Kevin,

I recently heard a term that I don’t understand. What is “Q Factor”? My imagination is going everywhere but I don’t have a Q, er, clue!

Amanda

Hi Amanda,

I like your pun but really, Q Factor is quite easy. It is the measurement of how far apart your feet are when on the bike. If you stand with your feet at shoulder width, and then move them together so they touch, you are reducing the Q factor. Some bike cranksets have a bigger Q Factor than others and this not only impacts how your knees line up over your ankles but it affects cornering clearance as well.

Your cleats can also be adjusted inwards and outwards and that changes your Q Factor as well. Most people like the Q Factor to be as small as possible and in fact, will adjust their cleats so their ankle barely clears the cranks. The further outboard you move the cleats, the more inboard you are moving your feet and the Q factor is reduced.

Kevin

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Kevin,

I bought a carbon fiber bike last year and was told not to grease the seatpost as it would destroy the carbon. I used an aluminum seatpost and this year I needed to replace the saddle which meant that I needed to move the saddle up a little. When I tried to adjust the seatpost I found that it is stuck in there solid. There is a little white powder around the seatpost where it enters the bike and my bikeshop told me that the seatpost had become welded in place due to corrosion. Can carbon fiber corrode? Oh. This was a used seatpost that I took out of my old bike and it had some of this powder on it when I took it out of that bike too.

John

Hi John,

I am sorry to say, you have a problem! Your bikeshop may be able to cut the old seatpost out but it won’t be easy and they may damage the frame in the process. What you have experienced is the phenomenon called galvanic corrosion, which happens when you combine carbon fiber, aluminum and perspiration. That white powder is corroded aluminum and it is a real problem for some people who have just the right combination and amount of electrolytes in their sweat.

Interestingly, some people do not cause their bikes to corrode, and some others really have a problem. I bet your cables and other metal components corrode as well, so this is not a problem with the seatpost alone.

There are three ways to prevent this. The first is to keep the bike dry. Well, this is not possible when riding in the heat and rain, but keeping the bike clean does help. Second, insulating the two materials is possible, using grease or assembly paste. The anodization of the seatpost is another way to insulate the raw aluminum from the carbon fiber but since your post was used, some of that protective coating was gone. Many framebuilders will put a layer of fiberglass in the seatpost receiver to prevent the carbon fibers from touching aluminum parts. Finally, choosing similar materials is a good thing. A carbon seatpost in a carbon bike presents no problem. Aluminum seatposts need to be greased no matter what frames they are installed in, and that is what your initial problem was.

These lightweight modern bikes have many advancements over older bikes but they can still suffer from galvanic corrosion. If you keep your bike clean, regularly disassemble, clean and relubricate it and choose components wisely, you will minimize these problems in the future.

Kevin

Kevin Recommends

We only recommend products, services or companies that we have actually tried or worked with personally. A recommendation, like a reputation, is very important and we do not take this responsibility lightly. The following links are to our friends at the Cooper Aerobics Center in Dallas. Dr. Kenneth Cooper is considered “The Father of Aerobics” and has put together a group of world class companies that have a direct impact on us as cyclists and as professional people:

Cooper Complete – We have arranged for 10% off anything you buy from Cooper Complete if you put “KGS” in the coupon link and then “recalculate”.

Cooper Clinic - The world renowned Cooper Clinic is starting to create medical exams and services aimed at professional adults who ride bicycles.

Cooper Fitness Center – The Cooper Fitness Center has a special strength training introductory program for cyclists.

These links are to our frame builders and other providers that make KGS Bikes the premiere custom bicycle studio in the world:

Co-Motion Cycles – We’ve long enjoyed a reputation for building tandems that simply handle better.

Guru Bikes – Our approach is based on combining the best of both worlds: cutting edge technology delivered by hand and with an old school attention-to-detail.

Kirklee Bicycles – KirkLee is an up and coming great framebuilder from Austin. We are very excited about the quality and performance they bring and are proud to offer KirkLee frames as part of our KGS custom bicycle options.

Parlee Cycles – Simply put, PARLEE frames are the best built and best riding carbon fiber frames available today, at any price. They are functional works of art.

Red Licorice Events – The “Sweet and Twisted” team that promotes Austin’s best athletic events. KGS Bikes is an ongoing sponsor of triathlons produced by our friends Erin and Leilani and we are thrilled with the relationship.

River Place Country Club – This is our Austin address where we can meet in person to define your custom bike. We arranged with the folks at River Place CC to rent space on an as needed basis to offer a quiet focused environment to determine your ultimate bicycle position and then design a custom bike around that position. The New York Times describes cycling as “the new golf” and River Place CC recognizes that they can offer more than golf to the active lifestyle advocate.

Sem Custom Paint – Dave Sem is the best extreme detail painter in the world.

Serotta – Only Serottas have the extensive engineering of our proprietary Colorado Concept tubing design. It’s the foundation behind the unique ride of each and every Serotta.

Source Endurance – They are teaming with us to provide physiological testing, data analysis, training consultation and long-term coaching. They have two state-of-the art labs, one in Austin and one in San Marcus. We are proud to recommend them and invite you to check them out.

Tacx – Home of the Fortius Virtual Reality trainer. This is the trainer component of our “Ultimate Spin Bike”. Tacx also makes many other fine products. KGS Bikes is an Authorized Tacx Testing Center.

Topolino Technology – Our wheels embody this ethic: A fundamental redesign of wheel construction to take advantage of extraordinary materials with amazing properties, yielding a wheelset that performs like no other.

Zinn Cycles – For more than a quarter of a century, Zinn Cycles have been working to make cycling more enjoyable for customers, and that commitment remains at the heart of everything they do.

About KGS Bikes and Kevin

KGS Bikes is known around the world as the premiere custom bicycle studio. Kevin Saunders, President, has over 25 years experience in bicycle fitting and design of custom bicycles. He also has a broad knowledge of anatomy, structural engineering and industrial design. KGS Bikes creates custom bicycles with the best components available and uses framebuilders such as Co-Motion, Guru, KirkLee, Parlee, Serotta and Zinn. Visit kgsbikes.com for more information, including beautiful photography of the bikes carefully created for their owners. Don’t forget to find us on Facebook, twitter and at your next event to photograph your bike position and post it on Facebook and Flickr for you to share with your friends.

Please feel free to forward this newsletter to your friends! We appreciate your time and interest.

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