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Old 09-17-06 | 02:12 AM
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maunakea
too many bikes
 
Joined: Feb 2006
Posts: 662
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From: Hawaii
The Mauna Kea bike

I was not happy with the sag in the forks of my DT VIIIFS. Don’t get me wrong … the DT FS is the absolute best 20” folder for the money, but I’m used to adjustable shocks (downhill, MTB, MX). Suspension sag is nominally 10% to 30% of fork travel (and shock travel), and the sag on the BMX suspension fork on the FS was about 80%, nonadjustable. The price/performance of the OEM fork is understandable … but the fork is designed for BMX bikes, and BMX rider weights. The bottom line is I realized that what I loved about the DT FS was the frame and rear shock … everything else could go. Everything but the frame and rear shock did go. I also wanted taller gearing … like 53/9, more length in the cockpit (I'm 6'2", 188 cm), and less handlepost flex.

I present the “Mauna Kea bike”, a DT FS frame with (see pix, I suggest the MnKea_Wh_Side.jpg pix first):

an adjustable, carbon fiber fork (MEKS, Hoosier Bicycle Supply), sag set between 10% and 30%, depending on ride profile; the MEKS fork is very popular on ‘bents. White Bros. fork is even better, but I paid $149 for the MEKS, and White Bros. start at $600.

threadless headset (necessary for the MEKS fork) (dremeled the I.D. of the top nut of Shimano STX headset to an al dente fit; a desperate builder’s trick, don’t try it at home; a compression ring and real threadless headset would probably work, but the MEKS steerer tube is smaller than nominal 1-1/8”)

sleevepost (sleeve handlepost) like a Swift or Airnimal (Aircraft Spruce, 6061T1 tubing, 1-1/8 and 1-1/4 O.D.s, 0.58 wall, homebrew; smaller tubing is stempost, larger tubing clamped to top of steerer tube and to bottom of stempost using seatpost clamps; inserted star nut in steerer tube, cut a section of the larger tubing to use as a compression spacer, cut the front off of an Icon stem ($1.98 from Pricepoint.com) to use as a steerer tube clamp; sleevepost slips off to pack the bike, a la Swift). Importantly, the stempost rests flush against the steerer tube of the fork, inside the sleeve. This makes the sleevepost very rigid, much more rigid than a folding handlepost, and much lighter. I plan to cut a 180 degree piece from the steerer tube, and the opposite 180 degree piece from the stempost, so that the two will fit together, leaving only the stem to stempost clamp as the source of play/adjustment between the bars and the front wheel.

double crankset (53/39) (175 mm crankarms, Nashbar/FSA, ISIS drive, with Shimano BB and Speedplay Frog pedals ... 1/4" wider than a folded, folding pedal, but with the advantage of cleated power)

front derailleur (Shimano R440, SRAM Microshift, homebrew cable hanger, inverted, on hacked FD hanger mounted on the bottom of the seatpost; flange of inside cage arm on FD dremeled to conform to DT swingarm to provide chainline clearance to largest cog from 39 chainring)

Dura-Ace 9-speed rear derailleur on SunRace RD hanger (biketoolsetc.com) and SRAM Attack shifter

Shimano Capreo hub and 9-speed cassette (9/26) (Harris Cyclery) on Velocity Razor rim (wheelbuild by J. Gaerlan), Primo Kevlar Comet 1.35 with 1.5 layers of 26” Spinskin, SRAM 9-speed chain

Shimano 105 front hub on Velocity Razor rim (wheelbuild by J. Gaerlan), Primo Kevlar Comet 1.35 with 1.5 layers of 26” Spinskin

Euro touring bars (Harris Cyclery) with SRAM 9.0 brake levers, and Nashbar inline brake levers on Nashbar barends with Lizardskins; Nashbar adjustable stem, loosen stem pivot bolt and fold bars against stempost to pack)

Nashbar and Promax V-brakes, KoolStop pads, Jagwire adjustable noodles, all cable housing replaced with Avenir, all cables replaced with Teflon-coated

Kalloy suspension seatpost, Vetta SL saddle

Finally, I have won the battle with the rampworkers at the airports here. That’s not black paint on the bike ... that’s truck bedliner (NAPA). When the bag tossers manage to chip bedliner (they do), I just dab some more bedliner on.

So…. the only original part is the DT frame.

Riding impressions
The bike is VERY fast and comfortable … smoother over bad pavement than a 700c Ti frame with CF seat stays. The Capreo hub is at least 105 quality, maybe Ultegra level. I didn’t think I would notice how much better the bike rolls, but after moving the Primos from the OEM wheels to the Velocity Razors, the difference is noticeable … feels like 1 cassette tooth faster for the same peddling input on the 53 chainring. The sleevepost flex when pulling near the rear of the bars is pretty much like that of a Swift, but when tucked in and pulling on the barends, there is understandably more flex, but still much, much less than the flex of a folding handlepost.

Almost as stable as my Swift, but more cockpit room due to the barends forward of the Euro bars, better ride than the Swift due to full suspension. The MEKS fork meant I didn’t need a Thudbuster, so I put the Thudbuster on the Swift and put a Kalloy suspension seatpost (adjustable preload, two rider-weight models with the split at 175 lbs; Biketoolsetc.com) on the Mauna Kea bike.

The 53/9 combination gives 117.8 gear inches, and the 39/26 gives 30 gear inches. Perfect for coastal roads and the climb to Kula.

For a lower end, e.g., like the Mauna Kea Observatory Access Rd, I put an 11/34 cassette on the OEM hub, Vredstein S-Licks, also with 1.5 layers of 26” Spinskins (I HATE flats, especially on tires that have PIA beads and need 200 psi to set the bead). Change rear wheel, change and adjust RD (Deore LX), and Megarange!, brought to you by the SRAM master link.

RD shifting is just as fast as on my road bikes. Shifting the FD to the 53 chainring takes care, since there’s an unused third position on the shifter … but the Microshift was the right price and definitely helps to tune the chainline. The rule about working outside to outside, inside to inside, between chainrings and cogs is critically important on this bike.

I feel I have a high end Bike Friday equivalent (or better) for 1/3 the cost.

Yan, what a terrific frame! I publicly beg for your FS frame made with Ti. On your next trip to Asia stop by for a test ride.
Attached Images
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MnKea_Inline_Brk_on_Horn.jpg (87.6 KB, 265 views)
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MnKea_BarsShftrsBrks.jpg (84.7 KB, 227 views)
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MnKea_RD_RDhanger_Capreo.jpg (83.8 KB, 259 views)
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MnKea_RiderView.jpg (98.8 KB, 254 views)
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MnKea_Sleeve_HndlPost.jpg (64.6 KB, 208 views)
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MnKea_SleevePost_Side.jpg (79.5 KB, 209 views)
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MnKea_Thrdless_Headset.jpg (47.9 KB, 390 views)
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MnKea_ThrdLess_MeksForks.jpg (99.6 KB, 321 views)
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MnKea_Wh_Front.jpg (86.0 KB, 208 views)
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MnKea_FD_CableHgr.jpg (97.2 KB, 177 views)
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MnKea_FD_Frogs_FSAcrank.jpg (96.9 KB, 278 views)
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MnKea_Wh_Side.jpg (87.4 KB, 830 views)

Last edited by maunakea; 09-18-06 at 01:57 AM.
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