How do I find the right bottom bracket?
11-12-19, 04:33 PM
#1
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How do I find the right bottom bracket?
I took the measurements of the place where the bottom bracket goes on my bike frame, and the width on my frame is 68mm, then i measured the inside diameter of where the bottom bracket goes and it was 51mm. I watched a bunch of videos on how to find measurements for the bottom bracket and most of the time the diameter is like 46mm or 48mm. So I was confused because no bottom bracket with that outside diameter was showing up when I was looking for one. So I ordered an FSA PF30 because I know that my frame uses press-fit and tried it on today but the Bottom bracket was too small for the frame and it wouldn't stay in place as I've seen in other bike building videos. So now I am confused because I can't find a bottom bracket for my frame, and I am wondering if maybe my bike frame is faulty or something because I've gone on multiple forums and no one has this problem.
11-12-19, 10:24 PM
#4
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is this enough information?
11-12-19, 11:54 PM
#5
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The specs of the frame say ''Large bottom bracket for 1 piece cranks''. You are limited to bmx cranks and bb's. You need an 'American' pressfit bmx bottom bracket if the shell is 51mm.
The FSA Afterburner Modular 392 Evo MTB crank will not work in that frame. There are no 51mm pressfit bb's. The largest pressfit BB size is 46mm.
Last edited by trailflow1; 11-13-19 at 12:03 AM.
11-13-19, 12:54 AM
#6
Senior Member
This may be of use.
https://www.grubee.net/products/wp-c...conversion-kit
As an aside, the frame you have is explicitly designed and built to house a gasoline engine. It is not really meant to be a bicycle, in the strictest sense.
https://www.grubee.net/products/wp-c...conversion-kit
As an aside, the frame you have is explicitly designed and built to house a gasoline engine. It is not really meant to be a bicycle, in the strictest sense.
11-13-19, 07:47 AM
#7
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Thread Starter
The specs of the frame say ''Large bottom bracket for 1 piece cranks''. You are limited to bmx cranks and bb's. You need an 'American' pressfit bmx bottom bracket if the shell is 51mm.
The FSA Afterburner Modular 392 Evo MTB crank will not work in that frame. There are no 51mm pressfit bb's. The largest pressfit BB size is 46mm.
The FSA Afterburner Modular 392 Evo MTB crank will not work in that frame. There are no 51mm pressfit bb's. The largest pressfit BB size is 46mm.
11-13-19, 08:49 AM
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Sorry for any confusion. You need a 1 piece crank AND an 'American' PressFit bmx bottom bracket together. Watch some youtube videos to get an idea how they work.
Also be aware when fitting pedals. Alot of 1 piece cranks have 1/2'' pedal threads. If you want to use pedals with 9/16'' threads (more common) then you'll need to 1/2'' to 9/16'' adapters nuts. or instead buy pedals with 1/2'' threads.
Nope. The FSA PF30 cranks or FSA PF30 bb's won't work in that frame at all. The Grubee Skyhawk frame isn't
designed be used with mtb cranks.
Last edited by trailflow1; 11-13-19 at 09:03 AM.
11-13-19, 09:17 AM
#10
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Thread Starter
Sorry for any confusion. You need a 1 piece crank AND an 'American' PressFit bmx bottom bracket together. Watch some youtube videos to get an idea how they work.
Also be aware when fitting pedals. Alot of 1 piece cranks have 1/2'' pedal threads. If you want to use pedals with 9/16'' threads (more common) then you'll need to 1/2'' to 9/16'' adapters nuts. or instead buy pedals with 1/2'' threads.
Nope. The FSA PF30 cranks or FSA PF30 bb's won't work in that frame at all. The Grubee Skyhawk frame isn't
designed be used with mtb cranks.
Also be aware when fitting pedals. Alot of 1 piece cranks have 1/2'' pedal threads. If you want to use pedals with 9/16'' threads (more common) then you'll need to 1/2'' to 9/16'' adapters nuts. or instead buy pedals with 1/2'' threads.
Nope. The FSA PF30 cranks or FSA PF30 bb's won't work in that frame at all. The Grubee Skyhawk frame isn't
designed be used with mtb cranks.
11-13-19, 09:38 AM
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take a few pics and post them on c and v. someone will know for sure
11-13-19, 03:19 PM
#13
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11-13-19, 04:59 PM
#14
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11-13-19, 09:28 PM
#15
Cycleway town
Surely there's an adaptor available? You can be sure there's one on eBay made in a barn in China and shipped for peanuts, they're good at that sorta thing.
11-14-19, 11:04 AM
#16
Senior Member
Another option I thought of is to buy a 2 inch bottom bracket shell and have it brazed inside the 51mm BB and use a Wheels Manuf thread together bottom bracket. ( https://www.paragonmachineworks.com/...lls/steel.html. ) Then you would have multiple options as to the bottom bracket you want to install, PF30, T47.
If you get the BB shell for a T47 you won't need to ream it (46mm) to fit a PF30 BB.
If you get the BB shell for a T47 you won't need to ream it (46mm) to fit a PF30 BB.
Last edited by wsteve464; 11-14-19 at 11:08 AM.
