What is the skinniest a frame can be?

[Lza555]

I'm building a frame for the first time for a divorced ironhead I've been working on and it just looks way too wide at 8" in between the bottom rails. I'm probably just gonna use a 16" sportster wheel and I was concerned about the chain scrubbing but it just looks fat. How skinny can I get it down to without that being an issue?

[BurnoutNova]

Not trying to be a dick but if you are asking this question maybe you shouldn't be building frames?

[shovel625]

I'm building a frame for the first time for a divorced ironhead I've been working on and it just looks way too wide at 8" in between the bottom rails. I'm probably just gonna use a 16" sportster wheel and I was concerned about the chain scrubbing but it just looks fat. How skinny can I get it down to without that being an issue?

as skinny as you want, as long as you make the engine fit

[bobberadam]

My frame is 1 5/8" wide.... does that help?

[Tattooo]

[ATTACH=CONFIG]85360[/ATTACH]

My frame is 1 5/8" wide.... does that help?

And it looks DAMN good to boot.....

[kmanator]

8 inch's Maybe too narrow for the chain and the mechanical brake rod? My Divorced Ironhead is 8- 3/8ths and would have liked another .250 in the span.I built a hybrid Sporty/Bigtwin frame with a fabbed hardtail section after stretching the lower bottom tubes 7 inches after cutting at the sporty casting/uptube motor mount section off to make real estate for the softail 5 speed.What year Sporty motor are you using?

[Lza555]

Fuck off dude. I'm trying to learn about offsets and shit

[Lza555]

Yup lol I'm really worried about the rear end and the chain scrubbing. Not really the front half. Looks good though

[Lza555]

8 inch's Maybe too narrow for the chain and the mechanical brake rod? My Divorced Ironhead is 8- 3/8ths and would have liked another .250 in the span.I built a hybrid Sporty/Bigtwin frame with a fabbed hardtail section after stretching the lower bottom tubes 7 inches after cutting at the sporty casting/uptube motor mount section off to make real estate for the softail 5 speed.What year Sporty motor are you using?

Its a 74. I'm using a disk brake in the rear and after measuring everything it looks like it'll fit with about a quarter inch on each side but I've been looking at some choppers that look like they're 6" all the way back. It may just look that way though. Mind if I ask what you used for the primary?

[kmanator]

Its a 74. I'm using a disk brake in the rear and after measuring everything it looks like it'll fit with about a quarter inch on each side but I've been looking at some choppers that look like they're 6" all the way back. It may just look that way though. Mind if I ask what you used for the primary?

I had the sportster motor sprocket milled into a hub then .006 interference press fit into a double row shovelhead compensator ring gear then welded after the offset was established then used an 82 link bigtwin primary chain.The final sprocket has a .500 offset to get the sweet spot between the primary chain/trans. and final drive chain alignment.
This is the ring gear I used:

https://www.ebay.com/itm/NEW-HARLEY-Compensator-Sprocket-Shovelhead-Ironhead-23T-dual-gear-40283/401206716890?hash=item5d69c8a9da:g:63EAAOSw4shYAREL

[farmall]

Interesting thread! More details always welcome.

[Lza555]

I had the sportster motor sprocket milled into a hub then .006 interference press fit into a double row shovelhead compensator ring gear then welded after the offset was established then used an 82 link bigtwin primary chain.The final sprocket has a .500 offset to get the sweet spot between the primary chain/trans. and final drive chain alignment.
This is the ring gear I used:

https://www.ebay.com/itm/NEW-HARLEY-...EAAOSw4shYAREL

Awesome.that's the last thing I gotta do with the drivetrains I think. Thanks for all the help.

[Steelsmith]

I love that single-loop frame, soo clean!
While an unconventional approach, this is a very valid question. When considered without preconcieved notions of what a frame is, the answer is only limited by your imagination and safety constraints.
Dream-on, dude!