August 30, 2012

Gravel Bike Build – Part 6

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It’s time for wheels and there is nothing showing up on Ebay, Craigs List, or the bike forums.  Well there have been a few, but they all involved some kind of compromises or another, so I always talked myself out of them.
Compromise is the word of the day when it comes to wheels.  When I started this build I figured I would throw on a set of cheap 29’er wheels and tires and call it good.  When the bike was together enough to do a trial fit I tried to install the wheels and tires from my Trek Superfly.  Not even close.  They are WAY too big to fit in the frame.  So I put my road bike wheels and tires on.  They fit fine with plenty of clearance left for bigger tires.  700 x 38c or 700 x 32c?
So maybe the place to start picking a wheel begins with the tires.  After reading a ton of reviews and tech specs and making some measurements.  I decided a tire between 32c and 35c was the best for my needs.  I also want tubeless.  ROCK racing has had awesome success with Schwalbe tires.  So I checked them first, and really like the looks of this Smart Sam CX tire: 

Since I am using between a 32c to 38c wide tire, the inner rim width of the wheel should be somewhere around 19mm wide.  The Sheldon Brown website has a great chart for tire sizes and rim widths here.

Most of the 29er wheels I looked at were 23mm wide, too wide for my use.   This made me start looking at road wheels.  Which seem to have a good diameter and rim width, but are almost impossible to find with a disc brake hub and nothing in a tubeless.  I also looked at a few wheels meant for comfort bikes, but they seemed too heavy, and again none were available as tubeless.
It was looking more and more like custom wheels was the only way to get what I wanted.  Custom wheels would totally blow my budget.  But just maybe with some careful shopping of clearance bins and on-line deals I could put something together.

So over the past couple of weeks I’ve found some deal and ordered:
(2) Stan’s Iron Cross rims – 32 holes.  I’ve had great luck with Stan’s wheels before, and I wanted tubeless for this build.  So it was perfect when I found these on sale with free shipping.  The rim width is 20mm and the profile and diameter are made just for CX tires.

(2) Shimano Centerlock XT disc hubs – 32 holes.  I read reviews and compared prices on a bunch of different hubs, Shimano seemed like the best compromise between price and quality.  I like the idea of the splined center-lock hubs more than the ISO 6 bolt hubs.  Here is a good list of the pluses and minuses of the centerlock design:  Link

(70) DT Swiss 12mm alloy spoke nipples.  I picked red, should go good with my frame.  I only need 64 spokes and nipples, but I thought if I screw one up or break one later, it would be good to have a couple of extras.

(70) DT Swiss double-butted spokes 2.0 / 1.8mm.  The double butted spokes are supposed to ride smoother, stay strong, and be a little lighter.  I ordered black.  It took a while to figure out spoke lengths but I finally found an Excel based spoke length calculator, that I used to get the lengths figured out:

So with everything ordered,  I am back to waiting for parts to arrive again.  Check back for Part 7 soon to see how many mistakes I make building my first set o wheels.

Part 5                                                                                                     Part 7

August 21, 2012

Gravel Bike Build - Part 5

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The Truvativ Elita 53 x 39 crankset is another part I have leftover from the old Giant road bike frame I sold a few years ago.  The Elita is a pretty decent crankset, anodized black aluminum and hollow forged, making it light and stiff.  Since I'm doing the 1x10 drivetrain, I don't need the 53 tooth outside ring.  I've read from several sources that single front rings have a problem with chains dropping off on bouncy or washboard roads. So I will install a lightweight aluminum chain guard to replace it.
To get the right guard you have to count the number of teeth in the chainring you will be using.  Mine is 39.  You also have to measure the Bolt Circle Diameter (BCD) of your crank.  Mine is 110 BCD.  There is a handy cheat sheet / measuring chart here

The guard I am using is made by BBG.  It is very well made, only 49 grams, machined from .0125 inch 5000 series aluminum and anodized black.  It comes with a lifetime guarantee for "bending or breaking no matter how you ride your bike". You'll see in the pics below that it ends up fitting perfectly.  Not bad for $14, and Made in America!

To remove the five chainring bolts from this style of crankset you need two hex keys, 5mm and 6mm.  These bolts are not your standard nut and bolt.  You have to insert one hex key from each side so they meet in the middle, then loosen them. 

Here's a good close up picture to show the bolts.  They are 2 pc, internal and external threads with internal hex recesses.  These bolts are another reason why the chainguard has to be added.  The grip length of the bolts only works for the thickness of two chainrings and crank.  Any change to that thickness would need new grip length bolts.  Adding the chainguard preserves that original thickness.

Rings removed

Reassemble with the new BBG part and a small dab of grease on each chainring bolt.

Torque each chainring bolt to 72 - 80 in lbs.

BBG chainguard installed.  Looks good.  The fit at all the crankset mating surfaces is perfect.  And more importantly the ring is flat and true.  There won't be any wobble while pedaling to interfere with the chain.

As a final check I laid out a short length of leftover 10 speed chain to check the clearance from 39 ring to BBG guard.  Looks like it is going to be perfect.

Some of the things I have been reading say that I will also need a chain keeper on the inside of my chainline.  I'm not sure yet if I will..  I'm thinking I will try it with just this outside ring first and see how it plays out.

Part 4                                                               Part 6

August 16, 2012

Gravel Bike Build - Part 4

I continued the build today by installing the bars and shifters.  I began by loosening the four hex bolts on the stem faceplate.   I was able to wiggle the bar through the stem with the bolts just loosened, didn’t have to fully remove them.  The bar I am using is just an old cheapie I had in the basement, taken off of Lori’s road bike when she upgraded to a wider more comfortable bar.  It is a Scott 42 cm ergo bend drop bar with a 31.8mm clamp mounting diameter.  My road bike has a 44cm wide bar, so this one will probably feel too narrow for me at first.  I will just have to wait and see how it goes.  While I was studying up on all the different bar choices I found a great guide for picking a new bar here:

With the bar in the clamp, I used the openings in the clamp face to line up the marks on the bar.  It is now centered exactly.  I also rotated it to a likely position, but that will probably be adjusted after some test rides.

The stem faceplate hex bolts were torque to 45 inch lbs while holding the bar in position.  I tried to use a rotating pattern and a couple midpoint torque values before tightening them all the way down.

I took a few measurements to make sure the bars were centered.

Slide the shifters over the ends of the handlebar until they are approximately in the position you want them.  Partially peel back the boot on the shifter to reveal the 5mm clamp bolt.  Use a hex key to start tightening with one hand, while holding them in position with the other hand.  Once they are tight fold the boot back down.  These will get moved around again later when I get brake and shifter cables.  Then they get final installed when I wrap the bars with tape. 

Back in part one I talked about how dependent all the part decisions were on this bike build.  I had decided that I wanted a 1x10 drive train with an 11-34 rear cassette.  To get a cassette that size means using a mountain bike rear derailer.  I already have a crash damaged/repaired SRAM X.9 in the basement, so that will work out perfect.  But SRAM derailers don’t work with Shimano shifters, they have different cable-pull ratio’s, so I had to find SRAM.  I was figuring on buying some low end shifters to save money when I found an advertisement for a ‘barely used’ set of Rival shifters.  I met the guy in a grocery store parking lot, and the Rival shifters were mine.  Score!  These things are in perfect shape, not even a scuff, like they were never used.  Got the pair for less money than the best deal I could find on-line for a single shifter.  I’ve never used SRAM road shifters before so their double-tap shifting will take a little getting used to.

Done - looking down

Next up is crank and chain-ring install.

Part 3                                                                                                                            Part 5