Looking For EM Gray Metal Rear Spine


Well-known member
Hey Guys,

I am looking for a 7 inch ( inside measurement from edge of bill to rim of spike base )
This apparently is a long one.
I have 4 all too short.
I contacted Brian hoping he would have one in stock.
He had several NO DICE.
Can anyone help me out in trying to find these hens teeth ?


Well-known member
I've been trying to match spine lengths to helmet size for a while now. I still don't have enough data to make any 100% positive conclusion. Many of the spines are marked with a size (I've encountered 1 to 7 so far). Although I'm beginning to think that these size markings may vary from maker to maker. If it is any help I believe that the spine you are looking for maybe off a size 58 or larger helmet. Ones I've inspected from that size helmet run about 16.5cm to 17.5 cm (same length used on a size 60 helmet). Majority of these spines were marked with a 3.

I'm still collection data; If the spines you tried are marked with a number could you please let me know, along with their length (as you have measured) and if known the helmet size? Thanks.


Active member
I have 2 M15 spines that are both size 2s if that helps? I cannot find my measuring tape at the moment so I can't measure them.


Well-known member
Brian had a 5 that was about a 1/2 inch short.
I have a couple of 2's they are even shorter.
My guess would be about a 7 is what I need.
I hope it does not come down to me having to butcher 2 to make one
There is one on France's ebay that is 16cm or 6.3 inches
I need 7 inches or 17.78 cm inside measurement from round end to round end.
I could possibly cheat and go 6-3/4 inches or 17.14 cm.

The easiest way to measure a rear spine if you do not have a flex tape is to get the spine hold a strip of paper on the inside of the spine starting at one of the rounded ends and conform it to the length to the other end and mark it.
Then lay the paper down on a flat surface to get your measurement.

Thanks guys for checking.


Staff member
Finding a replacement rear spine for a helmet is extremely frustrating even worse than visor trim. At least with trim if it is too long, you can cut it to size. I am wondering if the stamped numbers refer to curvature which would also effect length? In my experience, a numbered spine is the exception, usually they are not marked.


Well-known member
Of my sample, 25% of those inspected were not marked. The marking is located on either upper tag (one that goes under the spike base) or the lower tag (the that folds under the rear visor). this upper one is not visible without removing spike.
Never gave any thought to the number referring to the radius of the spine, but that is a possibility.

The #1 marked spine was M'15 Baden helmet size 58, The #7 spine was on size 61, brass fitting, dated 1914, marked to JR 29

Good luck