Thursday, September 19, 2013

1984 Miyata Ridge Runner revamp

The Ridge Runner in its revamped form.
There has been a dearth of posts around here, which is usually accompanied by a surfeit of goings-on, as has been the case recently. Fortunately, my readership likely numbers in the single digits, so few, if any, have probably noticed. In any case, this latest installment outlines the recent rebuild of my 1984 Miyata Ridge Runner.

For years, I pined for my first Miyata; my original mountain bike that I had stupidly sold long ago. When I found a Ridge Runner as a replacement earlier this year, it was mostly stock, and had been seemingly unused for much of its life. As it turns out, lack of use is both a good and bad situation when it comes to the longevity condition of a bike. It took me some time to take the Ridge Runner apart, inspect it, and put it back together. Along the way, I rebuilt everything that could be rebuilt, and even so, had to substitute several items for those that were no longer up to par.

Join me now, on a whimsical adventure as I strip the frame and reassemble it, as only an old bike nut can.

First sign of trouble. The bottom bracket exhibited considerably less than free rotational action. At about this point, I began to wonder if only old timers like myself still possess semi-obsolete bottom bracket tools such as this. 

That is 29 years worth of old, waxy grease that no longer has any lubricating value. Difficult to spot in this photo are the tiny fragments of metal embedded throughout. You got it, a shattered bearing.

On the positive, inside the frame was clean and without any sign of rust.

My suspicions were borne out after cleaning the spindle, when the drive side race was clearly pitted. One of the ball bearings had mostly disintegrated at some point in the distant past, and its fragments subsequently chiseled away at the race.
Next up was the rear derailleur. The upper pulley of the SunTour MounTech derailleur had a thick wad of waxy grease and an impressive quantity of embedded hair wrapped around it. I don't know why, but hair often ends up in pulley wheels. 

Having things apart allowed me to confirm, as suspected, the frame features SunTour dropouts.

I cleaned the derailleur thoroughly. I have some experience with this era of SunTour derailleurs, which have an extra spring-loaded pivot housed in the center of the upper pulley which is incredibly difficult to service. The pivot is more than likely to explode if an attempt is made to open it. 
I cleaned the derailleur, but could not get the upper pulley to spin freely without an obvious feeling of gritty, impeded movement.  In the end, rather than destroy the MounTech derailleur in an attempt to make it serviceable, I decided to use a different derailleur. In the old days, most of the SunTour Mountech derailleurs from 1983 and 1984 were replaced under warranty anyway, so a replacement is in keeping with the practice of of this era. Apparently, the MounTech design worked well under perfect conditions, but was finicky and fragile. If you're interested in learning more, there's a good article about it here, and frankly if you've read this far, why not?

I have few spare SunTour derailleurs, so the first I considered was the Cyclone M-II.
The first SunTour rear derailleur that I considered for using on the Ridge Runner was a Cyclone M-II; a design that was produced between about 1982 and 1985. The one I have is in pristine shape, and has a sculptural smoothness and feeling of quality that no longer exists in mass-produced mechanical devices. It really is a beautiful piece of machinery, almost jewelry-like in its detail and sophistication. The Cyclone M-II is more finely engineered and crafted than most high-zoot watches I've ever seen.

However, the Cyclone M-II not quite right for my Ridge Runner. I don't intend for this bike to be a museum item, and it would be a shame to beat up the Cyclone off road. Moreover, it doesn't have quite the chain capacity that I need, so I dug a little more in my parts bin. I located a set of circa 1985 SunTour XC Sport 7000 derailleurs. The rear would likely have been of the sort used for warranty replacement of a faulty MounTech derailleur. Perfect. Incidentally, it was somewhere around this time that SunTour transitioned to being spelled Suntour, with the lower case T.

SunTour (Suntour?) XC Sport derailleurs.

Presto! The same derailleur, suddenly clean, through the magic of the internet.
While cleaning the frame and parts, I found some cryptic indicators denoting era of manufacture, further underscoring 1984 as the year of production of the majority of the parts on the bike. I couldn't help but think of the dates I found in relation to the events of my life at the time. Ninth grade. Not an entirely happy time for me. I suppose any year in which Ghostbusters and Star Trek III came out wasn't all bad, though.

The super clean Dia-Compe brake levers are inscribed "0184", likely month and year of manufacture

The end of the Nitto bullmoose bar is stamped "Cr-Mo" and "R-R", possibly meaning the bar design was specific to the Ridge Runner. Who knows? 

The "M" in the serial number signifies 1984, but I have no idea how to interpret the rest of the number. Yep, no chain marring here, baby.

Clean and temporarily devoid of parts.
Once I'd finished cleaning and inspecting the frame, fork and parts, and deciding what to reuse or replace, I began the task of putting it all back together. I like to assemble bikes, and took my time doing it just the way I wanted. That said, my goal was to keep with the spirit of the bike, if not always the precise year of parts for those items that couldn't tenably be used for anything amounting to actual off-road riding. Of course, I filed away all the original parts in my shop, just in case.

I've been wrapping the drive-side chainstays of my bikes with tube strips since 1988, and I'm sure others were doing it well before me. It's how I generally begin a build.

That's a Park Third Hand tool, a Park Fourth Hand tool, and a 10 mm wrench simultaneously used to adjust the front brake. As much as I like old bike stuff, I'll take the much simpler adjustment of Avid BB7 disc brakes over this any day.

The original bottom bracket was pitted and unusable. However, as it was an astounding 135 mm wide, I didn't have any replacements wide enough to enable the original Sugino AT cranks to clear  the chainstays. Therefore, I sourced the logic-al successor to the Sugino AT, a 1990 Ritchey Logic crankset made by Sugino. A Shimano UN-71 cartridge bottom bracket spins it all nicely.

Standing in for gear-changing duty, the Suntour XC Sport rear derailleur looks quite squared-away on the bike.  Minimal use or not, after 29 years, a new chain was in order. The chainstays are so long and the largest cogs so big that I didn't need to remove any links to achieve a proper fit. 

The Ridge Runner was originally spec'd with some sort of ergonomic grips, which are long gone. Ergon GP-1 grips are my current favorites, and blend in well. SunTour Power ratchet shifters are a joy to service and rebuild. Modern shifters don't come anywhere close. New cables and housing all around, of course.

Another stand-in are the wheels; Mavic M6CD rims on Deore XT M730 hubs that I had built in 1989. These wheels have been used very little in the past 24 years and the rims are nicely wide. The original Araya rims on SunTour hubs have bone-dry bearings and await me to repack them when I get a little more time. In the mean time, you gotta love the '80s Mavic graphics.

For rubber, I went with a pair of new, fat WTB Weirwolf 2.55 LT tires. I know, I know. For historical accuracy I should've used something with a skinwall. However, good skinwalls are hard to come by, and I want to actually ride this bike. The Weirwolf has a nice rounded profile with shortish knobs, similar to early mountain bike tires, and is about the fattest tire that will fit this bike. I've always used the fattest tires I've been able to find, and I'm sure the same would've been the case in 1984.
The present iteration of the Ridge Runner is finished, and I'm eager to get it out in the dirt. In the couple of short rides I've taken so far, the refurbishment has felt great. The bike feels like it is new, and I can tell it's got a lot of adventure left in it.


  1. Glad to see you back at it, and well worth the wait. We have finally arrived.... needed a wheel re-build and since I don't have a truing stand or the time, dropped off my wheel at Salvagetti, fantastic shop.

    Looking forward to seeing you on trail some time in the future.

    1. Welcome to Colorado. Salvagetti is a great shop and well worth visiting. When you level out from the move, we'll have to see about meeting in the real world.

  2. I have exactly the same bike and presently my rear derailleur (Mountech GTL 5500) tension coil spring snap in half. If you still have your old derailleur and don't mind to get rid of it I'll put it in use.