Curse of the Crab

Posted: April 7, 2014 in Uncategorized

This past Saturday, I participated in the the Curse of the Crab race.

I got a cool Twin Six jersey with a single speed theme.

My friend Chris must also have good taste in clothing. We were like twins.
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In the past few weeks, I have been pretty consistent in my riding and diet. My fitness is not great this time of year but I am starting to feel pretty good and losing about 15 pounds of fat over the past three months has helped me ride better.

Single speeders like me really think a lot about our gear. For Curse, I was on 34/20 gearing. This works out to be a 1.7 ratio. Most other riders were on bigger ratios. Crabtree is pretty flat and in hindsight I my ratio was a bit too low. Next year, I will try something bigger.  32/18, 33/19, 34/19, or 36/20 are close to 1.8 ratio.  I could run 35/20 for a 1.75 ratio to get a little more gear and avoid going too big.  Single speed is about riding with one gear and it is fun to consider all the options.

Races like this start with a short road section to thin the pack before we hit the singletrack. With single speed gearing and a low ratio I was spun out right away and watched a fellow racer named Michael take category lead as we entered the single track.

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Michael is a strong rider but I did my best to keep pace. By the end of the first lap Michael was about a minute up on me. In the second lap, he gained another minute on me. In the third and fourth laps I gained a little bit of time back but at this point the race was maturing and I settled into a pace that I could maintain. I was able to catch glimpses of Michael at various points where the trails would fold back upon themselves.

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Crabtree park is a hard place to race because with no major climbs the six hours is one constant and fast effort.  No part of the course is “easy”.  The flat terrain and open trails mean that you are usually riding very fast.  It is hard to eat or drink on a mountain bike and in this race I was on the edge where I was forcing myself to eat and drink something but also trying not to overload my stomach.

I was able to claw back some time in laps 7, 8, and 9. As I got closer on lap nine I could see that Michael was not feeling well. Later I found he had back problems.  I occasionally have similar issues and wish him the best in recovery. The Crabtree race course is hard and once you get struck down with back pain there is not much that can be done. Michael was forced to stop at lap nine although when I passed I actually did not know he was stopping. I thought was simply getting some food at the pit stop area.

I road lap 10 thinking that Michael was chasing me. I went my own pace and really was expecting to get passed at any minute. My final lap was also good and I let myself relax a bit. I did not bonk but my systems were fading on the last lap.  I was very happy to finish 11 laps of the course and meet my goal of 60 miles.

For this race I was very happy with my lap pacing. The very first lap was slightly longer because of the road section. As I expected, my pace for the first three laps was fast with times of 31, 29, and 29 minutes. The middle five laps were consistent with times of 30, 32, 31, 32, and 33 minutes. The final three laps were also pretty good with 33, 34, and 35 minutes. I finished 18 minutes behind the top geared rider.

At the finish, I felt spent but was happy with my effort.  After his back problems, Michael dropped back to third place in the race.  I only saw the second place finisher (also named Mark) a couple of times but found this great photo online. It looks like he was pretty happy on the course and with 10 laps it is clear he put in a strong effort.  Hopefully I will get a chance to ride with him at a future race.

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As expected, the bike performed great. The gear ratio was a little too small I think that is better then going out with one that is too large.

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Photos from the event from Torrenti Cycles and TORC mountain bike club.

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I have about 50 miles on the new single speed so it’s a good time to provide a review of the bike and components, and share some thoughts about how it rides.

Also photo dump with it properly dressed in mud.

Today was the first “big” ride on the bike with 30 miles and a good group of fast friends. Tom was almost as fast as Tom; I felt like John and I held our own. Good times, great trails with only really one crash.

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This is by far the best bike that I built. My process is not yet perfect but I get better on each build. In particular this bike has finally reached a level where I am not nervous when someone looks at it up close. Sure, if you are total bike geek like me you can find some stuff that is not perfect but in general I feel good about how this one turned out.

Every bike that I have built includes slight changes in design. I like to tweak things but don’t really like wild changes. This bike is VERY similar to my last couple single speeds. I built this bike longer than the last one and am riding a shorter stem. My position remains more or less the same. The change in weight distribution alters the bike handling and follows some general trends we see as the industry continues to refine 29er hardtail geometry.

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If you look close at this bike in person, there are improvements in little details. The bends on the seat stays and the balance of tire clearance in the rear end are improved vs. the bikes I built before getting my Pro Tools 105 bender. I had them make me some custom bending dies for bending the chainstays on a 7″ centerline radius.

The quality and consistency of the welding is also much improved. I spent a lot of time practicing in 2013 and continue to do a lot more practice TIG welding this year.

I am still rolling 2.0 tires but really this bike is built to allow 2.35″ tires. Down the road I will be running some fatter tires. The frame is built with plenty of room even with the chainstays in the short position.

One of the big changes on this bike is the Magura TS8 fork with a Tapered steerer tube running in a 44mm headtube using a Cane Creek headset. I ran an 80mm REBA on my last bike. My REBA forks have been great performers over the years but it is nice to be trying something new.

The bigger fork means the front end is higher so now I have my stem all the way down but really it is a similar position to what I road in the past. With this bike built to have the balance of weight a little bit more rearward the bike handles the rough stuff very well. The fork rides stiffer yet still absorbs trail chatter really well. Steering is super precise with the the through axle.

This drivetrain uses Paragon sliders, a 20 tooth Endless cog, 34 tooth Gusset chainring, and KMC 9 speed chain. My trusty SLX crankset and basic SPD pedals complete the power delivery side of things. The cranks turn on a Praxis Works bottom bracket in a press fit 30 shell. The combination is flawless. As you can see, I get lots of shoe rub but that is always the case and I have been riding these cranks for years.

This is my first experience with Industry Nine wheels. These are the best wheels that I have ever owned. The rear hub in particular is amazing with truly instant power engagement. I am now a huge fan.

The Thomson seatpost and stem are awesome. Once again, I am a huge fan and really don’t see myself using anything else on future builds. My butt likes the Specialized Phenom saddle although I might try an Ergon saddle at some point. Speaking of Ergon, the big bar ends are still my go to setup. These days I am using Answer Carbon 20/20 bar. XT brakes do great and this set was moved over from the last bike. Shimano brakes are top performers with solid reliability.

I think that about wraps it up. The bike rides great and I look forward to putting lots of dirty miles it this year.

Single Speed XC Bike

Posted: March 12, 2014 in Uncategorized

I built myself this new XC style single speed.
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An XC style bike is built to go fast off road.

I am the first to admit that I am not really very fast….

But I am not slow and I really like XC style riding and racing.

These days the only “race” focus that I have is for long distance single speed mountain biking. I don’t expect to “win” any races but I enjoy them and will admit that I am a bit competitive for races, group rides, and Strava. I ride a geared bike occasionally but the performances that I really care about are on the single speed.

This is my new single speed race bike. It’s a fairly light (for steel) frame with 969 downtube, 858 top tube, butted seat tube, paired with 5/8 tapered seat stays, “S” bend chainstays from NOVA. The drop outs, headtube, bottom bracket shell, and hose guides are from Paragon machine works. I got it powder coated here in Raleigh at Powder Coat USA.

The geometry is basic for a XC style bike.
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As shown here, the bike is 23.75 pounds. This is fairly light for a steel hardtail. I am sure I could get take a few ounces off by using normal grips rather then my huge Ergon bar ends. I could also save more weight with big money carbon bits, fancy cranks, or some ultralight wheels and tires. but that’s not really the point. The bike is plenty light as is.

The fork is from Magura, wheels are Industry 9. I am using Shimano XT brakes, simple SPD pedals, and SLX cranks. The tires, seat, and bottle cages are from Specialized. Thomson Post and Stem paired with Answer carbon 20/20 handlebar and Ergon grips. The headset is Cane Creek. The bottom bracket is from Praxis. Basically all mid to top shelf parts but nothing ultra high zoot.

I rode the bike for the first time last night and can’t wipe the smile from my face. It turned out great and meets all my goals. I am very focused on my process as I work to perfect each step of a build. In the past tire clearance and seat stay symmetry have been issues that I struggled with as I build short stay 29ers. This bike is built with the stays just past 430mm. They are pretty short but still give me room to run 2.35 tires with equal clearance at the chainstays and at the bottom bracket. The bends are also in phase and the placement is symmetrical. Fit and finish is not perfect but I am very happy with how this one turned out.

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MTB on the road

Posted: February 22, 2014 in Uncategorized

It gets pretty busy with commuting, mountain biking, and inline skating but then again, variety is the spice of life.

I have been thinking a bit about road riding and decided to set up one of my mountain bikes with gears and dropped bars.  Most of the parts are mountain bike components but I have TRP brakes, Duraace 9 speed shifting, and some fat road tires.  The bike has been a lot of fun for commuting and gravel roads in Umstead.   Today I decided to give the local road bike group ride a try.

For the group ride, we did around 65 miles.  The Raleigh Gyros group is really smooth with a nice rotating paceline.  The miles flew by at around a 20mph pace.  Based on how much fun I had today I figure building a “true” road bike is on the 2014 agenda.  The biggest thing with a “true” road bike is that I will run skinny road tires and an overall lighter package of parts.

The dropped bar mountain bike is not the perfect road bike but but it still did pretty darn good plus it is really an awesome fast commuter and gravel grinder.  The gearing on the bike is really tight with a straight 11..19 on the rear and 40/48 up front.

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Inline skate frames

Posted: February 10, 2014 in Uncategorized

I always enjoy watching the speed skating at the Olympics.

In addition to cycling I enjoy inline speed skating.

Several years ago I built myself some inline speed skating frames. The speed skate frame is the black anodized aluminum part holding the wheels to the bottom of the boot.

These were made on a CNC machine that I used to have in my garage shop.

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Back when I was in good shape I used to skate with the local cycling group.

Seat stay bridge

Posted: February 9, 2014 in Uncategorized

The seat stay bridge is one of the most difficult parts of a frame to TIG weld. In particular it is hard to get good torch angle for accessing the various parts of the joints.

When welding the bridge, I use aluminum foil to block drafts and help the argon shielding gas pool around the areas that I need to weld. For these welds in particular getting good body position is critical. The “tie in” points where segments of link together are often in points that are hard to access so it is hard to make a smooth transition.

The bridge is a hand mitered 5/8″ section of 4130. On this bike I am not venting the bridge to the outside but have drilled holes to vent from the bridge into the seat stays. The stays themselves are currently fully welded at the seat tube cluster but are currently only tacked at the drop outs. Later when the welding on the drop outs is complete the stays will become an air tight structure.

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Some TIG

Posted: February 8, 2014 in Uncategorized

Start with tightly mitered joints and clean metal
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Tack in four locations
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I am pretty happy with these welds; I will continue to improve. In particular I need to work on how I “tie in” from one segment to another. The start and stop associated with the “tie in” creates a bit of a stress riser. I think these joints will be pretty good even though they are not yet “perfect”.