Help with bottom bracket for bbshd

[Paul chef]

i have a Cube - 2013 Ltd Pro 29er and am just about to order a bbshd for it but a quick google on bottom brackets has now totally confused me
1 what size bbshd do I need
2 is the bottom bracket I have on the cube able to accept the motor
3 if it’s press fit, will I need specialist tools to remove ?

My knowledge of bike mechanics isn’t brilliant so sorry in advance

 

[wheeliepete]

I would say that you most likely have a press fit BB on your bike, so you need to know what type and whether there is a suitable adapter available before you order your kit. Your LBS should be able to help if you are unsure. Have a read of this may make things a bit clearer.

https://www.empoweredcycles.com/blogs/news/101474694-bottom-bracket-standards-and-bafang-mid-drive-motors

 

[tommie]

Measure your BB, most common is 68mm.
The BBSHD come in 3 sizes.

 

[Paul chef]

I would say that you most likely have a press fit BB on your bike, so you need to know what type and whether there is a suitable adapter available before you order your kit. Your LBS should be able to help if you are unsure. Have a read of this may make things a bit clearer.

https://www.empoweredcycles.com/blogs/news/101474694-bottom-bracket-standards-and-bafang-mid-drive-motors

I’ve had a read of that previously which has confused me no end

 

[Paul chef]

Measure your BB, most common is 68mm.
The BBSHD come in 3 sizes.

I tried to measure it earlier with a didgital calliper and got 76.60 but I’m partialy blind so not sure if I had both ends of the bottom bracket plus the small cog was fouling me being able to measure correctly

 

[tommie]

https://www.empoweredcycles.com/blogs/news/101474694-bottom-bracket-standards-and-bafang-mid-drive-motors

try to get the spec of your bike, should say in there somewhere

 

[wheeliepete]

OK, so it looks like your bike has a threaded BB51 bottom bracket which means you will need some custom made adapters in order to fit a bbshd.

 

[Paul chef]

OK, so it looks like your bike has a threaded BB51 bottom bracket which means you will need some custom made adapters in order to fit a bbshd.

Wheelie Pete, are you able to elaborate can I get these adaptors easily on line ? And is it much work to fit, I've seen utube videos which I think I could do in fitting the motor, but the adapter bit I'm unsure of

 

[wheeliepete]

Sorry Paul, having looked at the bb51 spec a bit closer it looks like the thread is standard english thread, so the BBSHD should fit fine without any adapters. If your bottom bracket is wider than 73mm you will have to order a 100mm BBSHD and fit some spacers.

 

[Paul chef]

Thanks for the reply, I think I’ll have to dismantle it over the weekend to get a proper measurement, before I take the plunge in to the pedalec world
And my son will be home to double check the measurements for me

 

[daveboy]

Mine was a bit awkward to measure with everything in the way, so i put a
piece of paper on it and marked it with a pencil, then measured between the
pencil marks....A few mm won't make any difference as you get a set of
spacers to line everything up.
Edit......Should have been clearer. The kit I got was for bottom brackets between
68mm and 73mm so I knew between these two measurements would be fine.

 

[Deleted member 4366]

You need to be absolutely sure which BB you have. That means that you have to dismantle the cranks and inspect/ measure it.

 

[wheeliepete]

Once you have it dismantled, if you post a photo of both sides of your bottom bracket and one from above showing where the chain stays join, along with some measurements, it will help identify it if you are unsure.

 

[Paul chef]

Hi all many thanks for your input, I’ve also been in touch with EM3ev who have sent me some detailed info. Not sure if the photos will upload properly, so dismantled it today the bottom bracket is 68.18mm diameter of the hole is32.9mm so looks like it’s the 68-73 version I need

 

[tommie]

That`s a common 68mm BB,

the 68-73 version will do the job ok.

 

[wheeliepete]

That all looks OK, the only other thing I would check is the clearance on the drive side chain stay for the secondary gear housing. Put a steel rule or straight edge across the face of the bottom bracket and measure from the point the rule touches the stay to the centre of the BB. You need at least 65mm or you will have to space the drive off the BB. Any more than about 5mm spacing and you will not have enough thread for the retaining nut on the other side and you will need to fit the 100mm version with spacers.

 

[Paul chef]

That all looks OK, the only other thing I would check is the clearance on the drive side chain stay for the secondary gear housing. Put a steel rule or straight edge across the face of the bottom bracket and measure from the point the rule touches the stay to the centre of the BB. You need at least 65mm or you will have to space the drive off the BB. Any more than about 5mm spacing and you will not have enough thread for the retaining nut on the other side and you will need to fit the 100mm version with spacers.

Thanks for that wheeliepete, thought I was Home and dry , but spending almost a grand with everything I’ll have to double check again, cheers

 

[Paul chef]

That all looks OK, the only other thing I would check is the clearance on the drive side chain stay for the secondary gear housing. Put a steel rule or straight edge across the face of the bottom bracket and measure from the point the rule touches the stay to the centre of the BB. You need at least 65mm or you will have to space the drive off the BB. Any more than about 5mm spacing and you will not have enough thread for the retaining nut on the other side and you will need to fit the 100mm version with spacers.

Taken the measurements and it’s 40.69, so looks like I may need 100 MM B.B.

 

[wheeliepete]

Ah, thought that might be the case, if you move your straight edge along the chain stay, keeping it parallel with the BB, until you have 65mm, then measure the gap between the BB and the straight edge, double it for the other side to keep the drive central and then add your BB width. This will give you your minimum drive length. As long as this figure is between 73mm-100mm, you are good to go with 100mm drive. You can play around with the spacer sizes once you have the drive in your hands and it will hopefully be a bit clearer what you need to do.

 

[Paul chef]

Space was approx 12mm so 24 and 68, 92mm so 100 on order
Many thanks for your help would I be correct in thinking there will be spacers included?
I’ve also read on forum it’s best to get a battery from uk supplier, any recommendations?