Tuesday, April 26, 2011

Cross frame crank compatibility...

Being out of the bike industry insider club for several years, I missed the regular technical updates from Shimano and SRAM. The pages that make up these manuals are a bike designer's bible. When I designed the chainstays of the cross frame, I used what I had and thought I had all my bases covers so that a road compact crank would be compatible with the cross frame.

Well, I got it almost right. I physically checked the frame by installing compact cranks with external bearings from both SRAM and Shimano. External bearing cranks have no left/right adjustability with regards to chainline, arm clearance, ring clearance. Bearings go in. Cranks go on. Done. So I installed cranks from both Shimano and SRAM and thought - good, they fit.

Doh! I didn't check the new Shimano 105, Ultegra, and Dura Ace compact cranks. It seems their arm stance is narrower than their Tiagra compact or R600 compact cranks by enough that these cranks are not recommended on the Black Mountain Cycles cross frame.

Check out the chart below and notice the dimension W5. Here are some cranks and their respective W5 dimensions for reference.

SRAM Red, Force, Rival, Apex, S900, S500 compact doubles: 60.0 to 61.0mm (okay)
Shimano Dura Ace FC-7950 - 57.2mm (too narrow)
Shimano Ultegra FC-6750 and 105 FC-5750 - 57.6mm (too narrow)
Shimano Tiagra 4550 - 59.5mm (okay)
Shimano R600 - 61.0 (okay)


In summary, Dura Ace, Ultergra, 105 compact cranks - not compatible with my cross frames. Any others are good to go. Sometimes compromises need to be made to fit those fat tires. I'm not sure about the compatibility of the previous generation of Dura Ace, Ultegra, 105 cranks, but will try to squeeze the info out of Shimano.

EDIT 3/16/16 - As of the second version of frames, the chainstay shape was changed from a straight stay to an s-bend stay and there is no issue running any Shimano, SRAM... crank on the frames provided the ring size does not exceed 50/34 or 46/36.  Triple cranks are no problem on any frame.  Square taper cranks are no problem on any frame.

(What's playing: KWMR Musical Variete and some Albert King)

Don't wait, get your frame now...

Finally got the last frame sizes weighed and noted. Frame weight is a somewhat minor factor in my list of parameters for a bike. The most important factor is ride quality and I do have to say my frames ride really damn good. Anyway, here's the frame weights weighed with water bottle bolts and seat collars as recorded by my Park digital scale.

Road frames
50cm: 3lb. 13oz.
53cm: 3lb. 15oz.
56cm: 4lb. 1oz.
59cm: 4lb. 4oz.
62cm: 4lb. 6oz.
Fork with uncut 300mm steerer tube: 2lb. 2oz.

Cross frames
50cm: 4lb. 6oz.
53cm: 4lb. 8oz.
56cm: 4lb. 10oz.
59cm: 4lb. 12oz.
62cm: 4lb. 14oz.
Fork with uncut 300mm steerer tube: 2lb. 5oz.

(What's playing: KWMR Musical Variete)

Saturday, April 23, 2011

Have you ever seen the first one...

You know. Like the very first bottle of Stone beer. The first Chuck Taylor Allstar shoe. The first bike frame made by Steve Potts. I don't know where, or even if, the first two exist, but the third one has been taking up residence in my shop for the past several weeks. Steve made this in 1981 or 1982 for a close family friend. It is the first frame he made after he returned from a mountain bike trip to New Zealand with Joe Breeze where he decided he wanted to convert his considerable metal working skills into making bike frames.

Looking at it from a technical standpoint, there's nothing really special about it. It's simply a nice fillet-brazed frame and fork. The paint is shot. There's rust showing through the paint. The steel on the components are corroded. But it's the first one of thousands of frames. And it's still around and still going to be ridden by its octogenarian owner. Steve brought it to me to get it into rideable condition, which basically meant replacing cables and putting on some new tires.

Numero Uno (with one from the early 90s in the background)
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The custom headbadge of SP-1 with the owner's initials and an icon to his heritage.
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When you're in your 80s, you can run whatever bar setup you want.
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(What's playing: A little J.S. Bach on KWMR)

Thursday, April 21, 2011

So what do you really get...

I was perusing my usual morning web browsing of cycling sites with my coffee this morning when I had one of those moments that makes you go "huh?" and scratch your head. Now, honestly, I do know the reasons, but that still doesn't make any difference.

So here's the deal. Reading bikerader.com's story on Easton's new carbon mountain bike wheelset got me thinking "can you buy a carbon framed 29" wheel mountain bike for $2600 (the cost of the Easton wheels)? You know, the whole bike complete with gears, not a single-speed. The whole bike with a suspension fork. The whole bike with its own 29" wheels and tires. The whole bike.

The answer is yes. It didn't take much time to find one either. I only searched for carbon 29"ers from three different companies. The first bike company I looked up was Specialized (soft spot in my cyclist's heart for Specialized) and I found the Stumpjumper Comp Carbon 29er that was a bit more than the $2600 wheels at $2900. Close, but I wanted to find something at or below $2600.

Next on my search was Giant. Giant always has bikes priced fairly aggressively. And they did not disappoint. Their XTC Composite 29er 1 was priced a full Franklin below the price of the Easton wheels. $2500 complete bike with carbon frame, Fox fork, and a press fit bottom bracket! Holy cow!

At face value, it seems pretty ridiculous that a set of wheels cost as much or more than a really nice complete bike. And honestly, I've built wheels that cost more than a lot of bikes. And at face value, in this comparison, I tried to compare a bike with carbon frame complete with all the shifters, derailleurs, suspension fork, crankset, brakes...with a set of carbon wheels that only have two rims, two hubs, spokes. Maybe what this really shows is how much bike one can get.

(What's playing: Dolly Parton Jolene)

Monday, April 18, 2011

I need to write a post but...

I've always written posts based on what I feel folks might want to read and not because I set myself a deadline or need to have a Monday post or a Wednesday post or a... But dang, I probably should do something to post a little more regularly. So here's some random mind farts of some stuff I'm thinking about or doing.

Did a couple of really nice rides yesterday and today. Two days and a little over 6 hours in the saddle. Today saw the forecast with winds out of the southwest and a 60% chance of rain. A south wind usually means that a ride out to the lighthouse can be a bit of a chore, but the return trip back can be great fun with the tailwind. So, ignoring the rain forecast, I donned my vest and wool knee and arm warmers and headed out to the lighthouse. It was lightly raining as soon as I left the house. I thought about a rain jacket and booties, but decided against in a WTF moment. Turned out to be the right choice. The wool does a great job of keeping your warm when wet and the full fenders on the bike keep your backside and feet dry. Finished the ride with a perfect cappuccino from Toby's. Here's a few shots.

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Looking out over the Pacific.
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Wet roads, but the fenders kept the water off my feet.
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Looking down over Drake's Estero.
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Bunch of these short, steep climbs that suck with a head wind, but knowing there will be a tailwind on the way back makes it totally tolerable.
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The steed of the day. And I would be derelict in my duty if I didn't interject here that there are still plenty of Black Mountain Cycles frames available. Road frames in all sizes and colors. Cross frames in brown only except for one each 50cm and 53cm.
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The fog horn was bellowing and visibility wasn't very good at the lighthouse. This is a steep cliff and the Pacific Ocean down there. I knew it was there because I could hear the waves.
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Out there riding, I got to thinking about a series of posts I started long ago, but haven't followed up with more posts. I'm about to rectify that. What I refer to is the "Things I Like," "Things I Want To Like," and "Things I Dislike." I've been using KMC DX10SC chain and really like it. It doesn't cost a bloody fortune. It shifts well and is quiet. I'm running it with a Dura Ace shifter and derailleurs, Ultegra 6700 cassette, and a Ritchey crank with a 50t ring and a 36t Salsa 9-speed inner ring. Shifting is spot on in front and in back. If you need a chain replaced on your older Shimano 10speed (not compatible with the newer asymmetric 10 speed systems) or SRAM 10 speed, this is a good alternative and won't break the bank.

Wednesday, April 13, 2011

A couple of new bikes...

I built up a new cross bike for an Portlander yesterday with Nitto Moustache bars, but forgot to take pictures of the finished bike. Trust me, it looked pretty cool and after his first test ride said it rode "f'in awesome!"

I did manage to get some pictures of what I call a neo-retro road bike build I did for Bill in New York who is planning on racing this in the retro class at the Furnace Creek 508. It was pretty coincidental that Bill called up to commission this build as I was pondering a similar build kit that I'll offer. I like the look of the bike with the down tube shifters. I think I may have to build myself a simple, stripped down road bike like this.

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The other bike that got built up was Ari's bike that he'll use for some endurance races in the mid-west this year. Ari works at a bike shop and did the build himself. I'm liking the white with the orange. The white bar tape with the orange frame remind me of some of Eddy Merckx's old rides.

Also got a really neat set of wheels built for Bill's Salsa Mukluk. The blue NoTubes Flow rims come from project321.com.

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(What's playing: Hump Day on KWMR)

Tuesday, April 12, 2011

More on tires (and spokes)...

I already feel, to some extent, that I've beaten a dead horse on the topic of tire size and air pressure. Besides a properly clean and lubed drivetrain, I think tire selection and air pressure is the biggest thing you can do to make your bike ride as comfortably and fast as you can make it go. A recent ride and a new video posted on YouTube got me thinking more about tires and pressure.

Starting with the video, which is making the rounds on Facebook, it portrays a very telling story of what a bike's tire/wheel goes through over the cobbles of the Paris-Roubaix race. The same thing actually happens to your tires when you ride on the road, albeit on a much smaller scale. The film's slow motion really does a great job of capturing what happens to a tire and wheel on a road surface.

Check out what happens to the rear tire as it rolls off of a piece of pavé and momentarily gets airborne at 1:36. The tire, even with lower air pressure, momentarily slips and loses traction. This is the same thing that happens, at a much smaller scale, on a rougher road with high tire pressure. The tire bounces, loses traction. Any time traction is lost, the rider must somehow make up for that loss by increasing output. This video really shows how tough those guy are who race Paris-Roubaix.

The other cool shot happens at about 2:05. As the front tire rolls over a rock, the tire absorbs some of the shock, but not all. The rim also absorbs some shock and ever so slightly deforms causing the spoke that is perpendicular to the impact to lose some tension momentarily. You can see the spoke wiggle. Every time that happens, the spoke nipple could potentially loosen. The moment this happens in the video lasts all of a fraction of a fraction of a second considering these guys are probably moving across the pavé at 25-30 mph. Imagine what happens to a wheel with 28 sections of pavé during the race's 162 miles. It's no wonder teams spend so much time and thought on tire and wheel selection for the race.

(What's playing: Tom Waits Who Are You)

Monday, April 4, 2011

Week of April 4 hours...

Going to be closed a few days this week. I apologize if this affects your needing to purchase a Black Mountain Cycles bike decked out with the latest and greatest. If this is the case, operators are standing by ready to take your order. Well, not really. Here's the hours this week.

Tuesday April 5: Closed
Wednesday April 6: 11:00 - 3:00
Thursday April 7: Closed
Friday April 8: Normal hours resumed

(What's playing: Ha Ha Tonka Lonely Fortunes)

Sunday, April 3, 2011

It's like church, but better...

Bikes, building bikes, and specifically riding bikes soothe my soul and give me time to think, ponder, and enjoy being outside. Here's one that was a joy to build and during my test ride on it, discovered that it is an incredible riding bike - so smooth and comfortable (even if it's several sizes too small for me). The new owner conveyed the same saying that he felt right at home on it immediately and there was no period of time to get used to it. Hop on, ride, forget about anything except the ride.

This particular bike is a Steve Potts titanium all-rounder, do-it-all, expedition, adventure (you get the idea) bike. The frame was built with clearance for fat 29" tires. The owner will ride it with either a touring type tire because of the condition of his country's roads or a 29" Nanoraptor. I really like the ride quality of THE tire on both dirt and road. I keep trying to put together a drop bar bike built around Nanos, but keep getting off track. Soon it will happen.

Parts ready.
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It's not so easy to build a bike for a customer who lives in a different country and across part of an ocean. However, the power of the digital age is very convenient when I can send a photo of his bike with his seat height and handlebar position so he can see the relative seat/bar position and we can determine how much to trim the steerer tube.
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S&S coupled bike for easy travel.
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With the Nanoraptors.
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And now it's time for me to get out on my bike this morning. Whatever you do on your Sundays, enjoy.

(What's playing: The Mavericks Hot Burrito #1)