Rallye navigation bracket photo thread

[theantipaul]

The issue of rider safety has pretty much eluded me, so when Mudguts & Armageddon started talking break away devices, I tried to apply it to the tower. With the HDPE side plates you'd have to use more then 2 bolts to keep the RB mount from moving since the HDPE is so slick, then you'd need more force to overcome the fasteners, sheer the plastic and have it pivot out of the way when your body moves over the bars dynamically.



That piece was 3/16" thick with a .090 wall around the mounting bolt, bolts up marginally and shears pretty easy. That will most likely need some tweaking, but seems plausible as a solution without having components separated from the tower. Easily fixed on the trail and I think dirt cheap insurance

Then decided to take the rest to failure with a 5lb deadblow mallet, both pieces are 1/4" HDPE the white is natural, the black is marine grade. I now have no doubt that if the Nav components are taking the brunt of the impact they will move to an extent, absorbing and dissipating the impact and spring back to an extent. How much? Depends on the impact.






The results, after repeated blows continuing to the edges of the supports, the HDPE shears out the bolts and deforms plastically.



Thoughts?

[wrk2surf]

As someone said earlier, many riders including Meoni have been injured or killed by towers.. I know since riding with mine i have always had a chest protector but have slammed it a couple of times on slow speed.. that is not what im worried about my concern is a high speed get off over 50/60 mph where it seems this idea would really do the trick as long as you had a spare or two.. to keep in the rally!

on top of it all im sure it is much more vibration resistant..

I would use it!

BTW.. I sure wished I lived close to your shop!

[jesusgatos]

That's a great idea Paul, and think it's a winner if you refine the geometry (maybe move the pivot-point back so there's no chance that any kind of top-down impact could be inline with the pivot/bracket). Sorry, that might not be clear. What I'm trying to say is that if you move the pivot-point back, it'll be more likely to collapse under any kind of top-down impact.

[Gany]

Nice work Paul! Love to see the equivalent video with aluminium uprights!

Are the holes less likely to shear with thicker spacers?

Wonder if the white piece or some other piece could be designed so that it moved rather than failed, without it moving under normal riding conditions? Picture something like the white piece that was a hook, so an impact would cause the bolt to force out of the hook allowing the tower to move hopefully without destroying the white piece. You could then either unbolt or force it back into the hook and keep going? Or something like a string of holes joined together but where the holes touch its say half the thickness of the bolt so the plastic has to compress to allow the bolt past it.

Anyhow, food for thought.

I was going to run with 10mm thick HDPE but based on your testing it seems ~6mm/ 1/4" will hold up just fine!

Keep it coming!!

[jesusgatos]

Hard to say without seeing a whole assembly, but also looks like you might be able to make the two main vertical sideplates shorter. The more compact you can make that part of the assembly, the better.

[tileman]

Originally Posted by Gros Buck

It will be simpler because of simpler needs. Nothing anybody here needs. I need something WIDER cause I want to put two 90 mm BI-LED lamps. Which means 100 mm in between.

I ran a similar width between side plates on mine. I made something similar to the JVO kit that J-mo used.

http://i492.photobucket.com/albums/r...t/DSCF0156.jpg

1 centre spine for no better term and then spacers to get the width.

[640 Armageddon]

That is indeed a great idea Paul ! Thumbs up for the quick response to this safety issue . I have no experience in injuring myself in the bloody thing (and I hope I will never have ) but it is indeed a major issue.

I think the concept is pretty neat. Nylon bolts is another food for thought, I was going that way when the safety issue came up. A Nylon bolt is strong enough both in shear and in tension to hold the assembly but you can choose the correct size so that if the load exceeds a certain value the bolts fail in shear. You just then replace the bolts. An M5 for example will break in shear using almost 100 kgs so I think it is doable ... (An M6 breaks at 180 kg in shear so I think this would be for quite a heavy person ) In the design that I am using, there is a third adjusting bolt which I plan to use as a crample zone if I may say. You can see here what I mean, I put the video before but jsut for reference

http://www.youtube.com/watch?v=Aavtn...3&feature=plcp


In all of the above, I think we have to take in to account the cabling. If anything breaks, for safety reasons, may be it is a good idea to make sure that the instruments auto-disconnect from the bike to prevent damage in the cables. It would not be nice for the tower to hang around from three/four cables when smashed around. In Paul's design this is not a problem but I am just mentioning it for other people who may go to the extreme of getting the tower of the bike Another idea (if you go to the extremes that is ... ) would be to put steel cables to hold the tower close to the bike in order not to load the cables. Much like they do in the F1 with the wheels so the wheel does not get apart from the car. Too complicated in my opinion

I dont know how all rally towers are attached, but I have a question. If the tower is only supported in one pivot point. Much like the one that you use to put the roadbook in the handlebars (sorry, I do not know if there is a name for it but I think you know what I am talking about). Even if you do not have a ''crample zone'' I think if you do not overtighten these bolts the thing will rotate upon impact. There is nothing to prevent it from doing so. Or am I missing something ? For sure it would be better to move out of the way but just questioning myself ....

The nice thing is that in almost any tower you can use materials to make it safer in case of impact with very little or no modification at all. It needs testing to get the tightening torques right so it slides, breaks etc with the correct load but that is why we are here

[DRjoe]

Looking good Joe, I like the mr plow sticker

Originally Posted by Joe Watson

Thanks for all the great comments everyone. I can't wait to see it finished and all stickered up!




Paul, I have no idea what you are talking about?? I have had the Zumo 550 now for over 4 years and it has been anything but fragile!! I absolutely LOVE my Zumo and would buy another one in a heartbeat.

[tileman]

Originally Posted by theantipaul

The results, after repeated blows continuing to the edges of the supports, the HDPE shears out the bolts and deforms plastically.

Thoughts?

I would call this video a success. The tower coped quite well with repeated blows. Thinking sideways a bit are road books the same for both moto's, quads, cars etc? For now I shall assume so. In a car that for example is involved in a roll over the road book that should to solidly mounted won't cause a issue. On a moto the crash is quite different. Therefore is it an idea to try and machine out of solid of HDPE a road book holder? ( the outside container) Pretty easy stuff to machine, its engineering grade, another thought ready for comment/criticism

[Joe Watson]

Thanks! I thought you would like that!

Originally Posted by DRjoe

Looking good Joe, I like the mr plow sticker

[crankshaft]

Originally Posted by jesusgatos

Hard to say without seeing a whole assembly, but also looks like you might be able to make the two main vertical sideplates shorter. The more compact you can make that part of the assembly, the better.

It's actually pretty compact as it is, it is hard to two tell though without actually seeing it mounted in person. When I got the test model for the 690, I thought it looked big until it was mounted. weird huh

Looks good Paul, making good progress!

[Gany]

Machine a solid roadbook holder or how about just vac form one?

[640 Armageddon]

I guess the advantage of having an HDPE roadbook is only because it is cheaper. The flexibility is lost due to the geometry (an open box). So it will not give room (or not give as much as you would think) in order to try something like that. I would prefer the frame to take the blow and give away in case of an accident. Making the equipment itself flexible will not help as much.

A roadbook from composite materials will be lighter, you dont have the Aluminium welds as well but all in all it may be more expensive. touratech did not sell but then again Touratech did not sell well even with its Aluminium unit ...

The other thing that needs to be considered is that, let's say in Paul's design (because we have seen how it works, no offence Paul) say that the tower goes forward. That means that the fairing will most probable break and then the tower itself will be exposed. I am with safety here and I would prefer 1oo% to buy new equipment than to imprint my chest onto the roadbook but it needs some calculations so it does not break with blows that may not hurt you in the first place

[beechum1]

Originally Posted by 640 Armageddon

I guess the advantage of having an HDPE roadbook is only because it is cheaper. The flexibility is lost due to the geometry (an open box). So it will not give room (or not give as much as you would think) in order to try something like that. I would prefer the frame to take the blow and give away in case of an accident. Making the equipment itself flexible will not help as much.

A roadbook from composite materials will be lighter, you dont have the Aluminium welds as well but all in all it may be more expensive. touratech did not sell but then again Touratech did not sell well even with its Aluminium unit ...

The other thing that needs to be considered is that, let's say in Paul's design (because we have seen how it works, no offence Paul) say that the tower goes forward. That means that the fairing will most probable break and then the tower itself will be exposed. I am with safety here and I would prefer 1oo% to buy new equipment than to imprint my chest onto the roadbook but it needs some calculations so it does not break with blows that may not hurt you in the first place

fiberglass with a tricell or equive core would make for a great light bracket, and breakaway in a crash, but again... it'll break away and then how do you pack the front end out??

[Gregg Wannabe]

I too am concerned about the safety of the towers in an accident but even more so about the danger of sharp edged fairings. When I had my KTM 950 Adventure that small windscreen always made me nervous and I did bump it a few times while offroading. (Never had a bad crash) It looks like it could chop your head clean off. I bought some clear hose, split it lengthwise and put it on the edge of the windscreen like a bead. Blunted the sharp windscreen a bit and made me feel better.