Hot-setting 6061 Frame

Joined
Jul 6, 2017
Messages
62
Looking into the newer QS Motors line with 200mm dropout widths for a custom Ebike project based on the A2B Octave/Metro Frames.
Have developed newer 1/4" 4130 dropouts for both sides of the swingarm but am now looking to stretch the dropouts width from 155mm to 200mm to accept their higher torque motors. I can get 200Nm of torque roughly out of their 155 versions but 350!!! from their 200mm versions. Cold-setting is most likely not going to work as its 45mm of stretch on a hefty aluminum swingarm when only 15mm works on small road bike frames. Heat-treatment after and/or before seems necessary. Near the silicone valley area so manufacturing/prodtuction will be easy enough once I get a game plan going. what does ES think?
 
coolbobjoe said:
Looking into the newer QS Motors line with 200mm dropout widths for a custom Ebike project based on the A2B Octave/Metro Frames.
Have developed newer 1/4" 4130 dropouts for both sides of the swingarm but am now looking to stretch the dropouts width from 155mm to 200mm to accept their higher torque motors. I can get 200Nm of torque roughly out of their 155 versions but 350!!! from their 200mm versions. Cold-setting is most likely not going to work as its 45mm of stretch on a hefty aluminum swingarm when only 15mm works on small road bike frames. Heat-treatment after and/or before seems necessary. Near the silicone valley area so manufacturing/prodtuction will be easy enough once I get a game plan going. what does ES think?

Besides all the risks of getting the set even and the post bend heat treatment right; isn't moving the rear cogs over 22.5mm going to make getting a good chainline impossible?
 
a straight chainline is the least of my concerns at this point. My 100-200W of human pedal power is nothing compared to the 9kw coming from my hub motor. The pedals would be taken off at this point if it were not for the ALMIGHTY POWERS THAT BE WATCHING US ROADWAYS if you know what I mean. It currently runs a 7 speed freewheel to a decently complicated tensioning system for the full suspension. I never take it out of 7th gear at this point so a single speed freewheel conversion will probably come along with the ride on this one. I can adjust where my chain lies through two pulleys before and after the chainring to account for quite a bit of play. have enough room for adjustment to fit a 10 sp. freewheel in there but not really worth the effort at this point in time as roughly only 1% of my power is actually coming through my pedal system.
 
Buk___ said:
coolbobjoe said:
Looking into the newer QS Motors line with 200mm dropout widths for a custom Ebike project based on the A2B Octave/Metro Frames.
Have developed newer 1/4" 4130 dropouts for both sides of the swingarm but am now looking to stretch the dropouts width from 155mm to 200mm to accept their higher torque motors. I can get 200Nm of torque roughly out of their 155 versions but 350!!! from their 200mm versions. Cold-setting is most likely not going to work as its 45mm of stretch on a hefty aluminum swingarm when only 15mm works on small road bike frames. Heat-treatment after and/or before seems necessary. Near the silicone valley area so manufacturing/prodtuction will be easy enough once I get a game plan going. what does ES think?

Besides all the risks of getting the set even and the post bend heat treatment right; isn't moving the rear cogs over 22.5mm going to make getting a good chainline impossible?

a straight chainline is the least of my concerns at this point. My 100-200W of human pedal power is nothing compared to the 9kw coming from my hub motor. The pedals would be taken off at this point if it were not for the ALMIGHTY POWERS THAT BE WATCHING US ROADWAYS if you know what I mean. It currently runs a 7 speed freewheel to a decently complicated tensioning system for the full suspension. I never take it out of 7th gear at this point so a single speed freewheel conversion will probably come along with the ride on this one. I can adjust where my chain lies through two pulleys before and after the chainring to account for quite a bit of play. have enough room for adjustment to fit a 10 sp. freewheel in there but not really worth the effort at this point in time as roughly only 1% of my power is actually coming through my pedal system.
 
I might think that hacking one side off at a time and rewelding/sistering the opposite side might allow you to get it more even and true; then repeat for the other side. Do the heat treatment after welding and you are set....
 
12-C said:
I might think that hacking one side off at a time and rewelding/sistering the opposite side might allow you to get it more even and true; then repeat for the other side. Do the heat treatment after welding and you are set....

Very solid idea actually. Any thoughts on filling the swingarm with more material while im in there already?
 
If you will go to a single speed then just mill the axle flats further so you make the drop out width of the axle smaller.
 
Please register and insure your motorcycle, and stay out of bicycle facilities. Thanks.
 
I would try to do it cold, because once it's been hot from welding or a torch, it will be T-0, T-1 temper and has something like 1/5th to 1/7th the initial strength of T-6 6061.
 
SlowCo said:
If you will go to a single speed then just mill the axle flats further so you make the drop out width of the axle smaller.

Are you saying to bore into the swingarm as to make the axle inside of it basically? Not really down on removing material from the already weak link in a chain
 
Chalo said:
Please register and insure your motorcycle, and stay out of bicycle facilities. Thanks.

Work in a bicycle shop so can't really get out of here! lololol but seriously please take the hate somewhere else though! We have videos of people doing near 100mph through the streets on their bikes on here.... :lol:
 
coolbobjoe said:
SlowCo said:
If you will go to a single speed then just mill the axle flats further so you make the drop out width of the axle smaller.

Are you saying to bore into the swingarm as to make the axle inside of it basically? Not really down on removing material from the already weak link in a chain

No.
Remove the axle from the motor and (have someone) mill the axle flats further to the center both sides as much as possible. On the disk brake side as much so the disk has minimum clearance with the swing arm. You could even turn down the aluminium motor cover so the disk sits closer to the cover if you will use a bicycle brake caliper (slimmer than a scooter caliper). On the freewheel side mill the flats as much so the single speed freewheel can just rotate freely. Maybe you can gain enough to get the drop out width of the axle closer to the inside width of the swing arm so just a little stretching is necessary.
 
I would be very surprised if you could find a heat treater willing to take on your project due to the liability issues. If you do find a shop to do the work for you may find that the process distorts your part requiring cold straightening afterwards. If I was building a cycle capable of 100mph+ speeds I would want to be sure the work was done correctly and would want any welder to be certified and any heat treater to be certified for aviation/aerospace work.
 
SlowCo said:
coolbobjoe said:
SlowCo said:
If you will go to a single speed then just mill the axle flats further so you make the drop out width of the axle smaller.

Are you saying to bore into the swingarm as to make the axle inside of it basically? Not really down on removing material from the already weak link in a chain

No.
Remove the axle from the motor and (have someone) mill the axle flats further to the center both sides as much as possible. On the disk brake side as much so the disk has minimum clearance with the swing arm. You could even turn down the aluminium motor cover so the disk sits closer to the cover if you will use a bicycle brake caliper (slimmer than a scooter caliper). On the freewheel side mill the flats as much so the single speed freewheel can just rotate freely. Maybe you can gain enough to get the drop out width of the axle closer to the inside width of the swing arm so just a little stretching is necessary.

Ah, very interesting idea!
 
I did this to a 9C hub motor. It only needed one side and 7mm milling to fit but I liked that better than expanding the aluminium swing arm of my bike.
 
some pics/info about doing it:

https://endless-sphere.com/forums/search.php?keywords=grind*+mxus+flat*&terms=all&author=amberwolf&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
 
coolbobjoe said:
Chalo said:
Please register and insure your motorcycle, and stay out of bicycle facilities. Thanks.

Work in a bicycle shop so can't really get out of here! lololol but seriously please take the hate somewhere else though! We have videos of people doing near 100mph through the streets on their bikes on here.... :lol:

I also work in a bicycle shop, and in a pedicab fab shop. I ride and build e-bikes and I design and build e-pedicabs. I don't hate them. But your bike isn't a bicycle; it's a motorcycle. I don't hate those either, but they have their own set of rules that exists whether you like it or not. Follow them.
 
WoodlandHills said:
I would be very surprised if you could find a heat treater willing to take on your project due to the liability issues. If you do find a shop to do the work for you may find that the process distorts your part requiring cold straightening afterwards. If I was building a cycle capable of 100mph+ speeds I would want to be sure the work was done correctly and would want any welder to be certified and any heat treater to be certified for aviation/aerospace work.


You actually only get one shot at welding and heat-treating an area afterwards. Because the HAZ area precipitates out various alloying components in the 6061, it can not longer achieve T-6 temper on a re-treatment, and is lucky to achieve T-4 on a second treatment even if you had the best aerospace guys in the world doing it.

A bunch of distributed cold bend locations, each with only a small amount of metal displacement to not begin a crack formation, and no heating involved would be the path forward for high strength.

If it's aluminum that's already been welded and heat treated, and you heat it or weld it again after, it's become scrap metal.
 
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