Comment here on the current newsletter issue, or about anything you see on the site. All we ask is that you maintain civility and respect for your fellow cyclists. Thanks.
A couple of comments on eBay from one who has both bought and sold ...
1. Don't expect a great bargain! What eBay provides you is, as Jim mentions, is CHOICE, especially for obsolete or specialty parts. By the time you out-bid other people (auction format) and pay shipping (either auction or Buy It Now format) you will end up paying what you would in your LBS ... that is, if they were able to get the part in the first place.
2. Be EXTREMELY WARY of hidden shipping costs if you live outside the USA. eBay partners with UPS for shipping. Here in Canada, though, UPS is famous for tacking-on a "customs brokerage service charge" payable at your door on delivery. These charges can run up to 40% of your item's value. Surprise! So, be very picky with your seller on exactly what method he / she uses, are there extra charges, and will the seller pay them. If you can, specify no UPS.
By the way UPS was the subject of class action lawsuits about hidden service charges in at least one Canadian province. Don't know the outcome.
Jim's initial comments about eBay are accurate and helpful; however, one glaring issue with eBay is their PayPal subsidiary restraints. In short, one is permitted an initial purchasing ceiling ($10,000) using one's own credit card and then one has to commit to PayPal's own requirements for becoming verified. This verification rule requires one to either take on PayPal's own Mastercard account or to permit PayPal access to one's own bank account.
My concerns with either of these verification requirements is that additional credit cards are not alway useful and having anyone access your private banking resources is inviting serious economic risk from hackers. Everyday we arer reminded of the increasding success hackers are having with stealing or harming financial transactions.
For all the benefits of relatively easy transactions the Web provides, the risks for mischief and misdeeds make using the Internet increasingly untenable.
I wouldn't want anyone to do anything they're uncomfortable about, lilygirl, but I feel like I need to stick up for ebay and PayPal now. I have been using ebay since 1999 and have never had a problem buying or selling in the bicycle category where it would be pretty unusual to ever buy an item for 10K. Maybe if I was selling/buying cars for big money I wouldn't be so lucky, but in the bike genre ebay has been a great place - a lot like bicyclists in general, really.
So, yeah, be as safe and smart about it as you can, but ebay and PayPal are pretty easy to use and safe, and they can really help you enjoy cycling, too. For example, I now pay most of my race registrations with my PayPal account - the money from used bike parts paying for the fun rides... to me that's pretty cool to think about... no more charges on my credit card to worry about.
Thanks for the feedback,Jim Langley
A few years ago when Bradley Wiggins converted full time to road racing from track racing, he dropped a lot of weight, including a lot of muscle mass. I remember reading an article how he was able to do this without sacrificing power. He is nothing but a stick now yet obviously still has a lot of power. I've always been curious what that method was. But it appears it is possible given his success. His top end power may not be quite the same as it was on the track but he doesn't need that in road racing. I suppose if we all had Garmin and Sky's resources, we might be able to accomplish this as well. Oh well.
I've always been curious about Wiggins' weight loss techniques too. I wonder if he was a naturally thin rider who bulked up for his track racing career. In that case it would have been easy to lose the extra weight and return to his normal build.
There are lots of cases of riders who lost considerable weight and did well. Bjarne Riis is an example of a rider who became almost emaciated in order to win the Tour. In his case, other factors may have helped as well. But Riis has gained all his weight back (and more) so a lot of the extreme leanness we see in pro bike riders has to do with the big miles they ride. If they could only do 3 or 4,000 miles a year, they'd likely look more like a recreational rider and less like a lean pro climbing machine.
The important thing for us recreational riders is not to get carried away with weight loss. I remember one pro who advocated riding long miles with no breakfast. He didn't use a sports drink or eat while riding either. This may cause weight loss but it's also a recipe for muscle mass loss and learning to ride extremely slowly while feeling miserable.
I ride a fix gear (with front break) on my commute to work. Sensible gearing selection allows me to spin downhill, get up any hill on my route (without excessive pressure on my knees) and maintain good speed on the flat.
It aids pedalling technique, improves bike handling and removes the thought process of which gear should I be in. It simplifies the ride and makes it enjoyable for what it is.
Long live the fixie on the road!!
I believe we all have our own particular make-up i.e. our own natural build. We should find what that is and then train to improve the areas we want to improve.
I'm naturally slim, so will never be a sprinter, but I can climb extremely well even though I'm 6'2" tall.
Take Mark Cavendish, for example, the world fastest road sprinter. But also one of the worst climbers.
Accept what you naturally are, identify your strengths (and weaknesses), and improve them as best you can.
A race is always dynamic. You never know what to expect. The only thing you can be sure of is the course and how it fits you as a rider. Try and race the course the best way you can, save your energy when possible for use when you really need to stay in touch or make a break for it.
Ride your race, not the competitors race otherwise they will beat you.
I agree that we all have our own particular physiology and that making the most of what you have is the key. We can't all be one thing or another, but we can work to maximize the specific things our bodies allow us to excel at, and work to improve the others.
I recently found out I had high blood pressure. I live in Michigan and ride with a skull cap and baseball hat in cold weather. This last week I rode with just the baseball hat. Today was cold and I rode with the skull cap and baseball cap again and noticed the helmet was very tight. I wondered if riding 90 minutes per day for the past 8 months with a tight helmet (chin strap was tight) could have possibly caused my blood pressure to rise. Would welcome any comments if anybody has had a similar experience.
Thanks Scott. Funny and sadly very true. This has been my experience several times. Still looking for that special women who can drop me.
I found that, just before I reach a headset's pre-load torque setting, I can no longer rotate the steerer tube/stem spacers with my hands/fingers, no matter how hard I try. Periodically I try this and, if I can rotate the spacers, I re-torque the headset. This only works if you have enough spacers to get a grip on.
The first question I ask new riders when I see an irregular position on the bike is whether any body part hurts after a long ride. If your knees hurt, something is off kilter and needs to be adjusted. Hopefully, its something on the bike.
A good, quick, layman's guide on whether your knee position is correct is to watch your knee motion while riding at your target rpm. The knee should go straight up and down in a fairly flat plane that may or may not be exactly vertical. While riding, watch to see if your knees stay in their respective plane.
If your knees are splayed outward, the two planes would make a "V" when visualised from straight ahead or behind. If your knees are pinched inward, the two planes will make an inverted "V". Few riders have parallel planes and most have some degree of lop-sidedness where one plane is at a slightly greater angle than the other.
If your set up is not correct, your knees will not stay in a plane but will appear to rotate in a circle as they go up and down. The size of the circle will tell you how far out of "fit" your set up is.
The answer can be in the pedals, the cleats, saddle height or angle, or just body mechanics. It can be as simple as placing a wedge of one or two thicknesses of aluminum foil under one side of a cleat.
Once corrected, record the exact fix in the same record you keep your other bike measurements.
It is worth the time to investigate. If there is problem, fixing it will significantly increase your enjoyment of riding. If there isn't a problem, you'll know that it's just your preferred position and you can tell your "expert" critics to back off.
That's a good tip for visualizing your pedal stroke. I also like the approach of fixing it if something hurts, but leaving it alone if not. Good stuff.
Great article on headset service. I believe you overlooked the importance of torque on the stem. We get customers that over-torque the stem bolts leading to stem cracking.
Headset loosening Tip: Got this one Chris King web site. If you are experiencing problems with your headset always getting loose every several months, check for carbon spacers and replace with aluminum spacers. This drove me crazy for a year and no one could fix the problem. Tried replacing the stem and carbon grip gel without any luck until I replaced the spacers. Chris King recommends using their expensive spacers but I used the cheap ones that come with a spacer kit.
Thanks for the great tips, cwakefield. If you own a torque wrench, know how to use it, and know the correct torque, it's always a good idea to use it. But, those issues can make it a challenge for the average home mechanic who doesn't have a torque wrench or know how to use it - or if their stem doesn't have the recommended torque written on it. But, yes, if you've got the tool and information, torquing bolts is the best thing to do.
Torque wrenches aren't magic, though. I've seen people destroy parts because they read inch pounds in the instructions and then tightened to the right number but in foot pounds. Torque wrenches kind of give the mechanic permission to stop thinking and just crank away trusting the tool. That's a bad thing. A mechanic always needs to think and judge and feel what they're doing. I think the best tools for most people are preset at the factory to only provide a given torque that's right for the specific component, such as Ritchey's simple stem torque T.
That Chris King tip on carbon spacers compressing and letting the headset loosen is a good one. I've never experienced that but I believe it can happen. Thanks!
I forgot to mention another headset check that's really easy to do. You can just grab your spacer(s) and try to turn them. If they turn, it usually means your headset needs tightening. That's one really easy headset check that anybody can make.
Thanks for the great tips,
Nice review on the 3T aero carbon clinchers. However, given that this is a new part of 3T's product offerings, and that 3T has had recent recalls with both aero bars and carbon forks, I think I'd leave this product alone for a while and wait for "version 3". My aero wheels are made by a long-standing major industry player; they may cost a bit more, but I'll stick with them for the assured product quality, thank you very much.
The wind invades your personal space, It sours your attitude.
Ok so I get that physics. And I know wind is my friend in training, and I use this mantra in my mind. But why in the hell (sorry) does maintaining tempo (or whatever zone, say 170w) or doing some intervals, or God forbid spints seem so much harder riding into the wind than riding with a tailwind? BTW I have been a fan an subscriber for a long, long time.
Thanks for all the good stuff along the way.
Polli Schildge (Old gal rider and mom of a pro)
PS The formulas are interesting, but I just want to understand why holding the same power/intensity feels so much harder in the wind. I tried to do sprints rinto a strong headwind recently, and it was super challenging getting the cadence and gearing right, and I kept telling myself that it sould feel something like hill sprints, but it really did not. Yes, I talk to myself on the bike.
That is a very interesting observation. Maybe in a headwind it is more difficult for the legs to follow the pedal circle due to the increased air drag on the shins through the top dead center (12 o'clock crank position). So the biomechanics of pedaling may become less efficient for the leg muscles when riding into the wind (need to push forward with large force instead of mostly downward force in hill sprints and smooth pedaling with tailwind). This is similar to running in waist-high water. Different (untrained) muscle groups are used to push the legs forward with large force. Performance is limited by force rather than by power. This is just a hypothesis, I have no proof of it.
Good question. I think most of us have had your experience. I suspect that part of the answer is psychological and part is physical. Mentally, a headwind feels hard regardless of your power output because it's pushing on your body. A steep hill exerts its force on your wheels or so it seems and having something physically push you back, like a strong headwind does, seems more intimidating than having to work against gravity.
There's a physical aspect too in that most headwinds aren't steady but come in gusts so the resistance isn't even. Instead you're pushing hard one minute into a gale then without warning the resistance drops during a lull in the wind and you experience an easier section which you have to adjust to. Then the gusts pick up again necessitating another change in effort. All this variation becomes wearing mentally. And of course it wears on the body as well.
I'm sure there are other factors but I've had plenty of time to think about the phenomenon as I fight the wind and these are the major culprits I have identified in my own riding.
Kerry Irons’ formula for calculating watts is correct. But like the original post by Bob Howland, his analysis is partially applicable, because ground speed Vg and airspeed Va are not independent of each other, and both depend on wind speed Vw (in a headwind, when wind speed increases, bike speed will decrease). Therefore, power should be the independent variable in the equation. So, the formula we need is the equation for the root of the power formula given by Kerry Irons, where watts is the independent variable, and where Va and Vg are related to each other by another equation. For a direct headwind scenario, this second equation is simply Va = Vg + Vw, where Vw is the wind speed measured on the ground. But in general, a direct headwind condition cannot be assumed, so the general equation has additional terms. That is when the Pythagorean Theorem enters the equation. Jobst Brandt’s analysis published in Bicycle Guide in 1992, referenced here in the post by gregtitus, uses that complete equation. Jobst Brandt’s article is a rewriting of the original article that I wrote and published in Bike Tech, the technical newsletter of Bicycling Magazine, in 1984. Here is a link to the original article:
I appreciate yours and all the commenters' time today in adding to this discussion. It's great that the RBR community is engaged and always willing to share information.
Thanks once more to all of you!
I don't need a complicated formula to tell me that it's harder to go faster when riding into a headwind.
I became an English major just for this reason! And I agree that riding well in windy conditions is independent of formulas. In fact, I wrote an eArticle about handling wind and using windy conditions to improve your fitness. It's available on the RBR bookstore--Win Against Wind.
I live in one of the flattest, windiest parts of the country - the Texas panhandle.
If you don't ride in the wind here, you don't ride period.
Hence we always tend to have at least 3-4 on rides so we can share the work.
Also when I travel to the Rocky Mountains, the climbs seem pleasant compared to a headwind.
PS - I don't really need to know too much about the math/physics of riding in the wind any more than I need to know why there is wind in the first place. But if YOU need to know, that's fine too!
Your usage of the Pythagorean Theorem gave me a chuckle. I didn't understand a word of it, but I was reminded of the "Pythagorean Maxim" that I ran across when I recently, after a 60 year hiatus, re-read Moby Dick. I hated the book when I was assigned it as an 18 year old college freshman because no one told me about the ribald humor in its pages. When I stumbled on the P.M. on about page five my curiosity caused me to look it up and I found that it says, "Don't eat beans!" Ishmael says that he wanted to be a regular sailor standing on the forecastle with the wind in his face and the P.M. in full operation towards the other sailors. A fart joke in Moby Dick. Oh the things we miss when we're young!
Remember from school; A squared + B squared = C squared. He solved immediately for C. To get C by itself, you need to take the (square root of (A squared + B squared)). That's all he did.
You're thinking about the Pythagorean Theorum. In Moby Dick Melville mentions the Pythagorean Maxim. There were lots of maxims. The one Melville referred to was "Don't eat beans."
Thanks for adding a little levity to today's comments!
Perhaps we should strive toward a Pythagorean RBR Maxim -- "Don't do math!" It would certainly let us face the wind without having to look back at the pollution our math has left behind us. ;-)
Although your premices are right you math/physics are a little shaky.
Yes, we've heard from a couple of other readers, too, about the physics and math not being precisely correct.
Bob Howland, who was kind enough to tackle the question for us, makes no bones about his not being an expert in this particular area. He's a physics teacher who stretched to try to help out his fellow riders and fellow RBR readers.
And I switched from an engineering major to journalism 30+ years ago for good reason!
We could totally shy away from these sorts of questions for fear of not getting it exactly right. Or we can give it our best shot at risk of embarrassing ourselves a bit. We chose the latter.
I hope trying to explain the premise in layman's terms is helpful and interesting. That's the real aim.
And I'm thankful for other readers chipping in their expertise as well!
The analysis of forces required into a headwind is only partially correct. It is correct to state that the drag force increases with the square of velocity, but the drag force must be multiplied by speed to determine power, so in fact the power increases with the cube of velocity.
The total power required includes frictional forces (tire rolling resistance, bearings, chains) and gravity which are both linear with velocity. Power required to overcome aerodynamic effects increase with the cube of velocity.
Here is a formula for calculating power:
watts = [Vg*W(.0053 + %G/100) + .0083(Va^3)]*2
Where Vg is ground speed, %G is the grade in percent, W is the rider weight in lbs., and Va is the rider speed through the air. Note that you can't simply add "wind speed" to riding speed to get the rider's speed through the air because wind speed is measured 30 feet above ground and away from buildings, hills, trees, etc. In practice a rider experiences roughly 1/3 of "wind speed" at ground level. Of course it is totally different riding through a thick forest compared to open, flat plains.
Jobst Brandt, in an article entitled "Riding in the Wind" that appeared in the 1992 issue of Bicycle Guide, clearly describes the forces (in understandable language) that provide resistance to the cyclist. In short, your forward speed increases in a simple linear progression (20 mph is twice as fast as 10 mph), the air resistance to that forward motion increases in a geometric fashion (there is 4 times as much resistance at 20 mph as at 10 mph), and the power needed to overcome air resistance increases with the cube of the speed (it takes 8 times as much power to ride at 20 mph as at 10 mph). It's also interesting to note that studies have suggested that in a pace line, the #2 cyclist saves 23% of the effort the #1 cyclist is making, the #3 and greater cyclists save 33%. If you're buried inside the peloton, you're saving about 36%. After a good hard pull, don't drop back to #2, go to the end of the line! (or at least #3), for maximum recovery.
Please let us know how to adjust the FD when using Rotor Q-rings?
When you combine both math formulas, you get the following (a) use C24's wheels, no high dish, (b) get as low as you can get - to lower the center of gravity, will make you much more stable, (c) the square footage side area makes a difference so the thinner, smaller cyclists will feel less buffeting.
Ride as hard as you can into a headwind, I will be right behind you drafting :-)
I tried to basically post what the outcome is and how to better ride in wind in laymans terms.
If in a cross wind, the less square footage the rider can present to the wind, the less buffeting. Some of these 'solutions' are thinner dish wheels (24's vs 50's), flapping vests, belly hanging over the top tube ;-), etc. I see guys riding their C50's on a windy day being blown all over the road.
When the winds get REAL heavy, crouch down and get low. Lowering you Center of Gravity (CG) makes you much more stable.
Another IMPORTANT point, When its REAL windy, DO NOT FORCE THE FRONT WHEEL TO HOLD A SPECIFIC LINE, LET THE FRONT WHEEL FLOAT A LITTLE.
Interesting discussion on winds, but it's not entirely correct.
First, riding slower in a crosswind does not increase one's gravity vector (unless one stops to chow down on a few burgers and fries first), it stays the same, but becomes a larger percentage of the cumulative velocity.
Second, the analysis of head winds is not correct. Assuming all other variables remain constant except for the rider's velocity the increase in effort as speed changes from 15 to 20 mph is (20**2)/(15**2)-1 or +78% higher, not 40/15-1 or +167%.
Actually the formula for wind Power is: P = .5ρAv^3
The formula you posted was for the Force, not Power. This only makes the point even more extreme, because the Power of the wind is related to the Velocity cubed, not squared.
bybarelyw is correct. I shorthand the increase to (20 x20) / (15 x 15) = 400 / 225 = 1.78, or a 78% increase in power needed in a wind - but that's in still air.
If you are moving 15 mph into a 10 mph headwind, though, you have a relative speed of 25 mph. THis means you are working much harder than going 20 mph in still air. how much more effort? (25/25)/ (20 x 20) = 625 / 400 = 1.56, a 56% increase. That's why headwinds ae so much work, and why we slow down.
This is why reversing direction on a ride, so that you go from a 10 mph headwind to a 10 mph tailwind. 15 mph into the headwind takes the effort that 35 mph would take with the tailwind! So, make sure you always have the tailwind on your rides -- you;ll feel more powerful.
Meanwhile, Mr. Editor, please have someone check your math before you post on this topic again, or find a good Web site.
I too have a favorite water bottle, the Polar Bottle. What I hate most when I've been riding for over an hour on a hot day is grabbing a gulp of hot water! With the Polar Bottle I can enjoy a gulp of cold to cool water for as long as 3 hours in 90 degree weather, and the Polar Bottle stays colder longer then the Camelbak version. Some people complain that the Polar Bottle is too hard to squeeze, not sure what that's all about since my 5 year old grandson has no problem drinking out of one! And the Polar Bottles come in a wide assortment of colors and designs to suit anyone's sense of artistic design. Polar Bottles are just really cool.
One of the things Scott forgot to mention is that both waters bottles must be the same for a given ride.
There is nothing worse than assymmetry on a bike (other than a Dogma). The number of times is staggering that I have had to chastised people for having two different water bottles on a ride.
You dont 'throw' your bottle when they are empty like the pros do? haha.
The thing that irks me and I tell guys all the time...they are wearing their team kits with arm warmers with the teams name or sponsors name on the warmers. Inevitably, 1/2 of them have the warmers on the wrong arms so the sponsors name is upside down when riding.
PEOPLE, CHECK YOUR ARM WARMERS for correct positioning of the name!
if you are carrying a smartphone, take a photo of your drivers license and store it in the photos section (i created a separate file for these id's).
if concerned about security, use program like ewallet that offers password protection for this data.
appreciate all the good tips others have offered for keeping the good times rolling. Unfortunately, as cyclists we're vulnerable to serious accidents, so...
You should have the word ICE (in case of emergency) associated with people that should be called should you be found along the road and unable to communicate.
I really hate to offer this advice, but it could be necessary. In taking care of my elderly mom, i realized i needed to have a copy of her living will availalable to me 24.7, so i made a pdf copy of it available through my email account on my cellphone, so i could produce it immediately should she be taken to the hospital. I then realized that i shoudl have the exact same thing for myself, unfortunately, should i be involved in a bike accident...
I keep my spare tube in ziplock bag with some tire talc. The bag protects the tube and the talc makes it easier to install.
I am not a big fan of having one tool kit and switching it from bike to bike. I have a dedicated tool kit on each bike. Keeps me from forgetting it, and each kit can be tailored to the specific bike.
I don't know . . . just got an MTB, my first time using discs. Only did 5 or 6 rides, but I have to readjust the things after every ride. No matter how I adjust it, there's ALWAYS some kind of intermittant rubbing noises. Now, I'm getting this weird pulsating feeling when applying the brakes. Sheesh!!! If this is how all discs act (up), I'll take calipers anyday!
I have a MTB with hydraulic disks front and rear and I am over the moon with them and would like to have similar braking ability on my road bike. There is absolutely no comparison with the rim brakes on my previous MTB or my road bike - give me disks any time.
Disc brakes on my MTB are light years ahead of my old rubber rim brakes in stopping power and ease of use. If the weight was kept reasonable then disc brakes on my road bike, no question. Although, after having tried to bleed my MTB brakes and failing, they make home maintenance more of an issue for the mechanically challenged. Good news for the LBS.
I see you are comparing OLD rim brakes, probably with worn out or ozone hardened pads, to new disc brakes. Please go try the new Shimano Dura Ace 9000 rim brakes, then come back and tell us disc brakes are still better. I dont think you will be able to. YES, the 9000's are THAT GOOD!!!
My tip is to carry 2 spare tubes, each in a sock of its own. The sock protects the tube so you won't have holes worn in it when the time comes to pump it up. You can also use the sock to wipe your hands should you need to.
I enjoy stopping to help other riders but CO2 cartridges can get expensive. I went by the local brewery supply company and bought a case of 12 gram oil-less CO2 cartridges for less than a dollar a piece.
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