Crazy05 Posted March 28, 2007 Report Share Posted March 28, 2007 Thats why you need to talk to the experts. They will tell you exactly what you need for your 150 hp for the drags and the hill. And it will work right the first time. We are all just giving you bits and peices that we think we heard from a guy that heard from a guy that read it on some forum. If your gonna have 180 ponies, you might as well have all the chasis and swinger and shit to get the most out of it and to have it leave the dig straight and stay stable up top. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 28, 2007 Author Report Share Posted March 28, 2007 Thats why you need to talk to the experts. They will tell you exactly what you need for your 150 hp for the drags and the hill. And it will work right the first time. We are all just giving you bits and peices that we think we heard from a guy that heard from a guy that read it on some forum. If your gonna have 180 ponies, you might as well have all the chasis and swinger and shit to get the most out of it and to have it leave the dig straight and stay stable up top. Like, I said, I have had four different professional opinions given to me. The delta between the shortest and longest arm is 6 inches. I am sure alll of these people know what they are talking about, but their opinions are so different that I am also being receptive to others opinions, experienced or not. This is sort of turning into a design by committee situation. Quote Link to comment Share on other sites More sharing options...
BenBB Posted March 28, 2007 Report Share Posted March 28, 2007 Like, I said, I have had four different professional opinions given to me. The delta between the shortest and longest arm is 6 inches. I am sure alll of these people know what they are talking about, but their opinions are so different that I am also being receptive to others opinions, experienced or not. This is sort of turning into a design by committee situation. I won't even hazard a guess, but I got another guy to consider calling, especially since you're movin' up that way; Dan Wade at Patriot Racing. He's in Bonney Lake, Washington (don't ask I have no idea where in Washington that's at lol), and he'll be gearing up for the summer dune season soon. He did all the porting and head work on my RZ motor and hooked me up with sponsorship, a good guy and great to talk to. Anyway his email is dan@patriotracing.net, website is http://www.patriotracing.net/. Damn I just looked at his web page and he might be difficult to get ahold of, but I think it would be worth tryin'... Quote Link to comment Share on other sites More sharing options...
RNBRAD Posted March 28, 2007 Report Share Posted March 28, 2007 Like, I said, I have had four different professional opinions given to me. The delta between the shortest and longest arm is 6 inches. I am sure alll of these people know what they are talking about, but their opinions are so different that I am also being receptive to others opinions, experienced or not. This is sort of turning into a design by committee situation. Well you have to think that not all people running those motors are running the same length swinger and chassis set-up. There's never a consensus as to this is "The Best". You will have to get the info and figure some of the details out for yourself. This is what keeps the competition going between different set-ups and builders. Quote Link to comment Share on other sites More sharing options...
racer Posted March 28, 2007 Report Share Posted March 28, 2007 what about statics? You roughly know your horsepower, so convert that to torque. then you have a moment equation about the axle, assuming the tires dont spin. that pretty much makes the bike a heavy lever. using some known, or calculated weights figure out where you need to place the centroid in relation to your axle. then you will know your arm length. Lemme know what you think. IM curious to see if im learning anything. ha Quote Link to comment Share on other sites More sharing options...
racer Posted March 28, 2007 Report Share Posted March 28, 2007 just noticed that GTperf has a four link setup. that would be cool cause you can change lengths all day long with different size links, and chains. just gotta have a huge brake line. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 28, 2007 Author Report Share Posted March 28, 2007 I won't even hazard a guess, but I got another guy to consider calling, especially since you're movin' up that way; Dan Wade at Patriot Racing. He's in Bonney Lake, Washington (don't ask I have no idea where in Washington that's at lol), and he'll be gearing up for the summer dune season soon. He did all the porting and head work on my RZ motor and hooked me up with sponsorship, a good guy and great to talk to. Anyway his email is dan@patriotracing.net, website is http://www.patriotracing.net/. Damn I just looked at his web page and he might be difficult to get ahold of, but I think it would be worth tryin'... I grew up in Washington. Bonney Lake is sort of East of Tacoma, which is south of Seattle (it's probably best that you never take driving directions from me). :ermm: I know know where Dan's shop is and I have talked to him a few times in the past. The last I heard was that he was sort of taking a break from his business. I don't know if that's true or not, but I'll try and get ahold of him. :thumbsup: Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 28, 2007 Author Report Share Posted March 28, 2007 Well you have to think that not all people running those motors are running the same length swinger and chassis set-up. There's never a consensus as to this is "The Best". You will have to get the info and figure some of the details out for yourself. This is what keeps the competition going between different set-ups and builders. The problem is that I can make a case for anything between a +10" arm to a +14" arm. I really don't know how to sort it out much past that. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 28, 2007 Author Report Share Posted March 28, 2007 what about statics? You roughly know your horsepower, so convert that to torque. then you have a moment equation about the axle, assuming the tires dont spin. that pretty much makes the bike a heavy lever. using some known, or calculated weights figure out where you need to place the centroid in relation to your axle. then you will know your arm length. Lemme know what you think. IM curious to see if im learning anything. ha That is one way I tried to make my problem a little more black and white. I think the big unknown for me is what the coefficient of friction between the tires and the sand is. If I were able to put a good number to that, then everything else is really easy. :geek: Quote Link to comment Share on other sites More sharing options...
Crazy05 Posted March 28, 2007 Report Share Posted March 28, 2007 Another thing you can do is attend some of the drags that the top contenders race and see whos fast and what they are using. Take your duner and and enter some races and look around. Spy some pics and measurements. On the hills with bumps might be a different story. Long enough to keep it from flipping over and able to glide thru the bumps. A freind of mine has 95 rwhp 12p 12" and it still comes up on him sometimes. You will definately need to stretch the front also. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 28, 2007 Author Report Share Posted March 28, 2007 Another thing you can do is attend some of the drags that the top contenders race and see whos fast and what they are using. Take your duner and and enter some races and look around. Spy some pics and measurements. On the hills with bumps might be a different story. Long enough to keep it from flipping over and able to glide thru the bumps. A freind of mine has 95 rwhp 12p 12" and it still comes up on him sometimes. You will definately need to stretch the front also. The front of my frame is stretched. I think Ihave narrowed my choices down to between a +12" and +14" linkage style swingarm. :thumbsup: Quote Link to comment Share on other sites More sharing options...
racer Posted March 29, 2007 Report Share Posted March 29, 2007 I think the big unknown for me is what the coefficient of friction between the tires and the sand is. You dont need that. Figure everything with no tire spin, much like a coefficient of 1.0. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 29, 2007 Author Report Share Posted March 29, 2007 You dont need that. Figure everything with no tire spin, much like a coefficient of 1.0. You really do need that. The whole equation is bogus if you assume a 1.0 coefficent of friction. Changing the coefficient of friction by a couple of tenths wil wildly skew torque transmission through the lever by hundreds of pounds. Beyond that, there is essentially no practical case where you have a coeeficient of fristion that is 1.0. From what I understand, a smooth racing tire under labratory conditions will only establish a coefficient of friction of 0.98 on a tire dynamometer. Quote Link to comment Share on other sites More sharing options...
racer Posted March 29, 2007 Report Share Posted March 29, 2007 You really do need that. The whole equation is bogus if you assume a 1.0 coefficent of friction. Changing the coefficient of friction by a couple of tenths wil wildly skew torque transmission through the lever by hundreds of pounds. Hmm, i didnt realize it would be that wild of a variation. Even if you had a coef. it would only be for one snad compound. Wet or dry, fine or coarse would also make a huge diff. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 29, 2007 Author Report Share Posted March 29, 2007 Hmm, i didnt realize it would be that wild of a variation. Even if you had a coef. it would only be for one snad compound. Wet or dry, fine or coarse would also make a huge diff. You are correct sir. That is why I have stopped working on the launch simulation spreadsheet I was working. Now, I am pretty much going to flip a coin between a +12" and +14" linakge style swingarm. If it winds up not working well, I will get a different arm of fool around with the Marvin Shaw nitrogen sprung shock I plan on using. :thumbsup: Quote Link to comment Share on other sites More sharing options...
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