Short Norton Roadholder Forks bends

ET43

Well Known and Active Forum User
Non-VOC Member
Calm down chaps

Little Honda's 6mm threaded bolt would I am sure pull out of any alloy it was screwed into, especially with one ton hanging from it. Roy the machanic might be right about the Yamaha brake's bolt being ok in shear, but one has to remember that one club member got tossed over the handlebars last year when the much larger bolt on his brake failed! Whoever is right is up to the mathematicians in the club to let us know should they care to do so.
I have seen sidecar fittings fail on quite light bikes and sidecars, so who knows. However Roy, you are out of order by being rude no matter how clever you are. Let's use less of the aggro please. Life is too short. Phil Primmer, the hysterical one!!
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Hello All. I did worry when I first had the Norton Forks, With a figlass front mudguard and a single disc, The front of the guard moves sideways when you put the brake on, But 36 years on, It still does it !! I think you have to think about the twisting of the leg and the bolt strength. Cheers Bill.
 

mercurycrest

Well Known and Active Forum User
VOC Member
I'm with Roy, put a fork brace between the sliders and heavier triple clamps if needed. Make sure each side of the sliders have at least two bolts holding it in place. I saw a guy get killed once using one bolt per side. The brace pivoted backwards and jammed into the tire!
If you want to see another "twisty" front end, lift the front of your Vincent in the air, grab the girdraulics and the engine, push one and pull the other sideways. For something even better, try it between the swingarm and frame on a Commando!
Maybe a little flexing isn't all as bad as we think?
Cheers, John
 

roy the mechanic

Well Known and Active Forum User
VOC Member
Reference the 6mm bolt- as the fork in question uses 1/4 bolts i have checked with the S A E bolt charts and have found the following, 1/4 x28 tpi (unf) bolt will break at a minimum 4,368 lbs in tension, 5,024 lbs in shear. this works out to be-1.95imperial tons and 2.9125 tons respectively. so, according to "the book" my estimate of 1 ton is well within the safety limits of the accredited body. From experience, provided that the thead engaged is at minimum twice the diameter in depth when screwed into aluminium it will function without problems! As there are 2 bolts per side this is doubled, i doubt even a moto g p rider could generate such forces in this area!
 
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