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Post by shutz on Oct 17, 2010 20:00:14 GMT
Just a thought that might help any budding builders is there any do's and don'ts in sidecar design that any ones picked up this year racing/or development. Apart from don't crash.... I was wondering what would be a good head angle. picked this up when trying to find a good place to start. "As with any design aspect, more is not necessarily better; for a road bike with a 73 degree head angle the optimum trail seems to be around 2 to 2 ½ inches (5 to 6.3cm.)" davesbikeblog.blogspot.com/2007/05/trail-fork-rake-and-little-bit-of.html. Also was pondering the benefits of adding suspension to the side car wheel. Nowt fancy just like a similar set up to a mountain bike. What do you reackon. Cheers Shutz
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Post by Organgrinder on Oct 17, 2010 20:47:20 GMT
Not really sure what head angle we are running, but we did a "suck it and see" job and slackened off our BMX frame by a few degrees when we added extra length and the machine seemed perfectly stable at 45mph+ at Dalby. Not convinced about suspension being needed, as having it would change all the geometry as the monkey shifted his weight round the outfit, which could make for even more interesting handling.
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Post by team-art on Oct 18, 2010 12:30:11 GMT
Hi shutz, When I built the trike I did a bit of research (on low head angles/large trail), about all I could find was "don't do it", but no real evidence to back up that stance. I wanted a low CofG and a very relaxed steering response. I experimented a bit and settled on about 37 deg (as the most I could possibly go). Trail is more than 8"!! about 210 mm. Any more and I felt wheel flop/turning circle was a problem! I did take out some insurance using steering stops (to make sure flop was restricted), and also fitted a self centring/adjustable steering damper (rubber bands). Very low head angles don't seem to self centre well. The result is very nice stable/relaxed steering, feels very controlled, nice weight, no twitch and the ratio feels just right (and it centres)! So it depends what you want, but don't be afraid to experiment with angle/trail, don't be put off by anyone saying "it won't work" if in fact they don't know. Suspension: No idea! Again it might work! Try it! Easy to replace a suspension unit with a solid link if it's no good! Cheers Rich
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Post by shutz on Oct 18, 2010 21:44:28 GMT
Cheer Rich, nice to see a few close ups, always helps with ideas. Might not go quite as low for a sidecar outfit though. ;D Will want to reduce the head angle and increase trail a bit though but will just have to as you say experiment a bit. Likewise with the suspension which can be made ridgid easy enough with a tie bar. Intentions were to use a 16" wheeled frame just to be different and keep it low but i reackon i can get a low bike part by modding the frame a good bit on a 20" wheeled bike that i have also got. Looking to sit forward of the rear triangle like i said to get nice n low rather than sitting over the back wheel. I will use the 16" one as the side car wheel mounting the rear triangle by welding the drive sproket to the frame this will allow it to rotate on the bearings. Using this i should be able to fine tune the chair wheel height either with a tie bar or suspension mount. Found a local supplier for steel and drawn up my shopping list of 3mm inch box and 2x1 inch rectangle should be strong enough although im no structural engineer...Thats where test runs come in
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Post by azuma on Oct 19, 2010 17:37:05 GMT
Shutz, 3mm x 25mm (inch) should be bullet proof if triangulated and welded properly. Most Lotus 7 type kit cars only use use 16SWG (approx 1.6mm) x 25mm box. Triangulation is the key when building a chassis. Other important factors are: ensure that the the edges are champhered when going above 1.6mm wall thickness, set up the sections with the required gap between the pieces (when butt welding) to maximise weld and penetration(ooh eer!!) and take time to thoroughly clean the materials (i.e. scuff to bright with an angle grinder. Practice on some scrap bits first to get the weld perfect. Check it looks right and then knock lumps out of it with a hammer. If it holds you have got it right, if it fails its a bummer, but safer than failing at +40mph. I apologise if I am preaching to a welder, but only trying to impart some knowledge that has been passed down to me, to anyone one else it may be of use to.
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Post by shutz on Oct 19, 2010 19:36:36 GMT
Spot on Azuma, interesting to note the thickness of kit car chasis material, rather be belt and braces through. Pick up the steel tomorow, got the welding stuff and stripped the bikes so it could be all systems go to stretch the frame at the weekend... I know theres loads of stuff out there for welding and how toos etc but you can't get enough good advice...surprised theres not a welding thread on here!
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Post by azuma on Oct 19, 2010 23:39:02 GMT
Glad to be of some help. The problem with starting a thread on something as critical as welding, is someone will always come back at you if you got it wrong and someone gets hurt . I am not a trained welder, but have read enough and picked enough brains to run a decent weld. I tried getting by when I was younger and rushing a job, but the only way to do it is to do it right. I am quite happy to pass on help when I can, as will no doubt countless others. Most on the scene are good welders and have learned to become just that, either through college courses / work or trial and error. Get the basics right and learn how to set up your welder, through practice, before starting for real, is the best advice I can give on welding. Also, a couple of other pointers: if gas MIG welding, you are not going to get much weld time out of the little bottles, don't be tempted to use pub gas, they put a higher percentage of nitrogen in it now, really s**ty welds, block off any draghts, wind will cause the sheilding gas to be mixed with air and give you bad welds. Good luck once you get started and get some pics posted. Pictures are much better than words
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Post by peasnbarley on Oct 20, 2010 1:23:54 GMT
I only use flux cored wire because I can't be bothered with the faff of always running out of gas. The wire gives a good weld in windy conditions but it does produce a lot of fumes indoors and despite what some people will tell you the polarity of the welder makes a big difference to the amount of spatter produced. However the spatter tends not to be that hot and is quite easy to remove once the weld area has cooled. The reason people don't tend to give advice on welding is that we might be good welders but few of us are technical experts in welding procedures and as soon as you put something in print one of those lads will pop up and make you look like a right tit. ;D
Also there are some very good videos on Youtube showing good welding procedures and tips plus masses of stuff if you can be bothered to Google for the information. Some people will never manage to weld because they can't control their body position properly and move their hand in a controlled and steady manner.
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Post by Organgrinder on Oct 20, 2010 11:48:48 GMT
I'm told that learning good control of body position and moving hands in a controlled and steady manner is key to success in other physical activities
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Post by team-art on Oct 20, 2010 12:27:00 GMT
"move their hand in a controlled and steady manner"
Yes, I'm sure Charlie is talking from experience.
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Post by peasnbarley on Oct 20, 2010 15:51:07 GMT
Someone running with the name 'organgrinder' is just asking for trouble posting stuff like that; especially when he teams up with a fellow who admits to having silly thoughts while in his bath and runs his trike down hills with his arse stuck up in the air, instead of sitting like a proper cartie man. ;D My comments are not in any way intended as a dig at any proper side-car monkeys who as we all know have their own problems of which it is no longer politically correct to mention.
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Post by grahamk on Oct 20, 2010 16:42:31 GMT
"move their hand in a controlled and steady manner" Yes, I'm sure Charlie is talking from experience. Charlie is also handy with an angle grinder as i found out at Dalby. ;D
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Post by Organgrinder on Oct 22, 2010 15:09:24 GMT
I'll make sure I keep all my angles well tucked in
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Post by team-art on Oct 22, 2010 19:21:42 GMT
I'll make sure I keep all my angles well tucked in Thats acute idea. It would be obtuse not to! ;D
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Post by peasnbarley on Oct 23, 2010 13:58:51 GMT
Well our silly posts (good clean fun) seem to have mucked up a sensible thread about welding, so I will drag it back and try to be sensible. I had a look at one video demonstrating the push technique with Mig/gas and have to say the demonstration was not the best and the results would have had me starting all over again. www.youtube.com/watch?v=i7iCOTnFb_4 www.youtube.com/watch?v=N7CJwS5isrQ&feature=channelThis one demonstrating Glassless/Flux cored wire was in my opinion of far more help to anyone starting off welding. www.youtube.com/watch?v=pVyYvcEqkcQ&NR=1 The term 'gas less' is actually wrong in that the weld pool area is protected by gas only it (the gas) is generated by burning the flux contained in the wire.
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