much, you may end up having to make new stems to get a lower position.


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## pvd (Jan 4, 2006)

C Dunlop said:


> If you do any number of hours on a road bike you build more flexibility in your position.


I put in about 150 road miles in during weekdays and I have a really bad back (Fractured 3 lumbar vertebrie when I was 20). I think that I'm where I need to be. Also, I do a special fit on road bikes that makes the drops more usefull, more of the time. It's great for decending and for long solo stints in the wind (I commute the length of Ocean Beach, SF). This leaves the tops slightly high but I can use the drops for 40 minutes straight and kill on decents.


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## eMcK (Aug 22, 2007)

Have you been hanging out with Grant Peterson?


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## pvd (Jan 4, 2006)

dbohemian said:


> ...So I am going to play devils advocate for a moment...


That's cool.

My riding position ends up being exactly the same as on a traditional bike. The zero offset post and short stem length and steeper HT, slack the seat tube and increase the top tube. I was trying to get more of my weight over the front wheel to improve handling. I've got too much weight on the rear (big boned american boy). The chainstays are slightly longer than average.

Integrated makes a huge difference. Build two identical bikes with that the only change and you will see. It really is noticable. Also, traditional headsets move all over the place inside the tube. It's something that you can't see, but it's happening. When I was prototyping my inserts for IS, I powdercoated a bike without brazing them in place to see if I could get away with one less step. The insterts were pressed in steel on steel w/o lube enought to expand the outer tube. The paint cracked within a few hard offroad rides. It kept cracking all the way around. An aluminum cup with only a slight press fit and lube is moving all over the place for sure.

I belive that sloping top tubes make perfect sence for road bikes. Do you care about the angle of your down tube? No. So why do you care about the slope of the top tube? Also, smaller triangles make for much stiffer frames, so I can lighten up my tubing. I also use all that post extention in combination with a carbon seatpost to add a lot of comfort to my ride while still having a stiff frame out of the saddle.


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## pvd (Jan 4, 2006)

eMcK said:


> Have you been hanging out with Grant Peterson?


Thanks for the insult.


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## eMcK (Aug 22, 2007)

It was mostly a joke. But there are quite a few things this bike has in common with some Rivendells. And this isn't a bad thing. Longer chainstays, low BB, high handlebars, sloping top tube, clearance for wide tires and/or fenders. For non-racing bikes these all make lots of sense.


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## pvd (Jan 4, 2006)

Rivendell makes me sick. Their bikes are an insult to anyone interested in progress.


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## Schmitty (Sep 7, 2008)

Really nice renderings.....


-Schmitty-


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## eMcK (Aug 22, 2007)

Well regardless of hatred, looks like a great project. 

I'm with pvd when it comes to stems. It took me awhile to reset my internal fred-o-meter, but now I prefer a riser stem to the stack of spacers.


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## HotBlack (Feb 9, 2008)

How nice.


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## Schmitty (Sep 7, 2008)

eMcK said:


> Well regardless of hatred, looks like a great project.
> 
> I'm with pvd when it comes to stems. It took me awhile to reset my internal fred-o-meter, but now I prefer a riser stem to the stack of spacers.


What about just getting the top of the ht where it needs to be?

-Schmitty-


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## pvd (Jan 4, 2006)

Where do you think it should it be? Specifically.


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## rickthewelder (Sep 16, 2005)

pvd said:


> Thanks for the insult.


Be sure to check all the patent laws too........

Looks good man.
RTW.


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## Thylacine (Feb 29, 2004)

If you want some more usable handlebars esp if you have reach/flexibility issues, have a look at the 3T Ergosum bars.


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## shiggy (Dec 19, 1998)

While I disagree with PVD about a lot of things, the riser stem is not one of them.

There can be advantages to a low-slung frame and using a conventional/traditional stem would negate many of them. The riser stem can be stiffer and lighter. A little extra steerer and you can still use a small amount of spacers to fine tune the position. It is not a big deal to make several stems either.

This is a _custom_. Built to fit one rider, and he knows how he wants to sit on the bike.


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## unterhausen (Sep 28, 2008)

I would really like to see that fork, looks like there is no clearance.

As far as the stem goes, I don't think it even breaks the top 50% on the goober scale.
I'm still stuck in the '70s as far as stems go though, the Cinelli 1A is still my favorite
stem even though one of them tried to kill me recently. When I was riding as a teenager,
we were all obsessed with how long of a stem we could use. Now everyone is
obsessed with how low they can get their handlebars, and everyone with a stem
that has rise is advised to flip it. I'm sure there are people that would
be riding faster if they ignored that "wisdom."

I was just reviewing the stems on the bikes on the Rivendell site and now I have to go laugh.


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## Vlad (Feb 7, 2004)

I can't wait to see the finished product.


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## Schmitty (Sep 7, 2008)

pvd said:


> Where do you think it should it be? Specifically.


Don't know about you or your bike, but in general, when weighing a thick stack vs.a high rise stem, where the top of the ht is should be considered as well, as you can often simply make the ht longer and do away with with goober stacks/boner stems, or at least minimise them.

-Schmitty-


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## pvd (Jan 4, 2006)

Schmitty said:


> or at least minimise them.


Ok. So what's the goal? Let's assume that I didn't put a huge amount of experience and planning into designing every tiny detail of this bike, where should the top of the head tube be located? If I am minimizing spacers or stem rise, then what is the minimum? When is a head tube too long?

I'm firmly in favor of using rise stems on road bikes, but I want to here exactly what you are getting at. How do you design a frame.

Let's just say, for example, that You've got a handlebar height off the ground of 930mm. What would you do?


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## Schmitty (Sep 7, 2008)

pvd said:


> Ok. So what's the goal? Let's assume that I didn't put a huge amount of experience and planning into designing every tiny detail of this bike, where should the top of the head tube be located? If I am minimizing spacers or stem rise, then what is the minimum? When is a head tube too long?
> 
> I'm firmly in favor of using rise stems on road bikes, but I want to here exactly what you are getting at. How do you design a frame.
> 
> Let's just say, for example, that You've got a handlebar height off the ground of 930mm. What would you do?


Just saying in my reply to emck, ht height is also a consideration when talking about spacer stacks and stem rise. It's no commentary on your setup.. I have no idea of your goals with that frame or your fit reqs.

I aim for 5mm of spacer stack for my bikes, knowing my position pretty well. I'd rather pay more attention to the top of the ht, than to the slope of the tt within reason obviously. I often look at bikes/frames and just think the silly amount of spacers and/or stems rise could be avoided by a either a properly sized frame, or simply a longer ht, either keeping the tt intersection the same and having a bit more ht 'extension', or moving the top of the ht and the tt/ht joint up a bit.

-Schmitty-


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## dbohemian (Mar 25, 2007)

Schmitty said:


> I often look at bikes/frames and just think the silly amount of spacers and/or stems rise could be avoided by a either a properly sized frame, or simply a longer ht, either keeping the tt intersection the same and having a bit more ht 'extension', or moving the top of the ht and the tt/ht joint up a bit.
> -Schmitty-


This is what I was getting at, but did not say as well.

Dave B


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## DWF (Jan 12, 2004)

pvd said:


> I put in about 150 road miles in during weekdays and I have a really bad back (Fractured 3 lumbar vertebrie when I was 20). I think that I'm where I need to be. Also, I do a special fit on road bikes that makes the drops more usefull, more of the time. It's great for decending and for long solo stints in the wind (I commute the length of Ocean Beach, SF). This leaves the tops slightly high but I can use the drops for 40 minutes straight and kill on decents.


Why don't you use a bar with less drop? That would allow you keep the hoods at a useful height (even pros spend most of their time on the hoods) and give you better access to the drops without having to increase your flexibility. I broke my back in '86 (4-5 compression fracture) and understand where you're coming from, but ability to get low over the bike is not really a back issue, it's a pelvic issue. You want to rotate your pelvis and not arch your back. Try stretching your hip flexors, glutes, & hamstrings.

RE: the riser stem versus non-riser issue, from an aesthetic standpoint I think riser stems on road bikes look wrong. A builder has to be both engineer AND architect otherwise everything ends up looking like this:










Functional yes, but ugly as hell.


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## smudge (Jan 12, 2004)

I'm chiming in for two reasons. First, I'm agreeing with Don's assertion that you should check out some compact drops. I have some hip flexibility issues and I dig the short drops. Specifically the Oval compacts. FSA short & shallow bars have a decent shape as well, but the widest they make, a 44cm, is only 42cm ctr to ctr at the hoods. 

A lot of us who are building bikes for customers have to make compromises some times to please the aesthetic appeal of those customers. The HT length/spacer stack/stem is one of those issues and I understand the appeal of attempting to keep a traditional look. Pete's making this bike for himself and if he's the only one he has to please. If a high rise stem puts the bars where they need to be and he's cool with the looks, what's the difference?


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## pvd (Jan 4, 2006)

DWF said:


> Why don't you use a bar with less drop?


I've tried shallow drop bars. I don't like them. My hands feel squished in place and they lack a lot in positions. The bends are entirely different than the normal drops. I think that the shallow drops may be good for some people, but not me.


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## Thylacine (Feb 29, 2004)

smudge said:


> I'm chiming in for two reasons. First, I'm agreeing with Don's assertion that you should check out some compact drops.


See post #20 

So hot right now.










You know Pete, if you squint and imagine your bike has really fat tyres, it looks like a Cunningham.


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## pvd (Jan 4, 2006)

He lives a few blocks from me.


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## C Dunlop (Sep 26, 2008)

also check FSA omega as a bar. Good stuff if you want a cheapy but 3T is better if you put your hands on top. 3T is also the flavour of the month it seems.


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## dbohemian (Mar 25, 2007)

Thylacine said:


> See post #20
> You know Pete, if you squint and imagine your bike has really fat tyres, it looks like a Cunningham.


Such a cool bike.


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## coconinocycles (Sep 23, 2006)

fit trumps looks. rock it. building that far out of the norm is always educational. i have built bikes with a 68* ST angle. as long as you have your TT length & FC figured you are all good. i build a suprising # of frames for people with back/neck issues, and you gotta do what you gotta do for fit. i can walk with an ugly-ass brace but not with out. does the look of the brace make me not walk? hell no. my only $.02 would be with that much ST extension above the top of the TT i would rotate the binder slot to the front.


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## Thylacine (Feb 29, 2004)

dbohemian said:


> Such a cool bike. [Cunningham]


And it still has more bar-to-saddle drop than Pete's bike! He's going to be a complete brick in the wind at anything over 35kph. Hopefully if we keep hounding him, with our 'expert' feedback it actually will be "road, only better".

:thumbsup:


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## D.F.L. (Jan 3, 2004)

Aluminum headset cups don't move around in the head tube. If you've ever had an improperly-sized aluminum cup or damaged HT, you know the noise and wear that occurs. Any movement quickly wears the cup. Aluminum's short fatigue life would also lead to frequent broken cups if 'any' movement was present.

I recall this argument a while back, but no control experiment was done to prove movement with the aluminum cups.


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## smudge (Jan 12, 2004)

Thylacine said:


> See post #20
> 
> So hot right now.
> 
> ...


Looks similar to the FSA in shape. I did it on the road bike since it gives a nice flat transition from the bars to most of the new lever shapes. It works particularly well with SRAM. Hate it on the cross bike for the same reason. That flat transition isn't great (for me) when my hands are all muddy and slippy and I'm going down hill. That's where the Ovals are better (for me). I think the Newton shallow drops are similar.


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## rickthewelder (Sep 16, 2005)

dbohemian said:


> Such a cool bike.


I'm curious, whats so '' cool '' about it ?
I mean that sincerely.
Rick.


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## shiggy (Dec 19, 1998)

rickthewelder said:


> I'm curious, whats so '' cool '' about it ?
> I mean that sincerely.
> Rick.


The Cunningham may seem blah now but in the early '80s it pioneered many features now considered standard mtb design.


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## dbohemian (Mar 25, 2007)

rickthewelder said:


> I'm curious, whats so '' cool '' about it ?
> I mean that sincerely.
> Rick.


Well, since you ask sincerely.....Shiggy already hit the nail on the head. You have to think back to the mid 80's. Most mountain bikes where just road lugs with Tange prestige and bullhorn handlebars. The Cunningham was a real departure from what was basically the norm back then and the fact that it even looks like a modern mountain bike is amazing.

First, Aluminum. Mr Cunningham was one of the first to use aluminum. The geo and sloping top tube were really out there at the time but we all know they are positive attributes. The seat post/stem and handlebars were custom, those didn't exist. It had good tire clearances for the time, the brakes were sweet. The stem/hanlebars were completely original during a time most were still using threaded 1'' and it was even gussested with faux lugs. 
If you don't know your history you don't really know the new. It all had to start somewhere and although of course none of this is revolutionary on it's own Cunningham was one of the first to put together the whole package and it goes down as one of the greats.


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## ATBScott (Jun 4, 2006)

I'm voting for the "Form follows function" side of this argument. The bike doesn't look traditional or classic - and that is fine. It definitely looks custom to fit a specific need - and isn't that a good portion of what this part of MTBR is all about? Maybe nobody else will use the ideas that PVD is putting into HIS bike, maybe someone will. If you go back through the ages of bike building I'd bet that none of his ideas are completely new, though like Charlie Cunningham, he may have grouped a few ideas together here that have not been compiled before. While aesthetics are of importance, much more so is comfort, performance and reliability, IMO. If it works for him - great. If it doesn't, it was his experiment to find that out. All you nay-sayers out there can keep building bikes just the way you see them at all the "box stores" and that is entirely your perogative - don't let anyone beef on you if that is what you choose to do. People vote for frame designs with their wallet when it comes to dealing with builders. PVD - I hope it works out for you. Let others ride it and get their opinions. I bet some will like it and some won't. If even a few other people think it feels good that can be considered a success.


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## Schmitty (Sep 7, 2008)

Silly to flip somone so much s**t based off of looking at a frame only. What are his objectives? What will it look like built? What willl it look like with him on it?

-Schmitty-


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## herbn (Sep 17, 2005)

how are you clamping the stem? I always thought it might be cool to integrate the steerer into the stem,you can have some really smooth lines in that area. and pinch bolts in the crown,i'd still have the lower bearing seat as part of the crown.


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## rickthewelder (Sep 16, 2005)

dbohemian said:


> Well, since you ask sincerely.....Shiggy already hit the nail on the head. You have to think back to the mid 80's. Most mountain bikes where just road lugs with Tange prestige and bullhorn handlebars. The Cunningham was a real departure from what was basically the norm back then and the fact that it even looks like a modern mountain bike is amazing.
> 
> First, Aluminum. Mr Cunningham was one of the first to use aluminum. The geo and sloping top tube were really out there at the time but we all know they are positive attributes. The seat post/stem and handlebars were custom, those didn't exist. It had good tire clearances for the time, the brakes were sweet. The stem/hanlebars were completely original during a time most were still using threaded 1'' and it was even gussested with faux lugs.
> If you don't know your history you don't really know the new. It all had to start somewhere and although of course none of this is revolutionary on it's own Cunningham was one of the first to put together the whole package and it goes down as one of the greats.
> ...


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## Vlad (Feb 7, 2004)

No, Charlie Cunningham, one of the three founders of WTB.

Richard Cunningham did some pretty cool stuff with Mantis, too.


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## Vlad (Feb 7, 2004)

How is the Bird of Prey coming along?


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## shiggy (Dec 19, 1998)

Schmitty said:


> Silly to flip somone so much s**t based off of looking at a frame only. What are his objectives? What will it look like built? What willl it look like with him on it?
> 
> -Schmitty-


Or the only thing that really matters: How does it ride (for the rider it is intended for)?


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## pvd (Jan 4, 2006)

Vlad said:


> How is the Bird of Prey coming along?


It's all cut and tacked. I just need to weld it. Work got nuts these past 2 weeks. I'm hoping to weld it up tomorrow.


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## Cracked Headtube (Apr 16, 2006)

how goes this project?


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## pvd (Jan 4, 2006)

Argg! It's been a hell of a month. Lots of stumbles and distractions.

I'm finishing the stem today. I should have the bike into paint tomorrow afternoon or Monday morning. RAL 5015.

The stem is going to look amazing. This is going to be one of my best builds yet. The chainstays are off the hook!


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## dbohemian (Mar 25, 2007)

pvd said:


> . I should have the bike into paint tomorrow afternoon or Monday morning. RAL 5015.


I am painting a bike almost that exact same color as we speak.


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## Thylacine (Feb 29, 2004)

You guys didn't get that memo? Mid blue is no longer a colour. It's been officially banned by the Societie du Graphis Artisinales as an affront to any person of taste or trained in the arts.


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## Adam_M (Aug 8, 2008)

LOL at Thylacine! For what it's worth, I agree. RAL 2004 is soooo much better, FACT.

Looking forward to seeing the pictures, PVD!


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## herbn (Sep 17, 2005)

what a riot , frigg'n hi larious


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## Francis Buxton (Apr 2, 2004)

pvd said:


> The chainstays are off the hook!


I believe the proper terminology is "off the chizain".


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## Vlad (Feb 7, 2004)

No. "*****in'."


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## pvd (Jan 4, 2006)

Adam_M said:


> For what it's worth, I agree. RAL 2004 is soooo much better, FACT.


http://www.pvdwiki.com/index.php?title=PVD_5.5"_Fork_Hardtail_R2#The_Gift

FYI, everythings done. The bike goes to paint on Monday. I hope to have some pics by Tuesday or Wednesday. Got some hot 7900 to spruce up the old girl.


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