Custom Build Advice

[Mr. X]

Hello everyone,
I am currently building a fully loaded designer/show stretch cruiser/chopper bike, and I need some advice on material to build the frame. I am currently thinking of using T6 aluminum or 4130 steel. I would like to save on weight so I am leaning toward the Al. I am an experienced welder so I am aware of the process needed for the T6. Although the bike is intended for show, I would also like it to be of course functional for standard city riding. I am not too familiar with T6 structural properties (for use on a bike) so, my only concern is choosing the appropriate diameter and wall thickness for the tubing to make the frame structurally sound. If there is anyone out there that has any experience in T6 frame building or someone who could point me in the proper direction (or talk me out of using T6, and why) your advice would be greatly appreciated.

Here are a few of the general specs.
Overall length (wheel to wheel) = approx. 9.5'
Frame length (head tube to rear dropout) = approx. 6'
Fork length = approx. 38"
Fork angle = 45 degrees
Head tube = 10"

Thanks to anyone that can help.

[Brian]

9.5' feet of bicycle is going to weigh a lot, no matter what. In the end, the T6 would probably be heavier due to all the gussets and webbing you'll need to build in. Steel is real. Much cheaper too, and you'll find it easier to work with.

[sydney]

Steel is real.

Hot damm!! That clinches it.

[sydney]

Hello everyone,
I am currently building a fully loaded designer/show stretch cruiser/chopper bike, and I need some advice on material to build the frame. I am currently thinking of using T6 aluminum or 4130 steel. I would like to save on weight so I am leaning toward the Al. I am an experienced welder so I am aware of the process needed for the T6. Although the bike is intended for show, I would also like it to be of course functional for standard city riding. I am not too familiar with T6 structural properties (for use on a bike) so, my only concern is choosing the appropriate diameter and wall thickness for the tubing to make the frame structurally sound. If there is anyone out there that has any experience in T6 frame building or someone who could point me in the proper direction (or talk me out of using T6, and why) your advice would be greatly appreciated.

Here are a few of the general specs.
Overall length (wheel to wheel) = approx. 9.5'
Frame length (head tube to rear dropout) = approx. 6'
Fork length = approx. 38"
Fork angle = 45 degrees
Head tube = 10"

Thanks to anyone that can help.

You think you don't need to worry about daimeter and wall thickness with steel on a rig like that?

[andygates]

Gotta be said, the Alu verison is going to look a whole lot chunkier than the steel. With some cunning you oughta be able to get the steel one to look scarily gracile...

[Brian]

Hot damm!! That clinches it.

Disclaimer: Titanium is still my metal of choice. But choppers should be steel.

[BikerLRY]

Disclaimer: Titanium is still my metal of choice. But choppers should be steel.

I agree with you on the titanium part.

[Mr. X]

I like to work with all metals, and was considering doing a titanium frame, but the massive size of the frame alone would cost a fortune, so I scratched that idea. I would have to say though that I'd love to build a titanium chopper frame.
There is one other reason I was considering using Al for the frame which I left out in my first post. I would like to have two tones of a gunmetal finish (frame darker, fork brighter). It would be fairly easy to anodize the Al to achieve the color. I guess though, the frame (if steel) could easily be painted. I really wouldn't want paint on the fork, so there is the possibility of keeping the fork Al and anodizing it. Unless there is some other process to achieve a gunmetal finish I am not aware of?
By the way, thank you everyone for all the input. You all have brought up many valid points that I need to consider.
Thanks.

[Brian]

It will look like the HD Wide Glide if the forks are made from aluminum. You'd need something along the lines of 40mm tubing.

[phidauex]

If you are doing the aluminum you should take a good look at some downhill alumnium frames, and take some measurements. If you can look at a frame that isn't built up yet, that would be perfect. Notice where they put their gussets, and plan for gussets in the same places. Also, don't be afraid to overbuild, it is a chopper after all.

Steel is generally my prefered bike material, but aluminum might be nice for such a big bike.

I'd gusset at the headtube/top tube junction, and around the bottom bracket. Perhaps behind the seat tube as well. Don't bother with butted tubing, and make sure your mitering is dead on. If you can arrange to have the entire frame heat treated after welding, that would be best, otherwise you might consider a 7xxx aluminum, which I've heard doesn't require the same amount of heat treating after welding.

And finally, post pics when you are done.

peace,
sam

[kaiser&cross]

and the turning radius would be.......? wish i had the skills. i'd love a 10ft. good luck. Jim