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

[LukeTheJoker]

Is that the white on your muscle bike from a MBBO build ago or two? That would be a good one. Show off those chunky black tires!

That is the one! Showing off the tires was my thinking too, match the big KENDA lettering!

Well I've missed a few days of this one, it's coming together nicely Luke.
I've learned in the past year on this site, white looks good on bikes. This one will be no exception.

Thanks Falstaff!

Wow thats a great looking bike!

That side shot is fantastic!

Thank you Sir!

Luke, the work is exceptional.

Thanks Gig!

Looks great, expectations are mounting but I doubt it will pose a problem you can't overcome. Short wheelbase and classic lines. Hmm, white paint with two tone and darts for the Klassic Klunker look?

Carl.

I had not thought about darts, but I do have some decals...

Just working out the sliding dropouts now, I don't have much room to play with as the rear drive is only a 14 tooth, not allowing much room either side of the chain stays, so I have to find a way to get it all perfectly lined up and still match the curve on the seat tube, I may have to move the seat tube forward slightly closer to where I originally planned it, not too hard at this point as I have not tied the twin stay/top tubes in to the seat tube yet.

Luke.

 

[LukeTheJoker]

Turns out there is plenty of clearance...

Those sprockets look so small compared to the frame and wheels!

Luke.

 

[GuitarlCarl]

Yeah I think them BMX sprockets are tiny looking too, but you get clearance that way. As far as the darts go, I've been reading up on klunkers, and IMO the best looking ones have the original paint or a nice repro job.

Carl.

 

[Fv2]

Turns out there is plenty of clearance...

View attachment 16885

Those sprockets look so small compared to the frame and wheels!

Luke.

I had to zoom in on that to see the teeth on that one.

 

[OddJob]

I had to zoom in on that to see the teeth on that one.

AKA the Gabby Hayes cog..... (now that one might make you think....)

 

[LukeTheJoker]

Been doing some designing on the dropouts. Looked at a few designs of sliding dropouts and then found a reference to pivoting dropouts, and down the rabbit hole I went!

Started designing, I think I am close to a finished design here, but I am contemplating lengthening the slot and putting two lock bolts in the bottom instead of just one.

Drive side:

Brake side:

I might make the pivots a bit stronger too, still a work in progress...

Luke.

 

[LukeTheJoker]

Maybe for the ultimate strength a combination of sliding and pivot drops with full circles at the axle? It would mean removing the whole area to change a tire, but that is only three 8mm Allen heads per side, and I am more worried about extreme strength than wasting 1 or 2 extra minutes changing a tire...

Luke.

 

[zmoon]

bmx hub?

 

[LukeTheJoker]

bmx hub?

Yep, Odyssey Hazard, 14mm axle, 4 sealed bearings, 48 spoke.

Luke.

 

[OddJob]

Luke, what would be the benefit to a pivoting hub? Seems like extra weight in bolts, more complicated welds, potential for slippage, etc. Just wondering...

 

[LukeTheJoker]

Luke, what would be the benefit to a pivoting hub? Seems like extra weight in bolts, more complicated welds, potential for slippage, etc. Just wondering...

I just was not impressed by the sliding designs I have seen or the one I came up with:

It is hard to make a sliding design work with the rear loop without looking excessively bulky.
If you imagine the frame white and the arms black on the pivot/slide design, I think that will lighten the look considerably.

Actually I just came up with an idea to make the slider look better, back in a minute or two...

Luke.

 

[LukeTheJoker]

Yep, this design could work nicely!

Plenty of area off the back to mount the disc calliper mount on the brake side too...

Luke.

 

[Schwinnspastic]

"Killer build" Luke, I have always been a sucker for the loop tails ! As always your fab skills are shining through .
Mark

 

[LukeTheJoker]

Refined it a bit more:

Luke.

 

[LukeTheJoker]

"Killer build" Luke, I have always been a sucker for the loop tails ! As always your fab skills are shining through .
Mark

Thanks Mark! I love looptails!

Luke.

 

[Dr. Tankenstein]

So, they're dropouts with built-in chain tensioners?
BRILLIANT!


Sent from my iPhone using Tapatalk

 

[metalchewy]

Refined it a bit more:

View attachment 16979

Luke.

Looks lile you've got this one figured out. Great idea!!

Building... riding...

 

[zmoon]

Just wondering what is the tire clearance and how a sliding dropout will affect it Dont want it to get to

 

[zmoon]

look at a firestone twin flex drop out

 

[ind-chuckz]

Lookin goooood....