'36 Elgin Osprey.

[bikewhorder]

I know I'm late to the party as always but this is a bike that I've wanted to build for a few years now. I've been working on finding the time and space to do it but I think I might finally be there. The concept is what if Elgin tried to come out with a dual suspension bike like Huffman and Colson and Monark did. It's going to use leaf Spring suspension front and rear. I think I've got the design all worked out but I just need to build it now. Super excited to see this thing become reality.

 

[MattiThundrrr]

I know I'm late to the party as always

That's going to be a problem. You are going to have to come up with something good to get past it.

The concept is what if Elgin tried to come out with a dual suspension bike like Huffman and Colson and Monark did.

You are good. All is forgiven. You had me at "what if Elgin..."

 

[OddJob]

Bring the magic @bikewhorder ! Can't wait to see your latest iteration of rat rod bike genius!

The new site requires you to click on the word 'Insert' after you upload your image, and then click on 'Full Image'. Then you will get this result on your photos:

 

[bikewhorder]

Bring the magic @bikewhorder ! Can't wait to see your latest iteration of rat rod bike genius!

The new site requires you to click on the word 'Insert' after you upload your image, and then click on 'Full Image'. Then you will get this result on your photos:

View attachment 182083

Thanks i fixed it.

 

[bikewhorder]

Some progress! I'm starting with the bottom bracket. It will pivot inside a larger outer shell that will hold the bearings. I turned a chunk of locust for the bending jig for the outer shell. Its going to clamp together in two parts.

 

[Mr. Monkeyarms]

This is gonna be cool!

 

[bikewhorder]

I did a li'l mockup of the rear end to make sure things were going to move like i was imagining they would. I thought I needed that pivot over the rear axle but it looks like it will be fine without it.

 

[curtisfox]

This is getting interesting, love what you are doing...........Curt

 

[bikewhorder]

Usually I've done a full size drawing before any spark start flying but I couldn't sleep tonight so I finally did one.

 

[OddJob]

I love watching you work!

Off Road RaT oN~!

 

[ifitsfreeitsforme]

more more more !

 

[bikewhorder]

more more more !

Thanks for the encouragement! Here's some more recent progress. I'm making the parts for the outer bottom bracket shell. These will be cut in half and clamped together with screws to encapsulate the bearings. I keep telling myself "Im not building an engine" but I gotta say these parts are well within spec.

 

[hamqqea]

Using the outside BB shell as a rotation point is something I've wanted to explore seeing the frame below. Although not rotational, I immediately got the idea, a what if moment. Heavy design but should be very stable. Lots of interesting fab work going on in your build.

 

[Tallbikeman]

I like your self imposed leaf spring limit. I can only watch in wonder.

 

[bikewhorder]

Using the outside BB shell as a rotation point is something I've wanted to explore seeing the frame below. Although not rotational, I immediately got the idea, a what if moment. Heavy design but should be very stable. Lots of interesting fab work going on in your build.
View attachment 182481View attachment 182482

Yes and the reason that I wanted to make the bottom bracket the pivot point was because I'm trying to eliminate any sort of chain slap or brake jacking. This could be easily done by making a unified rear triangle like the Trek Y

frame but those don't really engage the suspension unless you're seated. I was first thinking I would do something like this obscure Kawasaki frame (1 of 1)

https://thecabe.com/forum/attachments/538c6200-57cc-4348-90ad-dfdb6cfbc0b0-jpg.1411388/ but then i realized that without a deraileur my single speed I" pitch chain set up would probably get bucked off as it compressed. I thought the whole concept was pooched until I realized I could make the B/B pivot on the inside of a fixed front triangle. That was an epiphany that had me giddy with excitement. Once I had that idea then I just had to build this thing. To my knowledge I invented this. It's possible it's been done before and for some reason doesn't work but I need to build it and find out for myself. From what I can tell it's going to work fantastically. There could be excessive amounts of pedal bob but I'm not too worried about that.

 

[Karate Chicken Industries]

Yes and the reason that I wanted to make the bottom bracket the pivot point was because I'm trying to eliminate any sort of chain slap or break jacking. This could be easily done by making a unified rear triangle like the Trek Y frame but those don't really engage the suspension unless you're seated.

URTs do not have a tendency to chain slap because the chain stay length does not change throughout the travel. Well designed FS MTBs tend to have that same quality, such as a properly proportioned Horst Link. However, as someone who rode a 1996 Y-11 for a few years and also observed other URT bikes (such as the Klein Mantra) I know that they are very prone to stinkbugging. You are also correct in that URTs are semi-active.

 

[The Renaissance Man]

Subscribed.

 

[bikewhorder]

OK well progress has been non existent lately but don't count me out just yet. I've taken off work for the last 2 weeks of February so maybe I can throw something together. I was working on the drawing tonight, revising the fork suspension to something much more functional than what I originally drew. Shaggy decided to help.

 

[bikewhorder]

Inching closer to being able to build again. I moved last summer, and had to cram 15 years of hording stuff in a giant old house and 3 story barn into a 2 car garage. This is how it looks now versus after I moved. What you can't tell in the new photo is that its about -2 degrees F in there tonight. Tomorrow I'll sheath the wall on the left so there's a possibility of heating the space.

 

[bikewhorder]

Ok actual progress. I got my last interior wall done and it's doing a good job of blocking the wind and snow drifts. And now I've finally begun welding up some parts. I got 12 days but it's all I'm going to do for the next 12 days so let's see how far we get!