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Diy Bike ...ideas, Suggestions, Improvements


Alex Dark

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Right, so here it is: for my final project in college ( 5 months or so away ) I have decided to build a bike, im going to make as much of it as i can by hand...

So it'll be Frame, maybe forks, bashring and a couple of other smaller bits.

So far ive decided a few things....

External headset

Stock or 24

135mm rear spacing

interchangable barke mounts ( maggie and vee, both removable )

Removable disc brake mount

Made out of aluminium

Ideally under 2.2kgs

1070ish length, 380 cs, 72ha..... stock geo

has to be strong

Low stand-over

Original!

Atomz style bolt in drop outs maybe :S

in-built booster

So...basically, any other suggestions for design, features or geo...especially frame shape, pictures of prototypes etc :)

Horiz or vert dropouts?

built in tensioner?

4 bolt?

removable disc mount?#

Thanks in advance, Alex

oh and advice would definitely be most welcome from Forteh, Chris Hayton, and Dang!

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I did a frame for my alevel project, and had a few good ideas since doing it...

I'll edit this post when I find some pictures...

edit:

n791055157_4317453_9825.jpg

n791055157_4317454_145.jpg

n791055157_4317455_441.jpg

n791055157_4317452_9489.jpg

and to prove it was rideable ;)

n791055157_4317451_9222.jpg

Only problem I had with it was tyre clearance in the rear.

I was thinking about making another version with 116mm spacing for a 14mm axle, then I could use a profile BMX hub with a hollow 14mm axle, which will be lighter, stiffer and stronger than 95% of trials hubs and still with awesome engagements etc.

Also came up with a really cool integrated brake mount/booster design, where the brake is sandwixhed between two plates. Sound's shit, but it's awesome. I'll try and dig out some cad models and stuff.

I have loads of frame Ideas...

also eccentric 360 dropout with a bolt-through axle... Have some cad models of that too.

No big companies are allowed to steal these ideas by the way, only Alex.

erm, msn me if you want to have a chat about some stuff. I can send you a copy of my coursework and that documents all the problems I encountered along the way.

Edited by NVWOCI WVS
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Welding aluminium could prove to be fun.

Good luck with it, i'd try and keep it as simple as possible, removable brake mounts sounds like a good idea, you'll have to think pretty heavily into how it'll attach, and how strong it'll be.

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Blimey, I get a mention on the list of people what is clever :D

A couple of points: -

Going for as much of a self built full bike is imho too big for a college project I think you would do better to concentrate on one particular part of the bike (perhaps a frame/forks) and look to develop that properly rather than cobble together numerous different elements. Quality not quantity :)

Perhaps concentrate your efforts into an area of trials bikes that could be improved upon, for example a standard HG spline interface that could fit onto threaded cranks, ie: you can fit a standard cassette sprocket onto your favourite cranks.

Possibly even an integrated BB/crank interface similar to the shimano saint cranks that will allow the use of hollowtech BBs, an option could be to develop an axle that is compatible with the current trials cranks but also with hollowtech BBs.

I dont know how much time/funding/resources you get with your project but designing and manufacturing a frame (especially from aluminium) isnt going to be cheap, personally I would investigate something that you can fit to any bike and genuinely be a marketable product - that way you can be really proud and say "I designed that!" - Its happened to me alot at work and its a great feeling to know that something you designed works :)

Im not trying to put a damper on your ideas, purely speaking from personal experience from college, uni and the last 8 years working in a design office.

Good luck with your project :D

Edited by forteh
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WAY to much work there. I remember the frame I built for A-level, that took a very, very long time and it was no where near perfect. If I were you I would pick a project that gets the most marks but isn't too complicated. I know its fun to build everything but you could do that in your own time and enjoy it a lot more.

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That's the one. It rode really well. 135mm horizontal dropouts and snail cams.

I recomend butted steel tubes and brazing it up if you have the skillz with a torch?

well, my lecturer thinks i can do it with aluminium, although i will look into steel now you've mentioned it (Y)

Welding aluminium could prove to be fun.

Good luck with it, i'd try and keep it as simple as possible, removable brake mounts sounds like a good idea, you'll have to think pretty heavily into how it'll attach, and how strong it'll be.

Yeh, it will be.....interesting..:P

I think im going to try a dmr style brake mount ill post pics if someone doesn't know what these look like

Blimey, I get a mention on the list of people what is clever :D

A couple of points: -

Going for as much of a self built full bike is imho too big for a college project I think you would do better to concentrate on one particular part of the bike (perhaps a frame/forks) and look to develop that properly rather than cobble together numerous different elements. Quality not quantity :)

Perhaps concentrate your efforts into an area of trials bikes that could be improved upon, for example a standard HG spline interface that could fit onto threaded cranks, ie: you can fit a standard cassette sprocket onto your favourite cranks.

Possibly even an integrated BB/crank interface similar to the shimano saint cranks that will allow the use of hollowtech BBs, an option could be to develop an axle that is compatible with the current trials cranks but also with hollowtech BBs.

I dont know how much time/funding/resources you get with your project but designing and manufacturing a frame (especially from aluminium) isnt going to be cheap, personally I would investigate something that you can fit to any bike and genuinely be a marketable product - that way you can be really proud and say "I designed that!" - Its happened to me alot at work and its a great feeling to know that something you designed works :)

Im not trying to put a damper on your ideas, purely speaking from personal experience from college, uni and the last 8 years working in a design office.

Good luck with your project :D

Im fairly set on making a frame if im honest, and i need to do some other work towardsmy diploma, so im happy to knock together a bash, and maybe some forks as practice for the frame

Adam's steed

Was thinking bb shell cut, and headtube cut as well, as i have access to plasma cutters etc....and im really willing to put lots of work into this...to make it a proper frame that i ride.

Any other suggestions?

Someone's already made an xc frame before me last year, and that went fine....and i reckon im pretty clued up on this sort of thing,

Headtube (top and bottom) gussetts are a must i think.

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I think im going to try a dmr style brake mount ill post pics if someone doesn't know what these look like

Good plan.

It's Sam ;)

Was thinking bb shell cut, and headtube cut as well, as i have access to plasma cutters etc....and im really willing to put lots of work into this...to make it a proper frame that i ride.

I used a bb shell and headtube from a 4130 steel xc frame. Definitely a good bet.

Headtube (top and bottom) gussetts are a must i think.

Definitely a good idea. This is where mine cracked eventually. It was just fillet brazed, but it took a few pretty hefty gaps to front.

However, don't make the weld all the way under the down tube, as this will create a weak point and encourage cracking.

Get it baked after you've welded it all up (Y)

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If you are going to continue with the frame idea then I would recommend looking at steel rather than aluminium, the cost and ease of working would make it a far easier project. Also look at brazing as you will have less problems with HAZ and you can always leave it lacquered bare metal & fillet braze for an awesome look :D

Have a look at other steel frames for headtube gusseting, particularly bmxs; for example the standard STA frame for pretty much bombproof gussetting (I can take photos of mine if youre struggling ;) ). Also consider your different options for strength to weight ratios, if you can make it out of a higher grade, larger diameter, thinwall tube then it will be stiff whilst carrying minimal weight - you need to consider dent resistance aswell though.

It is possible to make an incredibly strong yet light structure from steel, put some clever design and you will get there.

If you want me to have a look at some ideas and offer opinion/pointers then give us a yell, more than happy to help :)

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So it'll be Frame, maybe forks, bashring and a couple of other smaller bits. Why bother doing so much its only A-level... not anymore than that.

interchangable barke mounts Again why? If you want a maggie, make it with magura mounts, if you want to run a vee make it with vee mounts... its you custom bike so build it how you want... thats the whole idea!

Removable disc brake mount why would you ever need to replace it? I dont think its a bad idea to have a diskmount on there but whats the real benifit of being able to remove it? weight? I just don't understand. Also there notiously easy to brake.

Made out of aluminium Again why make it harder for youself? Welding aliminium is a mish and the project is hard enough without making it hard for hards sake. Also have you to consider getting an alluiminum headtube, also you cant simply braze magura mounts on, BB cup etc. etc. it all adds up when you brake it down and start to think more rationally.

Ideally under 2.2kgs Why aim at a target weight? If it weighs more then it does? Are you planning to add up the weights before you start or have you just picked a figure out from thin air?

has to be strong - A self welded aluiminium frame will not be strong!

Original! Well its your custom bike so inevitibly will be....

Atomz style bolt in drop outs maybe :S again why? where do you plan to source all these parts?

in-built booster Can easily be welded on under the brazed mounts maybe? Like making your frame rigid without having to see it or adjust it. Becuase it wouldn't get in your way?

Horiz or vert dropouts? verticall would be a lot easier to source and fit I would imagine.

built in tensioner? Again why? 99% of frames don't because its too hard, and when it snaps your f**ked.

4 bolt? if you buy brazed mounts from crc then they will be.

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WAY to much work there. I remember the frame I built for A-level, that took a very, very long time and it was no where near perfect. If I were you I would pick a project that gets the most marks but isn't too complicated. I know its fun to build everything but you could do that in your own time and enjoy it a lot more.

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If you have access to CNC equipment doing the frame in Aluminium will be less of a problem as you can use CNCed aluminium for things like the headtube area and the chainstay bridge where clearance is tight. By extending the CNCed parts down the tubes they join on to, particularly from the headtube area, you should be able to avoid having to put welds in areas of high stress altogether. It will also make cutting the frame tubes easier as you can decide the shape and position of the interface between the tube and the BB/headtube area and make it easy to align and weld rather than being at the mercy of your mitering equipment.

This frame also presents the opportunity to design a chain tensioner integrated with the frame (Something very impact tolerant) if you're using vertical dropouts or a means of moving the disk mount as the chain is tensioned if you're using horizontal dropouts. I'd go with vertical dropouts as they give constant chainstay length and make aligning disk and brake mounts correctly a lot easier.

I'm pretty sure the spline on a freehub is smaller than the threads for a freewheel on a crank, so making a convertor wouldn't be feasible (Though I'd have to check to make absolutely sure). Designing cranks with a freehub spline would be class - but only really useful if there was an ENO or product of similar quality manufactured to be compatible with it :).

The DMR Mounts are very solidly made and a great place to start. If there's a bolt on 4 bolt Magura or Canti mount to fit it and it'll do 24 and 26" wheels (The reason DMR designed the mounts that way in the first place), you'll have a frame that will potentially do everything...

Edited by psycholist
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I'm pretty sure the spline on a freehub is smaller than the threads for a freewheel on a crank, so making a convertor wouldn't be feasible (Though I'd have to check to make absolutely sure). Designing cranks with a freehub spline would be class - but only really useful if there was an ENO or product of similar quality manufactured to be compatible with it :).

Im 90% sure the HG spline is larger than the 1.37" thread on cranks :)

Obviously if youre running FFW then there is no need for a splined attachment, however not everyone uses FFW ;)

Sorry wandering off topic here...

As you were :D

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erm keep it simple. having welded alumium before, i actually found it slightly easier than steel(granted machine was pre set up for me, and my joints wernt tested for strength) but it just seemed easier to see where your going, and to keep the weld pool flowing where you wanted it. but with no heat treating etc, and the higher cost of the material, (and the availability of it in your desired sizes) steel is probably a better option.

got a bunch of old 1inch steerer steel frames if you wanted them, just drop me a pm nearer the time.

likewise got some horizontal and vertical drop outs in alumnium, an aluminium bb or 2, and a 1 -1/8 aluminium head tube if you wanted it.

Dont see your adjustable brake mount being hard to make, but is it going to get you extra marks ( braze a steel plate on with some bolt holes on at 12.5 inches from the centre of the axle. can then make adapters out of 1/2 or 3/4 inch square steel bar, either drilled and tapped ( 1 set for maggies, 1 set for v brakes, for each wheel size) ) seems easy, but in reality, its several hours work + for something your not really going to get much use out of (how often do you change your brake, and is the frame going to last that long) and may not get any better marks for.

EDIT : i wrote this before psycholist posted, but took to long in replying before you all flame me for copying.

Edited by Fish-Finger-er
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I'm pretty sure the spline on a freehub is smaller than the threads for a freewheel on a crank, so making a convertor wouldn't be feasible (Though I'd have to check to make absolutely sure). Designing cranks with a freehub spline would be class - but only really useful if there was an ENO or product of similar quality manufactured to be compatible with it :).

Im 90% sure the HG spline is larger than the 1.37" thread on cranks :)

Obviously if you're running FFW then there is no need for a splined attachment, however not everyone uses FFW ;)

Sorry wandering off topic here...

As you were :D

The cranks would be useful but not really useful if only fixed sprockets were available. It's even more of a pain to remove freewheels than fixed sprockets from screw on cranks.

On further checking I found this:

k7hub-3-styles.jpg

From: http://www.sheldonbrown.com/k7.html#hyperdrivec

Showing some of the older uniglide freehub bodies which had a threaded top gear sprocket that also acted as a lockring. This set me wondering if the threads might happen to be 1.37" diameter...

Just back from a trip to the garage - having compared them directly I can confirm that a freehub spline is smaller in overall diameter than a 1.37" BB/freewheel thread, but not by much, so the uniglide lockring threads may be borderline compatible with screw on sprockets, but making a 1.37" thread to freehub spline convertor definitely won't work...

Pretty irrelevant, but at least I learned something new :P...

Now back to frame making - what sort of equipment do you have for forming/cutting material? Seatstays and possibly chainstays will need to be curved for correct clearances and depending on the look you're after curvy tubes are in these days. If there's no CNC then the mitering will have to be worked out... Some sort of jig to hold the frame in correct alignment would also come in handy...

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If you have access to CNC equipment doing the frame in Aluminium will be less of a problem as you can use CNCed aluminium for things like the headtube area and the chainstay bridge where clearance is tight. By extending the CNCed parts down the tubes they join on to, particularly from the headtube area, you should be able to avoid having to put welds in areas of high stress altogether. It will also make cutting the frame tubes easier as you can decide the shape and position of the interface between the tube and the BB/headtube area and make it easy to align and weld rather than being at the mercy of your mitering equipment.

No cnc machine im afraid, only milling or lathes

This frame also presents the opportunity to design a chain tensioner integrated with the frame (Something very impact tolerant) if you're using vertical dropouts or a means of moving the disk mount as the chain is tensioned if you're using horizontal dropouts. I'd go with vertical dropouts as they give constant chainstay length and make aligning disk and brake mounts correctly a lot easier.

I just want some provision to bolt a 74kingz style tensioner to the frame.

I'm pretty sure the spline on a freehub is smaller than the threads for a freewheel on a crank, so making a convertor wouldn't be feasible (Though I'd have to check to make absolutely sure). Designing cranks with a freehub spline would be class - but only really useful if there was an ENO or product of similar quality manufactured to be compatible with it :).

The DMR Mounts are very solidly made and a great place to start. If there's a bolt on 4 bolt Magura or Canti mount to fit it and it'll do 24 and 26" wheels (The reason DMR designed the mounts that way in the first place), you'll have a frame that will potentially do everything...

Thats what i thought...seems like the best bet i reckon. Ideally i'd like it to be 24" compatible as well (Y)

The cranks would be useful but not really useful if only fixed sprockets were available. It's even more of a pain to remove freewheels than fixed sprockets from screw on cranks.

On further checking I found this:

k7hub-3-styles.jpg

From: http://www.sheldonbrown.com/k7.html#hyperdrivec

Showing some of the older uniglide freehub bodies which had a threaded top gear sprocket that also acted as a lockring. This set me wondering if the threads might happen to be 1.37" diameter...

Just back from a trip to the garage - having compared them directly I can confirm that a freehub spline is smaller in overall diameter than a 1.37" BB/freewheel thread, but not by much, so the uniglide lockring threads may be borderline compatible with screw on sprockets, but making a 1.37" thread to freehub spline convertor definitely won't work...

Pretty irrelevant, but at least I learned something new :P...

Now back to frame making - what sort of equipment do you have for forming/cutting material? Seatstays and possibly chainstays will need to be curved for correct clearances and depending on the look you're after curvy tubes are in these days. If there's no CNC then the mitering will have to be worked out... Some sort of jig to hold the frame in correct alignment would also come in handy...

Ive got a milling machine to use, but no cnc im afraid :(

Ill have to make a jig up i reckon

Edited by Alex Dark
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You dont need a cnc machine to cut and mitre the tubes, it may make manufacturing yokes and dropouts easier though.

A frame building jig is pretty easy to knock up, getting the tubes all cut to fit 1st time is the hard bit :D

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You dont need a cnc machine to cut and mitre the tubes, it may make manufacturing yokes and dropouts easier though.

A frame building jig is pretty easy to knock up, getting the tubes all cut to fit 1st time is the hard bit :D

Im sure i can mill the tubes out to the right profile....

Cutting the tubes is going to be interesting.....as is my welding..

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The milling machine (With the correct cutter) should be perfect for mitering the tubes.

Have you tube bending equipment? If not it's going to be quite hard to get reasonable tyre clearance at the chainstays, but you could go all DeKerf on the seatstay bridge: http://www.dekerf.com/Details.asp?id=13.

One trick I'd try for maximum chainstay clearance would be to make the chainstays where they leave the BB from a flat plate. Cut a hole the size of the BB shell in one end and weld it around the BB shell to give maximum weld area as well as sitting the chainstays as far apart as they can be without interfering with the BB fitting - going partially around the BB shell would still give extra weld area. ISCG mounting holes could be put in this type of chainstay without having to add a separate plate too, so useful for non-trials bikes as well... You'd have to cut the chainstay height down after the part around the BB shell to make sure there's room for the chain of course.

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The milling machine (With the correct cutter) should be perfect for mitering the tubes.

Have you tube bending equipment? If not it's going to be quite hard to get reasonable tyre clearance at the chainstays, but you could go all DeKerf on the seatstay bridge: http://www.dekerf.com/Details.asp?id=13.

One trick I'd try for maximum chainstay clearance would be to make the chainstays where they leave the BB from a flat plate. Cut a hole the size of the BB shell in one end and weld it around the BB shell to give maximum weld area as well as sitting the chainstays as far apart as they can be without interfering with the BB fitting - going partially around the BB shell would still give extra weld area. ISCG mounting holes could be put in this type of chainstay without having to add a separate plate too, so useful for non-trials bikes as well... You'd have to cut the chainstay height down after the part around the BB shell to make sure there's room for the chain of course.

so koxx levelboss style?

dekerf elysium?

yeh i should be able to bend the tubes.....vital to get the s-bends in the chain stays

Edited by Alex Dark
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All the DeKerf bikes have the same sort of seatstay bridge - the fork I linked to shows it better then the frame picture I think - If you want to be truly frightened the fork with a custom paint job and V and disk mounts comes to CAD$830, so over £464 for a rigid steel fork :D...

I haven't seen a levelboss frame in years and then it was only briefly, so I'm not sure if they do the chainstays the way I described.

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All the DeKerf bikes have the same sort of seatstay bridge - the fork I linked to shows it better then the frame picture I think - If you want to be truly frightened the fork with a custom paint job and V and disk mounts comes to CAD$830, so over £464 for a rigid steel fork :D...

I haven't seen a levelboss frame in years and then it was only briefly, so I'm not sure if they do the chainstays the way I described.

i saw the fork price...crazy :o

Er, this?

Koxx chainstays

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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 :D

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 :D )

frame%20weight.JPG

Edited by forteh
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