Technical FAQ
Who's that masked man? Jack Bauer stayed warm...

Technical FAQ: Helmet fit with a winter hat; reusing cables and housing

In this week's Technical FAQ, a reader weighs in about using a warm hat and how it impacts helmet fit; plus, is it OK to reuse your cables and housing after trimming away the fray?

Dear Lennard,
In the past, I’ve had two helmets of the same model: one size small for the summer, one size medium for the winter. I would put a cycling cap underneath the winter helmet. If I did not wear a hat under the winter helmet, the helmet fit just a tad loose, even when tightened all the way down, so I never wore that one without a hat. Is the wearing of a bigger helmet in order to fit a hat underneath a safe practice?
— Steve

Dear Steve,
Here are some answers from helmet brands.
― Lennard

From Lazer:
Regarding Steve’s question, it’s not possible to know the answer because of how many variables are involved each time a helmet undergoes an impact.

As you know, helmets are tested under a very strict protocol depending upon the market where the helmet will be sold. In the USA the helmet is tested using a process determined by the Consumer Products Safety Commission (CPSC). They place a specific size helmet to a specific size head form and drop a specific shaped weight from a specific height and measure how much of the force is dissipated by the helmet and how much force is transferred into the head form. If the force to the head form is under a specific amount, then the helmet passes the certification test.

The problem is when you start changing the variables like adding a hat between the head and the helmet you may change the result of the test. Maybe for the worse, maybe for the better. Unless you test for it there is no way to know. The hat might act like a MIPS liner and help prevent a rotational brain injury, or maybe it interferes with the operation of the helmet during an impact. It’s really an impossible question to know the answer to unless it is tested.

Add this to the fact that every crash is different and the force to the helmet may not have even been taken into account in the certification test. Lazer helmets are all designed and tested to exceed the certification standards, but even with that no helmet manufacturer can guarantee safety in all impact circumstances.

One thing I can say is that we would recommend doing the very thing that Steve is doing rather than not wearing a helmet at all!

—Christopher T. Smith
US Marketing Manager
Lazer Sport North America

From Limar:
A hat and the hair are just means to let the helmet move a little on the head, not to be released.
Do you know the MIPS system? It is a sliding movement.
Therefore, as long as the helmet is securely fastened and does not leave open areas in the head, common sense would suggest that the use of a cap does not seem to interfere with the safety of the helmet, not any more than hair would do.

— Bianca Bernardi Marshall
Export Manager
LIMAR S.r.l.

From Giro:
Regardless of a hat or no hat, helmets have to be properly fitted in order for the wearer to get the full benefit of the helmet. If the wearer gets a proper fit while wearing the cap (comfortable, secure, straps properly adjusted, field of view not compromised, etc.), the helmet should function as designed.

— Eric Richter
Giro Sr. Brand and Business Development Mgr.

From Specialized:
This is what we state in our helmet owner’s manual:
WARNING: Do not wear anything underneath your helmet, such as a cap, hood, bundled hair, headphones, barrettes, as the helmet may loosen or come off. Do not wear anyone else’s helmet and don’t loan your helmet to anyone else.

— Bob Friedrich
Product R&D
Specialized Bicycle Components, Inc.

Dear Lennard,
Thanks for the steady stream of useful advice. I wanted to ask about whether it’s acceptable to reuse cables and housing after a proper inspection and trimming.

I try to limit waste in this time of heavy consumption, and so I often trim rear brake and derailleur cables and use them for the front after a careful inspection. I also will sometimes trim the ends of housing that shows no signs of cracking, sun fading or corrosion and reuse in shorter runs.

Is this being practical, or penny wise and dollar foolish?
— Zach

Dear Zach,
As long as it works, it’s fine. I have done the same may times in the past. The cable in particular can be inspected easily for roughness, fraying, kinks, etc. The plastic liner inside of the housing is more of a concern, as it can get grit inside and can wear on the curves, with or without grit in there, causing cable drag. Squirting lube through can conceivably rinse some grit out.

Bottom line: If the derailleurs and brakes are functioning properly and the cables are clean and visually are undamaged (and hence in no danger of breaking), then there is no reason not to do it, as long as you’re willing to change them out if they do stop sliding smoothly.
― Lennard

Dear Lennard,
I purchased a Campagnolo EPS V.2 group a few years ago for a build that ended up not happening. I am keeping it for a future project but worry about the battery shelf life. Campagnolo’s maintenance manual states that batteries must be charged “every six months” in case of longtime storage, but the context is of a battery already in service. Do new batteries still in their boxes require identical care?
— Francisco

Dear Francisco,
I doubt it. On the other hand, unless you don’t want to break the seal on the packaging, it can’t hurt to charge it occasionally.

I have a bike with this exact battery on it—Record EPS with the V.2 battery mounted inside the seat tube with bolts through the bottle bosses. It came with a magnet strap that shuts down the system when wrapped around the seat tube at the top of the battery. If I store it without the magnet strap, it completely discharges if I leave it for a few months in a cold garage. However, if I store it with the magnet strap in place, it doesn’t seem to discharge at all over a very long time. I have a lot of bikes and rarely ride this one. Every time I pull it out and remove the magnet strap, it has a full charge, even if I’ve left it in the garage for six months without touching it.
― Lennard


Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”
He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn