Maurice_King Posted October 16, 2014 Share Posted October 16, 2014 If any was wondering where I have been of late, I have been tidying up the tail end of the Gravity Bike Championship for Australia.I am happy to report that I am now Number 2 in the sport in Oz and can now proudly wear the 2A number plate on my Bike. Unfortunately like many sports it is not without it's risks . And as a Result of the last race meeting for the season I am sporting some nice bruises as well as a couple of breaks - collar bone that is in 3 places no less.But the Pain is certainly worth it , as I wasn't going to let these young fellas have all the fun. Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 16, 2014 Share Posted October 16, 2014 Ouch!!! pain and ecstasy wrapped up in a nice package with pictures as well. Nice trophies Mozz I like the modern ones either side of the traditional silver cup. Link to comment Share on other sites More sharing options...
Derek McAllan Posted October 16, 2014 Share Posted October 16, 2014 See? Told ya you were mad Mozz... But congrats on the trophies and the ranking mate!! Link to comment Share on other sites More sharing options...
TreeTops Posted October 16, 2014 Share Posted October 16, 2014 I just knew I could see straight through you Mozz. Good onya mate. Well done. Link to comment Share on other sites More sharing options...
paddler Posted October 16, 2014 Share Posted October 16, 2014 OK, I had to look it up and watch a video to find out what Gravity Bikes are all about. Well done Maurice! Quite an achievement indeed. Speedy recovery. Link to comment Share on other sites More sharing options...
Taph Posted October 16, 2014 Share Posted October 16, 2014 Well done Maurice, looks like did a good job on both hope the recovery goes well Taph Link to comment Share on other sites More sharing options...
caaront Posted October 16, 2014 Share Posted October 16, 2014 Congrats. Link to comment Share on other sites More sharing options...
sightseer Posted October 16, 2014 Share Posted October 16, 2014 Wow! Congratulations! and also - Ouch! seriously... hope you get better from that asap. I will have to look up gravity biking as well. Link to comment Share on other sites More sharing options...
spirit_66 Posted October 16, 2014 Share Posted October 16, 2014 Well done and get well soon. I would like to see a picture of your bike. Spirit Link to comment Share on other sites More sharing options...
Mark Abdey Posted October 16, 2014 Share Posted October 16, 2014 Blimy, you did a good job on that collar bone.. ouch!... can they rebuild you? I just had a look at your sport, and it looks insane!... being so low must make the speed feel, er fast. Congrats on being no.2 Any pics? Link to comment Share on other sites More sharing options...
Iain Emms Posted October 16, 2014 Share Posted October 16, 2014 Congratulations Maurice on the Trophy wins mate I hope you get on the mend soon. cheers Iain Link to comment Share on other sites More sharing options...
Ziggy Posted October 16, 2014 Share Posted October 16, 2014 Attaboy!!! Way to go!!! Link to comment Share on other sites More sharing options...
Venturi Posted October 16, 2014 Share Posted October 16, 2014 crazy ba%$tard! Link to comment Share on other sites More sharing options...
Stillwater Posted October 16, 2014 Share Posted October 16, 2014 I like the 1st shot more than the 2nd. Best wishes to recover soon, don´t forget to have a good stock of Ibuprofene (Lysinate) always at hands! Link to comment Share on other sites More sharing options...
TerribleT Posted October 16, 2014 Share Posted October 16, 2014 You certainly proved the adage Mozza: "no gain without pain" but well done and recover soon as .... Link to comment Share on other sites More sharing options...
tom Posted October 16, 2014 Share Posted October 16, 2014 'On ya Mozz ... and all the best for your recovery. Wondered where you'd been of late. When does your thrust for no.1 begin ... can't imagine you being happy at no.2 for long. Cheers mate, and go carefully (until mended). Link to comment Share on other sites More sharing options...
Maurice_King Posted October 16, 2014 Author Share Posted October 16, 2014 Thanks for the wishes fellas, Tom the calender hasn't been finalised for next year yet , but there is a round locally here in the Snowies then Blue Mountains then SA, Vic, Qld, And then finally Tamworth again.I was just 6 points behind the leader who I might add is a past 2 time World champ until I crashed in practice after forgetting to tweak my rear suspension after pumping the tyres up Next year maybe Link to comment Share on other sites More sharing options...
chumley Posted October 16, 2014 Share Posted October 16, 2014 The Bionic Moz A young fella would have remembered to tweak the suspension. Link to comment Share on other sites More sharing options...
alank Posted October 17, 2014 Share Posted October 17, 2014 Surely Maurice, at your age you should be moving towards a more sedate type of sport ... Have you considered base jumping maybe or perhaps wingsuit flying ...? get well soon mate! Link to comment Share on other sites More sharing options...
Maurice_King Posted October 17, 2014 Author Share Posted October 17, 2014 No WUCKING FAY any fool that leaves a perfectly serviceable airframe has shit for brains. I AM NOT going to arrive at the grave will a well preserved body but one thoroughly worn out and used up and have no regrets about "I wish I'd done this or wish I'd done that"! I'll arrive with a grin on my face screaming " Woo Hoo what a bloody ride" Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 17, 2014 Share Posted October 17, 2014 Hey Mozz, Somewhere back last year I remember an old post, didn't you also try your hand at this crazy sport. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 17, 2014 Author Share Posted October 17, 2014 Yes I did and do. my best speed has been in the order of 105 KPH and on the gravity bike a little faster but they were test runs out with friends on some knarly hills around here Not bad for something powered by nothing more than gravity huh !! Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 17, 2014 Share Posted October 17, 2014 Not bad at all Mozz 105Kmh. Speaking of gravity, maybe this could be your next adrenaline junkie adventure. There' a crazy Frenchman or Canadian (Markus Stockl) who set a speed record 102Mph on a similar bike down the side of a volcano in Nicaragua. On his last attempt he barely survived, much more damage than a broken collar bone, I think he did a few km's on his face before he finally stopped. But hey maybe when you have healed. Link to comment Share on other sites More sharing options...
chumley Posted October 17, 2014 Share Posted October 17, 2014 I have been up a shade above 75kmh on a racing bike and it was a great adrenaline burst. Reality set in when I had a fleeting 'what if' moment as the bike reached maximum speed and a bend came into view. Brakes are wonderful - when they work. The run off if the bend weren't taken would have seen a splashdown in a local creek suitably filled with rain run off. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 17, 2014 Author Share Posted October 17, 2014 Markus would have been hard pressed to get decent speed anywhere else I suspect, now there is a nutter Link to comment Share on other sites More sharing options...
Maurice_King Posted October 17, 2014 Author Share Posted October 17, 2014 Yes Chumley that would be why I have a 200mm+ disc on the front and a 160 on the rear. Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 17, 2014 Share Posted October 17, 2014 Nice bit of kit there Mozz, good brakes are essential IMO but the weakest point would be the spoke wheels, unless they are larger diameter rods or exotic metal, but I guess that's for weight reduction. Have you looked into having a pair machined from a billet alloy. And are there special rules governing class and build for the particular championship race. Link to comment Share on other sites More sharing options...
spirit_66 Posted October 17, 2014 Share Posted October 17, 2014 Thanks for the picture of your bike (I guess it's yours). Spirit Link to comment Share on other sites More sharing options...
Maurice_King Posted October 17, 2014 Author Share Posted October 17, 2014 There are rules governing the wheels yes Disk on the rear only (apparently there is some BS fear of cross winds at speed screwing with the riding stability). But besides that there is a 34 Kg Weight constraint as well so a billet wheel would give that a fair nudge and cost a hell of a lot too. When I built these wheels I selected rims that were able to be cross laced actually as this imparts tremendous Lateral strength. Each spoke on these hubs is laced with 36 spokes tensioned at 100 KG each and the spokes also cross over on the way from the left flange to the right side of the rim. basically the strength you get from crossed spokes in drive and braking is extended to left to right as well. The Spokes I used are SAPIM and they were not cheap The Rims Eclat Exodus extruded rolled 6061 T6 Alloy. Cost including Tyre for each wheel was just short of $200.As you can see the spokes are off set adding tremendous lateral strength. Frame is Alloy 100 x 50 RHS except for the swing arm which is 25 x 45 with all mounts and gussets of 10 mm Flat stock. I can post other images if liked. Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 17, 2014 Share Posted October 17, 2014 Thanks for expanding on your original post Mozz, it shows that you are a true professional. Thanks for the info about your wheels, it is very clear to see the offset and the cross-laced rim, clearly you have an excellent knowledge about the forces at play and how to minimise the risk. Having the rim anodised also adds strength, the red colour may be, I'm guessing is anodised treatment or possibly a molly treatment. I'll do some googling on the design specs that might tell me how the alloy is treated. As you can probably tell this topic has grabbed my attention, the build quality and design engineering is something I could see myself doing, but maybe not the other side of things, throwing my leg over the crossbar for a downhill run maybe not. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 17, 2014 Author Share Posted October 17, 2014 Jeff you are always welcome to have a go. Yes the Rims are Anodised and Heat Treated for Stress relief, Although the photo is an older one the Swingarm pivots which are free floating concentric mounts have pegs mounted on them which allows virtually all my weight to be transferred to my knees and thus push the C of G much lower. I will also made brackets and mounts to move the rear pegs slightly further forward but mounted of the rear sub frame so that foot weight does not upset the rear suspension tuning due to additional unsprung weight - this was likely the cause for my unceremonious get off at Tamworth as the course was rather rough..My chest is prone with the top bar allowing full and free movement of the arms for steering. Now you might be interested to know that as the bike sits it is 24+ Kg and due to my design calculations ends up with %50 front - %50 rear weight distribution. With the addition of some Shot as ballast I hope to bring thin forward to the ideal 55/45 front rear biasI can post images of the Forks and their modifications so you can see what was done if you like as others may be interested too. Having my own Lathe and Milling machine if extremely handy Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 18, 2014 Share Posted October 18, 2014 Hi Mozz, I agree moving the foot pegs to the seat support frame would prevent any unsprung weight interference through the legs with the rear swing arm, you could even attach the pegs to extenders so that you have a more natural riding position. I have taken the liberty of reworking your photograph, adding a few little tweeks here and there, mostly to do with moving the Center Of Gravity, but also foot peg extenders. So at the risk of sharing a bad idea here is the reworked picture. The Triangular section made of aluminium, bolted or welded to the frame, with cutaway sections to remove some un-needed sprung weight, has slotted sections through the vertical / Horizontal / diagonal planes (Red /Green). These slots would allow a movable/adjustable bob-weight, which could be moved on the fly or through testing to any position through these planes. It could also be adapted to having extra or less weight depending on the race setup or rider, getting you closer to that magic 55/45 weight balance. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 18, 2014 Author Share Posted October 18, 2014 One jump ahead of ya son, I have machined up 2 standoff's for the main frame a spacer that will triangulate things just in front of the rear tyre and sufficiently far above the rear arm but mounted off the main frame extending back from the kneeler's and down from the seat post at around 45 Deg. The pegs will end up about 50 mm forward of the current location. The front down tube you have your mass balance weight on will be unused as there is a shot chamber in the down tube and eventually there will be mass balance weights on a sliding arm that will give adjustment from just in front of the rear wheel to just behind the front wheel , so experimentation can be had and once the sweet spot found it be fixed in place so ballast can be added or removed depending on the course. But I am more in favor of finding the sweet spot and locking things down for that just as I did when road racing. I am currently uploading some more images of the construction since your interested and have a good understanding of what I am doing. Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 18, 2014 Share Posted October 18, 2014 Sounds like a plan to me, how are you operating your tools with one arm out of action. Looking forward to the coming pics. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 18, 2014 Author Share Posted October 18, 2014 I'm not and I have several jobs waiting Brake calliper mount mod Right side pinch mount Front end The Fork End showing the stepped sleeve setup. As fitted. Close up of the Steering Head checking clearance and angles. on the Jig Frame just about weld ready , checking clearances and angles, and making some tweaks here and there as needed. Close up of the swing-arm pivot, rear swing-arm etc checking for squareness and so on . More to follow if you like Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 18, 2014 Share Posted October 18, 2014 Great pics Mozz, Aluminium welding is an art, are you using Torch and Rod, or Tig / rod and Gas. I've done some welding in my time of all sorts, stainless & mild steel, aluminium, but mainly small parts and some small structures, automotive componentry. Have not and can nolonger see well enough to weld to save my life. Tac and tac and weld and weld, ain't that how it goes. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 18, 2014 Author Share Posted October 18, 2014 Tack it all together and check symmetry adjust as needed and weld. both TIG and MIG actually . Mig to tack and preheat along with preheating with the Gas Axe , then TIG weld the joints . Not sure if you grasp how the front wheel is secured but ask away. More to come Link to comment Share on other sites More sharing options...
Jethro VH-JET Posted October 18, 2014 Share Posted October 18, 2014 Well Mozz, I'm thinking forks to frame or do you mean front wheel hub/spindle to forks. I can see that you are intending to form the diagonal main frame section to the alloy pivoting boss on the forks, welding these two together, and then weld the piece that forms the seat and resting place for you to lay down is going to be welded to the top of this boss. If its the wheel hub/spindle then I assume it has something to do with that internally threaded turned chunk of aluminium sitting resting atop the black knuckle joint in Post#35 picture 4 & 5 where the knuckle locates the hub centrally and the turned piece locks the spindle to the knuckle so that the forks don't twist. Then the only thing bearing any lateral or vertical load is the hub race. Link to comment Share on other sites More sharing options...
Maurice_King Posted October 18, 2014 Author Share Posted October 18, 2014 The Stepped sleeve nut as shown with the Cast fork end and hub with disc behind it is designed literally on the fly . Once I discovered that the hub was wider that the internal space between the fork legs, I recessed this area similar to the recess on the outside . What this does is centralise the hub within the forks , the alloy sleeve or Step nut as I call it then threads onto the axle but locates the axle centrally in the hole and this is tight left to right, the final thing is the pinch bolts in the fork ends are tightened locking the Alloy Stepped nuts in place and the axle and wheel along with it preventing any and all axial or lateral movement. The steering head as shown checking the frame pieces was done that way to assist in 3 key areas , 1 torsional strength, 2 Support for the down tube lastly a wide flat area for the chest padding. The Steering head is 50 x 5 mm tubing with 2 bearing pockets machined up in solid then interference press fitted to the central tube and this welded to the frame, there is an anti crush tube and shims to space out the inner bearing races so there is no side load on the bearings in the steering , the bottom bearing has an integral thrust race as well (hard to find these but I managed) The swing arm pivot shows the trimming and locations , the bottom pivot was made in a similar fashion to the steering head - I used again 50 x 5 mm tube and cleaned a flat recess on the inside then the pivot cups with bearing clearance lands were pressed into the central tube with a .005 thou crush. The ring for the Shock is also welded in place after checking angles etc. I hope that explains the images a bit better. Link to comment Share on other sites More sharing options...
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