Technical Q&A with Lennard Zinn - Of sealant, socks and steerer tubes
Dear Lennard,
My friend has a new Felt AR2 and on the weekend we went out for a long ride. Rain was on and off but never to the point where we were soaked. So today doing some after weekend maintenance, we noticed some water dripping out of the seatpost when turned upside down. Water continued to trickle so we decided to take out the post and drain it. We drained a good 8-12 oz. of water out of the bike.
It seems like water enters the frame on the trailing edge of the aero seatpost. I suggested using some silicone sealant to close up that gap but we are unsure about any reactions with carbon. Maybe an Oxygen Sensor Safe Sealant would work best.
Katsu
Dear Katsu,
You needn’t worry about a reaction between a carbon frame and silicone sealant. And as long as you’re not running gasoline in that bike, there’s no need for Oxygen Sensor Safe Sealant, although that also could do the trick.
Lennard
The below string of questions from a reader are interspersed with answers from Shimano.
Dear Lennard,
I just bought a new bike which came with Shimano 105. I've read several articles which discuss problems with the left shifter. Apparently, Shimano made a version that was intended for both double and triple. Many say the left shifter breaks very easily, and I'm concerned about my new kit. I also read Shimano scrapped that one and went back to a dedicated double or dedicated triple front shifter.
Bob
Shimano response
The current version of Shimano 105, designated by model numbers of 56XX format, has a dual control shifter that is both double and triple crank compatible. The switch to this format first occurred for the 1999 model year in an effort to simplify the line for bike manufacturers and retailers while adding versatility for cyclists. All Shimano components are actually subject to the same rigorous quality standards prior to mass production, whether they are Dura-Ace or Sora.
Q: Is there any way to tell if my shifter is one of the double/triple models? Or the later 'corrected' model?
Shimano response
One thing that Shimano does is consistently examine any products that are returned under warranty as well as monitor market feedback on the product. In doing so, there are often continuous improvements made in every product during its life cycle.
Regardless of when in the life cycle of the product your part the part was produced, Shimano has enough confidence in the product to offer a 2-year warranty (3 years on Dura-Ace and XTR). Non-conformances do occur occasionally, and when they do, they typically show up early in the product’s use. The shifter can be identified by model number, which is stamped on the plastic perch (under the rubber hood).
Q: Is there anything I can do proactively to prevent the shifter from breaking, other than upgrade?
Shimano response
The levers are designed to handle a variety of conditions and should function well with very little care. One of the easy things to avoid is shifting the lever in static conditions. This winds the cable without allowing the derailleur to move and puts excessive force on the internals. While this will not necessarily break the shifter, it does create a load that can impact the internals. Contamination of the lever and cables is the other issue to be aware of that can impact performance.
The shifter internals are well protected and some cleaning can be done will compressed air, but the best is to avoid getting too much debris on the internals. Cables and housing are easily replaced.
Responses from Devin Walton
Media Relations Officer, Shimano American
SRAM’s response to a letter from “King” in the September 9 column regarding a failed SRAM shifter.
Dear Lennard,
A reader had written you regarding a failure with a SRAM shift lever, we can understand his disappointment but we are glad he chose SRAM. He mentioned that he had been waiting for some time for his replacement part, he also inquired about how many levers a “handful” was that I had mentioned had failed.
No customer should ever be waiting a month, but he did fail to indicate that he was in the Philippines. International policies vary by region but in all cases our distributor partners make every effort to service the customer as soon as possible. It is a challenge to maintain the exact same standards for any company on a global scale. Regardless, the part is warranteed and he deserves to get a replacement in a reasonable amount of time.
Regarding his “handful” question, I spoke to our quality engineers and product manager, who confirmed that we have over 100,000 shift levers in the field at the time of this writing and confirmed a total of 46 had failed. We reacted to improve our internal shifter bracket mechanism after we saw only six fail.
We have had stock of new replacement shifters for many months and we will ship out the next day to any shop anywhere in the U.S., this has always been our policy. We ask our distributors internationally follow this policy as closely as possible.
Again, we do apologize for the failure and lost time on his bike.
Michael Zellmann
SRAM U.S. Road PR & Media Manager
Dear Lennard,
Thanks for all the great advice in your tech column. One subject that I have not seen explored is the replacement of tapered forks. My current ride has a tapered fork/headtube, with a 1-1/2-inch bearing on the bottom and 1-1/8-inch up top.
In looking for a replacement aftermarket fork I could not find any that have tapered steerers. Do you have any insight as to where a fork like this could be located or is there a bearing combination that would allow the use of a standard fork? In other words, how would you remedy this situation?
George
Dear George,
Below is a response from Chris King regarding headset solutions that will allow you to use a replacement fork with a cylindrical 1-1/8-inch steering tube in a frame with a tapered head tube meant to house a tapered steering tube.
Lennard
An answer from Chris King
We do offer multiple headset options that will allow the use of a 1-1/8-inch straight steerer in a tapered headtube. Basically, a 1.5- to 1-1/8-inch Devolution baseplate will need to be used with one of our 1.5-inch bottom bearing designs. There are a variety of tapered headtube designs on the market and while our headset may not accommodate all of them here are the options we have available. Which option to use will depend on the design of your headtube.
If the headtube uses an external 1-1/8-inch top cup (33.9 mm internal diameter) and a 1.5-inch external bottom cup (49.6 mm internal diameter) then our NoThreadset headset for tapered head tube can be used with the Devolution baseplate.
If the headtube uses a low stack 1-1/8-inch top cup (44.0 mm internal diameter) and a 1.5-inch low stack bottom cup (55.95 mm internal diameter) then our new InSet tapered headset can be used with the Devolution baseplate.
If the headtube uses a low stack 1-1/8-inch top cup (33.9 mm internal diameter) and a 1.5-inch external bottom cup (49.6 mm internal diameter) then our InSet mixed tapered headset can be used with a Devolution baseplate.
The specifications and examples can be viewed here:
http://chrisking.com/headsets/hds_inset
http://chrisking.com/headsets/hds_onepointfive
See your local authorized Chris King dealer to order or for more information.
Gabe Cabatic
Chris King Precision Components
Dear Lennard,
I recently purchased a pair of Northwave cycling shoes for my road bike, which is fitted with Look KeO pedals. The problem I have has nothing to do with the pedals but with the texture of the shoes. The shoes fit perfectly but when I wear my slick cycling socks, I feel that my feet move and roll inside the shoes no matter how much I pull on the straps. I've come to use regular, thick, cotton socks but they are too warm and not to mention, unfashionable.
How can I get some friction between the socks and the shoes so that my feet don't slide? I guess the tricky part is that most of the uncomfortable movement originates against the top and the sides of the shoes instead of just being a simple manner of lack of grip with the insoles.
Oscar
An answer from Northwave
While each shoe manufacturer uses their own proprietary materials and designs to secure the foot, Northwave has taken great steps to ensure comfort, performance and long-term durability of our cycling shoes. First and foremost Northwave introduced the BioMap design concept to direct this philosophy. This idea allows the foot itself to perform and function with regard to blood flow, foot security and temperature regulation for maximum comfort and performance. The features that are inherent to this design are:
• S.B.S. (step by step) Closing System
• Micro metric buckle with a release “step by step”.
• ASR2 Ankle Strap
• EVA instep pad to control heel movement and secure the foot.
• WLI, Wooden Lasted Insole
• Temperature control and dampening via full length wooden midsole, fully waterproof
• Web Power Cage
• Minimal usage of over-injected materials used with quantities of mesh and no overlapping materials.
• Aerator System
• Strategically placed ventilation to ensure maximum comfort and allow maximum performance.
• Heel Retention
• Using either the Ultra Y or Omega coupled with a “cat’s tongue” material creates perfect retention.
While each of these features cannot guarantee stand alone performance, Northwave has combined these to ensure the best possible combination of comfort and performance. Of course, fit also starts in the bike shop. Most shops have qualified and trained sales staff that can use each company’s fit concept and performance position to help the cyclist choose what is best for their needs. Every foot shape varies in terms of volume (width, length, height) and all of us have different tolerances and expectations of fit. Northwave uses 2 different insoles that are positioned with performance and price point in mind.
• Performance Pro
• Use of maximum perforation,
• 3D construction with a supportive arch support and heel cup
• Superfoam “core” material that gives all day comfort
• Microfiber topsheet that for wicking
• Performance Advanced
• Perforated for ventilation
• Superfoam core
• 3D construction
Either a custom or off the shelf insole system can greatly change the fit for the better. Whether you are looking to stabilize the foot for performance and energy transmission, take up a little volume or create volume by stabilization and reducing elongation of the foot. A different insole may also give the sock some grip for stability and keep it from moving too much in the shoe.
Northwave also recommends a dedicated cycling sock that ensures a close fit and transmission of energy to the shoe and pedal system. Northwave offers a number of different sock models that have a distinct composition and design.
• Comp Sock
• Coolmax material
• Reinforced toe and heel
• Topside mesh
• Tour Sock
• Meryl Skinlife material
• Topside mesh for moisture control and conformability
• Reinforced toe and heel
This hopefully answers your question and gives you a path to adjust your fit. You may also want to go back to the shop for another look at the shoe/foot interface and they can possibly give you some in store advice on the exact scenario and work with your current fit to make adjustments.
John McKone
Sports Marketing and Events
Northwave North America
Technical writer Lennard Zinn is a frame builder (www.zinncycles.com), a former U.S. national team rider and author of numerous books on bikes and bike maintenance including the pair of successful maintenance guides "Zinn and the Art of Mountain Bike Maintenance" - now available also on DVD, and "Zinn and the Art of Road Bike Maintenance," as well as "Zinn and the Art of Triathlon Bikes" and "Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists."
Zinn's regular column is devoted to addressing readers' technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn. Zinn's column appears here each Tuesday.
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