Thursday, March 8, 2012

Thurs-ti...

What's this? Four days this week so far and four posts? Let the roll continue with some titanium on this Thursday. This Merlin came to the shop a while back to get a new Steve Potts Type II fork. The plan was to also convert it to a single-speed bike. When it came in, it had a heavily customized RockShox Judy fork. Customized in that the lowers were carbon fiber and it had a very cool carbon brake bridge. The problem with this is the frame was made well before suspension forks hit the market and replacing the original rigid fork with a much taller suspension fork produced "chopper-like" handling.

A plan was hatched. The owner was happy with the location of the bars in relation to the seat with the taller fork. The Judy has a bolt-on crown which allowed me to drop it down the stanchion tubes and replicate the position of the new, proper length, Type II fork. Then we could create a new stem position with a Salsa fit-finder adjustable stem that matched the current fit.

After getting all that dialed in, we came up with a stem that needed to be 25 degrees x 150mm. I took the stem dimensions to Steve Potts for a new custom titanium stem. It just so happens that 25 degrees is the maximum angle Steve can create based on the extension tube diameter and the height of the Paragon Machine Works stem parts.

Fast forward several months now and all the parts are ready. The changes to the bike, in addition to the Type II fork and ti stem, included adding a front Avid BB7 disc brake, the new Jones cut H-Bar, Paul Love Levers, new King ISO disc front hub and overhauled rear King Classic hub laced to Velocity Synergy rims, 34t Salsa ring, Soulcraft chain tensioner, and a new Phil Wood bottom bracket axle.

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The before picture (it's the one in the front).

Merlin single speed
The after picture (the steerer was trimmed with 10mm of spacers under the stem).

Type II
New Type II fork with Avid BB7 disc brake.

Chainline
Soulcraft chain tensioner. We could have gone with a White Industries Eno Eccentric hub, but the bike already had the King hub and fixing the hub in one location means the brakes are always dialed perfectly to the rim.

Jones Potts
Potts stem with the Jones bar.

Paul Jones
Jones H-Bar with Paul Love Levers for canti brakes. More on the brakes - the rear brake is a WTB Speedmaster roller-cam brake which requires the cable pull of a canti lever. This brake was paired with Avids BB7 road disc caliper which has similar cable pull requirements to the roller-cam.

Cook Bros Racing
Cook Bros. Racing cranks in single-speed mode. The original bottom bracket axle was 128mm. This gave a much too wide chainline. I replaced it with a Phil Wood 17mm x 113mm axle to get a really dialed chainline and a much narrower crank q-factor.

Soulcraft
Soulcraft tensioner and a King cog.

Fresh bearings
There's a couple of fresh bearings newly pressed into the bottom bracket shell.

(What's playing: Louden Wainwright III Number One)

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