GT Edge Aero TT --> paint pron tarck conversion attempt

possibly clearance issues between dropout and hub?

Have you done a stress analysis for this?

Your hole size and the proximity to a weld are going to concentrate the stresses a lot especially if you do countersink them which sounds like a disaster. Three smaller fixing bolts might work out better than two big ones if you do the math for your available area, as you want to design it so the fixing bolt fails under load before the frame does.

Your main problem is going to be getting them parallel. I'd use a threaded axle with nuts on to bolt the track ends to, keep adjusting until width is perfect fit inside the rear spacing then assemble a jig around this and rear of frame for marking up and assembly.

There is not a right way for doing something wrong, just less wrong ways of progressing towards A+E

i doubt it will be that bad...

Have you done a stress analysis for this?

yeah... the naysayers are stressing me out. that is all.
#hatersgonnahate

I am not an engineer, so have just a laic explanation, but could it not add some sturdiness, help splitting the clamping force on a bigger area? Maybe just a countersink with a washer? As said before it would be on the steel dropout on the inside and on the other side a recessed nut with a washer? Anyway, worth exploring all the options before starting drilling, a more scientific approach would surely be in order :)

I think @mdcc_tester will have all the answers!

I definitely agree - I am going to be very cautious before drilling/shaping the aluminium bits. I have been a bit less careful with the steel, because they are just cheap bits of steel, so forgiving and I can start over if necessary. I think I am happy with the first evening's work on it, but that was the easiest bit.

I am going to try to catch @mdcc_tester 's ear and see if there is a sensible, non-professional approach to this. I am actually wary of flattening out the area where the trackends will sit, because it means removing aluminium at some of the potentially vulnerable points (namely the welds) but also not sure what I could add to get a nice flat surface without causing temperature issues with the aluminium (6061 is quite finicky in terms of heat treating I have heard), and without a tig welder.

conquistador
Have you done a stress analysis for this?

Fire up solidworks!! was thinking the same but can't be bothered to start mine

I understand the budget is tight but can't you just spend £10 in aluminium dropout and pay £40 for a welder to do it? Much easier/faster/safer.

I think the key here is budget.

If you start paying for work to be done by a third party, you might as well get the FD hanger removed, rear brake bridge sorted, welds smoothed, headtube changed to tapered, etc... Then you have smashed £300-£400 so you might as well buy a used aero track frame.

Ha yes, sorry i would have commented but was away.

Looks cool what you've done with the end. Didn't expect it to happen so quickly. Hope it works. what are you planing to do with the brake cable bosses?

the plans for the gussets are noice. Yeah i wouldn't go for the chainstay gussets either for much the same reason.

regarding the attachment of the ends i would go for a threaded end. Countersinking, as @trunkie said, sounds risky due tot he loss of material and the joint to the end with the stays is probably somewhere where you wouldn't really want that considering the stress (I think) it would be under.

@santino I thought the cost for changing dropouts/ends was much higher, obviously dependant on the builder, but around the £80 mark.

And @young_gun , you can never go too far.
For example:

why stop there?

Fear not, you'll all be able to vote on the gusset options when the time comes for that - I'll do sample cut outs of the foam/aluminium and blue tack them in place to give an idea of what the different options will look like. I have to admit I was tempted to emulate the Look (upper one, not lower one), but it probably would be a lot more work.

I think I am settling on next steps of trimming the track ends slightly more so that I don't have to remove as much aluminium around the welds, but I should really do this with a grinder, which I have but is not set up at the moment, so it may be a few weeks before I make much progress. I am also starting to think that removing a bit of alu from the dropouts will be fine, because these are solid (whereas I can't be as sure that what is hollow and what is solid around the welds to the chainstays). Any aluminium removed that contributes to a flatter surface for bolting the ends on should be more than made up for by the added strength of the superior joint. The reality is, it is probably along the lines of 1-1.5mm of the 5m thickness, and then the track ends are 6mm thick each (I measured them - thicker than I thought!) so the total thickness will be 9.5-10, which should be plenty hefty. There are some odd bits on the side where the derailleur hanger was, but I think I can work around this.

So unfortunately I am going to have put this on ice really until I get my bench grinder set up, though I may do a bit of filing on the aluminium (really, I'd prefer to save that until I am at the point of no return). In any case, I am out of the country for the next week, so don't expect any updates :( I am still on the lookout for some forks, preferably carbon, that will suit this (1" steerer, >140mm threaded, or 175mm threadless).

@HHC well it is if you speak to a frame builder but if you know what you want and can prepare the frame so it is only a welding, you can speak to a "generic welder" who can do the same job even better as he weld all day along. He will do the job for much cheaper as you bring the frame to him ready to weld, take him 20s to lock the dropout in place and 20s to do a perfect welding. £40 cash in hand and you are done. You can even bring an old wheel axle so the guy can point the dropout before to weld it, perfectly in line that way.

you can speak to a "generic welder"

I'd say this is the same principle as - why pay £40 for shot blasting at a restorers when there is person on the industrial estate who will blast it for £20 cash. They do it all day and isn't going to be any hassle if you do all the prep. Trouble is, do they know the correct pressure to not thin the tubing and when all day they do chassis and sheet metal, a bike frame is a bitch as you have to keep turning it.

Trouble is that generic tradespeople (try hard to be gender balanced) don't do intricate precision jobs all day. A welder who does straight steel-steel joins 90% of the time can make a hash of it. Not because of lack of skill but because it isn't routine. If you're taking it to an experienced welder who regularly does one off, cash in hand, precision jobs then it is likely to be more than £40 due to their high demand and likely a waiting list. It is a weld but maintaining exact parallel spacing after cooling is not as easy as bolting it down.

I'm talking of a guy doing funny welding all day repairing everything and anything. I know one who even managed to weld golf club and straighten then perfectly. I think it's more a matter of finding a good welder who weld funny stuff all day, he will know instantly what to do. Not talking of a guy who weld al 3 time per year and only do basic welding the rest of the time. It never costed me much more than £40 cash in hand for a 5 mins job. Even cheaper or free if i get it back to france but i use to be client to them for high end expensive welding.

This is all well and good, but unless someone is actually offering to do this job for £40, I am not really any better off, because I don't happen to have lots of friends who do TIG welding all day long. Truth is, I'd rather not spend the time trying to find someone, and rather just get on with doing it myself, which is actually more fun!
Or better yet, write about what I am going to do here (purely to wind people up? - not quite yet, but it is tempting!), while I am pretending to work (oops!), rather than actually doing it ;)

purely to wind people up?

Ahah i understand the temptation must be hard to resist. Some people react like if there finger was already on the trigger.

I do appreciate the input @santino and if you know someone in London that would actually do this job for £40, I'd love to get their details (at least as a backup). I do actually think the risk is relatively low, given I will be testing it very thoroughly before actually taking it into the wild with the track ends.

looks get special permission to be as crazy as they want.

Very true

Unless I missed something, you're planning on ruining a perfectly good frame that was bought for £50 ( at that price I should of grabbed it!) to fit bodged track ends and fake gussets? Why not start with a budget steel frame and go nuts gusseting and craft gluing shit to that? Really don't understand - your time and your money but this wont be rad, just bad. sorry but it seems nuts, and not in a good crazy engineer way.
There's just so many other options to get that into a rideable state - magic gear, eccentric hub - just build as a 1 x 6 or 7 speed etc. etc. anyway, I'm sure you don't care!

I think your under the impression you're going to end up with a beautiful and unique aero track frame for less than Pre Cursa money.

I think what you will end up with is a botched up mess that you'll have no hope of reselling and you'll wish you'd just bought a Pre Cursa.

That's coming from someone who has completed a bolt on conversion to track ends by the way.

pics?
I'd love to see how your bolt-on ends looked.
One of the reasons I am putting the track ends inside the existing ends/dropouts is actually aesthetic, as I think it will look relatively inconspicuous with an inch of steel peeking out from the shadow of the aluminium stay ends.
The aero body work is clearly the more difficult part to get right, but I reckon filler covers over a multitude of evils, and if the frame does actually turn out as hoped shape-wise, a good paint job will definitely do me some favours (this is one of the reasons for the low budget - to be able to get it properly painted if all goes well).
I am definitely going for "unique" and ridiculous more than "beautiful", and I appreciate that if I wanted something beautiful I should have just bought something off the rack (like a pre-cursa), but where's the fun in that?

^exactly. Do what you want.

If the cp threads become regulated by what is safe then they will just descend into crap.
Remember the guy who wanted to build his own aero helmet. That was fun and yet one of the worst ideas I've ever heard in my life.

Agreed. I follow the CP threads because they are way more fun than the polemics we get into in the general area. Who knows? This project might turn out to be amazing, but we'll never know if we don't let @santino do what he wants