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Diy Bike ...ideas, Suggestions, Improvements


Alex Dark

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Alex i have an idea for the brake mounts. Forget the idea of thin seat stays. Instead produce the stays like a normal frame, but machene the bottom part of the brake mount into the top of the stay. That way when the top part of the mount is bolted in, it will be an integral part of the frame. However to do this you need to have a weighty solid seat stay. Of which ihave no solution <_<

anyway, i doubt it would work, just throwing up ideas.

Ah, I was planning this...but then realised if the axle is used in the horizontal dropouts, the wheel will move in relation to the brake mount :(

That looks like a massive weak point :(

I know :(

Edited by Alex Dark
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how about mounts like this?

Immence paint skills coming into play here....

edit: feck just read your last post. erm, vertical dropouts?

Got me heart set on horizontal :P plus...even if it was vertical, if different rims were used the pads may still not hit the rim in line.

Sorry, my post wasn't very clear. The text below the image refer to the other discussion relating to the BB shell and isn't aimed at the brake mount area/chainstays at all.

Ah no problemo :), thanks for your help Dave

Edited by Alex Dark
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Are boostered forks really necassary? I haven't heard about any snapping there in a fair while.

Do people:

a) Not run maguras any more?

b ) Not make a big deal of it any more, as it's expected?

c) Did the manufacturers already overcome the problem?

Not ridiculing in any way - just curious as to the motives.

Edit: "b )" without the space becomes B). How gay.

Edited by aener
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Are boostered forks really necassary? I haven't heard about any snapping there in a fair while.

Do people:

a) Not run maguras any more?

b ) Not make a big deal of it any more, as it's expected?

c) Did the manufacturers already overcome the problem?

Not ridiculing in any way - just curious as to the motives.

Edit: "b )" without the space becomes B). How gay.

If they're reverse mount I reckon it makes sense. I've seen at least 3 pairs cracked at the top of the magura mounts.

a ) nope, seems to be in fashion for natty stock riders at the moment

b ) People seemed to be ridiculed for posting up snapped forks recently

c ) To an extent....

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I'm not sure what CAD program you're using - looks like Solidworks - you should be able to put in offset while keeping the forks straight bladed by selecting an axis where you want the legs to join at the bottom of the steerer tube, selecting a plane at the same time and then selecting the 'make new plane' option. Then draw your sweep path along that plane. Works that way in ProE anyway.

Straight blade forks are the way to go since putting the same curve on both fork legs will be a manufacturing difficulty depending on the equipment you have handy, and welding the brake mounts to a curved fork blade will be a pain. I'd put the brake mounts on the front of the fork every time. The reason being that by default the back of the fork legs will be in tension at all times except while you're endoing, so the fork will fail more quickly all other things being equal with the mounts on the back. The last fork I used with rear brake mounts was an Echo Urban, lasted all of 6 months before snapping. The replacement Onza fork is still fine 1.5 years on, though it is steel :)...

Edited by psycholist
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I'm not sure what CAD program you're using - looks like Solidworks - you should be able to put in offset while keeping the forks straight bladed by selecting an axis where you want the legs to join at the bottom of the steerer tube, selecting a plane at the same time and then selecting the 'make new plane' option. Then draw your sweep path along that plane. Works that way in ProE anyway.

Straight blade forks are the way to go since putting the same curve on both fork legs will be a manufacturing difficulty depending on the equipment you have handy, and welding the brake mounts to a curved fork blade will be a pain. I'd put the brake mounts on the front of the fork every time. The reason being that by default the back of the fork legs will be in tension at all times except while you're endoing, so the fork will fail more quickly all other things being equal with the mounts on the back. The last fork I used with rear brake mounts was an Echo Urban, lasted all of 6 months before snapping. The replacement Onza fork is still fine 1.5 years on, though it is steel :)...

Hmm, everyone seems to prefer the reverse mount :S I'll see i guess. Managed to get the steerer at an angle thanks to you (Y)

If you're planning on testing the frame and fork after you build it, here's the relevant European standard - If it can't survive this it'll be dangerous to use as a trials bike anyway: http://www.bike-eu.com/public/file/archive...glish-draft.pdf

Came through again :) thanks very much dude, was looking for this for me research

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Alex i have an idea for the brake mounts. Forget the idea of thin seat stays. Instead produce the stays like a normal frame, but machene the bottom part of the brake mount into the top of the stay. That way when the top part of the mount is bolted in, it will be an integral part of the frame. However to do this you need to have a weighty solid seat stay. Of which ihave no solution <_<

anyway, i doubt it would work, just throwing up ideas.

Doing that would be pretty strong, but you've have no adjustment on the mounts at all! So you'd be pretty limited to rims etc, surely?

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if different rims were used the pads may still not hit the rim in line.

Doing that would be pretty strong, but you've have no adjustment on the mounts at all! So you'd be pretty limited to rims etc, surely?

Yerp was my reckoning as well.....It;s still very much on the drawing board though; so any improvements are more than welcome.

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Are you using solidworks? for the CAD?

Certainly am :)

I'd still have questions about the BB yoke but it depends how far you need to take it and how clued up the assessor is. Are you actually planning getting the frame manufactured and built?

Erm, well in their eyes its fine as it is....however, as im building it i want it done to the best level possible. Any suggestions you have are more than welcome dave :)

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Erm, well in their eyes its fine as it is....however, as im building it i want it done to the best level possible. Any suggestions you have are more than welcome dave :)

secondrender.jpg

Hope that makes sense. Where the chainstays attach it might be worth tweaking it to actually meet the full section of the tubing as at the moment you'll end up with massive stress raisers at the ends of the 'C' section. There are also bits of the yoke edges which don't include a radius. It would tidy it up nicely if they all matched to create a nice, smooth flowing piece.

Where the chainstay parts of the yoke meet the BB shell itself I'm still not sure it'll be possible to produce it. If you could smooth the outside edges of the yoke to meet the BB cup ends it would make for an easier to manufacture piece although you may have to rework the lightening slots a bit as well.

The final point is probably just an oddity of the display but there seesm to be something a bit odd going on in the slot which passes through the BB shell.

It does look proper pimp in full render though! Very impressive :).

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