(ORBO) BACK40 by LTJ, design by OJ. (ROLLING! But withdrawing from the build-off.)

LukeTheJoker

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Nov 17, 2012
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Broken Hill, Australia
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So many bikes these days have a sticker that says made in China or designed in u.s.a.
This one should say designed in USA, made in Australia.
I like that! Already have all the decals made for it, but I may have to place another order!
Great idea!
@OneHorsePower is the man with the ideas! They look great! :thumbsup:

Luke.
 
Mar 26, 2012
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Maplewood, MN
Colour already picked out and I have it here in stock! :thumbsup:

Been thinking long and hard about the headtube angle and reading that info you posted, going with what you said: 69-70 degrees, be a shame to go to all this effort and have it not 'work' properly just because I want a marginally shorter wheelbase!

Luke.
Hope it works out well! Like it has been said on this RRB forum many times; it's one thing to plan / design a bike in your head, and another to actually put it together with hard parts and frame materials!
 
Sep 7, 2014
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Well, I got bored...

By the way, 48 spoke, 4 cross without a rim to copy, never done either before and got it right first attempt!
First time lacing a wheel or first time doing a 48h 4x?

Edit: I see where you said you did your first recently. A+ Good job on getting the valve hole thing right. Hard to keep off the wheel assembly once you get all the parts. My favorite part of a build.

They look sensational! I had to backtrack to see what the heat shrink was all about. Great idea and that looks awesome. Like the painted sidewalls too. Silver band kills the look of a black rim.
 

LukeTheJoker

Moderator
Nov 17, 2012
21,381
18,176
Broken Hill, Australia
www.ratrodbikes.com
First time lacing a wheel or first time doing a 48h 4x?

Edit: I see where you said you did your first recently. A+ Good job on getting the valve hole thing right. Hard to keep off the wheel assembly once you get all the parts. My favorite part of a build.

They look sensational! I had to backtrack to see what the heat shrink was all about. Great idea and that looks awesome. Like the painted sidewalls too. Silver band kills the look of a black rim.
Thanks Chad! I think this was my 5th and 6th wheel, pretty happy with progress in that regard, I put off doing it for years, but I find it fun now! ;)

Luke.
 
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LukeTheJoker

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Nov 17, 2012
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Did the fiddly stuff today.

Started by welding on the new 1 1/8th headtube to suit the forks, decided on 69.5 degrees in the end.

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Next step was always going to be fiddly, I had to make a joint for the chain stay to connect to in the very crowded area between the chainwheel, cranks and the oversize tires that are far further forward than normal due to the short chain stays. Started out with some 5mm flatbar and made up these stepped plates:

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Notice the one on the left has an extra amount of clearance ground into it at the weld to allow the chainring locator bolt to clear, that is how tight the clearance is! The slots at the other end are where the chainstays will slide in and be welded.

Inserted the cranks with the 30 tooth TuffNeck chainwheel to get everything checked out and tacked the plates in place:

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They will end up getting fully welded both sides once everything is checked, notice I have bevelled the outer edges where it meets the bottom bracket, that is so I can get a good weld in there and sand off any excess without effecting the strength of the weld.

Here is a pic to show the clearance issues and how close everything is even with these adapters in place:

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Can't get much closer than that! Glad that back wheel trued up nicely, or I might have had issues! Glad it is super strong too, don't want it going out of true on a ride, no clearance!

Anyway, that was the progress for today, annoying, time consuming stuff, but the next step is a cool one, welding in the rear triangle and top tubes, that will be a fun day's work!

Running ahead of schedule on this build, but that is good, looks like summer is heating back up here again and that will mean more 'total fire ban' days that make it illegal to cut, grind and weld outside.

Luke.
 

LukeTheJoker

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Nov 17, 2012
21,381
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Broken Hill, Australia
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Finally dug the bars and stem out of my parts pile and put them together!

Loving the look of the combination, big chunky high tensile hex heads with nylocks on the back of the stem and super wide but still low bars:

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In case those bars are too short I pulled these taller but still wide bars out too:

24305986906_b59096810c_z.jpg


Hoping I can use the short ones though, they just look tougher! :showingbiceps:

Luke.
 
Mar 26, 2012
7,286
14,118
Maplewood, MN
You are moving at a good pace my friend! It's almost as if it was one of my builds! Haha!:bigsmile: Those tolerances are tight at the bottom bracket. This bike is going to have a very "fat" look to it when it is done....which is always good!
 
Oct 3, 2015
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Denver, CO
Definitely looking sweet! Also glad you are having fun building wheels! I have done about 5 or 6 in the past couple months, mostly fat bike wheels this time of year. :)

Love the heat shrink tubing on the spokes BTW, seen colored spokes come back into style over the past decade, mostly in the BMX scene, and they tend to be pricey. How much would you say the tubing ran you per spoke? Also, I have seen the black ano'd spokes breaking easier at the bends compared to the stainless silver spokes, and this is a great way to get the color and the reliability! Thanks for the idea, will probably steal it from you at some point if you do not mind ;)
 
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LukeTheJoker

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Nov 17, 2012
21,381
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Broken Hill, Australia
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Love the heat shrink tubing on the spokes BTW, seen colored spokes come back into style over the past decade, mostly in the BMX scene, and they tend to be pricey. How much would you say the tubing ran you per spoke? Also, I have seen the black ano'd spokes breaking easier at the bends compared to the stainless silver spokes, and this is a great way to get the color and the reliability! Thanks for the idea, will probably steal it from you at some point if you do not mind ;)
If you go black or red it is much cheaper, probably $.20 a spoke, the less common colours (yellow, white, blue, green, clear) around $.25 a spoke.

Probably a little cheaper over there in the US though... Also will depend on length, these were 260mm spokes and I cut the heatshrink at about 245mm, meaning I got 4 pieces per length, bmx spokes you will get more spokes per length and so therefore cheaper.

I stole the idea from 1HP, and he didn't mind, so steal away!

Luke.
 

LukeTheJoker

Moderator
Nov 17, 2012
21,381
18,176
Broken Hill, Australia
www.ratrodbikes.com
You are moving at a good pace my friend! It's almost as if it was one of my builds! Haha!:bigsmile: Those tolerances are tight at the bottom bracket. This bike is going to have a very "fat" look to it when it is done....which is always good!
Thanks OJ! I hope I am doing justice to the BACK40 name!
Cool design. The build is looking good.
Thanks Locojoe!
So much win already in this build ! :rockout:
Thanks 1HP!, thanks for the cool idea with the heatshrink too, very cool!

Luke.
 

LukeTheJoker

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Nov 17, 2012
21,381
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Broken Hill, Australia
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Cool, sounds to be cheaper to use the heat shrink tubing rather than the colored spokes! Now to find long lengths, maybe spools of the stuff!

Sent from my SPH-M830 using Tapatalk
Much cheaper! Black and red seem to be available in spools, but the others I was only able to find in 1,200mm lengths... (4 foot)

Luke.
 

LukeTheJoker

Moderator
Nov 17, 2012
21,381
18,176
Broken Hill, Australia
www.ratrodbikes.com
Curved seat tube, 69* head angle and square chainstay tubing? As a Canfield Brothers nimble 9 rider, I support these things. I love those wheels, but you gotta go 27.5 or 29 to fit in these days ;) (Not my bike below, but mine's similar)
Those Nevegals measure out at 27", I am almost there! ;) :21:

Great looking bike... :thumbsup:

Luke.
 
Oct 3, 2015
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Denver, CO
26" wheels still rule! Loving my current ride, and am getting some sweet hand-me-downs due to everyone riding 29ers or going 27.5! Definitely would not mind upsizing to 27.5s but being a former DH racer and dirt jumper I love the nimble handling of my 26" wheels! Wish I hadnt been building my ride for the past 10 years, can I strip it back down to the frame and rebuild it for the ORBO?