Saturday, November 12, 2016

1992 / 93 Bradbury Manitou FS

Most fans of vintage mountain bikes are familiar with the Answer Manitou FS series of bikes. Built under license from Doug Bradbury starting in 1992 it was one of the more iconic bikes of the 90s. Fewer people will know that prior to Answer building the Manitou FS Doug made a small batch of these bikes out of his Colorado Springs shop. Made by hand and carrying many of the custom features developed on his hard tail bikes the Bradbury made Manitou FS is quite a unique machine!

Starting with the first prototype in 1991 Doug built approximately 60 of the FS bikes culminating in a small batch in 1993. I believe that the bike featured here is one of those last ones built in 1993 and represents the culmination of the design. You can see my writeup on the original prototype here : The main difference between the Answer made bikes and the Doug made ones is that like his hardtail frames they use a 145mm rear hub with an asymetrical rear end to enable the bike to use a dishless rear wheel. The front fork on this particular bike is a somewhat customized Answer Manitou 2 (Doug stopping making forks in 92) with 105mm hub spacing and a Titanium threadless steerer.

If the 90s era of mountain bikes was defined by CNCd components then this bike is the poster boy for the generation. Aside from the Shimano parts, the tires, seat and grips virtually every single component was made on a CNC machine.

Offset rear dropout required to fit the massive 145mm rear wheel.

Shimano M900 rear hub spaced out to 145mm using a custom made spacer pressed onto the hub flanges and a tandem rear axle.

Doug was well known for making stems for his bikes starting way back in 1988. The vast majority of the stems were the 1" quill version transitioning to 1 1/4" in late 1991 as he started using Easton tubing. At the very end of the run he made a handful of threadless versions of the stems, but for the most part they never really made out into the hands of the customers. This is one of three stems he had hung onto, and was built for this specific bike and fork combination. A rare piece indeed!

Unfortunately these and the later Answer made bikes were very prone to cracking, especially at the headtube. While ultimately this was a attributed to the strength of the Easton Variolite 7005 series tubing, exacerbated by too tight of a tolerance between the headtube and headset. In order to preserve this brand new frame I reamed out the headtube to create a 0.003" interference fit for the Chris King headset. As the bike was made interference was closer to 0.018", which when you think about would put tremendous load on the thin headtube and helps explain why some of these bikes were inexplicably cracked although they were never actually ridden!

Unlike the earlier 91 and 92 Easton made frames from Doug the late 92 and 93 made frames do away with the gusset at the head tube and top tube junction.

While I debated putting an original Bradbury made fork on this bike, Doug had selected this actual Answer Manitou 2 fork for this bike. Both the frame and fork (and stem actually) were labeled with the name of the French distributor for whom this bike was built, but never delivered. So, I decided to keep it as it was intended. Ultimately I found a custom made hub that fit the fork perfectly and so the entire package is as it was meant to be.

Custom made Manitou front hub spaced to 105mm to fit the custom Manitou 2 fork.

The upper rear pivot on the Doug made bikes is smaller than the production Answer bikes. Both use a Delrin bushing with a Stainless Steel sleeve, but the Doug made bikes have a smaller OD sleeve. The upper swing arm brace on this bike is a jewel of a machined piece. Fully hogged out of a solid piece of Aluminum billet it is represents the pinnacle of the design and is virtually identical to the production Answer made bikes. 

If it wasn't fully obvious the rear suspension on this bike is literally a Manitou fork with pivots swapped in for dropouts and a different crown that enables the assembly to pivot. The internal elastomer stack is virtually the same as fork, just a little bit shorter. The rear derailleur cable goes through a slot near the brake boss and then through a movable cable guide at the lower pivot location

The lower pivot and swingarm are also the most advanced versions of Doug's design differing from the earlier concepts by the degree of machining used for weight reduction.

Keeping up with appearances the cockpit is full of CNCd goodies from Grafton including Speed Controller brake levers and shifter perches used to mount the M900 XTR shifter pods.

The list of CNCd parts continues with a custom front derailleur clamp for the Shimano XTR front derailleur and a massive 31.8mm seat post with a head out of a Ringle Moby post.

There just are no bad angles for this bike, and I for one do not get tired of looking at photos!!

Growin up I had a poster of the first generation of the Answer Manitou FS hanging up in my room. That was T-H-E bike to have and at the time it seemed beyond unobtainable. Thinking back I didn't even think Doug made more than a couple prototypes of the design and to this I've only ever seen two to three of these in the wild. So, it's simply a dream come true to have had the opportunity to work on this project and be able to be able to hold one of these bikes in my hands. While this bike is not staying with me I am working on restoring the original prototype and hope to be able to put some miles on that bike!

Wednesday, November 9, 2016

1983 Mantis XCR

The 1983 fillet brazed Mantis XCR was a bike essentially lost to time. Until a few years ago there wasn't even a single example in the hands of collectors and aside from a bike rumoured to be located in an annex of the Shimano museum in Japan nobody had even seen one. According to the Mantis catalog the fillet brazed XCR was only built for one year, and was subsequently replaced by the composite (Aluminum/Steel) version of the bike most of us are familiar with. After speaking with Richard he implied that he only built 7-10 of these bikes during that first year, at this point five of these rare bikes have been found. Based on the serial numbers there could be up to 9 bikes out there so maybe a few more remain in the wild. 

The rarity factor of this bike is perhaps only undone by the fact that from a distance it is virtually indistinguishable from the Sherpa which is a somewhat more common of the early Mantis bikes. The two bikes only differ by the slightly more aggressive geometry of the XCR, 17" chainstays vs. 18" on the Sherpa and a longer standard top tube for a more racy feel. Apparently both the Sherpa and XCR share dual 72/72 degree head tube and seat tube angles, something I thought was not the case. Other small changes include removal of any extra braze ons and rack mounts on the XCR as it was built to be a racing rather than touring bike.

One the more alluring features of both the XCR and Sherpa are the ridged fillets along the junctions of the main triangle, most notably on the top tube. These fillets really showcase RCs craftsmanship and the attention to detail that he put into his bikes.

This particular XCR is original survivor that seems to have not seen much use, which is good as I've heard that both the XCR and Sherpa were somewhat prone to failure if ridden hard. Aside from a few part changes the build is virtually 100% original and as RC would have spec'd it back then.

Unique to early Mantis bikes are the Mantis S-1 stem featuring a cool triangular faceplate with internal cable routing, a Mantis Aluminum handlebar, custom seat post made by Richard by taking a Shimano DX BMX seat post head and pressing it into a longer 26.8mm Aluminum shaft, and a custom 2x drivetrain accomplished by modifying a Campagnolo Strada track crankset by adding a granny gear. For reference this bike originally came with a set of Specialized triple cranks (flag cranks) which were an option, but I felt the Campy cranks looks much cooler.

Side view of the ridged or raised fillets, really makes for a smooth transition between the tubes.

Here you can see a bit more detail on the ridged fillet on the top tube to head tube junction.

The steam is really a piece of work, I suppose RC could have fillet brazed it as well, but in a way the raw welds give leave the spotlight on the frame and form and in that regard complement it well.

Very few of these Bi-Plane forks survived actual off-road use and so it's an added bonus that this bike still has the original fork, which coincidentally has a matching serial number to the frame.

Phil Wood hubs, laced to Durex Ambrosio rims completed with Campagnolo quick releases, quite the setup.

I opted for Tomaselli levers on this build in lieu of the more common Magura levers, I guess I just prefer the look of these levers. Suntour XC shifters round out the cockpit controls, no index shifting here!

The Suntour Mountech rear derailleur is one of the most complicated and yet poorest performing rear derailleurs of the era. I can't imagine how that thing works in the mud, under load in race conditions. Then again, nothing really worked that well back in those days and I suppose that's a part of the charm, isn't it?

Bit more detail on the custom Campagnolo cranks, shifting on this bike is a combination of Russian roulette and a contact sport. I'll take the penalty on the plastic top clips, just not a huge fan of the metal ones.

Building this bike back up has been a real treat and offered me a insight into the pre-index world I hadn't had before. I've taken it out on a couple leisurely rides and can't say I expect to give the bike a proper ride test. While it is absolutely rideable off road, it's not really a bike that I want to abuse. I hope to find it a nice display location somewhere and let others see what an early bike from Southern California looked like. So much focus is on the NorCal bikes these days, I feel that providing a good counterpoint on the parallel developments would do well to round out the whole story.