1983 Diamond Back Ridge Runner

A venerable steel frame hardtail mountainbike bike with a rigid fork, from the days before mountainbikes became exotic creatures. Nice lugs and painted "decals" set it apart from other decrepit mountainbikes. Part list is here.



This bike and this site were built by C. Heg
cheg01 at comcast dot net


History


This was an early generation mountainbike, one of the first Far East imports to compete with Specialized, Ritchey, etc. When I bought this bike, it had the following:

   Sugino AT Triple Crank with 26/36/46 Chainrings
   Suntour Perfect 5 speed freewheel with 13/16/19/24/27 cogs
   Sugino Sealed Bearing Bottom Bracket
   Diacompe Cantilever brakes and levers
   Steel Bull Moose Handlebars w/ Integrated Stem
   Selle Royal Centurion Saddle
   Suntour XC-II Beartrap Pedals
   Toe-Clips
   Suzue sealed bearing hubs
   SR Laprade Seatpost
   Suntour Mountech Front Derailleur
   Suntour Superbe Tech Rear Deraileur
   Suntour Power Thumb Shifters
   Specialized Crossroads Tires
   Blackburn Alloy Rack
   Tange Headset

   The bike served well as a commuter and mountainbike in the '80s and early '90s. I had a sail boat in those days and I used to lash it to the stern rail and take it to the San Juan Islands for transport and exploration. I went all over Orcas, San Juan, Sucia, Lopez, and Stuart Islands. The biggest excursion was taking it to Alaska in the lazarette a workboat when I was employed up there as a merchant mariner. I had some very memorable rides on the old military coast road in Yakutat and around Unalaska Island and Dutch Harbor. Here are a couple of pictures from near Yakutat, on the Lost River road:





   Most miles in those days were on the road, commuting to classes at the University of Washington in the winter. I lived on my boat and had no car, so this bike was my all-weather way to class. Fenders were a problem at first. I had to modify a plastic motorcycle fender for the front and that worked OK. Wide fenders became more available after few years and I put the aluminum fenders. I discovered that they had to come off for riding in the snow or they would build up ice in the inside until the wheels stopped turning.

   Weight was never a consideration on this bike. I was looking for absolute reliability. One of the few things that ever broke were the band clamps on the thumb shifters. I replaced them with modified stainless steel hose clamps bands, which are still good to go 18 years later. I can't think of anything else that ever broke. The bike was getting tired, though.

   The rear derailleur was a sort-lived Suntour experiment with sealed bearing parallelogram design and, unlike normal derailleurs, was direct pull (from the front) with the cable run through a little steel noodle brazed to the chainstay. It used non-standard chainguide pulleys and, as is often the case, "Sealed Bearing" means that you have to throw it away when it wears out. The rear derailleur was pretty much shot by then and the front derailleur never worked very well to begin with. All the spokes were very rusted, probably from too many boat rides. The front wheel bearings were toast, the wheel would rock back and forth a quarter inch with the axle nuts tight in the fork and the hub was "sealed" so not repairable. The old 5 speed freewheel sounded pretty bad. The tires were an early "hybrid" design, 2.25 inch knobbies with had a center ridge for riding on the road. They were pretty skittish in turns on the street because the knobs would come into the equation at unexpected times.

   I had to avoided the small-small combinations due to the limitations of the rear derailleur. It was always tricky to get the FD to shift down to the small chainring, forget about doing it under high load when you really needed it.

Regeneration

   For various reasons, the bike was not used much for about 10 years (OK, I was busy driving my car). Last year, I decided to convert it to a foul weather commuter with better components. It's age was showing and technology has improved somewhat in 20 years.

   The new bike is more or less built around the tires. The Maxxis Hookworm is a 2.5" semi-slick designed for downhill riding on hardpack. They are very heavy but also very smooth rolling and puncture resistant. I also put on Maxxis downhill inner tubes, which weigh about a pound each by themselves. I was not entirely sure that a 2.5" tire would fit in between the chainstays on this bike but they were fine once I spread the rear dropouts for the new wheel.
   When I was building up my Folding Bike I bought a mixed lot of parts on ebay that included a pair of Sram 9 speed Grip Shifters and a Shimano Deore XT Rear Derailleur. I decided to put new wheels on the bike and a 9 speed rear cluster. I picked up a pair of Sun CR18 Rims with 9 speed Shimano Deore LX hubs for about $80 and a Sram 9 speed cassette for $25 on ebay . Since I was not planning to use it as a mountain bike, a bit more rise on the handlebars was in order. I bought some aluminum BMX riser bars and a Kalloy adjustable quill stem at a bike shop closeout. I have finally switched to SPD clipless pedals, so I switched the old beartraps for a set of Shimano M-515 pedals. The headset, crank, and bottom bracket are original.

   One unexpected problem that occured is that the rear tire interferes with the chain when the inner chainring is used with the two largest rear cogs, which makes the inner ring pretty much useless. I just took the inner ring off and now use the crank as a double. Since my largest cog is now a 32 instead of a 27 I didn't loose much range, and I don't really need a 25" gear for riding on the road anyway. That also solved the FD-can't-shift-to-the-inner-ring problem, but not the way I expected. Below is a comparison of the old and new gear charts:

Original Gear Chart
Cog Sprocket Gear Inches
13 48 96.0
16 48 78.0
13 36 72.0
19 48 65.7
16 36 58.5
24 48 52.0
132652.0
19 36 49.3
27 48 46.2
162642.3
24 36 39.0
192635.6
27 36 34.7
24 26 28.2
27 26 25.0

Current Gearing

Gear Chart
Cog Sprocket Gear Inches
11 44 110.0
12 44 100.8
11 36 90.0
14 44 86.4
12 36 82.5
16 44 75.6
14 36 70.7
18 44 67.2
16 36 61.9
21 44 57.6
18 36 55.0
24 44 50.4
21 36 47.1
28 44 43.2
24 36 41.3
32 44 37.8
28 36 35.4
32 36 30.9

I also switched from the beartrap pedals to a set of Shimano M-515 SPD pedals. The saddle was traded for a very comfortable Velo VL-6031 elastomer suspended saddle. Part list is here.

Here is a picture of the bike without fenders and rack, with the old shifters and pedals. Looks like the tires outweigh the bike...




COMPONENT DESCRIPTION
Frame&Fork 1983 Diamond Back Ridge Runner
Headset Tange 1" Threaded
Handlebar Alloy riser bars
Stem Kalloy Adjustable 1" Quill
Shifters Sram Half-Pipe Grip Shifters
Brake Levers Diacompe
Brakes Diacompe Cantilever
Seatpost SR
Saddle Velo VL-6031 Deluxe
Front Derailleur Suntour Mountech
Rear Derailleur Shimano Deore SGS
Rear Hub Shimano Deore LX
Cassette Sram 9 Speed: 11/12/14/16/18/21/24/28/32
Rims Sun CR18
Front Hub Shimano Deore LX
Bottom Bracket Shimano UN52
Crank Arms Sugino AT, 175mm
Chain Rings 44/36
Chain Sram PC 89
Pedals Shimano M-515 SPD
Tires Maxxis Hookworm, 65 psi
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