Mclewis1 said:I saw from your posting on another forum that the Wolf Tooth components B-RAD mounting products were mentioned. To me those and the Grin Technologies BOB products are the best quality options for mounting heavy downtube batteries (but there are a few other simpler options). One characteristic of your frame that negates one of the really effective benefits of the Grin BOB products is the shape of your downtube. Not being a round tube the "outriggers" on the BOB mounts don't look like they'll come into play (but I might still try them, it will depend on how deep the sides or outriggers are and whether or not they will contact the downtube). This will put more side to side twisting force on the mounting points on the frame.
If I was mounting a big downtube battery on your style frame I'd want to use more than just two threaded frame mounting points. So I might consider adding a wrap around type of mounting for the stand off mounting points which I think are very beneficial on their own as they provide a flat and long/wide mounting surface for the bottom of the battery. Given that bottom piece is structurally plastic (with a thin steel reinforcement to keep the bolts from digging in) I think anything that spreads out the load and keeps it more stable is also beneficial.
https://www.wolftoothcomponents.com/collections/b-rad-system
https://ebikes.ca/shop/electric-bicycle-parts/battery-accessories.html
Mclewis1 said:I saw from your posting on another forum that the Wolf Tooth components B-RAD mounting products were mentioned. To me those and the Grin Technologies BOB products are the best quality options for mounting heavy downtube batteries (but there are a few other simpler options). One characteristic of your frame that negates one of the really effective benefits of the Grin BOB products is the shape of your downtube. Not being a round tube the "outriggers" on the BOB mounts don't look like they'll come into play (but I might still try them, it will depend on how deep the sides or outriggers are and whether or not they will contact the downtube). This will put more side to side twisting force on the mounting points on the frame.
If I was mounting a big downtube battery on your style frame I'd want to use more than just two threaded frame mounting points. So I might consider adding a wrap around type of mounting for the stand off mounting points which I think are very beneficial on their own as they provide a flat and long/wide mounting surface for the bottom of the battery. Given that bottom piece is structurally plastic (with a thin steel reinforcement to keep the bolts from digging in) I think anything that spreads out the load and keeps it more stable is also beneficial.
https://www.wolftoothcomponents.com/collections/b-rad-system
https://ebikes.ca/shop/electric-bicycle-parts/battery-accessories.html
SlowCo said:Use more mounting holes by using threaded rivets and use glue/sealant to support the holder better. See this video at 5:38 and from 13:13:
[youtube]dyyPJC0E4VU[/youtube]
Thanks for idea, I'll go to buy wider washers.99t4 said:That one mounting screw I can see in your photo looks like it is deforming the plastic. A fender washer (wider washer with small hole) under the screw head might help spread the load and help stabelize.