Monday, June 25, 2018

1989 Mongoose Titanium John Tomac signature by Merlin

I never really heard of John Tomac until he shocked the world by racing a carbon Yeti prototype with drop bars at the 1990 UCI World Championships. I suspect that was the case for many others. However, before JT donned the neon yellow jersey and the turquoise frame he had a successful career racing for Mongoose. First it was BMX, but by the late 80s he was racing their mountain bikes and carrying his own line of signature models. The top of the line IBOC John Tomac Signature Titanium/Steel composite frame was introduced in 1989 and featured a Titanium front triangle made by Merlin bonded to a steel rear end. At a glance this appears to be the same bike that Tomac was using to tear around on the race course... but in reality Tomes was slinging an all Ti version of the bike made entirely by the good folks at Merlin. The main difference between this bike and a regular Merlin is obviously the monostay rear triangle. The tubeset is pretty much the same as the Merlin Titanium of that time (1 1/4" TT, 1 3/8" DT, 1 1/8" ST) and the bikes actually carry Merlin serial numbers. The geometry is really the main difference with steeper 72 degree head tube as compared to 70-71 on the standard Merlin and a flat top tube (Merlin had slightly sloping top tubes).  Because these differences are subtle to the lay person and your average Merlin fan will relate the monostay design to the later Taiga model which was poised as an entry level Merlin, the Merlgoose as some of us have come to affectionately call it has for the most part been overlooked by collectors. The relative scarcity of these frames with only a handful produced means that it has largely remained hidden in obscurity. So, having this bike here in my shop is really a treat and I can't wait to throw a leg over it and see how it rides...

The build on this particular bike was not meant to be an exact replica of JT's Mongoose, but rather reflect some of the main design elements and component selections with a couple choice substitutions. I would have like a Tioga Tension Disk on this bike but wasn't able to source a nice enough one to complement the rest of the build. There is always room for improvement I guess.

I have to admit that seeing all these flashy decals on a Merlin is sort of strange. I've become accustomed to the traditional monochrome look of the majority of Merlins and this bike still throws me. That along with the more polished finish set the bike off in a way I'm not yet fully convinced I like.

But then there is that monostay, it's such a unique feature and I think it was among the first in Titanium.

A subtle sign of who's really responsible for this creation.

Even before JT officially joined Yeti's mountain bike team he was sporting their iconic straight blade fork painted in a classic red/white/blue livery.

Classic Shimano XT drivetrain never gets old on these late 80s bike. No matter how many I build I just don't get tired of it.

One of the main areas of departure from an outright Tomac replica is in the cockpit. JT was sponsored by Tioga throughout his career and rode the T-Bone stem and prestige bars. Even thought I had those options available for this build I never liked the Tioga stems and this Titanium Litespeed stem coupled with a Cook Bros Titanium bar works really well with the frame and in my humble opinion a nice alternative to a spec build. I suppose a Helfrich Titanium stem would be one even nicer option.

The symmetry of the monostay and seat tube are quite attractive from this angle. This is a really good looking bike. 

Pressed in bottom bracket was typical on the early Merlins. While it offered an sealed cartridge bearing it was a rather small unit which wore out faster than the 6003 series used in Kleins and since the BB shell was small there was a fair amount of flex under load.

That's quite a densely packed seat cluster, lots of welds in tight area.

I really like that shape of the monostay, it's ovalized in two dimensions and clearly that section of the bike took some time to design and fabricate.  The brake stop and Titanium cable guide integrate very nicely and the overall design really stands apart from other early Titanium MTBs. Litespeed and Fat Chance would build their own monostay Titanium hardtails but not for another 3-4 years.

I must say that the geometry of this bike makes the proportions look a bit squashed. I imagine it will be an active bike with a busy or twitchy front end. I'm not sure what the monostay will do for rear wheel track and overall stiffness but I would be surprised if it's a dramatic improvement over my regular 89 Merlin. 

Sunday, June 17, 2018

1992 IRD Stroker

The early days of mountain biking were chock full of strange designs and concepts. Over time many of these coalesced into what at the time was considered standard geometry, which itself evolved as the sport changed and took on new challenges. Most builders fell inline with those standards and tweaked small elements here and there to optimize the design but largely followed the same formula, as far as hard tails are considered anyways.

There were however those who did not. Among those radical nonconformists were Rod Moses and Ray Baldwin collectively known as Interloc Racing Designs or IRD. They were well known among the MTB community for their component designs including U-brakes, seat posts, stems, the first infinitely butted Aluminum handlebar and the worlds first remotely actuated dropper post!! But few knew that IRD made some bikes too. The lineup included the Strokers (full and semi), the Circuit Racer and the FS. You can't talk about IRD bikes without starting with the cranks. Sure they had insanely short 16" chainstays, 13.5" bottom bracket height, 25" top tubes, and 76 degree seat and head tubes (TBR)... but the cranks... the Sequoias of pedal arms!! I don't think you could get an IRD bike with anything shorter than 190mm and a few came with 230s! Yeah, think about that for a minute...

I mean, when you compare the cranks to the 25.5" top tube they don't look that long...

In talking to Rod you get the sense that he wanted to build a bike that not only climbed well but it made it easy on the body. He is not fond of the roadie mentality that you get a short 170mm crank and make it up in RPMs, "that's for people who don't value their knees" he'd say. He wanted a forward climbing position and leverage / torque for a smooth climbing machine. Although my seat time in this bike is limited thus far (and plagued by technical errors), I can unequivocally confirm that it does make climbing easier (full ride report coming in the future). The ultra short stays coupled with that much moment arm translate into a comfortable cadence up the steepest of terrain.

The frame is constructed of straight gauge aircraft grade chrome-moly with a 1 3/8" down tube and a 1 1/4" top tube. This makes for a relatively stiff and responsive front end. The rear is quite compliant, by design, with 3/4" chainstays and get ready for this 1/2" seat stays. The lack of a seat stay mounted brake bridge keeps things nice and soft. Finishing off the frameset is IRD's own RID race suspension fork with 1 3/4" of travel vertically and a solid 1/2" fore and aft. The post, bar and stem are all IRD as well.

The front fork has taken a bit of time to sort out as the original was damaged when the original owner rode into an ATM with the bike mounted on roof. Luckily I was able to source another fork and get the bike going while Rod attempts to repair the original. Front brakes are IRD Switchlock which represent an early attempt at linear pull brakes. What they really are is the most difficult brakes to set up properly. They demand brake levers capable of longer cable pull, something period correct levers don't quite afford. A modification I'll have to explore in the future.

The IRD stem (not macaroni in this case) is my 2nd favorite components made by IRD (posts are #1) and one of my favorite stems of all time. Solid yet lightweight with a wide bar clamp that distributes load evenly, it's on the the most desirable stems out there. The IRD bars are very light and offer a little bit of compliance, especially when you boost them to 27"...

The curves on this rear end are unlike most other bikes of the time. Both functional (tucks rear tire in tight under the seat) and highly aesthetic they give the IRD Stroker a certain fluidity from the back that is otherwise betrayed by the spartan main triangle.

Gorgeous rear entry dropouts allow for easy wheel changes and are one of the more eye catching design elements of the frame.

Reinforced seat cluster keep things tidy and clean at the top. About the only thing this bike is missing is the IRD Remote QR (RQR) which I'd install if I didn't have to drill out the seat binder to accommodate the larger diameter bolt, something I haven't quite gotten the cajones to do to this lovely frame just yet. Though, I must admit I spent a lot of my ride time stopping to adjust the seat height on the descents, an adjustment that took the bike from scary to downright hospitable.

Cranks for the IRD bikes were exclusively made by Bullseye because nobody else back then could make cranks that long. This particular bike has 210mm cranks which are not as long as some other Strokers out there, but definitely longer than most of the semis.

Zerq grease port enabled you to shoot some grease into the BB shell, and I guess maybe flush out the bearings... but given there were no guides to route the grease you literally had to fill up the entire volume of the shell before anything came out and that's just nasty...

I never liked these headsets, until I got one on this bike. Seriously, there isn't another headset on the planet that would look better here... that's a fact!

My second third favorite IRD component (#2 goes to the seatpost) is the IRD Rotary U-Brake. Unlike the Switchback this one is relatively easy to set up and dial in and while a bit grabby at first, once you get used to it is quite an effective means of arresting your momentum. This particular bike had problems with the straddle cable bottoming out on the cable guide. I tried a different brake with a slightly different anchor point which effectively moved the straddle cable back and it all works now.

For some reason this bike is missing the chain anti suck plate which would have been bolted to the brake stiffener plate. Something I'll have to remedy at some point. 

The rest of the build is rather standard Shimano Deore XT, which Ritchey brake levers. The hubs are laced to rather rare FIR rims. FIR is an Italian company better known for their line of road racing rims. But apparently they also made some high quality off road rims in the early 90s.

Again... love those dropouts!

I've really come to enjoy finding and getting to know these non traditional bikes. I think anyone can jump on a Yeti ARC, or a nice Ritchey or something and have a great time and say tired old cliches like this bike climbs like a scalded cat or it's really solid on descents or whatever. Often times that's all true, but it's true for most 90's hardtails that are worth their salt. Sure there are some standouts like the WTB Phoenix (have yet to try a steel one) and a few others, but I think there is so much uniqueness out there that begs to be discovered. So, while I think a Phoenix or Cunningham will be tough to beat for all around competence and quality, bikes like the IRD Stroker, Grove Innovations Hard Core and a few others pushed the envelope of design in one specific dimension and gave us something unique and exciting. I for one a excited about these footnotes in MTB history and look forward to getting some serious miles behind the bars!