Characterization of various liquid lubricants in sliding conditions

• Test conditions – 5 N mass, 8 cm/sec slide rate for short-term tests, 10 cm/sec slide rate for long-term tests

• Ball specimen – 6mm 440C

• Disk specimen – Inconel

• Lubricants – WD-40, 3-in-1 household oil, Pro Link chain lubricant, Purple Extreme chain lubricant, Pedros Extra Dry All-Purpose Lube

Tribological testing was performed of various commercial lubricants to determine their effectiveness at lowering sliding friction in a standard pin-on-disk test machine. Testing consisted of first characterizing the dry sliding friction between 440C and Inconel, which is shown in Figure 1. Wear quickly develops and sliding friction converges to a value of approximately 0.8. After testing, a wear track was evident in the test specimen.

Figure 1. Sample friction time history of 440C on Inconel with no lubrication.

The wear track developed in the dry sliding test was used for each short-term wet test. Prior to applying a lubricant, a short test was performed to verify friction was on the order of 0.7 to 0.8. Then, a liberal amount of lubricant was added to the Inconel surface in the wear track. The specimen was cleaned, using methyl ethyl ketone and isopropyl alcohol, between tests. Figure 2 shows the performance of various lubricants.

Averages and deviations for the data shown in Figure 2 were computed for the various lubricants. “Best performance” ranges were used. For example, for Purple Extreme, data prior to a decrease in performance was used. Thus, the values represent the most ideal friction coefficients.

• Pedros – s=0.1381, m=0.0163
• Purple Extreme – s =0.1119, m =0.0140
• 3-in-1 – s =0.1028, m =0.0017
• WD-40 – s =0.0961, m =0.0007
• Pro-Link – s =0.1106, m =0.0015

Figure 2. Short term testing of various lubes.

Since the above tests were performed with fairly liberal applications of lubricant, selected lubricants were retested with longer term testing and an application that would be typical of bicycle chain maintenance procedures (applying lubricant, allowing time to “seep in” and lightly wiping surface with shop rag). New wear surfaces were used for each test. The specimen was cleaned prior to the next lubricant test. Figures 3 and 4 show the performance of the lubricants tested (Figure 4 magnifies the initial stages). It can be seen from these figures that WD-40 and Purple Extreme quickly broke down and high sliding friction ensued. Figure 5 shows the performance of 3-in-1 oil, which suffered to breakdown and provided a consistent low sliding friction coefficient. It should be noted that in the 3-in-1 test, the slider slid over 9 km relative to the specimen in the same wear track (r=12.18 mm).

Figure 3. Long-term testing of some lubricants.

Figure 4. Enhanced view of long-term test.

Figure 5. Performance of 3-in-1 oil.

Hitting the deck :(

Week started off well. My new approach of "flying blind" when using the PCs has been great. Not being focused on time and power has made riding the PCs fun again. What hasn't been fun, however, is the air quality. Summer hasn't officially started yet, but the Houston air quality is in the crapper. There were multiple ozone warnings last week, and I was certainly feeling the effects of ozone on a couple of workouts. I had to limit my intensity and volume because of it - better to sacrifice some workout time rather than damage a lung. Unfortunately I live south of Houston, and the ozone here always seems to be the highest in the area. There was no coastal breeze to speak of, so the bad air just sat over the area. My throat was hurting and I just couldn't breathe like I wanted.

I did set up the PC bike with clip-on aerobars, and I quickly got adapted to them. I was spinning away with zero difficulty when down on the bars. I'd get off the bars because of discomfort in my forearms (not the best quality clip-ons/elbow pads) rather than any leg issues. Plan was to ride like this for a week and then transition the PCs to my spare TT bike.

But things all changed Saturday. On the group ride we had a few "b-teamers". I have no problem with slower riders as long as they don't cause trouble. On the second half of the ride, my pals were going for a sprint zone. I decided to take the throttle off and just relax a few minutes before we hit a "cobbled" section of 3 miles (I love to drill it there). There were 5 of us in a moderate 24 mph paceline, with me 5th wheel. Wheel #3 swerves (he said #1 and #2 swerved for no reason and he had to swerve to avoid hitting #2) and wheel #4 touches wheel. Wheel #4 goes down and I've got a bike on the ground to the left and front of me and a ride on the ground to the front and right of me. With nowhere to go I t-bone the rider at crash. The good news is that even though I landed hard on my left hip, which I broke in 2002, there was no subsequent fracture. The bad news is I'm REALLY sore several days after the wreck. I had to use crutches Saturday afternoon, but by Sunday I was able to walk on my own. I think I've got a bruised/fractured rib, but the rest is all just minor road rash and a lot of sore/strained muscles. Because of the road rash on my left elbow and forearm, there's no way I'll be using aerobars until the scabs go away.

It's my first crash in a few years, and crashes suck. They suck even more when you're an innocent victim. Lesson learned - don't let those with less fitness get in front of you. These guys were probably tired (we drilled it the first half) and had half their wits about them. I'll just make sure to drop them early next time and not be Mr. Nice Guy.

I'm hoping to get a light spin Monday evening or Tuesday at the latest. The wife isn't too pleased with the crash. I got the third degree when I got home Saturday...

PC time this week - 4 hours 10 minutes
PC time to date - 213 hours 45 minutes

Upping the PC time

After I got back from Italy it's been a whirlwind of activity to get back in shape. I've spent increased time on the PCs to make up for lost biking. I've also changed the way I'm scheduling my workouts. Due to the higher temperatures and humidty this time of year I'm taking it "easy" 4 days a week (Mon, Tue, Thu, Fri) and riding with PCs on those days. I actually don't know how hard I'm riding on those days as I decided to strip the PC equipped bike of all instrumentation. Staring at the powermeter while PCing away just makes me hate the bike (or rather, a PC equipped bike). I've turned to a heart rate monitor for PC rides, and even then I don't know how hard I'm going as the watch is tucked under my shorts near my knee (thanks to a broken band). So now I ride for enjoyment with the PCs and see how long I've ridden and my average heart rate for the ride once I get home. It really has made it more enjoyable.

PC time the last few weeks - 9 hours 15 minutes
PC time to date - 209 hours 35 minutes

The last few weeks - Italy, rest, back in the saddle, and PC related injuries?

The last few weeks have been consumed with work issues. I had to travel to Turin, Italy to help out with a modal test of some new hardware. I was looking forward to the trip to also get some good riding in before or after work. Unfortunately Lufthansa got in the way. I've flown my bike to Europe a few times now, and it has always been free. This time, however, Lufthansa wanted to hit me with a $500 roundtrip fee. Guess where the bike was? So I loaded up my luggage with pedals, shoes, helmet, etc with the hopes of a friend coming through with a rental bike. Ricardo called all over Turin to no avail, but when all hope looked lost, he found a wonderful couple. Federica and Francesco of Cuore da Sportivo (Via Domodossola 22 C/D in Turin) have a quaint shop that caters to cyclists, runners, skiers, and mountain climbers/trekkers. They offered to rent a bike to me which wasn't even built. Francesco built up the bike (an Italian brand called "Bike Tool") with a mix of 105, Ultegra, and third-party parts, and I picked it up early on a Saturday morning. A weekend of cycling awaited me, and I spent that entire weekend riding to and in the Alps. That weekend I rode many of the same roads from Tuesday's Stage 10 of the Giro. Saturday was a roundtrip from Turin to past Susa, and Sunday was Turin and about halfway between Pinerolo and Sestriere.

What made the riding more interesting was that I took the same shoes and pedals that I've been using on the Powercrank equipped bike. You may recall that I've had some ankle/foot issues with the PC equipped bike, and it seems to be related to the PCs and/or pedals. In Italy, I was on the bike for 4.5 hours the first day and 5.5 hours the second day and am happy to report that I experienced ZERO pain with the rental bike and Time ATAC pedals and shoes. 10 hours of riding and no pain. I had 5 days of no riding prior to the weekend in the saddle. Hmmm.

I got back late last week and did a quick hour on the PCs after another 4 days of no riding. Wouldn't you know it - after the hour I felt some tenderness in my ankle/foot in the usual spot. Then yesterday I did a 2:15 ride on the PCs and was feeling that pain again. I'll continue with the PCs in an attempt to put many more hours on them prior to July, and it will be interesting to see if the pain persists. Looking back at my experience in Italy and the pain I get with PCs, I can't help but think that the root cause must be the q-factor of the cranks.

Overly anal data digestion, part deux

With plenty of downtime ahead of me due to a work trip to Italy, I figured it was a good time to digest some data and look for trends in my performance. I’ve been using Powercranks since July 2008 with the heaviest use from August to February. In February and March I took a rest from them due to some nagging injuries. Now, at the beginning of May I have crossed the 200 hour mark with PCs – a significant amount of time with them which should generate some changes.

Since August of last year I’ve had some good max power values in several time durations. A few of those have been repeatable while others have been one-off performances. One-offs are great for bragging rights, but I’d rather have repeatable performances to draw on for race day. With that in mind, I’ve digested my power data going back to the 2003 season and looked at it from a max enveloping perspective as well as basing my data on my top 10 or 20 performances of the year (i.e., average my top 10 or top 20 powers for various durations). The latter is a measure of my repeatability.

The plots below (for normalized and average) show that the first two years of training with power were by far my worst. I was still within the first years of training in general so the data for 2003 and 2004 are certainly expected. The key thing is that the data from 2005 to 2009 is clustered together.

Because 2003 and 2004 are outliers in the sense that I was still training to get to my peak performance, I will ignore those years from the rest of this analysis. I’m not ignoring the data from the past, but placing importance on the more immediate past (the last 5 years).

Going back to 2003 I’ve got 1120 days of power data stored. That’s 1120 data points from which to extract power data for 5 minutes, 20 minutes, 60 minutes, or whatever duration I want. Most of the data is for years 2004 to 2009, so each year has nearly 200 data points and a good sample size from which to draw conclusions.

If I envelope my top 20 performances in a year I get the data below for normalized and average powers from 3 to 180 minutes. The solid red line represents the current season since starting with Powercranks, and the dashed red line is an average of the 2004-2009 data with error bands (one deviation plus/minus). Within a given year, the deviations are on the order of 3-6 W, indicating high repeatability in my performances. For the cumulative period of 2005-2009, the deviation is on the order of 2-4 W, within the tolerance of the Powertap itself.
Notice how tightly clustered all the data is until you get beyond the 120 minute range. For durations of 2 hours and more, I simply didn’t ride hard for that long in the past. As training evolved and my race team grew, the training rides got longer and harder. The higher power experienced in 2009 for more than 2 hours is primarily due to my weekly training ride being longer.

Since I’m primarily a time trialist, what interests me more is my power for an hour or less. Zooming in on the data above for the 10-60 minute durations we have the plots below. Here 2008 sticks out like a sore thumb. It’s clearly my worst year in the last five years, but even then it’s only off by a mere 5 watts from the average and about 7-8 watts from this year and 2007. Further, 2009 looks to be a carbon copy of 2007.

If I were to instead consider the top 10 performances of the year instead of the top 20, we would expect the curves to rise a bit. And they do. The next 3 plots are for years 2007 to 2009, and I’ve plotted my yearly best along with curves representing my top 10 and top 20 values. There is a difference between selecting the top 10 or 20 values, but honestly the difference is quite small. Indeed, the major difference is between these curves and the max curve. Ideally I’d want to have all three of these lines merge. What the curves do tell me, however, is to be careful with so-called “personal bests” which could be nothing more than aberrations. Was I feeling great that day? Was it from a fresh chain or newly cleaned and lubed chain? Temperature issues with the Powertap?

Another way to look at the data is by date. The plots below are my 20 and 60 minute normalized powers for the last several years. The plot is of all dates, but only rides in the specified wattage range can be seen (in other words, rides with lower normalized power are off the graph). The 2007 training year has better consistency in the 290 W range for 20 minute power, whereas 2009 shows more consistency in the 280-290 W range. 2008 just looks like a lousy year. For 60 minute power, 2009 shows two rides over 280 W for an hour, but 2007 appears more consistent, albeit by a only few watts. Which would a rider rather have? Those two peaks that are 5-7 W higher than the cluster in 2007, or that cluster of consistency?

Finally, what if I were to take my top 10 performances of the year for various durations, average them, and using the critical power model determine my “top 10 based critical power”? I did just that, looking at data at 3, 5, 8, 10, and 15 minutes in duration. Doing this since 2003 I get a performance increase after the first 2 years and then things all blend together. My expected hour power would be 262 W for 2003, 260 W for 2004, 271 W for 2005 and 2006, 274 W for 2007, 272 W for 2008, and 273 W for 2009. When I look at the data, 2007 sticks out the most; I had my highest anaerobic work capacity contribution in that year (though honestly it’s still pretty weak). In that year I spent several weeks doing heavy VO2 work. I had access to the roads west of Paris with several shorter climbs, including one that was ideally suited for 5 minute efforts. I also utilized track racing extensively in preparation for the state time trial championships. Looking back, it appears this VO2 work was the recipe for success. Fast forward to 2009 and I’ve been doing quite a bit of VO2 work, though my 3-5 minute power is 5-10% lower than 2007.

Looking at the data, there’s several things which could be stated:

1) One-off performances are great, but unless you can back them up they are useless if done out-of-competition.
2) Consistency is more important, and by looking at the top 10 to 20 workout and race performances you get a better measure of where your fitness currently sits.
3) I’ve been remarkably consistent the last 5 years. I busted my butt in the fall with Powercranks (tempo, threshold, and VO2 workouts with them) but still I seem to be right smack dab in my physiological limits. My workouts, as measured by TSS, are up about 10% over past years with zero gain. In other words, lots of extra work for nothing (or at most one or two more watts).
4) 2008 was my worst year in the recent past, but even as bad as it was, it really wasn’t that bad, just a few percent lower than past years.

Week of April 20

Coming into the week I've been carrying a lot of load in an effort to continue to drive up the chronic training load. I just hit 100 yesterday after a low of 78 just 5 weeks ago. A nice, steady ramp rate to get back to form. But with the increased load comes some residual fatigue...

Monday - I was simply tired. No motivation to ride and I fell asleep on the couch after work. Body was telling me something...

Tuesday - Still carrying some negative TSB but I think the main point was carryover fatigue from a hard weekend. Intended to do some VO2 work but the legs weren't there.

Wednesday - An hour and 45 minutes of PC riding at a nice endurance/low tempo pace. I have to admit that by the end my hip flexors were barking at me. Still, no problems spinning out for nearly 2 hours.

Thursday - A long tempo ride of 2.5 hours including a stretch of 1:45 at about 260 W. I was dead at the end. The negative aspect of bumping up your threshold.

Friday - No riding due to a ton of rain in the area.

Saturday - Good hard group ride.

Sunday - Ditto Saturday's effort but an extra 2 hours on my own to increase load.

A good week ending up with my CTL at just under 103. The ramp rate is decreasing a bit due to the threshold number getting reset. No personal bests but the form is back to the levels I was hitting over the winter.

PC time this week - 1 hour 45 minutes
PC time to date - 200 hours 20 minutes

Week of April 13

Some new personal bests this week! Yippeee!!!

Monday - 30 minutes of light indoor riding on the PCs

Tuesday - I wanted to do some quality VO2 work on the race bike, but I came into the workout with a highly negative TSB and my legs just weren't there. So instead I carried a mix of levels and rode for 47 miles just to keep the CTL increasing. I had some decent midrange, but the upper end was just flat.

Wednesday - Outdoor ride with the Powercranks just doing some endurance pace work for 75 minutes. Could have gone longer, but the winds were demotivating.

Thursday - Workout of the year. I was debating what kind of workout to do. Should it be 1) threshold, 2) a hybrid VO2 workout that sees some good training benefits, or 3) what I'm calling "300+" where I ride at 300+ W for as long as I can, take a short rest, and hit it again? I decided to go with door #3. I was expecting to have to throttle down after 10-15 minutes, but my legs kept rolling. It wasn't until minute 36 that I needed a break. Unfortunately after that I was a bit toasted, but I set some new personal bests for average power in the 15-30 minute range and normalized power bests in the 20-40 minute range. Mind you I beat my all-time bests by anywhere from 1-7 W, but those bets came a few years ago. After this portion of the workout I wasn't done. I decided to fill in some time with "surge tempo" where I ride at tempo and throw in some half-hearted out-of-the-saddle sprints out of every turn. The workout is shown in the graph below. The horizontal line is 300 W, and my current threshold is ~275 W. All indicators are saying I need to bump that up to 285-290 W (not just this data, but other ride data as well). The dips in the first part of the ride are due to corners on a local 6+ mile loop.


Friday - no riding due to some significant rain in the area. In fact, the rain was so bad that it forced the cancellation of the first day of the MS150 ride from Houston to Austin, the first time that has ever happened.

Saturday - The same weather system from Friday was still in the area Saturday. Pal Alex and I found an open window of no rain early in the morning for some riding. Just rode it hard to get some training load in. It was, however, a rain (lightening actually) shortened 1:45 ride.

Sunday - 4 hour 15 minute endurance ride on the race bike. With the training load I accumulated on the ride, I'm now up to a CTL of 100 and feeling strong again. Good thing as there are some races coming up soon.

I'm extremely happy about the new PBs. The question is why did I set those? I see 4 possibilities (or a combination of these):

1) PCs - nearly 200 hours of use in the last 9 months, using them more and more again after some injury issues in Feb/Mar. PC use has certainly declined compared to the first 6 months but I notice my pedaling style has more variety. I can pull up (hammies and hip flexors?) from 6 to 12 o'clock for significant periods at threshold to give the quads a rest.
2) increased training load and the fitness that comes with that - I'm slowly building my CTL back up over 100. I am running a negative TSB right now, but the higher CTL allows you do dig a little deeper.
3) caffeine - had some of my homemade candy bar of dark chocolate (85% cocoa) and whole coffee beans before the ride - probably about 100-200 mg of caffeine in a little piece. Not so sure about caffeine being the real factor as I've have indicators of improvement for a few weeks now.
4) the type of training I've been doing lately - very long VO2 intervals (sorry, only me and my team know the protocol)

Below you'll see my latest power-duration charts. The red line is the line corresponding to the time since starting with PCs. In both charts (average and normalized powers) note the bump ups in the 15-40 minutes ranges.


Clearly I'm well ahead of last year but still haven't significantly increased my all-time power numbers. I just need to hold the form through the summer so I can have a much better 40k this year than last. It would be nice to hit a low 56 minute 40k or dip into the 55s.

PC time this week - 1 hour 45 minutes
PC time to date - 198 hours 35 minutes