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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Hair-brained Idea... /cgi-bin/YaBB.pl?num=1399397074 Message started by Doody814 on 05/06/14 at 10:24:33 |
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Title: Hair-brained Idea... Post by Doody814 on 05/06/14 at 10:24:33 OK, so I've often said that my creative imagination far surpasses my technical ability, but this has got to be one of the wildest and crasiest off the wall ideas I've ever come up with... The other day I was reading a thread on hardtail struts, and saw the "crowbar" shaped strut, and was thinking how much I loved the look, but wasn't crazy about the potential uncomfortable ride that a rigid frame provides. That's when it hit me...what if the angled strut that follows the lines of the bike were combined with the "suspension" of a tortion spring similar to seat springs. You've seen Hardtails, you've seen Softtails...Ladies and gentlemen, I present to you the "Torsion Tail"... :-/ |
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Title: Re: Hair-brained Idea... Post by Doody814 on 05/06/14 at 10:26:05 bigger |
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Title: Re: Hair-brained Idea... Post by Doody814 on 05/06/14 at 10:28:59 I think the trick would be to have a torsion spring that supports the weight of the bike & rider without having too large of a diameter of coil & being too large of a wire diameter, but I think that it could posibly actually work. Thoughts? |
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Title: Re: Hair-brained Idea... Post by justin_o_guy2 on 05/06/14 at 10:37:11 I think if I was gonna go that route Id look at putting the coils down at the pivot for the swing arm. That would leave it cleaner back there & the spring would be located where the spring would more able to take the work. Youd have to include a limiter to keep it from throwing the swing arm down too far when ya get off or hit a big bump., Now, how big would it need to be? Dangfino.. I had a Duster that had torsion bars. It just had a 6 banger & they were pretty fat, but they were pretty long, too..That design youre talking about isnt really a torsion bar, its a spring, & w/o a shock Id expect it to bounce like the dickens going down the road,,but you mite be able to do a monoshock with some pretty good work in the frame, You ever seen a car w/o shocks? Theyre funny to watch,, I only saw one, when I was about 6. Yea, it was that memorable,, |
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Title: Re: Hair-brained Idea... Post by Doody814 on 05/06/14 at 10:53:48 I understand that it probably would ride like a pogo stick, but that's not the point. We're not going for the feel of a cadilac here, just an alternative to a hardtail. With that being understood, the topic of creature comforts went out the window a long time ago. What I'm going for is the look of a rigid frame, but won't rattle your teeth loose. And before anyone says "HD has done this, it's called a 'Softtail'..." I know, but that kind of conversion would take a crap ton of frame modification. My Idea incorporates the shock mounting points, so it would be a direct bolt-on replacement, and could easily be changed back to shocks without any mods to the bike itself. |
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Title: Re: Hair-brained Idea... Post by Demin on 05/06/14 at 10:55:19 Hmmmmmmm.Very very interesting(In my Artie Johnson voice from Laugh in)Showing my age. |
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Title: Re: Hair-brained Idea... Post by Serowbot on 05/06/14 at 11:01:25 Pretty simple idea,... yet, I've never seen one... Probably a good reason for that... :-?... |
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Title: Re: Hair-brained Idea... Post by Dave on 05/06/14 at 11:05:33 OK......so you have a spring....but no damper. What is going to keep it from bouncing for 1/4 mile after you hit the bump? Remember how bouncy that spring chair is? Your idea was used on cars back around 1900-1910......then technology improved. Cars weren't safe when they were bouncing around on those rough roads....you bike wouldn't be safe either. |
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Title: Re: Hair-brained Idea... Post by Doody814 on 05/06/14 at 11:38:40 Dang it Dave, there you go again smashing all my hopes and dreams with logic. :P The buggie & the patio chair are designed for comfort, and to absorb the compression, and therefore are nice and bouncy. Torsion springs can be designed to do a number of different things...provide a lot of torque, absorb impact, etc. All of these things are controlled by a few things: wire dia, wire tensile, coil dia, and number of coils. For asthetics and space limitations, a single coil with a fairly small dia would be needed. Also, you're kind of limited on wire dia because of the long canteleiver at the top portion, so it would need to be fairly beefy to keep from bending. Those variables would force it to be really stiff, so the wire tensile couldn't bee too high, so the spring rate would be slow enough not to "buck". I think it is "possible", but would have to be done in such a way that it would only take the "sting" out the larger bumps, and not to be a soft cushy ride. Which takes me back to my original point of it being a "softer" alternative to a rigid frame. With all that being said, the spring I just described requires the design engineering and special tooling to make that would price it about the same as nice used softtail. ;D |
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Title: Re: Hair-brained Idea... Post by verslagen1 on 05/06/14 at 12:33:17 You're certainly welcome to try... Just give us advanced notice so we can have the video machine primed and ready. ;D You did have one good idea through... use a crowbar to make that strut. 8-) |
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Title: Re: Hair-brained Idea... Post by gizzo on 05/06/14 at 15:01:33 I love the idea! I reckon it would look awesome with some funky chrome hairpin springs, just like your illustration. How about incorporating some friction dampers from a Castle fork into one end? Could work.... |
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Title: Re: Hair-brained Idea... Post by wickedbiker on 05/06/14 at 15:43:10 I already thought about it one good right turn would throw you. 5E4D5A5B44494F4D4619280 wrote:
That was actually my idea when you look at the one posted in the hardtail strut thread that is exactly what it looks like and it is amazing looking. But I think it is in between the strut mounts not on the outside if anyone wants to confirm. Heres the thread: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1392822524 |
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Title: Re: Hair-brained Idea... Post by WD on 05/06/14 at 21:04:11 I think we have a junk spring tooth harrow out back... More like leaf springs than torsion bars. Might have a junk branch rake section still, the rods are 5/16" diameter by about 3 feet long... Have to check the forge iron pile. If you want to be different, make the P in LS650P stand for "Power Plus" knock off... http://upload.wikimedia.org/wikipedia/commons/0/07/Indian_Power_Plus_1000_cc_1918.jpg Solid rod from swingarm to the leaf spring. That bike above is a 1918 1000cc, design debuted in 1916, same year Indian offered an electric starter... Hardly Runnerson didn't have a full production swingarm Big Twin until 1954... and electric start came out on them in 1965. Hey, I decided the P in LS650P stood for "Police", and built a scaled down 1950s English police bike out of my 2003... ;D |
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Title: Re: Hair-brained Idea... Post by ToesNose on 05/07/14 at 04:31:19 :-? No Damper = No Good If it's the esthetics you are mainly looking for try figuring how to incorporate some type of shock absorber It would take a lot of fabrication but a single mount shock absorber/MacPherson strut centrally mounted within the frame would work and could mainly be out of sight with the torsion springs being the linkage to the swing arm. |
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Title: Re: Hair-brained Idea... Post by Dave on 05/07/14 at 04:53:39 A lesson in undamped harmonic motion...... https://www.youtube.com/watch?v=rCukkwWBMDg https://www.youtube.com/watch?v=ng3hbZk9h50 [media]https://www.youtube.com/watch?v=rCukkwWBMDg[/media] [media]https://www.youtube.com/watch?v=ng3hbZk9h50[/media] |
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Title: Re: Hair-brained Idea... Post by mpescatori on 05/07/14 at 06:21:44 Before you all smash Doody's hopes from the start, may I offer a little encouragement. Doody, see how Moto Guzzi solved your problem : http://img.motorkari.cz/upload/images/cache/galerie/glo_znacka/24/20091216150839-219_5_jpg_resize_1000x830__type_jpg_.jpg and Moto Gilera as well http://www.lasviajeras.com.ar/modelos/modelo_motos/imagenes/gilera/640/mini-77741_Gilera-Saturno-1951_122_906lo.jpg Mind you, these were the hot rods of their day... look at the rear suspension: coil spring hidden in the fulcrum, and a "dialable" damper made of leather and cork discs which you could tighten so many "clicks" 8-) Now git to work ! ;) PS Add a springer front fork (or a girder, even!) and a drum brake, chain conversion and long hollow/trumpet exhaust, sprung seat, and you have a 1936 Savage ! :D http://www.rpw.it/images/Miller%20BT%20250/tn_Miller%20250%20BT5.jpg |
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Title: Re: Hair-brained Idea... Post by Doody814 on 05/07/14 at 06:39:44 Why does a guy sitting on a solo seat suspended by torsion springs, on a rigid frame, not get donkey kicked over the handlebars? Those springs aren't dampened. I've seen guys riding rigids defnitely get bounced around, and it's a rougher ride, but I've never seen them pogo sticking like those videos. What's the difference? (need to add a disclaimer after I read this...not trying to sound argumenative & defensive. This was a honest question.) |
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Title: Re: Hair-brained Idea... Post by Doody814 on 05/07/14 at 06:53:00 Sweet pics mpescatori! That last one especially is gorgeous. Thanks for the support, lol. Again, these examples are of full on functioning suspension, or at leat an attempt at it. If I was going for function, I'd put on some nice progressives. My idea was not going for suspension per se, but more of an impact absorbtion. |
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Title: Re: Hair-brained Idea... Post by WD on 05/07/14 at 07:52:16 I've ridden a Power Plus, it isn't a very functional set up. It will damp some of the road surface irregularities, but you're going to notice them. Find a swingarm off a chain drive Yammerscammer Very Slow (Virago). It used a very British shock mounting, single coil over that connect to the frame backbone. Copy the upper mount on your Savage frame and graft on the swingarm, paint it black to match the rest of the frame cradle. Find a wrecked VN800, style doesn't matter, and get the rear section of the frame with swingarm and shock. Chop off the back of your frame and graft on the Kawasaki parts. Use the Kawi rear wheel, sprocket and convert your bike to chain drive. XV920 Yamaha...http://kickstart.bikeexif.com/wp-content/uploads/2013/02/yamaha-virago-3.jpg VN800 Kawasaki...http://www.boat-rap.com/bk_img/l_1157.jpg The Yammie has a little bit more obvious suspension, the VN has a cleaner look. And the best Japanese middle weight cruisers ever made were the VN800A, VN800 Drifter and VN800B (Classic). The 800A with a bit of tinkering will break the drive unit in its 140 mph speedometer as you go sailing past "pegging" the needle... or the cable (1st time) or rear drive unit (2nd time) I did that with my old one. |
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