Im confused about PF30 bottom bracket
07-09-20, 09:06 PM
#1
Member
Thread Starter
Im confused about PF30 bottom bracket
I accidentally bought a PF30 a few months ago while building a bike and I didn't return it. So now I'm planning to build another bike using that PF30. I'm not sure if it will fit my new frame (https://www.chainreactioncycles.com/.../rp-prod130452) because it says the bottom bracket it 73mm BSA while I measured my FSA PF30 and its bearing cups are 46mm, but online people say that a PF30 is either 68mm or 73mm, and if it is 73mm it should fit this frame right? Maybe I'm just measuring my bottom bracket wrong. I'm building this for my mom's bday so I don't wanna mess it up as I did with my bike.
07-09-20, 09:28 PM
#2
Senior Member
Join Date: Jan 2009
Location: San Diego, CA
Posts: 3,668
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 836 Post(s)
Liked 1,060 Times
in
744 Posts
Your frame has a threaded (BSA) 73mm bottom bracket shell which will not work with your PF30 (Press Fit 30) BB. https://wheelsmfg.com/bb-standards https://www.bikeradar.com/advice/buy...ket-standards/
You also need to have the BB that matches your crankset so check to see if the crank you use has BSA 73mm option.
You also need to have the BB that matches your crankset so check to see if the crank you use has BSA 73mm option.
Last edited by Crankycrank; 07-09-20 at 09:34 PM.
07-09-20, 10:48 PM
#3
Member
Thread Starter
Your frame has a threaded (BSA) 73mm bottom bracket shell which will not work with your PF30 (Press Fit 30) BB. https://wheelsmfg.com/bb-standards https://www.bikeradar.com/advice/buy...ket-standards/
You also need to have the BB that matches your crankset so check to see if the crank you use has BSA 73mm option.
You also need to have the BB that matches your crankset so check to see if the crank you use has BSA 73mm option.
07-10-20, 04:44 AM
#4
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
[QUOTE=Akjam101;21579256]How do you know its threaded?.../QUOTE]
"Bottom Bracket: 73mm BSA"
"Bottom Bracket: 73mm BSA"
Likes For dsbrantjr:
07-10-20, 08:15 AM
#5
Senior Member
Join Date: Jan 2009
Location: San Diego, CA
Posts: 3,668
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 836 Post(s)
Liked 1,060 Times
in
744 Posts
First, read the links I provided in post #2 which will answer all your questions. BSA (British Small Arms also referred to as "English Threaded") is a threaded standard. https://en.wikipedia.org/wiki/Birmin...l_Arms_Company The link you provided for the Shimano Hollowtech BB will work with a Shimano Hollowtech crank and maybe some others with the same dimensions.
Last edited by Crankycrank; 07-10-20 at 08:20 AM.
07-10-20, 08:25 AM
#6
Banned
PF is Press Fit ... It's the wrong BB for a threaded BB frame..External BB come with the crankset.
73 is a MTB type.
30 is the bearing mm ID. that's the measurement of the tube spindle that slips into those bearings..
73 is a MTB type.
30 is the bearing mm ID. that's the measurement of the tube spindle that slips into those bearings..
Last edited by fietsbob; 07-10-20 at 10:20 AM.
07-10-20, 08:36 AM
#7
Senior Member
Join Date: Jan 2015
Posts: 443
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 131 Post(s)
Likes: 0
Liked 21 Times
in
17 Posts
I accidentally bought a PF30 a few months ago while building a bike and I didn't return it. So now I'm planning to build another bike using that PF30. I'm not sure if it will fit my new frame (https://www.chainreactioncycles.com/.../rp-prod130452) because it says the bottom bracket it 73mm BSA while I measured my FSA PF30 and its bearing cups are 46mm, but online people say that a PF30 is either 68mm or 73mm, and if it is 73mm it should fit this frame right? Maybe I'm just measuring my bottom bracket wrong. I'm building this for my mom's bday so I don't wanna mess it up as I did with my bike.
BSA shells come in 68mm and 73mm.
PF30 shells come in 68mm and 73mm.
But that's where it ends.
68mm is road, 73mm is MTB.
The most important measurement for PF30 is the diameter which is 46mm.
BSA is 34.7mm diameter. But is more commonly referred to as 1.37 inch x 24tpi (thread size)
would this BB work? https://www.worldwidecyclery.com/pro...bottom-bracket
Instead buy the Hollowtech MTB 73mm english threaded BB if you are fitting a Shimano Hollowtech mtb crank.
What crankset are you planning to fit ? That is the detail left out. PF30 BB's can come in many types like either BB30/PF30/HT2/GXP cranks etc. So more info is needed. If you are trying to fit a 30mm crank into a BSA frame then you need a BSA30 BB and your cranks spindle needs to be long enough to accommodate the extra width of the BSA30 BB.
Last edited by trailflow1; 07-10-20 at 11:51 AM.
07-10-20, 09:33 AM
#8
Senior Member
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Posts: 9,842
Bikes: Kirk Custom JK Special, '84 Team Miyata,(dura ace old school) 80?? SR Semi-Pro 600 Arabesque
Mentioned: 106 Post(s)
Tagged: 0 Thread(s)
Quoted: 2337 Post(s)
Liked 2,820 Times
in
1,540 Posts
figure out what crank you are using based on how many speeds etc then get the matching BB that fits the 73mm BSA/.English standard Crank first then matching BB not BB and match crank. Cranksets have different spindle size or may not have attached spindle but use the spindle that is part of the BB assembly
So what Crankset are you using?
So what Crankset are you using?
__________________
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
07-10-20, 07:21 PM
#9
Member
Thread Starter
The 68mm and 73mm numbers just relate to the shell width of a frame. It doesn't have anything to do with compatibilty between BSA and PF30 which are completely different from each other. BSA is not cross compatible with PF30 even if they are 68mm or 73mm.
BSA shells come in 68mm and 73mm.
PF30 shells come in 68mm and 73mm.
But that's where it ends.
68mm is road, 73mm is MTB.
The most important measurement for PF30 is the diameter which is 46mm.
BSA is 34.7mm diameter. But is more commonly referred to as 1.37 inch x 24tpi (thread size)
Technically it will work but it's for a Shimano road crank and road frame with a 68mm shell. The Brand X frame is 73mm shell. So the middle protective sleeve will be 5mm too short. The middle sleeve isn't absolutely neccesary. The BB will work without it but then there less protection of the spindle
Instead buy the Hollowtech MTB 73mm english threaded BB if you are fitting a Shimano Hollowtech mtb crank.
What crankset are you planning to fit ? That is the detail left out. PF30 BB's can come in many types like either BB30/PF30/HT2/GXP cranks etc. So more info is needed. If you are trying to fit a 30mm crank into a BSA frame then you need a BSA30 BB and your cranks spindle needs to be long enough to accommodate the extra width of the BSA30 BB.
BSA shells come in 68mm and 73mm.
PF30 shells come in 68mm and 73mm.
But that's where it ends.
68mm is road, 73mm is MTB.
The most important measurement for PF30 is the diameter which is 46mm.
BSA is 34.7mm diameter. But is more commonly referred to as 1.37 inch x 24tpi (thread size)
Technically it will work but it's for a Shimano road crank and road frame with a 68mm shell. The Brand X frame is 73mm shell. So the middle protective sleeve will be 5mm too short. The middle sleeve isn't absolutely neccesary. The BB will work without it but then there less protection of the spindle
Instead buy the Hollowtech MTB 73mm english threaded BB if you are fitting a Shimano Hollowtech mtb crank.
What crankset are you planning to fit ? That is the detail left out. PF30 BB's can come in many types like either BB30/PF30/HT2/GXP cranks etc. So more info is needed. If you are trying to fit a 30mm crank into a BSA frame then you need a BSA30 BB and your cranks spindle needs to be long enough to accommodate the extra width of the BSA30 BB.
07-10-20, 07:23 PM
#10
Member
Thread Starter
figure out what crank you are using based on how many speeds etc then get the matching BB that fits the 73mm BSA/.English standard Crank first then matching BB not BB and match crank. Cranksets have different spindle size or may not have attached spindle but use the spindle that is part of the BB assembly
So what Crankset are you using?
So what Crankset are you using?
07-10-20, 07:32 PM
#11
SE Wis
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 10,507
Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970
Mentioned: 40 Post(s)
Tagged: 0 Thread(s)
Quoted: 2743 Post(s)
Liked 3,390 Times
in
2,053 Posts
07-11-20, 10:01 AM
#12
Senior Member
Join Date: Jan 2015
Posts: 443
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 131 Post(s)
Likes: 0
Liked 21 Times
in
17 Posts
Ok, thanks. This was actually really helpful. I found this BB (https://www.coloradocyclist.com/shim...YaAlrbEALw_wcB) but it says its both 68mm and 73mm, how does that work.
If I can use this BB I plan to buy this crankset for it, will this crank be compatible with my BB?(https://www.benscycle.com/Shimano-Al...kaAlIBEALw_wcB)
Last edited by trailflow1; 07-11-20 at 10:07 AM.
07-11-20, 10:21 AM
#13
Member
Thread Starter
Don't worry about it. It will work fine. Some older 90's/2000's mtb frames use a 68mm shell. And you'll find some modern steel mtb/touring frames around today that have a 68mm shell. The BB above will come with a set of spacers to fill the 68mm out to 73mm. But in your case they are not needed.
Yes. The Alivio M4050 crank is 100% compatible with the XT MT800 BB.
Yes. The Alivio M4050 crank is 100% compatible with the XT MT800 BB.
