bottom bracket bbshd

hi, trying install the bbs hd and it seems my bottom bracket has what looks like a shell inside that is the only thing stopping it going in, anybody had a similar experience know if it can be got out or overcome? tia

yes ive took the crank out, that is the inside of my bottom bracket, it is a jorvik electric trike, but some scroat nicked the front wheel/bafang hub motor and finding a 24" fat bike wheel is a task, so i changed the forks and headset and put a 26" front wheel on and got the 100mm bbs hd as the bottom bracket is 80mm wide, it appears to be standard 1.37" 25 tpi thread other than that, but as you can see on the picture there is a lip inside, the motor goes in as far as the threaded parts but wont go past the lip in the middle other than where the motor is threaded, its one of these https://jorviktricycles.com/jorvik-electric-mountain-trike-jmt3-500w.
i thought maybe get the threading tools and thread it right through but im just concerned i might get the tool and it might not take that much off and just bind up, and i dont have anything to measure it accurately as my calipers wont go in that far
my brother thinks i should get some emry cloth and sand it off
i was looking at broaching tools but they are designed for mag drills which i dont have, nor is the job suited for a bench lol
so unsure of the best way to go about it
cheers

If you want to check how much material you have to remove bore gauges are pretty cheap these days.
https://ibit.ly/jWrR

If it's not much you can use a brake hone to move some material out of there but admittedly it's a slow process.
https://ibit.ly/68Sz

That looks like a perfectly typical interior of a BB on a bike that's been ridden a while, with the BB shaft and bearings removed.

The "tube" inside it is almost certainly just the unmachined center area of the BB tube, the rest of it toward the ends having been machined away to allow threading of the ends inside. Typical enough of aluminum frames I have worked with.


As has been recommended by Diggs, removing the material with a hone, etc., should allow you to install your drive unit, but it will require care and patience, so you don't damage the threads on the BB (if they are not needed by the drive, it won't matter, but if you end up having to go back to regular cranks for any reason it could present a problem at that time).




FWIW, I do recommend, to all posters helping anyone, to use a method in presenting troubleshooting options that only presents the options, and doesn't "demand" anything of them.

Some people find it confrontational otherwise, and arguments then ensue, helping no one.

ebuilder said:

Further clarification needed to give you corrective action.
Whatever 'albatross' you have inside that bottom bracket, remove it and take pictures of both sides of the bottom bracket shell 'without that mess' inside.

There is no way there was a crankset inside where you have 'that mess' inside the bottom bracket so whatever you have blocking the inside of the BB shell must be 'your doing'. Take it out and take pictures would be my suggestion.

Click to expand...

One could also use an adjustable reamer like the ones used for King Pins.
Would have to be vary careful not to past the thread peaks.

Thanks for all the advice, I ended up using a 33mm diamond holesaw I already had and a file to finish it off, not sure the threads will be unscathed, ran into another problem being there is a box next to the bb that housed my old controller, had to grind the corner of that off as well.

Lol no probs mate, all up and running now, a few bits to finish off, need an extension for the speedo getting 21h fault which has it power off every 5 mins, rather annoying, but the speedo cable isn't long enough to reach any of the wheels, only getting about 25mph, probably need the program cable too, to get more out of it, calculating from a 12.4 mile journey I just made took 7.2ah to charge back up so with a 40ah lifepo4 battery think I should get about 60 mile which is great does that sound about right? The fuel gauge needs calibrating for my battery as when full I'm only getting just into the green on the 500c display, I'm hoping the lvc on the controller isn't going to cut me off early, don't know why that is as voltage should be close to 14s lipo as its 16s lifepo4 unless its set for 15 or 16s lipo? Not sure I'll have get the cable, cheers craig

I had a GT Zaskar and needed to file the BB in order to remove some material in order for a BBS02 installation. The threads were "buggered" by the motor, but I had them "chased" by my LBS when the bike was returned to analog (for want of a better term).