Hells Angels motorcyle?

From:  "ajjameyeril"

What is the relevance of 81 to the Hells Angels motorcycle club?

Alicja:  In answer to the question asked about the relevance of 81 in the Hells Angels club, I believe it comes from a line of biker clothing and merchandise used to financially support imprisoned brothers and their families (a defense fund), and so it is advertised all over. The name came from longer ones, and was just shortened to Route81 for convenience for prisoners...

So it appears that we may have answered this question a little wrong so here's are updated answers.

bastard was the first to correct us with this: 

From Denmark I heard that this is a sponsor clothing but 81 stands for hells angels H is the number 8 letter in the alphabet and a number 1 thus is 81 hells angels unofficial wear.

Ernie reply back with this:  

The "H" is the 8th letter and the "A" is the first letter. 81=HA (Hells Angels). That's why you see "Support 81" stickers and t-shirts. Wearing something with Hells Angels on it is a no-no unless you're a member.

H.A.M.C agreed with this:  

Hell's Angels, The #8 is for the 8th letter of the alphabet and the #1 is for the 1st letter. 81 = H.A. (HELL'S ANGELS). And that's from the horses mouth.

spoogie added this comment: 

The question below has been answered wrongly
What is the relevance of 81 to the Hells Angels motorcycle club?
81 is the numbers of the letters of the alphabet
H=8 A=1 81 H..ells A..ngels

Twobees summed up the corrections: 

The significance of 81 to the hells angels. H is the 8th letter, a is the first. 81 = HA. The club has a whole host of signs that have meaning to other members, although much of it is now known outside the group.