Modern MOOSEGOOSE build. FRAME 2!

LukeTheJoker

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As most long term members will know, I love large frame 20" bikes, minivelos and BMX...

Obviously the holy grail bike in that style is the late 70's to early 80's Mongoose Moosegoose:

Moose ad.jpg
Chrome goose.jpg
red goose.jpg
Screenshot_20190325-203602.jpg


:inlove:

Of course they are rare now and if you can find them, very expensive!
Which made me decide to build my own!

With some research I found this drawing:

moose-angles.jpg


Add in some help from @Rat Rod and @RustyGold and I had enough measurements and angles to go on to start a build.

I didn't want to cut up an early BMX to build this first one, in case I made some errors or found some issues along the way, but I do have a few newer BMX frames and complete bikes that are not collect-able or worth much, most of which are cheap bike store bikes or even department store ones, so decided to build one out of these frames and parts.
The build will end up heavier and with oversized tubing compared to the originals, but it will give me the information I need and still be a cool bike on its own merit hopefully.

The main donor picked from the pile would have been a half decent bike at some point, a roughly 2005~ish Mongoose Menace Pro, but it had some dents in the main tubes and some damage to the chain stay and a sanded down headtube for some reason:

IMG_20190406_153654728.jpg
IMG_20190406_153659977.jpg
IMG_20190406_153707076.jpg


Perfect donor to build my "Moosegoose" from!

Started by measuring and then cutting the frame up, separated the rear triangle out and removed the bottom bracket but left the seat tube attached, fitted some of the parts to my jig that was set to the right angles and measurements:

IMG_20190406_165640658.jpg


Needed to extend the chainstays, so cut some tube and sleeves:

IMG_20190406_165643842.jpg


Thankfully I was able to fudge the 1 degree less seat tube angle by just tilting the seat tube back before tacking them up:

IMG_20190406_165921937_HDR.jpg
IMG_20190406_170137636.jpg


Next up was extending some forks and the headtube, I didn't have any Mongoose forks, so decided on some Diamondback ones, they needed a 4" extension:

IMG_20190406_173839585.jpg


Cleaned and drilled for plug welding a sleeve inside to add strength due to the extra length:

IMG_20190406_175403610.jpg


Plug welded:

IMG_20190406_175543694.jpg


Of course I needed a 4" extended headtube to match, so another DiamondBack frame donated its headtube to make that happen:

IMG_20190406_181623057.jpg


After surgery:

IMG_20190406_185048613.jpg


Then I could fit the forks and headtube to the jig and set it to the right angle:

IMG_20190406_185401749.jpg


Then measure for the downtube, cut from some 1.5" diameter tube and hand fish mouth the ends:

IMG_20190406_192313010.jpg
IMG_20190406_192320067.jpg


I went with 1.5" tubing rather than the smaller tubing of the original to help balance out the oversized stays and headtube.

Tacked that in place and then I could measure for the seat tube, I still have not found a local supply for the tubing to make my own seat tubes (probably going to end up ordering in Chro-Mo once I get better on the TIG) so an old Repco mountain bike donated to the build too, added a small sleeve of 1" tubing inside the join:

IMG_20190406_194722502.jpg


New pinch point drilled and cut on top and then tacked it in place too:

IMG_20190406_195242290.jpg


That was as far as the build got today, but I had to throw some parts at it and some tape lines on the frame to get an idea of how it will look when the top tube is done and the seat stays are raised up:

IMG_20190406_195609135.jpg


I'm very happy! Measurements and angles all add up, and it looks good.

Looking forward to finishing it off, assembling it and going for a ride! :rockout:
 

LukeTheJoker

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Great job!! I can't wait to see it done. In 96 I purchased a NOS moosegoose from my Mongoose rep. I sold it a few years later and I kick myself everyday for it!!
:13: Dang!
Looks awesome Luke!
One question from the drawing....what’s a ‘fork brake’?
Nice job Luke!

I believe it says fork rake. lol
Thanks Dr.T and TRM, and yes I believe it is Fork Rake!
Cool!
What do you do for seatpost and stem, having the internal sleeve? Is stem threadless?
The seat tube sleeve is at least 8" down from the top, so plenty of room for a seatpost to adjust down, the forks and stem on this build are indeed threadless, so the sleeve is not an issue with them, I have sleeved threaded forks before, it is just a matter of making the join as low as possible so it doesn't get in the way.
This is so epic!! heck yea man!!
Very cool Luke...love seeing this built!
Awesomeness! :thumbsup:
Thanks everyone, glad you are enjoying it! :thumbsup:
More progress soon, and at some point I will be trying to build another using more accurate tube sizes and vintage styled parts, already have a set of used Gold Araya 7X's with high flange Suzue hubs put aside for it... It may even happen before the build-off if I don't get carried away on this one.
 
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LukeTheJoker

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Speechless..............:whew:
In a good way I hope! :21:

No major progress today, my wife was not well, so I had to snatch some time where I could rather than getting a decent run at it, seeing as it was going to be that way I couldn't be bothered getting into overalls for welding, so just did cutting, sanding and cleaning of tubing.

The top tube for this frame is cut and notched ready for tacking in place, but couldn't go much further without removing the jig from the frame to cut off the seat stays, and I don't want to remove it from the jig until the top tube is in place, so instead I started gathering parts for the next frame, the more vintage correct one...

There is a pile of parts in the corner of the workshop now: A bottom bracket with skinny 5/8" diameter chainstays and seat tube stub ready to go, a set of seat stays also in 5/8" tube, a 1.1/8" diameter down tube, a 1" diameter top tube, a 14" long seat tube extension and two threaded headtubes to join into one long one, I was unable to find any straight tube forks with 7/8" or 1" diameter legs, but I did find some chrome ones with 1.1/8" diameter legs, so that will do.
Pretty sure there are some 5/8" tubing looptails from another project stashed somewhere and I should be able to harvest some Mongoose stamped dropouts from another junk frame.

For those worried that these could be passed off to an unsuspecting buyer down the track as the real thing, don't worry, I will be stamping LTJ TRIBUTE 2019 or something similar on the bottom brackets to try prevent it.

Stay tuned, more progress in the coming days! :113:
 

LukeTheJoker

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Awesome build! So are you saying this is a practice run and you're going to do a more refined version later? This one look pretty good to me.
Thanks!
This one is not so much a practice run as a "I wont be upset about losing the parts if it doesn't work" build, these modern frames are everywhere and cheap, so I don't feel bad about cutting one up for an experiment that could have failed.
This heavier build will probably be my favorite of the two as I am a bigger and heavier guy, but I want to do the more accurate one too, mainly just to see what they would have been like back in the day.
:thumbsup:
 
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LukeTheJoker

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Absolutely in a good way!!! :rockout:
:thumbsup:

Good progress today!

Started by fitting the top tube and completely welding all the pieces together, then removed the old seat stays:
IMG_20190408_183007084.jpg
IMG_20190408_183001628.jpg


Made sleeves and some extensions for the top of the stays to get them the right length:

IMG_20190408_194139768.jpg


A little clean up, it will need more work, but more on that later:

IMG_20190408_200429352.jpg


Then it was time to ream the seat tube out.
Whenever you weld it tends to shrink the metal, especially thin tubing, so even though my welds were clean with no blow through or over penetration the seat pole was now stiff in the tube, perfect time to test out my new tool!

I bought a 26mm mill broach a while back just for this purpose, welded it to an old bolt and set it up in the chuck of my drill, add a little transmission fluid for lubricant and ream away!

IMG_20190408_201141527.jpg


Results were good, I was a little nervous because that is some thin tubing and an aggressive broach but it was all good and the inside of the tube is really smooth and the pole slides perfectly!

You know what had to happen next!

Assembly mock up!

Screenshot_20190408-210703.png


It looks great! :thumbsup:
Geometry seems spot on, I would normally have built in a longer top tube length for more room to suit my height but it seems good with the factory lengths, and feels very balanced!

Only thing I am not happy with is the top of the seat stays, I don't like the way I built them, it just looks wrong. Thinking of cutting the top off and redoing it with straighter stays that join at the seat tube.
Unfortunately, if I do that it will shrink the seat tube even further and then I will have to ream it again which I don't want to do as it will get really thin!
So if I redo the stays I will have to replace the seat tube too, it's not the end of the world, just annoying.

On a more positive note, how good does it look on those red gum walls? :inlove:
They came with the wheelset which was found on Facebook Marketplace, once I saw them I knew they had to be on this build even though it meant a hour and a half round trip to get them.
(The reflectors were removed straight after this photo.)
Bronze anodized Mongoose hubs, flip flop on the rear, oversized axles, nice Alex rims and 48 spokes on each.

IMG_20190409_002602983.jpg
IMG_20190409_002631813.jpg
IMG_20190409_002829335.jpg
 

LukeTheJoker

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Yes on the frame, yes on the wheels, yes on the tires. So.....yes!yes!yes!
:113:

I decided to sleep on whether or not to change the seat stays, decided in the morning that I would not be happy with it if I didn't...

But I did come up with a new design which looks better and meant I didn't have to shrink the seat tube further.

Chop, chop...

IMG_20190409_152825043.jpg


Decided it would be a good time to get the matchbox cover plate done while I had better access, trimmed up some 16ga sheet and grabbed the number and letter stamps:

IMG_20190409_152835309.jpg


Welded up, not overly happy with the welds on this or the whole frame actually, but they are strong!

IMG_20190409_153623425.jpg


Then on to the new seat stays, sleeved the tubes and ready for welding:

IMG_20190409_154619232.jpg


Trimmed out the center tube and replaced with some 7/8" tube to match the piece still attached to the seat tube, added another LTJ while I was in there even though it will never be seen, shame I didn't quite get the lettering straight when I welded in the tube!:21:

LTJ tube.jpg


And then assembly mock up:

IMG_20190409_165751020.jpg


Much better looking, cleaner and simpler.

Time for a profile view at the front of the house:

IMG_20190409_165416260.jpg


Time to strip it down, clean it up and start thinking about paint...

:39:
 

LukeTheJoker

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Awesome work!
Thanks Chuy!

A member of the Moosegoose appreciation club was kind enough to share a very detailed blueprint, while my measurements and geometry was correct thanks to the other drawing I had, it looks like my assumptions regarding tubing sizes was a bit off...

Rear stays were 3/4" not 5/8", the top and down tubes were both 1.1/8", the seat tube was 1" with a 22mm post and the forks were slightly under 3/4" tube.

Going to put off building the super accurate one until I have ChroMo tube to work with and a bit more practice on the TIG.

I might build another oversized tube one in the meantime out of a DiamondBack frame, good excuse to practice more with the TIG before the Build-Off! ;)

I spent an hour on the TIG today, just getting the settings sorted took ages, this TIG is far more complicated than what I last used 20 years ago!

I'm not stacking dimes, but better than what is on most box store these days!

Bring on the next build!

IMG_20190412_172329851.jpg
 

LukeTheJoker

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Time for more TIG practice on frame 2!

Decided to be a little less fixed to the original angles and lengths and just see where this one led me.

Started with the Diamondback Joker that donated the forks to the other build:

IMG_20190415_085718795.jpg


Of course that meant I needed the forks back, so needed to make a new set for the Moosegoose, extended some Norco BMX forks to suit:

IMG_20190415_091840728.jpg


Now I can use the Diamondback forks on the new build, chop chop time:

IMG_20190415_100535209.jpg


Left the down tube in place this time, ended up 1/4" longer wheelbase, 3 degrees less seat tube angle and 1 degree more headtube angle, so it should be similar but a bit longer in the cockpit, be interesting to see how it rides in comparison!

Needed to extend the chainstays 1.5/8":

IMG_20190415_102723191.jpg


Then I broke out the TIG and got a bit carried away, forgot to take pics but ended up here for the day:

Joker mock day 1.jpg


Stays fully welded, headtube extended and seat tube extended.

Slowly getting better with the TIG, it does take a fair bit longer as it requires more forethought as to how to position things for welding, but should be far less cleanup, probably only slightly longer on total time for a build, but should be less heat shrink issues and better looking welds, so worth it overall.