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

[LukeTheJoker]

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!

I will hit the heatshrink with a heat gun after the final truing is done tomorrow on my wheel stand.

Still have the front to do, but not tonight, that was hard work!

Luke.

 

[OddJob]

Do the vintage frame for sure! Being my ADD self, I couldn't wait for this winter's ORBO, so while I was waiting for the rest of the RRBO 10 field to finish, I built this klunker / big BMX out of a Hiawatha bike I picked up locally on CL. Here are a couple of shots of that build....(sorry Luke for the mini-hijack of the thread, but he did mention my name...)
What I started with...


Stage One...vintage suede San Marco saddle, 1978 MX bars from a Yamaha, bike swap BMX stem, moto grips, fenders and chain guard off, custom lay back seatpost from RRB member....


Paint stripping...


New paint...my favorite blue...


Add some white lock-on grips, and CST Cheyenne 26 x 2.4 knobbies, and bear trap pedals...
end result...Desert Sky...


...And I promise I won't hijack the thread any more LTJ!

 

[OddJob]

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!



View attachment 14993

View attachment 14992

View attachment 14994

I will hit the heatshrink with a heat gun after the final truing is done tomorrow on my wheel stand.

Still have the front to do, but not tonight, that was hard work!

Luke.

Sweet wheels Luke! That spoke cover idea is a cool one, not sure I have seen that before...but again, Noobville when it comes to this vintage rat rod bike stuff!

 

[LukeTheJoker]

Sweet wheels Luke! That spoke cover idea is a cool one, not sure I have seen that before...but again, Noobville when it comes to this vintage rat rod bike stuff!

Only seen it once before and that was in 1HP's 'Widening a rim without welding' thread.

(sorry Luke for the mini-hijack of the thread, but he did mention my name...)
...And I promise I won't hijack the thread any more LTJ!

All good!



How does this ride OJ? Just noticing the similarities on angles to my plan. (my proposed angles in red):

Looks like BACK40 would be slightly steeper all around, but not by much...
Love the bike by the way!

Luke.

 

[Funkme]

Well your not wasting any time on this bike.
Seems like you have this sorted...

 

[LukeTheJoker]

Huh! Just learn't how to do overlays on Paint.net!

Both bikes are very similar in the riders area, Back40 is dramatically shorter in the stays though! What do you think @OddJob?

Luke.

 

[Fv2]

Huh! Just learn't how to do overlays on Paint.net!

View attachment 15002

Both bikes are very similar in the riders area, Back40 is dramatically shorter in the stays though! What do you think @OddJob?

Luke.

Looks like the position of your rear drop outs might have yours looking a little lower than OJ's, but I think you have the right stance.
Well done Luke.

 

[OddJob]

Huh! Just learn't how to do overlays on Paint.net!

View attachment 15002

Both bikes are very similar in the riders area, Back40 is dramatically shorter in the stays though! What do you think @OddJob?

Luke.

Luke, in the last overlay, is the "drawn seatpost" where your finished one would be, or the "red line"? Quite a difference between the two. With the really short stays, I would say if you could be closer to the angle's on my Desert Sky (and I don't know what those are, and don't have the bike with me) that you would be better off than so slack as the red line (65 degrees?) would be. Then your proposed red line HT angle should work. It will also depend on the rake and "trail" of your fork that you plan to use. This old cruiser has a fairly long rake on the fork as you can see, which makes it more stable in the downhill sections. And I believe when I was putting this together, my overall wheelbase (axle to axle measured on the tire touching ground) was around 42-43". Want to say the chain stay measured around 16.5-17". I have ridden this off-road on my local mtb trails, and other than it weighing 35 lbs and being single speed with fairly high gearing, it handled well!

 

[OddJob]

This might be helpful....good resource on geometry and handling.
http://calfeedesign.com/tech-papers/geometry-of-bike-handling/

 

[LukeTheJoker]

Luke, in the last overlay, is the "drawn seatpost" where your finished one would be, or the "red line"? Quite a difference between the two. With the really short stays, I would say if you could be closer to the angle's on my Desert Sky (and I don't know what those are, and don't have the bike with me) that you would be better off than so slack as the red line (65 degrees?) would be. Then your proposed red line HT angle should work. It will also depend on the rake and "trail" of your fork that you plan to use. This old cruiser has a fairly long rake on the fork as you can see, which makes it more stable in the downhill sections. And I believe when I was putting this together, my overall wheelbase (axle to axle measured on the tire touching ground) was around 42-43". Want to say the chain stay measured around 16.5-17". I have ridden this off-road on my local mtb trails, and other than it weighing 35 lbs and being single speed with fairly high gearing, it handled well!

The blue tube in that pic is the seat tube, it runs right behind the red line.

I think I may have measured the angles wrong, I measured from the BB to where the seat will end up, same way I did the black lines on your build, guessing that is not the way to do it!

This might be helpful....good resource on geometry and handling.
http://calfeedesign.com/tech-papers/geometry-of-bike-handling/

Thank you! Will have a read!

Luke.

 

[OneHorsePower]

View attachment 14994
I will hit the heatshrink with a heat gun after the final truing is done tomorrow on my wheel stand.
Luke.

Wow , that is one sweet set of wheel luke !
thanks for the props on the spoke trick
i always shrink them before i lace the wheels , did you choose to do this after cause the spokes fit tight in the hub flange holes ?
in yellow its awesome ! only tried with the black one so far
heat gun !!! might work better and faster than my candle heh?!

 

[ind-chuckz]

 

[The Renaissance Man]

Huh! Just learn't how to do overlays on Paint.net!

View attachment 15002

Both bikes are very similar in the riders area, Back40 is dramatically shorter in the stays though! What do you think @OddJob?

Luke.

Luke, the overlay thing can be very deceiving if your not careful. The camera causes distortion due to perspective. Notice how you can see both dropouts and each are in very different places relative to the rest of the frame. That's caused by taking the photo from close range. Whenever I use a photo for digital mock ups and scaling, I always try to back away as far as possible and use my zoom to bring the bike in close. Also, I try to get a straight shot as level with the center of the bike as possible and of course centered left to right. It's impossible to get it perfect, but the farther away you are, the less distortion you get. Hope that helps! -Jim

 

[LukeTheJoker]

Wow , that is one sweet set of wheel luke !
thanks for the props on the spoke trick
i always shrink them before i lace the wheels , did you choose to do this after cause the spokes fit tight in the hub flange holes ?
in yellow its awesome ! only tried with the black one so far
heat gun !!! might work better and faster than my candle heh?!

Yes, exactly right 1HP, the holes in the hub are too small to run the shrink tube through. I'm hoping the heat gun will work well, I really want to avoid the smoke blackening you can get from an open flame...

Luke, the overlay thing can be very deceiving if your not careful. The camera causes distortion due to perspective. Notice how you can see both dropouts and each are in very different places relative to the rest of the frame. That's caused by taking the photo from close range. Whenever I use a photo for digital mock ups and scaling, I always try to back away as far as possible and use my zoom to bring the bike in close. Also, I try to get a straight shot as level with the center of the bike as possible and of course centered left to right. It's impossible to get it perfect, but the farther away you are, the less distortion you get. Hope that helps! -Jim

Thank you! I think you are right there!

The first one should still be right though as that is actual measured angles:

OddJob's frame is the black lines, Back40 is the red lines...

Thanks Chuckz!

Luke.

 

[KJV]

Looking forward to watching.

 

[LukeTheJoker]

The wheelset is done!

I may have managed the rear first time with no issues, but I messed up bad the first time on the front, just one hole off on the second flange and I had to strip 3/4 of it and start again! Got there in the end, both wheels trued up very nicely and the heatshrink looks awesome now it has been shrunk with the heatgun.

26" 48 spoke, 4 cross pattern.

I'm sure someone else somewhere has done it before, but this is the first set of 48 spoke, 14mm axled, disc braked 26+ wheels I have ever seen! They look great! Really happy! Not bad for someone who never never laced a wheel until a couple of months back...

Luke.

 

[Fruttolo]

Nice wheels! 48 spoke is sturdy


Just one thing, in mtb one refers to "plus" wheels when the tire is over 2.7" less or equal than that and it's still a "regular" tire

 

[LukeTheJoker]

Nice wheels! 48 spoke is sturdy


Just one thing, in mtb one refers to "plus" wheels when the tire is over 2.7" less or equal than that and it's still a "regular" tire

Ah! Thanks for the heads up, I had read it was 2.5 or over...

Glad you like the wheels, I had a lot of fun making them!

Luke.

 

[OddJob]

Looks great LTJ! Those are the epitome of "bombproof"....
Will be interesting to see what color you do the frame in with those yellow spokes!

 

[LukeTheJoker]

Looks great LTJ! Those are the epitome of "bombproof"....
Will be interesting to see what color you do the frame in with those yellow spokes!

Colour already picked out and I have it here in stock!

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.