Planned BBSHD build. Does this frame look weak?

[bandaliro]

hi, I am new on here so hi all,

I am making plans to build a bike with a mid drive, BBSHD because of its reputation for reliability.
I am not asking for links to components, just opinions on the frame and my intended use for it.

basic info:
I would have fat wheels (26x4) on a rigid fork, suspended seatpost, an internal geared hub in the rear, and a single speed chain with a tensioner.
Alternatively 7-8 speed HG cassette rearranged/spaced out so that the important gears are in proper chainline.
rider weight 65kg.

this is the frame I chose, for under 300dollars :




unknown manufacture. fits at least a 26x4 inch tire, standard seat post diameter. I pefer the regular shaped tubes for easy mounting of clamps etc. reinforcement plate where down tube meets head tube.



the dealer says it is "fat bike steel", other than that there is no other info about the grade

intended purpose:
exploring rough forest roads
no jumping, mostly just rugged forest paths (bumpy dirt/gravel, few rocks sticking out), long level sections with mud/ loose dirt, which
I think the fat tires and suspension seatpost would do well on.
relatively slow riding (my gearing will be for slow climbing rather than speed)
terrain is hilly, not very steep, long climbs (definitely not like hardcore steep mtb trails),

for whoever sees and reads this, my question is: by looking at the frame,"unknown grade steel", do you see any problems / weakspots with it? assuming it is the cheapest grade steel acceptable for bike frames, can you see it holding to the level of stress I described? (rider weight is 65kg + some stuff on a rack, at least a
15ah battery mounted on the downtube inside triangle). do the chainstays look strong enough to handle the motor torquing? I would run it at 48volt, stock setup (no over powering or anything like that)

I dont know how much can someone experienced tell just from pictures and the info I provided, but please share your thoughts

 

[2old]

FME with a BBS02 in a 1985 Fuji steel, rigid MTB frame and another one in a no name steel frame with Fox fork, "no problem". The internal geared rear hub - "potential problem".

 

[n00b]

You gonna use a left-hand throttle for the geared hub or something?

 

[n00b]

Idk about Chinese steel. Also Idk about finding good chromoly fat tire stuff. In for learning something.
I saw an SE fatbike earlier. Not sure if 29" or not. SE or G.T. should be chromoly.
I like chromoly. I do. Perhaps if it cost that much it's good?
Reynolds steel was no joke, either. I think the Trek 400 I had was that, it was tough.

 

[E-HP]

hi, I am new on here so hi all,

I am making plans to build a bike with a mid drive, BBSHD because of its reputation for reliability.
I am not asking for links to components, just opinions on the frame and my intended use for it.

basic info:
I would have fat wheels (26x4) on a rigid fork, suspended seatpost, an internal geared hub in the rear, and a single speed chain with a tensioner.
Alternatively 7-8 speed HG cassette rearranged/spaced out so that the important gears are in proper chainline.
rider weight 65kg.

this is the frame I chose, for under 300dollars :

View attachment 385406View attachment 385407View attachment 385408


unknown manufacture. fits at least a 26x4 inch tire, standard seat post diameter. I pefer the regular shaped tubes for easy mounting of clamps etc. reinforcement plate where down tube meets head tube.

View attachment 385409

the dealer says it is "fat bike steel", other than that there is no other info about the grade

intended purpose:
exploring rough forest roads
no jumping, mostly just rugged forest paths (bumpy dirt/gravel, few rocks sticking out), long level sections with mud/ loose dirt, which
I think the fat tires and suspension seatpost would do well on.
relatively slow riding (my gearing will be for slow climbing rather than speed)
terrain is hilly, not very steep, long climbs (definitely not like hardcore steep mtb trails),

for whoever sees and reads this, my question is: by looking at the frame,"unknown grade steel", do you see any problems / weakspots with it? assuming it is the cheapest grade steel acceptable for bike frames, can you see it holding to the level of stress I described? (rider weight is 65kg + some stuff on a rack, at least a
15ah battery mounted on the downtube inside triangle). do the chainstays look strong enough to handle the motor torquing? I would run it at 48volt, stock setup (no over powering or anything like that)

I dont know how much can someone experienced tell just from pictures and the info I provided, but please share your thoughts

The frame looks strong enough.
I know you’re not seeking other advice, but just making sure you’ve already checked for clearance.

 

[mrmojorising]

If you reach out to the manufacturer/supplier you can usually get them to provide the exact steel alloy used, they don't tend to hide this stuff, they're just not good at adding info to listings.

While I can't exactly compare my frame to yours, this may give you some piece of mind. I'm running an old 2006 Kona Unit, which uses a quite rare dedacciai sat 14.5 steel, with a 72V BBSHD pulling 3500W max power (over double the stock power) and a battery that weighs about 8kg. The frame is holding up nicely after close to 1000km, mostly road riding but with lots of variation in road quality.

Pic for reference, the chainstays and similarly thin

 

[OlderGiantFan]

A BBSHD would be fine in nearly any old frame, even an aluminium one. I used to think steel too until I bought a pre-converted old aluminium frame mtb. It has full suspension though and that can take a lot of the sting out of all that extra weight.

As for sharing my thoughts, well you've taken on quite a project, building one from the frame up with non-matched wheels etc. If it was me I'd have just bought the bike style I was after and then fitted the motor. I can only assume you have a lot of experience with bicycle maintenance and modding?