Diy Bike ...ideas, Suggestions, Improvements

[Alex Dark]

Alex, you may be interested to see how the triton chainstay yoke is done, being titanium its a bit of a no no to just whack a huge block of milled metal in there

Its constructed from titanium plate and nothing else, will get a photo for you later if you want. Tyre clearance isnt an issue, it fits a 2.4 rubber queen in there without any major hassles

edit: found a picture of aforementioned chainstay yoke (plus a sneaky boasting photo of how light the frame is )

that looks awesome, is it not just a cnc'd block then?

Mounts look weird so do the hose guides

[psycholist]

Most of that strangeness is because we're mostly used to the way these things are done in Aluminium, so it's weird to see how little metal is needed when you move to steel or Ti...

[A.Baxter]

I think removable brake mounts sounds a fairly bad idea, sorry, maybe just do 4bolt and disc mounts ? Then design a vee brake adaptor your a level though so up to you what to do

Adam

[forteh]

that looks awesome, is it not just a cnc'd block then?

Mounts look weird so do the hose guides

The 2 angled side plates appear to be flat bar stock with a pocket and the ends machined, the box construction is all plate

The mounts are just threaded tube welded in, much neater and simpler imho; the hose guides are just a saddle that seats the hose and has a hole for zip tie to secure it.

[Alex Dark]

The 2 angled side plates appear to be flat bar stock with a pocket and the ends machined, the box construction is all plate

The mounts are just threaded tube welded in, much neater and simpler imho; the hose guides are just a saddle that seats the hose and has a hole for zip tie to secure it.

ah right...

the mounts look cool i reckon, obviosuly far less material needed than with aluminium. Hose guides are also pretty neat...

[Alex Dark]

Okay, time to bump this topic as i've now started doing research for my project. Has anyone got any more suggestions for me?

Definitely being made out of aluminium now, Geo will be a shorter Coust v2 ( 1085, +35, 380, 72 ) I thinks....with a rear disc mount and magura specific mounts. Tempted by this whole press fit isis bb jobbie, any ideas? anything to stop me pulling apart an old sealed bearing isi bb, and getting the right size bearings and simply pressing into frame?

Still trying to debate over horizontal and vertical drop-outs.....i'll definitely stick with 135 spacing though I reckon.

Any views or Suggestions would be more than welcome

Thanks

[Revolver]

Definitely being made out of aluminium now, Geo will be a shorter Coust v2 ( 1085, +35, 380, 72 ) I thinks....with a rear disc mount and magura specific mounts. Tempted by this whole press fit isis bb jobbie, any ideas? anything to stop me pulling apart an old sealed bearing isi bb, and getting the right size bearings and simply pressing into frame?

If the bearings and the BB shell aren't made perfectly, it will be too loose or too tight.

[forteh]

Okay, time to bump this topic as i've now started doing research for my project. Has anyone got any more suggestions for me?

Definitely being made out of aluminium now, Geo will be a shorter Coust v2 ( 1085, +35, 380, 72 ) I thinks....with a rear disc mount and magura specific mounts. Tempted by this whole press fit isis bb jobbie, any ideas? anything to stop me pulling apart an old sealed bearing isi bb, and getting the right size bearings and simply pressing into frame?

Still trying to debate over horizontal and vertical drop-outs.....i'll definitely stick with 135 spacing though I reckon.

Any views or Suggestions would be more than welcome

Thanks

Thats almost the geo of the triton (1085, +30, 385, 72)

With the press fit BB you will need to machine the BB shell after welding/heat treatment, it will also need to be to correct bearing tolerance fit; dig out a copy of the limits and fits chart and see if you can make head or tail of it

Making it a cupless BB could work pretty well, you would need an isis spindle and machine the shell to suit the bearing spacing (there should be a stepped shoulder on the spindle to position the bearings right). I think you will also need to have seperate spacer rings between the crank arm and the inner bearing race, similar arrangement to profile cranks. Im not familiar with isis BBs as I only use taper.

Vertical or horizontal dropouts is much of a muchness, aslong as you jig the frame up properly prior to welding then it shouldnt be any problem.

Edited September 22, 2009 by forteh

[Alex Dark]

If the bearings and the BB shell aren't made perfectly, it will be too loose or too tight.

Hmmm, ill have to get the tolerances pretty exact then

Thats almost the geo of the triton (1085, +30, 385, 72)

With the press fit BB you will need to machine the BB shell after welding/heat treatment, it will also need to be to correct bearing tolerance fit; dig out a copy of the limits and fits chart and see if you can make head or tail of it

Making it a cupless BB could work pretty well, you would need an isis spindle and machine the shell to suit the bearing spacing (there should be a stepped shoulder on the spindle to position the bearings right). I think you will also need to have seperate spacer rings between the crank arm and the inner bearing race, similar arrangement to profile cranks. Im not familiar with isis BBs as I only use taper.

Vertical or horizontal dropouts is much of a muchness, aslong as you jig the frame up properly prior to welding then it shouldnt be any problem.

Yep, mint geometry, really want a deema

after heat treatment, eh? Ill have to ask my lecturer about the right tolerances and suck

Ah, i think a normal 128 spindle, once machined should do the job? Ill check it out

yeh, im thinking Horizontal now

[trialsmax04]

Hmmm, ill have to get the tolerances pretty exact then

Yep, mint geometry, really want a deema

after heat treatment, eh? Ill have to ask my lecturer about the right tolerances and suck

Ah, i think a normal 128 spindle, once machined should do the job? Ill check it out

yeh, im thinking Horizontal now

Alex are you going to be making the cranks? Because if you are thinking of going CNC there is a engeneering works near me that would let you use there macheine for a drink

[Alex Dark]

Alex are you going to be making the cranks? Because if you are thinking of going CNC there is a engeneering works near me that would let you use there macheine for a drink

Are you actually serious?! that'd be amazing.... I could make the dropouts and maybe even bb yolk headtube.....and cranks!

Epicness.....PM me! heh

[Revolver]

If I were you I'd just use a threaded BB shell.

[forteh]

It would be much better if you could machine the tubes yourself on a lathe, forget all this cnc bollocks, in your case its not going to achieve anything except taking up a load of time programming (unless you have a full 3d cad/cam suite available which Im presuming you dont have as you might be using someone elses machine). All a cnc machine is good for is repeatability.

Go back to basics and do the machining the good old way how they used to do it 30 years ago

For dropouts I would get them laser profiled (yes its cnc machining I know) as its quicker and cheaper than profile milling them, you do of course need to know a friendly laser cutter

[Alex Dark]

If I were you I'd just use a threaded BB shell.

Hmm, Might just be easier I guess....

It would be much better if you could machine the tubes yourself on a lathe, forget all this cnc bollocks, in your case its not going to achieve anything except taking up a load of time programming (unless you have a full 3d cad/cam suite available which Im presuming you dont have as you might be using someone elses machine). All a cnc machine is good for is repeatability.

Go back to basics and do the machining the good old way how they used to do it 30 years ago

For dropouts I would get them laser profiled (yes its cnc machining I know) as its quicker and cheaper than profile milling them, you do of course need to know a friendly laser cutter

haha okay, duly taken on board

I now need to look out for aluminium suppliers.... 6061 t6? or could i get away with something cheaper?

[forteh]

I now need to look out for aluminium suppliers.... 6061 t6? or could i get away with something cheaper?

Go for what you can afford, Im not up on what aluminium frames are commonly built from, I know my santa cruz is 6082 though

It would be wise to follow the masses and go for whatever is widely used, chances are it will be cheaper and more readily available. Ideally you should be able to size and spec the material in order to withstand the forces put into it, however knowing and understanding those forces whilst allowing for cyclic loading (fatigue) is likely well beyond A level. You can do it by eye, look at it and say yup that looks about reet, not exactly a good engineering approach though

Bear in mind the T6 is in reference to the heat treatment, if you buy tubes in T6 form then that will possibly affect machining and welding. I may be wrong but I would have thought that ideally you would need to build the frame and finish all welding before sending it off to be heat treated. It would be worth enquiring around some heat treaters to see if they will/can do the frame for you.

Knowledge is power in this case, if you can find a man who knows aluminium heat treatment, sit him down and ask lots of questions regarding material choice and appropriate heat treatments. If you get your heat treatment wrong (make it too hard for example) then your frame is likely to just crack immediately, make it too soft and youre not going to get enough strength out of the alumium.

[psycholist]

By the time you've welded 6061 it'll be nowhere near the T6 condition anywhere it matters, so no point in buying T6 treated tubes AFAIK. You can get away without heat treating 6000 series aluminium provided you build heavier to begin with. If I was to build in Al I'd choose 6061 if I had no heat treating facilities.

From what I've read (Though reliable information is very limited to be honest) 7000 series Aluminiums must be heat treated after welding to be any use. Investigate 2000 series Aluminium too - it's used for a lot of handlebars, so it should have very good toughness. It's possible the reason it's not used in any bike frames I know of is because it can't be welded though.

Another possibility for making complex parts like the chainstay yoke and headtube is to sand cast them if you have the facilities are available. You'd have a very custom frame indeed after that.

[Matt Vandart]

By the time you've welded 6061 it'll be nowhere near the T6 condition anywhere it matters, so no point in buying T6 treated tubes AFAIK. You can get away without heat treating 6000 series aluminium provided you build heavier to begin with. If I was to build in Al I'd choose 6061 if I had no heat treating facilities.

From what I've read (Though reliable information is very limited to be honest) 7000 series Aluminiums must be heat treated after welding to be any use. Investigate 2000 series Aluminium too - it's used for a lot of handlebars, so it should have very good toughness. It's possible the reason it's not used in any bike frames I know of is because it can't be welded though.

Another possibility for making complex parts like the chainstay yoke and headtube is to sand cast them if you have the facilities are available. You'd have a very custom frame indeed after that.

Hmmmmmm..........

Matt

[psycholist]

Even cooler would be investment casting so you could carve what you want in wax, coat in ceramic and melt out the wax before pouring in the molten metal. I'm pretty sure you should be able to find an alloy suitable for both casting and welding... This all depends on the facilities handy though - you're not going to set up a casting workshop from scratch just to make a few bits...

[Guest itstroy08]

why downt you try a single tube?

or maby make two smaller ones reinforced by a cover to look like one, and keep wealds inside, and try a bashplate on it

id buy a 26 if it had a bash

[Alex Dark]

righto, just a topic bump as im properly starting my project now. I'll be updating my topic with what i get up to, and what the design turns out like etc for anyone that's interested

Any help is more than welcome, and im looking for some ideas / help with the following at the moment:

* Material choice still, having talked to my college lecturer i reckon it will be 6000 series aluminium, and hopefully heat treated.

* I'm planning on integrating the magura mount into the frame , so the brake will be protected from knocks and hopefully improve performance.

* The tubing profile to use

Basically any ideas or feedback, and what you'd like to see in a well designed frame.

Thanks, Alex

[Alex Dark]

anyone any ideas at all?

pictures should be uploaded tonight of cad designs for anyone that's remotely interested

[forteh]

Interested to see how this pans out

If I have any thoughts once your designs are uploaded Ill let you know

[ogre]

have the magura mounts underneath the seatstays so it's got a clean profile to the frame

[Matt Vandart]

Yes, come on Alex, I have been waiting patiently to see how this is getting on for long enough now.

Pictures please.

[forteh]

have the magura mounts underneath the seatstays so it's got a clean profile to the frame

That will affect the operation of the brake though, same as reverse 4 bolt mounts on forks. In theory it should increase the hold backwards (on the edge of blocks) as the pads will be pulled backwards through the frame, as a result bite will be reduced.

I dont know if its been tried before though.