Thursday, September 3, 2009

Finding a bike helmet

I wanted to start riding my mountain bike again. One thing had been holding me back -- my old helmet would not work with my CI. The external headpiece is in a location on my head right where just about all bike helmets have a strap assembly. I could not come up with any way to modify this area without compromising the helmet's function and safety.

After a bit of online research I found a helmet made by Fox Racing, model name "Transition," that does not have any strap components in the area of the CI. The price of $50 is reasonable for a bike helmet.

Transition helmet on foxracing.com

It looks in style like a combination between a skateboarding and BMX helmet. I found some favorable reviews noting that it is lighter and better ventilated than similar models.

My idea was to remove a small area of the inner shell at the location of my CI magnet. My goal was to make three main improvements:

1. Safety: A recess in the shell at the CI headpiece location should lessen the impact on the headpiece and internal implant if the helmet takes an impact in that area.

2. Comfort: Eliminate the pressure of the helmet on the CI headpiece

3. Function: Prevent the CI from cutting in and out as the exterior CI headpiece gets moved by normal helmet jostling.

I found one at a local store, and after checking that the inner shell was accessible for some cutting at the general area of interest, I purchased it.

Donning the unmodified helmet confirmed that it put a lot of pressure on my headpiece. It would be uncomfortable and unsafe to wear.

NOTE: MODIFYING A PIECE OF SAFETY EQUIPMENT IS NOT RECOMMENDED BY THE MANUFACTURER. DOING SO VOIDS ALL WARRANTIES AND COULD COMPROMISE THE OVERALL SAFETY OF THE HELMET. DO SO ONLY IF YOU UNDERSTAND AND ACCEPT THE RISKS.

Here's an overlay photo that shows the area in question in my case:



STEP 1: Mark the location

I had my wife use a small piece of white tape to mark the location of the headpiece while I put the helmet on and off several times.





I then marked the interior to match the location.



STEP 2: Excavate inner core for headpiece

I used the tip of a 3/8 inch bit in a standard drill to slowly grind away an area about 1.5 inches in diameter and about 3/16 inch deep.



After donning the helmet and checking that the location was correct, I deepened the excavation to about 3/8 inch and rounded the edges slightly, and made a small bevel in the location of the headpiece's wire attachment.



STEP 3: Excavate for implant (if necessary)

Since I have an AB implant, the implant is about the size of two quarters placed next to each other. I also removed about 3/16 inch in the area of that location which is toward my ear.



I finished it off by smoothing the surface and edges of the excavation by simply rubbing the area with my thumb. The material is relatively soft.




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The helmet fits and feels very comfortable after making the modifications. I was also pleased to find that the helmet curves quite closely to my processor over and behind my ear. Not too close to hit it, but close enough to keep it from popping off easily.

And, as an added bonus, my little boy looks like Dark Helmet in Spaceballs when he puts it on :)