Monday, August 13, 2018

Mantis Valkyrie EC

Love it or hate it, this frame has loads of character. It wasn't enough for Richard Cunningham and the crew at Mantis to create one of the more unique frame designs of the 80s with the X-frame, but they decided to up the ante by incorporating their elevated chainstay concept and create the Valkyrie.

The Valkyrie or the Valkyrie EC as some refer to it became on the of the more iconic mountain bikes concepts and essentially sparked the elevated chainstay revolution, however brief it may have ended up. The original X frame was first built in 1986/87 and as best as I can surmise 15 or so non-elevated frames were made. Richard put to torch to each one personally, and they were essentially his magnum opus. The elevated Valkyrie came out in 1989 and remained the only steel Mantis available until 1992-93 when Richard sold the company. Although I have not dug too deeply into the build quantiles of the elevated version it seems that many more were made, and I'd put forward a figure of 50 or so frames as a possible build total.

Before I get into it, here are some interesting figures you may want to think about before you really judge the bike. First, an average mountain bike is made of approximately 10 pieces of tubing (HT, ST, DT, TT, stays, BB shell and maybe a brake bridge) - the Valkyrie has 13 plus all the little braze ones. Then there are the sheer number of welded junctions at 28 (not counting the cable guides/stops and the compound joints in a few places) vs the normal 15 or so... all of this means that a lot of work went into this bike!!

I've been working on this bike since around 2014 when I bought the frame on eBay in a rather sorry state. Basically only the frame was salvageable as the rest of the components including key things like the stem and fork were not correct. I was able to source a fork by sacrificing a Mantis XCR which made do with a Rock Shox RS-1. I was lucky to find an original Mantis stem down the road and so the game was on.

For the build I decided to go with a mix of American Classic, Shimano XT and featuring Cook Bros cranks and Grafton Speed Controller brakes. I have never used AC components and have always liked their quality and aesthetics. I always thought that the later elevated Valkyries were ideal candidates for a high end build and so rather than go for the typical heavy on the anodizing Ringle/Grafton build I opted for a more subtle but still somewhat edgy build. About the only thing I didn't use from AC were their quick releases as they were mostly painted black and I was unable to find a nice enough pair that when stripped would polish up nicely. So, that remains as something to correct in the future.

There are so many details to talk about on this bike. Starting with the overall frame construction there are two things that I think people notice first. One is of course the elevated chainstay, which for many people today is quite unique. Those of use who were around in the late 80s and 90s instantly recognize it as a has been design trend, but still interesting. Personally I think the regular X-frame was perfect as it was and I feel that incorporating the EC design into it was the wrong decision. It makes the bike heavier, much much more flexy, prone to failure at the seat tube joint and lastly and maybe most on the nose for me it makes an otherwise gorgeous bike look like something from a sci-fi movie. It just looks a bit too edgy and I think that is in stark contrast to the quality of craftsman ship that went into making it. I don't know, it's just too much for me.

The second major talking point is of course the main triangle with its unique twin lateral cross members. The design concept here was to use smaller diameter and therefore lighter tubing and achieve the same or even greater level of overall frame strength. RC has said in the past that he got this idea after doing some frame strength testing for Gary Fisher and they ended up testing an old Schwinn frame and realized that it was incredibly strong compared to the light weight steel Fisher frames of the time.

This being a late product Valkyrie the ends of the laterals have smooth shaped ends as opposed to the the earlier scalloped ends featured on the early X's. Personally I prefer the older versions (see my old 87 X frame) but whichever one you like either design makes for a wonderfully intricate headtube junction with the downtube.

The Mantis stem is a beautiful design. The ovalized section of the stem creates a strong joint at the quill portion and the fillet brazed junction with the handlebar clamp puts just the right amount of flair in a highly visible and less stressing joint. I really enjoy the mix of TIG and FBd joints on this bike and the thought that went into the choice between outright strength and the aesthetics. The internal brake cable routing is clean and results in a fairly smooth cable action. Under most circumstances I feel that the later Mantis bikes are best served with an aftermarket stem as RC stopped making these stems around 88-89, but I also really like the way it looks on the bike and have seen original elevated Valkyries equipped with the stems so I feel it's the perfect choice for this bike.

A Little more detail of the handlebar clamp transition. The little ridge on the centerline is reminiscent of the filed ridge on the early fillet brazed XCRs.

RC has said before that he left most of his fillets un filed, however this bike shows very smooth welds all around. So, I'm not sure if he changed his tune in later years or if some other welders did the finishing work resulting in the smooth, flowing fillets found on this and some other later Valkyries.

The amount of little guides and cable routing tubes on this bike is borderline funny. In a way they are all interesting little touches that add character. Another way to look at them are fixes required to enable the crazy design of this frame to still support the basic functionality that enables this bike to actually be ridden.

I think it's interesting that RC put all this work into the welds on the frame only to leave the fork with the relatively rough by comparison TIG welds. He did comment that he used TIG welds where they were needed for strength which I recognize the fork crown requires, but he could have put a light fillet over them to let the fork at least match the frame for aesthetics.

The American Classic headset is one of the more unusual designs, echoing some of the early Mavic designs. The headset eschews classic headset wrenches and I must say is somewhat challenging to install if the threads aren't perfect. I still really dig it!

I haven't ridden this bike, but I'd imagine there to be a fair amount of compliance in the BB shell...

One of my favorite viewing angles on this bike (no pun intended)

Fun aside. The decals on this bike are actually chrome inlays that were laid down and painted over and then the masks removed. This specific material was originally used on Merckx frames.

I may be a bit hard on this bike, but it's a degree of criticism usually resulting from a deep appreciation that can only be achieved by investing several years into a project. The elevated chainstay Valkyrie is a close derivative of one of my all time favorite bikes (the X frame) and to top it off I have spent nearly four years restoring it and building it up resulting in very high expectations. For me the first innovation that resulted in the original X/Valkyrie was the one and I would have left it there. In my opinion that added not only character but was practical and resulted in a fabulous ride. The elevated chainstay modification adds pretty much nothing but complexity. I say this largely based on the learned complexity in building this bike and off of input of others who have some serious saddle time in one (ride review on the non elevated Valkyrie here). Though I have to admit I haven't known anyone who's had any significant hours on both, a testament to how rare these bikes are. 

So in the end I think this is a rad bike, a crazy outlandish design, executed with a high degree of craftsmanship and flair. It's a standout design that is sure to get attention anywhere it goes and if you don't demand the world from it can be a capable mountain bike. 

Monday, August 6, 2018

Juli Furtado's 1991 Prototype Yeti ARC

I was looking back at the history of when I got this bike and started working on it and realized it had been over two years in the making. I still can't believe my luck in finding and getting this bike, and really enjoyed completing the restoration. You can see the original post documenting the finding of the bike in Doog Bradbnury's attic here. If you pick up a copy of Dirt Rag #206 you can see a nice write up on the bike and a bit of the history background of how it came to be and what it represents in terms of the development history of the Yeti Alloy Racing Composite (ARC).

I've discussed the unique details of this frame in the past and so I won't go into that detailed discussion yet again in this write-up and so I encourage any of you who are seeing this bike here for the first time to read the prior post in the link above.

What follows is the culmination of two plus years of restoration, repairs and research to complete one of the first prototypes of the fabled Yeti ARC and the actual, two time World Cup winning race bike of Juli Furtado. The build here represents the bike as it was at the start of the season. I didn't have a ton of info to go off of to complete this restoration. The most complete set of photos came from a French magazine and it showed the configuration of the bike at the very start of the 91 season. The parts appeared to have been directly taken off of Juli's C-26 and were perhaps later swapped back as she changed a few items throughout the early part of the season. I could have taken a few liberties and ran XT STIs or even a few XTR bits which Juli got early to test, but this initial build really spoke to me with its milled out brake lever and shifter mounts and the simple, tried and true XT components. I also really liked the lack of the ARC decals on this bike as it really predated that naming convention and so as a complete package it was really the ideal choice IMO.

Finding the original stem would have been impossible so I turned to the man who without a doubt made it for Juli back in the day, FTW. Frank did an impeccable job making a replica steel Yeti stem, even going so far as to use old stock tubing and aging it to give it that worn look.

Frank also wrote down the dimensions of the stem underneath, just like he would have done all those years ago. I love those little touches on bikes like these as they make the whole project really stand out and give it a degree or authenticity that is difficult to pull off otherwise.

Unlike Juli's later ARC which had a few brightly anodized components, this early build is rather sedate. The few splashes of color present are courtesy of the bright ODI Attack grips and some day glo orange Onza decals.

Custom, hand machined cable stops were the earliest iteration used on the ARCs. The 2nd version of the ARC actually had riveted on FRO cable stops welded onto a triangular piece of steel.

I did my best to locate original decals and replicate missing ones but there were two decals I was unable to locate and I didn't have sufficiently detailed photos to go off of in order to replicate them. 

As far as actual collectable mountain bikes old team or race bikes are my favorite bar none, I love all the team unique details, sponsor decals and the race pedigree. Sadly, I have yet to come across an old race bike (with some serious chops) that actually fits me, seems MTB racers back then were short. Sigh...

The one piece continuous rear section and the BB junction with the FRO like wishbone is THE detail that sets this Yeti apart from other ARCs after it. Only two prototypes were made with this design and this is the only one remaining, the other was cut up by Chris Herting during the development of the ARC-AS softail.

When I got the bike the seat tube was cracked, a silly thing given that it most likely broke not because of use but rather because it was left with the seat binder bolt tightened which put an excessive load on the nearly 30 year old and brittle material. Once again FTW came to the rescue and with some careful localized blending I doubt anyone would ever notice that a repair took place here.

This is one of the few ARCs that didn't have a cracked headtube, almost hard to believe!

The fork on this particular bike is what's commonly referred to as the 2nd generation Bradbury Manitou. For all intents and purposes it's identical to the Answer Manitou 1 released in the later part of 1991 at which time Doug slowly stopped making his own forks. This fork has slightly longer travel compared to a stock unit, and by slightly longer I mean it's closer to 2" as compared to 1.5". That's in ideal circumstances and with softer bumpers. Set up with a blend of medium/firm it still gets about 1.5". All those extra stanchions are good for in reality is to slacken the front end.

I don't care how many times I see this serial number it never gets old... 

The small size of this frame makes for a really busy rear end with cables running close to each other and forcing somewhat tight runs of the brake housing. Luckily the old style 6mm housing is softer and conforms a bit better to the tight routing. Running low profile brake in the rear and was a nice touch and I'm happy I was able to find enough info about the bike to catch this detail.

I'm sure people will disagree and point to some amazing fillet brazed steel beauty, but for me this is one of the sexiest rear ends on a bike ever made. Think about it for just one moment, the entire rear end is made from one continuous Aluminum tube, that's with contoured chainstays to boot!!!

Keep thinking about it!!

As another epic projects come to a close I can't help but reflect on the scarcity of finds like these and the opportunity to work on something truly amazing. When I first got into collecting and restoring mountain bikes these bikes seemed unattainable and almost otherworldly. Most of us assumed they were broken, busted and buried under a mountain of rubble or simply lost to time. Since then a surprising number of them have turned up and made their way into the hands of collectors. I've been fortunate  to have a few pass through my hands and am happier for it. However there was always a finite number of them and now fewer left unaccounted. So, while I'm proud of this work and happy to have seen it through to the end, I'm left feeling a bit sad that this particular ride is over and that I may not get another opportunity like this for a long time to come if ever again. So, I'll take my time making a few last tweaks here and there and relish the time I had to work on it and remember that it helped connect me with some truly amazing people and the relationships that came from that. In the end I think that's a good story and one I'll remember long after the smell of melted elastomers and fresh rubber is gone from my memory. 

Monday, July 30, 2018

1988 Bradbury Manitou

One of the bigger draws in restoring vintage mountain bikes is getting to know a builder through his or her work. It is why I like to focus my work on smaller, custom builders where each and every bike represents a specific design unique in some element(s) and which when placed along a time line marks an evolutionary step in their thought process. Among such builders Doug Bradbury is one of my favorites and his bikes are major focus of my restorations.

This particular bike was built around 1988, probably the later part of the year. Doug started making bikes for customers in 1987 and only made 24 bikes that year and another 27 in 1988. During that time he experimented with different tubing, gusset design and methods of joining the rear and front triangles. The earliest bikes had a chaninstay designed that strongly resembled the Mountain Klein and which looked like a combination of two flat U shaped sections welded into a single piece which joined the bottom bracket shell and then mates to the chainstays. This bike is the next iteration of that concept which uses box sections to form the chainstays and then welds directly onto the bottom bracket shell.

The gussets on this frame still follow the early design of tall on the top enabling a taller head tube and a flatter one on the bottom at the down tube to head tube interface.

Of the obvious evolving elements that can be seen on the early Manitous is the transition to a larger seat tube. The earliest bikes had a constant diameter 1 1/4" seat tube which over time transitioned to 1 1/2". If you put a select few 1988/89 Manitous in line you could see that 1 1/5" tube almost growing up from the bottom bracket until it spanned the entire seat tube with a necked down portion above the top tube to accommodate the 26.8mm post as the larger 31.6mm posts used in later bikes were not yet available. These seat tube transitions were at first accomplished by splicing the two different diameter tubes together with a welded junction. As I've mentioned before in another writeup these junctions were a stress riser in the frames and a common failure point. This frame had a minor crack at this junction which was expertly repaired by FTW.

Keeping things stiff at the bottom bracket junction was obviously a major concern as evidenced by the almost 2" diameter externally butted down tube and square stays. These bikes had very little lateral flex in the BB under load.

Keeping things sorted at the front was Doug's segmented fork with a 115mm front hub resulting in very precise steering yet still relatively compliant and comfortable on longer rides. I've done a few 20+ mile rides on my old 90 DBM and never felt like I was getting tired of the rigid fork.

Although the hubs appear to be widened Bullsyes they were actually hand made by Doug and his crew especially for his bikes. The common setup on these bikes was 28h in the front and 32h in the rear. The wide hubs made for stronger wheels and enabled even heavier riders to comfortably use lower spoke counts without sacrificing strength and durability.

Though Doug wasn't known for experimenting with drivetrain I did find a few photos among old archives that showed a couple bikes running a wide rear ratio with a 2x front. So for this bike I decided to try that with a 13-32 rear freewheel and a 32/40 front on a Shimano 6206 crankset. I haven't had a chance to try this in the dirt, but in theory and with some tweaking this could be a fun setup.

Though crude at first glance this design is nothing but efficient and appropriate for the task it was meant to perform. There are no flourishes and not much in the way of elegance, the welds are on the rough side. All of that however doesn't do anything to diminish the way these bikes look and more importantly they way they ride. By the time this and the later bikes were made they were much more than trials bike and turned into very capable mountain bikes. Their roots were still in technical riding, but Doug's experience over the years resulted in a well rounded design that could tackle most terrain with light footed surety.

These bikes are really pretty amazing pieces of mountain bike history. They represent a spirit of freedom and adventure, and are built with a degree of performance that enabled the lucky few who had a chance to buy one access to the outdoors and to ability to partake in that adventure. Personally the Bradbury Manitou is one of my favorite bikes and I consider myself infinitely lucky to have found one in my size and appreciate each and every outing I have on it.