Landracing Forum
Bonneville Motorcycle Speed Trials => Bville Motorcycle Speed Trials Rules Questions => Topic started by: nrhs sales on March 23, 2015, 03:26:52 PM
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So has anybody safety wired a set of forks with flush front axles? if so how did you do it. here is a pic to help show what i am talking about:
(http://0.tqn.com/d/motorcycles/1/7/J/1/-/-/Buell1125R_fork.jpg)
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Drill through the fork leg.PITA
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Yes - As Fred said, you have to drill through the forks and the axle as well as the pinch bolts. It is almost impossible to line up the holes the next time you put the axle back in so you end up drilling several holes over time.
I thread the wire first through the pinch bolts then the axle so that when it is twisted I can stuff the twisted end into the hollow axle.
Don
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Dan, is there a hole in the bottom of the leg?
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yes there is between the pinch bolts.
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I'm just curious :?, but why would you not just safety wire the pinch bolts.
Those forks have been design to the every "enth" degree by the manufacture, so I question just how wise it is to start poking holes where they don't belong????
Safety wire would never hold that axle if it started to move, anyhow, it would simply shear the wire off.
If safety wiring the pinch bolts don't satisfy the requirements as they are, I'd think that going with a thou bolt ( that can be properly safety wired) would have to be looked at to reliably solve the issue.
Rouse
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There is a post I did on Lorings page I did with pictures. Just a sec I will link it
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http://www.landracing.com/forum/index.php/topic,12935.0.html
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that should work. Thanks!!
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The fork clamp area is highly stressed, subject to cyclic loading, and an aluminum part. Any way to wire the axle and leave it untouched will reduce fatigue fracture worry.
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First, I am "unflushing" the pinch bolts on one of my bikes so I can safety wire it. Placing a small spacer between the bolt head and folk on a ~10mm longer bolt.
Second, on certain bikes, I have always questioned why we drill through a high stress point area to safety wire a recessed nut that can't turn without removing the pinch bolts.
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I have safety wired countless items on aircraft and I have never seen anywhere that you would drill holes in a designed part to safety wire a bolt.
safety wire keeps bolts and nuts from loosening, it is not a fastener. If the fasteners aren't right to secure the components properly, then change the fasteners.
Properly safety wiring the pinch bolts should be sufficient to do the job.
Did the idea of drilling thru component parts come from an aircraft engineer?? It's not unheard of for racing sanctioning bodies, and or tech. inspectors to go off on a tangent and over think what good engineering practices really are.
Rouse
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Second, on certain bikes, I have always questioned why we drill through a high stress point area to safety wire a recessed nut that can't turn without removing the pinch bolts.
I do not understand it either but these are the rules we are being forced to play by.
safety wire keeps bolts and nuts from loosening, it is not a fastener. If the fasteners aren't right to secure the components properly, then change the fasteners.
exactly!!
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Several years back a "Major Sanctioning Body" required that race car chassis be built using a certain grade of material. Within a couple years virtually every car in competition was built using that mandatory material. Well after some disastrous accidents involving severe wrecks and chassis breakage do to using that material, someone final took an engineering look at what was going on. The finding was simple, the mandated material grade had been forbidden in aviation for the past 70 years are more, because it was likely to crack or break. The material had a very good tensile strength, but very poor fatigue properties.
I am a safety "nut", so I am not trying to be contrary to safety requirements, just the opposite, however I do question when folks start to demand you do things that make no since whatsoever in engineering terms.
So back to the safety wire; If the axle is design to be held in place with the pinch bolts, then safety wiring them properly to stay tight should be what is require. If you are required to start poking holes in an engineered fork tube, then you should take a close look at just what effect that has on the area you poke a hole in.
Safety is your responsibility just as much or more than the tech. inspectors, I'd say more so.
Rouse
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Rouse, what is that steel? I need to avoid using it.
Try making a hex shaped plug that fits in the axle hole with about 1/4 inch sticking out. Then, drill and wire the plug. No holes will be in an engineered part. You can pull the plug out when it is time to undo the axle.
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Bo-
4130HT Is has a very good looking tensile strength when that's all you pay attention to. However it is very brittle and low impact strength and fatigues relatively fast.
That material was required as opposed to 4130 Normalized (4130N) which has a lower tensile, but the other mechanical properties are much better for the severe service of a race car chassis. The aviation industry outlawed the use of 4130ht back in the 30's, so it wouldn't have taken much research on the part of the builders and/or sanctioning body to know better than use that grade of material. By the time they figured out that there was a big problem nearly every car running was built with 4130ht, "what a deal!"
The biggest problem as for as I'm concerned is that once the issue was figured out, no one had any idea where or why the requirement came from in the first place.
That's why I tend to question folks when they start demanding things that don't make good engineering sense, in the name of safety. Is it really safer???
Rouse
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Would it be acceptable to run a loop of wire around the fork leg just above the axle and twist it. Then run the twisted wire down across the axle opening and back through the notch at the bottom of the leg. Then finally run the wires up around either side of the axle and twist them there. With that the axle shouldn't go anywhere and no structural part is affected.
Common sense is going to be required by both the person doing the wiring and the inspector. I hope this is a solution to the issue.
Pete
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Thanks, Rouse for posting that. It was the 1970's when I had all sorts of problems with chrome moly and it probably was that stuff.
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First, I am "unflushing" the pinch bolts on one of my bikes so I can safety wire it. Placing a small spacer between the bolt head and folk on a ~10mm longer bolt.
Second, on certain bikes, I have always questioned why we drill through a high stress point area to safety wire a recessed nut that can't turn without removing the pinch bolts.
I like this idea the best,although sourcing a proper longer axle bolt may be a problem. I'm surprised that the bike manufacturers don't offer a special axle that can be safety wired, as I've never been associated with a bike racing organization that didn't require it. Also, it might be a good idea to check with dealers and other bike racing organizations to see what they are doing. AMA should have an answer!
Tom
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REMEMBER....................Always question Authority...............................................................................
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Sez who?!?!? :-D
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Sez who?!?!? :-D
Me; if it don't pass the smell test, something is probably not right.
As for as safety wire, proper technique has been perfected for decades in the aircraft industry, so that would be my first clue as to whats right or not.
rouse
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Johnnie, I am on your side. I was just questioning bak189's authoritative comment! :-D
The US Army air farce taught me how to safety wire those fling wing things! And I never lost my Jesus nut! http://en.wikipedia.org/wiki/Jesus_nut :cheers:
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Woody,
That's the one you pray don't come off before it does, wouldn't help much after :-D
Rouse
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I ran my 2015 H2 Ninja at the ECTA in Ohio last weekend and only drilled and wired the pinch bolts. They accepted that. I can see how on older bikes the axle nut would have been an issue, especially when there was a cap at the bottom of the fork that would have allowed the axle to drop out. I will even go along with wiring the axle nut on that old design. With the new radial brakes holding the wheel in position and the pinch bolts pretty much locking the axle in, I just don't see the need for drilling the forks for wiring the axle. Getting the axle back into position is nearly impossible and I really hate drilling into an engineered part like that. My thinking is that the rule needs to be revised to say that they axle nut has to be wired if it is NOT restrained by the pinch bolts in the forks. Come on tech guys, think about this!
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I ran my 2015 H2 Ninja at the ECTA in Ohio last weekend and only drilled and wired the pinch bolts. They accepted that. I can see how on older bikes the axle nut would have been an issue, especially when there was a cap at the bottom of the fork that would have allowed the axle to drop out. I will even go along with wiring the axle nut on that old design. With the new radial brakes holding the wheel in position and the pinch bolts pretty much locking the axle in, I just don't see the need for drilling the forks for wiring the axle. Getting the axle back into position is nearly impossible and I really hate drilling into an engineered part like that. My thinking is that the rule needs to be revised to say that they axle nut has to be wired if it is NOT restrained by the pinch bolts in the forks. Come on tech guys, think about this!
I don't think tech should be put in the position of determining which axle configurations should be safety wired and which shouldn't. It's enough to just say all axles must be wired. I'll guarantee the insurance company agrees. These days no organization is going to back off on any safety related rule.
Personally, having my axles "pretty much" locked in just doesn't do it for me.