1990 Kestrel MX-Z
Part Diary, Part Technical Manual, Part Tips & Tricks

I've been fascinated by the e-stay mountain bikes of the 90s and had just started building up the Nishiki Pinnacle I bought a couple years ago. The Kestrel MX-Z was always a bike I kept an eye out for, because I love the early monocoque Kestrels and its an e-stay design as well - two birds with one stone. So I came across this bike from its original owner in Half Moon Bay. He had worked at Medical Composite Technology (MCT) in Santa Cruz, who was started by two of the founders of Kestral, after they sold the company to Schwinn. They had used the same advanced carbon fiber technology they developed for bicycles and applied it towards wheelchairs. So somehow through the connection, he had this MX-Z and later on a CS-X model as well. He says he only rode this bike a few times and its been hanging in his garage ever since. It was exactly the version I wanted, with the grey Zolatone finish and the matching steel rigid fork. So on February 6, 2016, I picked up this MX-Z, which will be a great sister bike to my 4000. Both were cutting edge, first to market, monocoque carbon fiber bicycles that ended up having a profound impact on the bicycle industry.

2/7/2016 - I spend a bit of time cleaning up the bike, adjusted the stem and seatpost. I noticed the headset was very loose, which caused the front brakes to squeak like crazy. So after adjusting the headset properly, the bike rode solid and the brakes became silent. The size of the bike fit me just right and the ride quality was really good. The over engineered carbon fiber frame makes the bike very quiet and feel very solid. I'm amazed the 26 year old Ritchey tires are still supple and ride just fine.

2/15/2016 - I didn't like the San Marco saddle, so I put a Turbo saddle on it. I spent a lot of time today cleaning everthing up, the crankset, chainrings bottom bracket, pulleys, cassette, and chain. I also installed brand new inner tubes as the original ones were ancient and crusty. So the bike is about as good as I can imagine, the only thing missing is a Ritchey Force stem, but I need to ride the bike a bit more to determine if I need a 120 or 130mm.

3/6/2016 - Went out for a ride between rainstorms. The Zolatone textured finish is like primer so dirt, dust, and mud clings onto the frameset with a lot of tenacity. A couple weeks ago I installed all new brake and shifter cable housing, as the original ones were not installed properly, so that part got sorted nicely. But the shifting has been a little off and I finally realized what happened. The 7-speed shifter actually has 8 index clicks, so the bike had 8 clicks spread over a 7-speed cassette. So at either extreme the bike shifted fine, but in the middle of the cassette, the bike would hunt between gears. So I adjusted the low limit screw to dial out the 8th click. After I took the slack out of the shifter cable, the 7-speed drivetrain now shifts perfectly as it was designed to do.

4/1/2016 - The stem that came with the bike always bothered me, it was so upright and bulky looking, so I finally found a Ritchey Force stem in black and installed it. The stem as a cantilever brake guide, so I removed the cable guide that was part of the headset and installed a couple spacers instead. The bike looks a lot better now, a lot racier. While fussing with the bars, I installed a new pair of grips as well. Although the original tires had plenty of tread left, the sidewalls were dried out and crumbling, so I installed a fresh set of Velociraptor tires. These changes resulted in a 7 oz weight increase. It feels like the bike is about done now, setup the way I like, now I just have to ride it.

Here are the specs:

Frame: 1990 Kestrel MX-Z, 20.5", monocoque carbon fiber with Spectra, 133mm rear spacing. Serial Number: 24109. Grey Zolatone.
Fork: Tange Prestige fork with lugged dropouts, 1" threaded. Grey Zolatone.
Front Hub: Shimano Deore DX HB-M650, 32H.
Rear Hub: Shimano Deore DX FH-M650, 32H.
Rims: Ritchey Vantage Sport, 32H, silver
Tires: WTB VelociRaptor, 26" x 2.1", folding bead.
Cassette: Shimano 7spd, 12-28T.
Cranks: Shimano Deore FC-MT60, 46x36x24, 175mm, 110/74 BCD. PD date code = 1991 April.
Bottom Bracket: Shimano D-3NL, 122.5mm spindle. PB and PC date codes = 1991 Feb and March.
Front Derailer: Shimano Deore DX FD-M650, bolt-on. OJ date code = 1990 October.
Rear Derailer: Shimano Deore DX RD-M650. PL date code = 1991 December.
Brakes: Shimano BR-M650, cantilever. OJ and OK date codes = 1990 October and November.
Brake Lever: Dia-Compe SS-5.
Shifters: Shimano Deore top-mount, SL-MT62.
Headset: Shimano Dura-Ace HP-7400, 1" Threaded.
Chain: Shimano Hyperglide (HG), Narrow.
Stem: Kalloy, 35 degree rise, 1" threaded, 130mm, 25.4mm diameter. Silver.
Handlebar: Kestrel Carbon, Filament Wound by Advanced Composites, 58 cm. Natural black carbon fiber.
Grips: Forte Team MTB, black.
Pedals: Shimano PD-M520 SPD, black.
Seatpost: Ritchey, 27.2mm, black.
Seatpost Clamp: Shimano, quick-release.
Saddle: Selle Italia Turbo, black.

The bike originally weighed 27 lbs 11 oz, the bike currently weighs 27 lbs 7 oz as shown.

The following are OE parts that I am currently not using:

Tires: Ritchey Megabite 2.0 Over Drive, 26" x 2.0", wire bead.
Grips: Tioga Biogrip, black.
Pedals: Shimano Deore XT PD-M735. OL date code = 1990 December
Saddle: Selle San Marco Professional, mfg 1990. Black.
Water Bottle: Shimano AX Aero. White.