Press fit bottom brackets

PB Forum :: Rocky Mountain Bikes
Press fit bottom brackets
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O+
Posted: Dec 8, 2020 at 11:18 Quote
looking at the current Rocky Mountain Thunderbolt series and I see that all models have pressed fit bottom brackets.
Are there any concerns over these compared to threaded bottom brackets?
greater maintenance?
issues over replacement?
Many thanks for any feedback.

O+
Posted: Dec 9, 2020 at 17:22 Quote
wwh wrote:
looking at the current Rocky Mountain Thunderbolt series and I see that all models have pressed fit bottom brackets.
Are there any concerns over these compared to threaded bottom brackets?
greater maintenance?
issues over replacement?
Many thanks for any feedback.

Lots of people have dislikes with press fit, a lot of it comes down to the fact that the threaded is the old way of doing it and there was not really a good reason to change it. They also have had creaking issues although I have not had issues with the BB92 on my Rocky bike. Home mechanics like myself needed to buy a new tool to install and remove press fit which sucked. I really hated the move to press fit.

All that being said, I am sure the manufacturing process saves a little money not having to thread the frame. Now that I have used press fit for a while now I have become fine with it. My Shimano 24mm PF92 BB is the lowest maintenance and longest lasting piece of my bike. Tied with the cranks and stem of course.

O+
Posted: Dec 10, 2020 at 12:10 Quote
ptrcarson wrote:
wwh wrote:
looking at the current Rocky Mountain Thunderbolt series and I see that all models have pressed fit bottom brackets.
Are there any concerns over these compared to threaded bottom brackets?
greater maintenance?
issues over replacement?
Many thanks for any feedback.

Lots of people have dislikes with press fit, a lot of it comes down to the fact that the threaded is the old way of doing it and there was not really a good reason to change it. They also have had creaking issues although I have not had issues with the BB92 on my Rocky bike. Home mechanics like myself needed to buy a new tool to install and remove press fit which sucked. I really hated the move to press fit.

All that being said, I am sure the manufacturing process saves a little money not having to thread the frame. Now that I have used press fit for a while now I have become fine with it. My Shimano 24mm PF92 BB is the lowest maintenance and longest lasting piece of my bike. Tied with the cranks and stem of course.



i appreciate you taking the time to respond and educate me.
Many thanks

O+
Posted: Dec 10, 2020 at 14:00 Quote
wwh wrote:
looking at the current Rocky Mountain Thunderbolt series and I see that all models have pressed fit bottom brackets.
Are there any concerns over these compared to threaded bottom brackets?
greater maintenance?
issues over replacement?
Many thanks for any feedback.

My observation on my last Rocky, a 2018 Instinct, was that the PF system worked flawlessly. No creaks for the life of the bike and I got three seasons out of the bottom bracket. There are three basic catches though: 1) you must use sleeve retaining compound and should use a plastic bb cup eg Shimano; 2) you need to be comfortable around a bearing extractor/press; and 3) you better like Shimano cranks, they're quickly becoming the only crank with a 24 mm spindle, and you DO NOT want to run a 30 mm spindle or DUB in a PF 92 shell. I put a more thorough explanation up at wrenchcenter.com

O+
Posted: Dec 10, 2020 at 16:13 Quote
Agree with all the above. Only problem I've had is with non Shimano, metal outer pf's.
It's real easy to have them not go in straight & score the bb interface. Shimano, being plastic is easy to replace even without a proper bearing press(though not recommended).

O+
Posted: Dec 12, 2020 at 13:47 Quote
cjeder wrote:
wwh wrote:
looking at the current Rocky Mountain Thunderbolt series and I see that all models have pressed fit bottom brackets.
Are there any concerns over these compared to threaded bottom brackets?
greater maintenance?
issues over replacement?
Many thanks for any feedback.

My observation on my last Rocky, a 2018 Instinct, was that the PF system worked flawlessly. No creaks for the life of the bike and I got three seasons out of the bottom bracket. There are three basic catches though: 1) you must use sleeve retaining compound and should use a plastic bb cup eg Shimano; 2) you need to be comfortable around a bearing extractor/press; and 3) you better like Shimano cranks, they're quickly becoming the only crank with a 24 mm spindle, and you DO NOT want to run a 30 mm spindle or DUB in a PF 92 shell. I put a more thorough explanation up at wrenchcenter.com

great info, thanks!

Posted: Dec 22, 2020 at 11:58 Quote
I'm looking at getting a RM bike here in the spring and was worried about the press fit vs thread in bb. I saw a lot of posts trying to shy people away from changing a press fit themselves. Now, I'm an industrial mechanic by trade and changing bearings is common on my job. No where have I seen heat/cold mentioned in the install process. ie toss the new bearing in the freezer for a while, and take a hairdryer ( or very carefully a heat gun on low), warm the area until its hot to the touch, then bam new bearing should slide right in. Easy peasy, in theory at least.

O+
Posted: Dec 26, 2020 at 14:38 Quote
Tombonombona wrote:
I'm looking at getting a RM bike here in the spring and was worried about the press fit vs thread in bb. I saw a lot of posts trying to shy people away from changing a press fit themselves. Now, I'm an industrial mechanic by trade and changing bearings is common on my job. No where have I seen heat/cold mentioned in the install process. ie toss the new bearing in the freezer for a while, and take a hairdryer ( or very carefully a heat gun on low), warm the area until its hot to the touch, then bam new bearing should slide right in. Easy peasy, in theory at least.

I don't do that but I have found it easy with the least expensive park tool press.

Posted: Dec 26, 2020 at 18:11 Quote
I thought pf was gonna be a nightmare. Turned out to be quite the opposite. I weigh just a tick over 200 lbs and my bike's pf bb has been trouble free going on two years now (knock on wood). If it worries you, you can always buy a crankset that will accept a wheels mfg thread together bb.A pf bb would not keep my from buying the bike I want.

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