Bike Physics

August 22, 2007

Filed under: Uncategorized john @ 7:07am

The Khamsin data has been posted. I guess it's no surprise that they are an impressive value for the money. The low spoke count and good hubs make for good performance. A beefy rim means that the wheel is quite stiff and will stay in true. The round spokes don't kill the aerodynamics, but bladed spokes would be even better. My only complaint is that "triplet" lacing doesn't belong on a front wheel. It means that two of the three spokes are at a lower tension, which could (in theory) lead to premature spoke breakage. Overall, you get Reynolds Attack performance and rock solid performance for 1/5th the cost. Ride them, race them, crash them occassionally. Don't worry, they can handle it!

August 21, 2007

Filed under: Uncategorized john @ 7:45am

After taking most of the summer off, I have begun to add data again. On Sunday I was able to measure a set of the new all-carbon clinchers from Reynolds (the Attack model) as well as the Campagnolo Khamsin. Everyone I've talked to has raved about their Khamsins and several people have been bugging me to measure a set. And here it is. I've already posted the results for the Reynolds and will get to the Khamsins tomorrow. By the way, the Reynolds wheels surprised me a bit. The hubs are like butter and they kept spinning forever. This made me think that they would compare favourably to something like the dura ace wheels. I was wrong. The conventional round spokes just aren't that aerodynamic. And the moment of inertia was only so-so. In fact, the wheel is very much average. Literally. When I average all my data it describes this wheel perfectly.

June 27, 2007

Filed under: Uncategorized john @ 9:27pm

It seems that the move to a new webhost has been completed, though we are still working out the kinks. Please stand by...

June 7, 2007

Filed under: Uncategorized john @ 3:54pm

bikephysics is moving to a new webhost. as we migrate the site i expect that there will be times that the site is down or simply messed up. please be patient and we'll be back to "normal" as soon as we can.

May 6, 2007

Filed under: Uncategorized john @ 1:51pm

Last weekend I measured a Zipp 999 tubular front wheel and a Zipp 404 clincher rear wheel. Today I analyzed the data and posted the results. Unfortunately, I screwed up the measurement of the Zipp 999. Oops! But the 404 worked out okay. It's interesting how similar all the rear wheels are. I think it's because they are asymmetric (i.e., dished) and half the spokes are effectively hidden behind the rim. So, it's no surprise that the Zipp 404 has about the same performance as every other wheel I've measured. It does a bit worse on aerodynamics because it has more spokes than, say, the Dura Ace wheels. But this neglects the aerodynamic benefits of the deep rim, which will make it a better performing wheel overall than the others. If only I hadn't screwed up the 999...

April 8, 2007

Filed under: Uncategorized john @ 9:52am

The Fulcrum Racing 5 front wheel has been added to the results. The hubs are packed with a thick grease, so the "b" parameter is quite high. Otherwise, the performance is much like the Campagnolo Eurus. I suspect that once I ride the wheel for a couple of hundred kilometers the bearing resistance will be much less. That's right - I bought a pair of Fulcrum Racing 5 wheels this weekend. :) They replace my Neuvations M28 Aero set which have been worn down from too many miles in the rain. I'm pleased that I get Eurus perormance at a much better price.

March 26, 2007

Filed under: Uncategorized john @ 7:24am

I know it doesn't look like much is happening, but the last few weeks have been spent on tweaking the website behind the scenes. For example, we can finally serve pdf files again - I still have no idea what happened there... The paper has also been revised with some minor edits for clarity. Speaking of the paper, there's a part in the analysis where I integrate the equation of motion and get back an ugly, ugly looking equation. In the paper I abandon that method and move on to another one, but recently I've gone back to it. I reworked the equation and was able to use it for curve-fitting the data and... voila! It worked. And the curve fit parameters agreed to within 0.5% of the original method which is awesome. But the curve-fitting is so painful and laborious that I will be sticking with my original method. Anyone interested in the further analysis I did should email me. I'll write it up and send you my findings.

March 11, 2007

Filed under: Uncategorized john @ 10:01pm

Good news! The new database is up and running, and I've added two new Eurus wheelsets. The rear wheel data will be up shortly. Also soon, you will be able to download a pdf report for each wheel. On the down side, the forums got wiped out, but we might be able to restore them. Stay tuned.

February 25, 2007

Filed under: Uncategorized john @ 7:48am

I'm working on a few improvements to the site. Things like putting the results into a sortable database rather than a table. Adding a link for each wheel which opens a pdf containing a full report with graphs and explanations. That kind of thing. Without getting into details, the biggest problem is adding the database without wiping out all the forum posts... It's getting a bit frustrating. Who here would be ticked off if the forums got reset and all the old posts were lost? What do you think of the proposed changes? Let me know.

February 11, 2007

Filed under: Uncategorized john @ 2:48pm

Thanks to La Bicicletta, I have some new data. I have measured some new 2007 Shimano Dura Ace and ultegra wheels. Check out the results section!

February 2, 2007

Filed under: Uncategorized john @ 6:59am

Great news. Vancouver's finest high end bike shop, La Bicicletta, has agreed to share their wheels with me for testing. I will have access to Shimano, Campy, Zipp and many others. I bought a used laptop last night which means that my lab is now portable, so I will be able to set up in the store and interact with people while I'm testing. I will have more details soon.

January 5, 2007

Filed under: Uncategorized john @ 7:28am

Embarrassing. A few nights ago a friend came over with some wheels to measure. Finally, more data to add to the site. And... I am missing part of my test setup! A cheap, easily replaceable part, but still. How frustrating/embarrassing.

January 1, 2007

Filed under: Uncategorized john @ 6:23pm

Happy New Years from bikephysics.com!

December 20, 2006

Filed under: Uncategorized john @ 3:47pm

Merry Christmas and Happy Holidays to everyone. At work I have been busy winding down my project and in the new year I will be beginning a new one. This means I will be getting back to a normal schedule of measurements and updates. I will also be posting some details about my titanium rim project. I expect to have prototypes before spring at the latest.

September 26, 2006

Filed under: Uncategorized john @ 6:41am

It's been a very busy time for me so there haven't been any new measurements this month. I'll talk to my teammates and see if I can get my hands on some interesting wheels before the end of the week. Speaking of teammates, on Sunday our team organized our very first cyclocross race. It was a brutally tough course in the Euro tradition, but that didn't keep the riders away. We had 120+ people roll up to the start line. Awesome. Here's some footage of the race. http://video.google.ca/videoplay?docid=4499489874611202316 Enjoy!

September 4, 2006

Filed under: Uncategorized john @ 8:46am

I have a teammate, Ryan Cousineau, who has been taking on-bike interviews with his cell phone during our Saturday team rides. I was whining that he hadn't interviewed me, so now I've got a full minute of air time. By far, my favourite moment is near the end when Fiona rides by and gives a big smooch. Check it out. And check out the rest of his blog including his Motobecane project. It's awesome. http://wiredcola.blogspot.com/2006/09/on-bike-interviews-2_04.html

August 7, 2006

Filed under: Uncategorized john @ 4:15pm

Surprise!! Of the wheels I've tested so far, the Ksyrium ES wheelset has the worst rotational aerodynamics. The problem is big and 'fluffy' aluminum spokes that are as far outboard as they can be. The rear has better aerodynamics than the front because the spokes are closer to the center of the hub and sheltered a bit by the rim, but it's still not very good. Other than that, the wheelset is light with a low moment of inertia. It is a stunning wheelset that is very well built. Big spokes are a killer though...

August 7, 2006

Filed under: Uncategorized john @ 2:27pm

I've just finished up a set of Shimano WH-540's. A workhorse of a wheel that doesn't often get much respect. Well it should now! The data was a bit of a shock - low spoke count plus decent rim equals low moment of inertia and stunning aerodynamics. Wow! Now if only the bearings were replaced with something a bit smoother... Stand by, I'll have even more data this afternoon.

July 30, 2006

Filed under: Uncategorized john @ 5:26pm

It's summer time and I haven't been posting very regularly. Or measuring wheelsets. I'll see if I can't get some more data in the next few days. In the meantime, I'm trying to figure out if I should contract someone to build me some titanium rims... That'd be cool. I'm also thinking about bugging Hanna to install a proper database for the results. Something that can be sorted and/or searched. Any opinions? Let me know.

July 20, 2006

Filed under: Uncategorized john @ 7:46am

I want to go a bit off topic, but I figure that since it's my website nobody is going to complain too much. I'm wondering why nobody has tried to make a tubular rim out of titanium? You could easily fold and weld sheet titanium to get the right shape. And it would have excellent characteristics! It could be made light and stiff and would be able to handle very high spoke tensions. The braking surface would be resistant to wear. I could go on and on. Anybody want to discuss this in the forum?

July 15, 2006

Filed under: Uncategorized john @ 9:09pm

The results are up for the Mavis Ksyrium wheelset! And what interesting data it is. The aerodynamics for the wheelset are excellent and the moment of inertia is quite low. If it wasn't for the bit of drag in the bearings, the wheelset would be the best yet. Excuse me while I go check for prices on the internet...

July 14, 2006

Filed under: Uncategorized john @ 7:41am

Tonight or tomorrow I'll be posting data for a set of 2006 Mavic Ksyrium Elite wheels. That's right, both the front and rear. Expect two to three more wheelsets to be posted in the next week.

July 12, 2006

Filed under: Uncategorized john @ 1:01pm

So, it's been about a week since my last posting here. That feels like a long time. What have I been up to? Not much. Hmmm. What have I been doing? Anyways, there hasn't been a lot added to the site in the last week. I haven't even started the review of the Kult wheelset yet. I will though. And if I'm right, I'll be posting results for four more complete wheelsets in the next week or so.

July 6, 2006

Filed under: Uncategorized john @ 6:48 pm

Thanks to Hanna the Librarian, I have a new script which makes analysis of the data much quicker. All hail Hanna. I've also just finished measuring the rear wheel from the Kult wheelset. Expect the data to be posted very soon. I'm very tempted to write a complete review of the wheelset to give my full impression of their performance as well as their durability and value. Stay tuned...

July 3, 2006

Filed under: Uncategorized john @ 1:33 pm

I've just analyzed the Neuvation M28 Aero wheelset. Check out the results. Note that the aerodynamics are the same as the Scirocco, but worse than Kult. That's the difference between big bladed spokes and small bladed spokes. The ultra smooth bearings on a Neuvation wheel give you back 0.5 W at 50 km/hr. Sweet. Check it out.

June 25, 2006

Filed under: Uncategorized john @ 9:35 pm

Results are now up! Okay there's not much, but more will be added all the time. I'm also adding more content like this news page which I'll probably treat more like a blog. You can come here and find out what's new and what my current thoughts are. I hope you enjoy the site, and don't forget to visit the forums.