The Downhill Thread

[Capricorn]

that's it. go thru the phases. mean time, polish up your understand of composites. You can reach yourself a lot before you get to final prototyping stage which will require you then to try for final fit and form, ie using carbon fibre/whatever material you will finally settle upon.

 

I dunno who you been talking to: but composites are not easy.

At all. The people who properly understand it can make it seem extremely simple, but it belies the fact that composites represents one of the most advanced technologies out there. I'm not trying to dissuade you from using carbon fibre in your design: but rather to not let the complexities of using carbon get in the way of the very basics of design: the creative phase. And once you've got your design in conceptual form, then to move to a rapid prototyping phase, where you dont want the complexities of a certain material to get in the way of realising in material form that which you've conceptualised. With wood, you can test for form and fit: will it fit on a bike with ISCG tabs. Does it even need to hook up on the tabs? etc etc. Then once you past that phase, you can move to alu. This will require machining (cost), and sourcing decent grades of alu. The lower grades will of course work in terms of fit and function, ie to see how it basically looks and functions. But it may fail the bashtest, so keep material strength vs material used in hte back of your mind so you not surprised by a negative result.

You could combine the two stages by going straight to material selection under impact conditions and check for fit and form using software: design for form and check for fit via software, and then base material selections on FE (Finite element) analysis in software as well. Once all that's been firmed up, you practically good to go into final prototyping phase using carbon. But getting good results from the previous stages requires quite a bit of learning. But it's well worth it.

 

Milestones to success: babysteps if you like. Realising the little goals along the way will only harden your resolve to bring to fruition that which your mind conjured up.

 

Go for it Murray, but be wise about how u go about doing it. My advice is go simple: work smart.

[DownhillingKing]

You probably wondering why carbon, and thinking man this oaks only 17 and just wants to use carbon because it looks cool. My reason is is that in the holidays I'm wanting to go work at central boating I think it is, or even at Steve's place in Muzenburg. That way my holidays will consist of work with fiber glassing and building carbon fiber masts. Meaning I will have some experience with the material.

 

But ja I will make many prototypes and try different things. Do you rate I go for box guide or wheels all round?

[Capricorn]

ok. then that will definitely help your learning curve. btw: that's awesome work experience!! While u there, get to understand why the fibres are arranged the way they are, in the various layers and thickness of the epoxy that holds it all together. It will definitely help you with using CF in general.

 

As for box guide or wheels: it's all about what you want to achieve. You might have more than one concept to begin with, hence the recommendation to keep the initial material selection cheap. But Go wild!

 

oh and dont forget to benchmark A lot of work has already been done in terms of hte basic design requirements for a chain device. So using what's out there that's common to all designs will be your basic starting point. How it eventually looks: that's all you

 

Do you have a photo of mark's CD? I'm really curious now that you say it looks seksi.

[loveme.DH/FR]

hey cap, sorry dude! I know its a bit of a tit trying to keep those berms hard! I think winter hasnt given us much rain, Its super dusty up there! Was thinking of a way to get water down? Maybe a 50L tank in a bakkie parked on the main road, and a long hose pipe, would be easy to siphon the water down the hill.. but a bithc to carry the hose pipe back up....

[Capricorn]

actually loveme.DH/FR, i was thinking of dropping a 25L drum on SH2 and another 25L on SH3, but bury it and just funnel whatever water the ground gets into it somehow. Then use as needed. In the interim, i'm just gonna lug up 5L cans of water to water them berms. Your berm needs a thorough hosing. I think it didnt get that wet when it rained cos of the canopy of leaves above it. quel dommage. Showed that berm some respect today

 

btw: i added a proper lip to that step down at the corner just after the log drop. so much better as u can now hip into the following straightway. Wanna help me farm rocks for the rockgarden? it's way too short. Need biggerass rocks with some decent spacing between them for a proper rockgardn.

[loveme.DH/FR]

Next time im At Signals ill try find and gather some rocks for the garden. I actually just got back from a morning ride there today! Theres potential for a really nice offshoot from the main-line SH2 just after the rock garden. I brushed the ground to make a visible trail and put a mini rock pile there so you could see it. Basically means a swooping left corner after rockgarden, which tightens then a nice gap (have to keep speed!!) might need a berm. The Gap isnt huge but you could fit a bike in there lenghtways. After the gap cut up above a little bit into a full 180 berm (U-berm?) then back towards SH2 and relink further down...

 

OTHERWISE Its looking good! Like the bigger drop off after the berm on SH3! Also found a nice line after the drop, over the "Hump" where its possible to get quite a bit of air! Just aim a little more to the left. Yo will see the brake-ing tracks in the grass.

[Capricorn]

yep, that left hand side line is better for popping off that mini tabletop. I'm gonna fix that 'berm' after that slope. not very nice to corner around that turn. I tend to hook out far to the left to cut the apex. that way I dont need to drift out or stamp to pivot around the turn. But after the logs+jump, the path toward the treehouse, i need to weedwack some: the grass is very thick and some of those branches are snagging me skin. not lekker.

 

that line of yours sounds interesting. but I dunno how you can hook that left, cos when i hip off that little stepdown before the rockgardn, it's practically full tilt all the way till the fire road.

BUT, it might just be possible, if you hip from the stepdown, but instead of hipping such that u face the rockgardn, hip facing the embankment on the right of the rockgardn, then I think it's possible to use the bulge of hte embankment to swing left into your track. Not where to turn off, but i will find your rockpile and see if i can pull it off as i suggested above.

[Capricorn]

btw: I think the overall plan, is to turn SH2+3 and in future SH1 into cape town's version of the DirtTV 1:04 track. Their's is of course quite a bit longer, but if we rope in SH1 at some point, then that hill is going to totally rock. Sucks for shuttles or pushups, but i want the track clear and ridable from top to bottom, hence the weedwacking in and around the treehouse.

 

oh yeah, forgot to mention: ramps (take off and transition) are going up for a jump about 10m down from the rockgardn. Lemme know if location is loco, or any other suggestion. I chose it cos it's nice long boringly straight section

[Oli G]

DHK Where are u?? just hubbing form home hey???

[patches]

here's a pic of me and the rig learning to fly. It's not anything spectacular, like I said, still learning, but good fun.

 

Sorry for the poor quality. Light was bad, and it's a screenshot from a vid.

 

(I think if you click on it, it will get bigger)

 

[Capricorn]

nice stuff Patches.

 

dont suppose you sent them nitro circus stuff? sent you a pm a while back, but u ignoring me dude

[craig82]

Sometimes I forget this is a photo thread Thanks for the reminder Patches.

[Capricorn]

heaven's forbid we actually talk in this thread, especially about all things DH. oh the pain

 

anyways, 5.10 successfully leaked a sneak-peak at their 2011 range of shoes. I'm conflicted

oh look! a pitcher!

 

[loveme.DH/FR]

Well we could start another topic and only use it for catching up on all things downhill. But this is the only topic i actually consistently check. Its like a little blog! It would be cool of we could get the topic moved out of Photos.. i guess!

 

Anyway..

 

The route ive been training on is the alternate, SH2 - SH2b linking back into SH2 above the log drop - over the rock garden - left into (proposed) SH2c over Gap/Step down round hard 180 berm and then back onto SH2. Hopefully in-time to hit the jump thats going up there.

 

The route is pretty clear and doable. Not to hard to take the turn esp. if you do the alternate route, and come into SH2 with less speed.

 

The only part that needs work is the section that goes through a pile of bush & trees before linking back up on to SH2.

 

The reason ive been looking at all these alternate routes is, im really trying to up my skills in regards to cornering, berms and confidence in coming in hot before a corner. I cant get to Tokai often enough, and whats going down in Signals is great!

 

Its pretty short at the moment SH2 and SH3 DIRECT. Cant wait for SH1!!!!

 

I guess ill see your Schwalbe Dirty Dans tracks soon!

[Capricorn]

hahaha.. DDs totally rock, especially on the wommins

 

you know what dude: i went down SH2 today totally committed to trying out your new track, and then totally blitzed past the turn off. Man, that track can be hairy if u lay off the brakes. I dunno how you find it, but at speed as far as I've experienced, those loose stones cause the bike to get all skittish.

 

I just need to remember to enter the rockgardn a lot slower. As for that brush that needs clearing, i bought a machete B) Will leave it with the rest of the tools on top. But move it around with the refuse bag as a weather cover. Just let me know where u hid it so i can tell my other riding buddy where to find it. btw: SH2b has developed in a bigger way than I had thought. My riding buddy and his gf bundubashed the new trail. I think it's pretty damn good. but i need to ride it myself first as I've only walked it todate.

 

Dude: all this assbreaking is exactly for all the reasons you just laid down: wanna get better at techy stuff,but dont always have the time to rock Tokai. Totally getit.

[DownhillingKing]

Slow down for a rock garden what? You got a marzocchi man!! Rock Garden Full speed!!! So Cap when you going to come check out the DJ track Alex, brandon and I have been working on?