K2 / Proflex Riders Group
General => Tech Forum => Topic started by: fyrstormer on March 05, 2010, 03:37:43 pm
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Not quite stock. ;)
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG3787.jpg)
Oh, right...hi, I'm new here. ;D
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What's that? Not quite stock eh?
(http://upload.wikimedia.org/wikipedia/commons/5/50/Its_a_Mad,_Mad,_Mad,_Mad_World_Trailer17.jpg)
Welcome fyrstormer. Where do you hail from?
Terry
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Where the hail am I from? Well, "from" is hard to define, but I'm currently living in Ashburn, VA. Ask me again in a year and it might be somewhere in California.
Yep, not quite stock. The only original part left on this frame is the front derailleur, and that I've re-ground to fit a custom 2x8 drivetrain config.
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG0100.jpg)
Why yes, I am crazy, thanks for noticing. :D
At this point my greatest wish is to install one of callum's rear disc adaptors on it...but I'm afraid the answer is going to be "you can't get one anymore." That would make me sad.
(I might settle for a used one. ;))
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OMG!!!
Look at those chainrings will ya. I did not know you could get the chain to make such a big jump. Nice one!
Terry
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Yep, it works fine as long as I don't put a lot of tension on the chain during the shift, which is to say, as long as I do the smart thing and shift before I hit a huge climb.
Basically I did the math and figured out the middle ring gave me no ratios I couldn't get with the big and small rings, and I never left the big ring unless I needed a low-low ratio RIGHT NOW, and I was tired of getting chain oil on my jeans, so I came up with this. I did it with the original crank too; this is the second setup I've done up this way, and they both work great.
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Oh! And I just won this on eBay.
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/def.jpg)
Because I need another ProFlex frame. ::)
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good man. You'll fit in here nicely ;)
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Good stuff, loving the 2x8 setup and the colour, well i do love blue! :)
Plans for the latest eBay purchase?
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If it's the same size, keep it and maybe swap the parts over. If it's a different size, flip it.
I got the thing for $86. What could possibly go wrong at that price?
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For those who keep up on posts (re: the last 5 posts on pride and joy topic) The next in our series "Two Ol' Mules for Sister Sara" It's nice to know I'm not the only nut job that names things! COOL lol
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So, um. Since the Hammerhead is no longer an option, is there a Brake Therapy kit that fits? It looks like there's a clear line-of-sight from the left edge of the hub to the V-brake boss.
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Brake Therapy is one option. Two others are to make a bolt-on adapter, and weld-on adapter.
Do a search, they will pop up somewhere.
Terry
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I've seen references to the homemade bolt-on adaptors, but I lack the equipment and expertise to make something that precise from scratch. The weld-on adaptors look nicer, but my swingarm is painted magnesium (I think?), so I seriously doubt it would stand up to welding and still look good afterwards.
Does anyone besides callum make bolt-on adaptors? I don't mind drilling and tapping holes; it's the alignment of the caliper I don't know how to do right.
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The swingarm is not magnesium. Perhaps a2z components has a universal bolt-on mount.
(http://www.woollyhatshop.com/varimg.php?id=120)
a2z DM-UNI
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I was looking at that, but I don't think it's compatible with quick-release skewers -- at least not unless I want to cut on it a bit. I suppose it would make a decent template to start working from, though.
Do you happen to know what the part number is for the Brake Therapy kit that fits the 756?
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Dunno, as you have to give some info. But the basic kit is $149.
http://2btherapy.com/index.php/bikes/brake-therapy-conversion-kit
I do have a weld jig/plate locator for fabrication and welding a disc mount to your swingarm. PM me for more information if you are interested.
Terry
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Welding definitely sounds like the best option, but I have no welding experience or equipment. I'd have to pay someone to do the work, and then pay for a paint job on top of it, and I don't have replacement decals for the swingarm. How much damage to the finish would I have to expect if I wanted to weld tabs onto the frame?
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Well the paint would need to be stripped about 1" away from the weld, and another area to attach a ground lead. Beyond that the rest of the paint will not be compromised.
Would be me, I would just repaint the welded tab area.
Terry
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Hmm. Would you mind terribly if I asked to see a couple pictures of your work, preferably on painted swingarms? If you can do the work, I think that's the direction I want to go in, but I'd like to know exactly how perfect or imperfect I can expect it to be. I only ask because I've tried to take such good care of the paint so far, which has been no small feat since I've been busy falling down hills and hitting moving cars on it.
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Hmm. Would you mind terribly if I asked to see a couple pictures of your work, preferably on painted swingarms? If you can do the work, I think that's the direction I want to go in, but I'd like to know exactly how perfect or imperfect I can expect it to be. I only ask because I've tried to take such good care of the paint so far, which has been no small feat since I've been busy falling down hills and hitting moving cars on it.
Well I don't have any pics of swingarms, but I do have pics I send to GT owners detailing mast repairs with inserts added. Along the same lines. I do more mast repairs that I care to admit.
(http://img.villagephotos.com/p/2005-6/1036595/100_3000.JPG)
(http://img.villagephotos.com/p/2005-6/1036595/100_3002.JPG)
(http://img.villagephotos.com/p/2005-6/1036595/100_3005.JPG)
(http://img.villagephotos.com/p/2005-6/1036595/100_3008.JPG)
And one swingarm I built in the late 80's
(http://img.villagephotos.com/p/2005-6/1036595/SSM24studio.JPG)
Terry
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Wow. :o So, um...I guess you've had time to practice. Sorry about the questioning, but I keep telling myself it's the one time I don't ask that I'll get burned. It definitely looks like you know what you're doing.
So, last question in public, and then we can talk about shipping and cost over PM: can you do 74mm post-mounts, or just IS tabs? Tabs are fine, but if I can get posts that's even better because that's the kind of brake I'll be using.
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Only standard tabs, sorry.
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Not a problem, just asking, thanks.
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Re: the air fittings on the alignment tool. Izzat for a nitrogen purge? We used to flood the underside of ss with nitrogen when welding countertops on ships.
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Shovelon is one fine welder. He fixed my Proflex 5000. It had cracked at the seat tube. And, he fixed my Evo at the head tube down tube junction. There are pictures in my gallery if you are interested. Aluminum welders are hard to find. The good ones even harder. My father was a very talented welder (acetylene, stick, union fixed station) at Geneva Steel for 39 years. He would just shake his head when talking about welding aluminum.
Thunderchild
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Don't you have to use an acid flux when welding aluminum? I remember something about needing to etch it, but on an existing part I have to think a liquid acid would be too hard to control.
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Re: the air fittings on the alignment tool. Izzat for a nitrogen purge? We used to flood the underside of ss with nitrogen when welding countertops on ships.
Good eye. ;) ;)
Actually alum does not need a purge like SS, 4130 or Ti. I use the tapered threads on coupler to expand the mandrel against the seatmast. That way I burn thru the seatmast and the molten weld lays agalinst the mandrel. The mandrel doubles as a heat sink, preventing overheating.
If I am need a purge, I can feed into the coupler and wrap alum foil around the seams to slow dissipation of the purge gas.
Here is a better pic. You can see the discoloration where the weld penetration was.
(http://img.villagephotos.com/p/2005-6/1036595/000_0374.JPG)
Here is a Ti seatmast that I purged, but without a mandrel. See how well the alum foil works. ;D
(http://img.villagephotos.com/p/2005-6/1036595/100_2800.JPG)
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Don't you have to use an acid flux when welding aluminum? I remember something about needing to etch it, but on an existing part I have to think a liquid acid would be too hard to control.
Alum brazing may need flux, but in welding you are melting the base metal and adding extra metal.
(http://www.delstron.co.uk/images/tig_welding.gif)
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Interesting. So why is aluminum so hard to weld compared to steel? Is it because it oxidizes so fast?
Anyway, on a different note, is it possible to remove the V-brake studs from a 756 swingarm? I remember trying years ago and I was afraid I was going to break the swingarm I was putting so much torque on the stud. Ended up damaging the stud and I had to sand it down so the V-brake would fit on it again. If I'm going to get disc tabs added, I won't need the studs anymore, and I'd like to remove them if possible, but I swear they were installed with an impact wrench or something.
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ASHBURN! I'm in Falls Church! We should ride sometime and I'll bring out one of the 'flexes! Ever head inside the beltway, e.g. to Wakefield?
Welcome!
- Doug :-)
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Terry, that bike you made is a really neat design...how did it ride?
- Doug
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Interesting. So why is aluminum so hard to weld compared to steel? Is it because it oxidizes so fast?
Anyway, on a different note, is it possible to remove the V-brake studs from a 756 swingarm? I remember trying years ago and I was afraid I was going to break the swingarm I was putting so much torque on the stud. Ended up damaging the stud and I had to sand it down so the V-brake would fit on it again. If I'm going to get disc tabs added, I won't need the studs anymore, and I'd like to remove them if possible, but I swear they were installed with an impact wrench or something.
Alum is easier to weld once you get past the learning phase and have to do it day in and day out. :P :P :P :P :P :'( :'( :'( :'( :'( :'(
Takes about 200 hours to figure it out if you last that long. Then about 1000 hours before I would trust you not to screw up, and 5000 hours before you are ready to certify.
The studs are bonded in. Takes some heat to break the bond.
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Terry, that bike you made is a really neat design...how did it ride?
- Doug
Like a ballerina on a bucking bronco. Not my cup of tea. Just way too much travel. The shock was custom made by Works Performance when they were in Northridge. Cost a fortune. >:( >:( >:(
Todd Shall and I built it along with another guy that made a custom tandem with his. Todd still has it now I hope. Actually just last summer we took a bunch of the spare swingarms and modified them for Honda 50 motorcycles.
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The studs are bonded in. Takes some heat to break the bond.
I had a feeling you were going to tell me that. Glad I didn't keep trying to twist them out. Any idea why they glued the damn things in when they could've just tapped some threads and screwed them in? I mean, what if they ever needed to be replaced?
When you say "some heat", are we talking boiling water, soldering iron, or blowtorch?
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ASHBURN! I'm in Falls Church! We should ride sometime and I'll bring out one of the 'flexes! Ever head inside the beltway, e.g. to Wakefield?
Welcome!
- Doug :-)
Hi Doug.
I live in Ashburn and work in Herndon, so my day-to-day travels don't take me anywhere near the beltway, and everyone I know lives outside it, so...no, I don't make it inside the beltway much. Also, I'm loathe to strap my Bones rack on my brand-new car, so my riding has stayed pretty local lately.
Where did you have in mind?
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The studs are bonded in. Takes some heat to break the bond.
I had a feeling you were going to tell me that. Glad I didn't keep trying to twist them out. Any idea why they glued the damn things in when they could've just tapped some threads and screwed them in? I mean, what if they ever needed to be replaced?
When you say "some heat", are we talking boiling water, soldering iron, or blowtorch?
They are threaded and bonded with a clear highstrength loctite. A soldering iron may do the trick or a propane torch if you have one. Be careful to keep the heat on the stud and not the alum.
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I have a butane-fired soldering iron with a torch tip. Think that'll work? If not, maybe I'll just ask you to remove them while you're adding the disc tabs.
I know you've already said my swingarm is aluminum and not magnesium, but the spots where the paint has been chipped off have a yellowish oxide layer on them that forms over time. Is this normal for aluminum? The only other place I ever saw it was on similar chipped areas on my old Manitou SX-R, which I know had a magnesium lower.
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The Butane jig should do fine, but I can take them out if you don't want em back. ;) ;)
Could be the surface was chem-filmed before paint. I do that alot. As far as knowing a painter, I know plenty. We could talk about that later. :-X :-X
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Very good then, let's add "remove those damn brake studs" and "send it out to get the tabs painted" to the to-do list. Once the tabs get welded on, I won't be needing the studs anymore anyway.
The butane jig didn't work, unfortunately. My best pair of Vise-Grips accomplished nothing more than tearing up the surfaces of the studs even more.
What do the "applaud" and "smite" buttons above your AV do? They look a lot like something I was suggesting for a vBulletin forum I belong to.
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I think you're right about the surface coating. Now that you mention it, the film is the exact same color as DuPont ChemKote.
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Applaud gives someone karma points, Smite taketh away.
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Well you learn something new every day! I wondered what they were for aswell.
Chris
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Never sure how I have earned mine, although I have given a few karma's!
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Never sure how I have earned mine
Ya think? ;D ;D ;D
(http://lh4.ggpht.com/_6W8YIz2gr1w/SwOrTkTmD6I/AAAAAAAACZM/crVGfr1qhJQ/s288/puzzled.jpg)
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Must...stop...ogling...Santa Cruz Superlight...
(http://www.santacruzbicycles.com/superlight/superlight_large.jpg)
If my 756 ever gets demolished, I'm putting the parts on this. :D
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Looking at the SC Superlight I'm amazed at how similar it is to the X57 bikes...I mean, the pivot point is the same...if the swingarm had that taller truss, and the shock mounted differently, it's almost the same frame. Makes me think that the sooner we have a workable, standardized solution for the rear shock adapter the sooner we'll be able to achieve at least some of the advantages of this frame, and the advanced shocks it's able to use.
- Doug :-)
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The 9-series frame would work like the Superlight if a set of rigid braces could be installed into the V-brake bosses and the strut could be clamped into those braces, to make a rigid triangle. Then a strut-to-eyelet adaptor could be attached to the strut where the shock normally attaches, and the shock could connect to the adaptor.
However, I'm not sure it's really worth the effort, because all you'd have then is a funny-looking hacked-together "normal" single-pivot bike. A Pro-Flex wouldn't continue to be a Pro-Flex if it no longer had the shortcomings of its design any more than than if it no longer had the advantages of its design.
Among other things, the strut design on a Pro-Flex gives the swingarm an incredibly linear leverage ratio across the span of shock travel; one of the big disadvantages of most single-pivot bikes is the the way the shock gets tilted towards vertical as the suspension compresses, thus giving the swingarm/triangle an increasing leverage ratio, which makes the suspension "feel" much softer as it compresses. That is probably a bigger factor in the "mushy" feel of older single-pivot bikes than anything else.
I think if someone wants a Superlight, they should just buy a Superlight.
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Besides the shock position it's just a 862 in wolfs clothing ;D
Hmmm if i just weld a bracket here :P & install a fox shock and fit a longer seatstay im good to go ;D
VOILA!! a superlight without the light >:(
Wonder if a 857 swingarm would fit the old girl to give me a little extra space to squeeze in a bigger shock ::)
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I dunno man, but that would be a crazy-long wheelbase. It would be like cornering on a dualie. And I thought my 756 was forward-biased enough already... :o
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Would be good for Hill Climb racing, as long as youve got the legs for it ;D ;D
Chris
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Anybody want to take some measurement's for me??
Pivot to dropout......?
Pivot to s/arm brace.....?
Seat stay length......?
And B/B to ground height......?
Thank you!!!!
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Got my swingarm back from shovelon today. Here's what it looks like with a coat of primer:
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4012.jpg)
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4015.jpg)
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4017.jpg)
Good stuff. :D
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Oh my...that is beautiful. I am speechless
Thunderchild
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As good as the factory welds, amirite?
Unfortunately the silver paint I got is darker than the original paint. I should've seen that coming, and actually I did, but I figured it would be close enough for government work. I should probably just paint the whole thing, but I'm too excited to go ride it tomorrow, and I don't have a new set of decals anyway. Maybe I'll send it out for a proper paint job this coming winter, when I've nothing better to do with it.
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VERY NICE , well done to you both.
Chris
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that is a great weld (almost said 'cracking' then, but thought better of it :D)
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Glad you put up the pictures . Thinking of doing this modification too, so I'll have a pro flex for riding in the mud. Looks like great welding shovelon! PF
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amirite?
Unfortunately the silver paint I got is darker than the original paint. I should've seen that coming, and actually I did, but I figured it would be close enough for government work.
What's Amirite????
And either you or someone you know is an engineer(government work)? ;D ;D ;D
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amirite?
Unfortunately the silver paint I got is darker than the original paint. I should've seen that coming, and actually I did, but I figured it would be close enough for government work.
What's Amirite????
And either you or someone you know is an engineer(government work)? ;D ;D ;D
Amirite == Am I Right, slurred together.
And yes, I'm an engineer working for a defense contractor. ;D In case anyone's curious, I've learned during my (thus far) short career that "close enough for government work" is ~75%.
More pics!
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4018.jpg)
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4019.jpg)
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Lookin' good Shawn!
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That's a really nice bike!!!
Congratulations!!!
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...and just today, the final piece of the puzzle arrived -- blue anodized Hope hose guides. Now my brake cable won't flap around when I hit stuff.
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4075.jpg)
(http://i5.photobucket.com/albums/y186/deusexaethera/bikes/CIMG4077.jpg)
I love the way all that mechanical stuff looks; I wish I could carry my bike everywhere so I could admire it and fiddle with it when I'm bored. ;D
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keep a picture in your wallet :D
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Hmm. That's just crazy enough to work. 8)