Is BB86 Pressfit the Best? I Need Your Help (LONG Read)

[Sakizashi]

I don’t think BB type or width between 73mm, 86mm and 68mm is a major contributor to lateral stiffness when looking at the whole bike. Sure when isolating the BB, wider is better, but the BB doesnt exist in isolation and improving something marginal, marginally isnt going to do much. BB86 is lighter though.

Regarding what the company manufactures, Flybike the parent of Carbonda and QuickPro makes BB86 frames for their customers and lists them as options for some of their latest models; so they do it, they choose not to for what they sell directly to consumers. Probably because people complained.

[jonathanf2]

I have one BB86 frameset with a built-in alloy cylinder sleeve w/indented stopper. When I install the BB, once they hit the stopper they're fully pressed in. Though I presume most BB86 frames are just an empty carbon shell, hence the need for a thread-together style bottom bracket, especially if there are issues like creaking.

I'm wondering why the built-in alloy cylinder sleeve wasn't implemented as standard on BB86 frames? It makes installation and removal very easy. Also this frame has never had issues with creaking and/or any bottom bracket related issues. I even prefer it over T47 and threaded BB68.

[toxin]

if you're bonding in an alloy sleeve because you can't make the carbon shell to tolerance, you're already so far from the ideal you might as well put threads on there and make final assembly easier

[pavlo.k]

for me bb86 is better but not for the ride feel reasons.

- lighter bb (dura ace bb86 is around 54 grams, sram dub t47 is around 87)
- lighter frame construction without bonded alu shell
- no additional failure point on the frame: shell can de-bond from carbon (happened to me on my MTB)
- with t47 there's always a chance of damaging the thread and potential corrosion
- easier maintenance. In a contrary to popular belief, I find it much easier to live with a press fit bb than with t47. I bet whoever says that t47 is easier to maintain never tried to remove it from the frame after a season of riding. Trying to undo the bb torqued to 45nm with just a few mm of splines is no joke. And those splines are not even standardized, i turns out that you might need multiple different tools for your t47 bbs depending on the model of the bb. With bb86 you only need a 20$ from ali to do the job and it works for any pressfit standard or you can just swap the bearing with it.

I am aware of all the problems people have with pressfit bottom brackets but personally never had any issues after years of riding either wester brands or cheap chinese frames. I did about 10000km with the worst possible combination: bb86 shell with dub crank and it was flawless. Bearing still spin like new and there's zero wear anywhere. No creaking

[hubba]

BB86 is great when it works. And now that we have 24mm titanium axles it's not that limiting anymore. I've had no problems with the frame I have now.

My previous frame started creaking and when I removed the cranks the bearing cups came out of the frame with them so the bb hole was oversize. Worked fine though after installing wheels mfg thread together bb.

[bichler.bua]

Interesting topic and thought Patty.
I am not an expert in bearings, but interested in your testing and experiences since (as you mentioned) you actually ride bikes.

Anecdote from about ten years, when I re-started road biking by refurbishing a steel frame from the 90ies.
Changing from a square taper crankset to Shimanos hollow tech significantly transformed the ride feel, even if the bike still was an old steel frame.
So yes, the bottom bracket system and cranks do impact how a bike rides and feels.
But I also believe that stem & handlebar and wheels & tires do impact how a bike rides.

Some questions in this context:
When you say "bikes I've truly enjoyed" and "more immediacy in power" - do you think that this feature suits your way of riding and is key for you over other bikes features?
Many people will argue that titanium bikes ride special, probably impacted by "this is in my head" - what was your experience with the titanium frames you rode?
Did you test the Quick Pro with different wheelsets, was there any impact and do you have one / two standard wheelsets that you use for testing and your verdicts?

[jfcb]

For maximum stiffness you want a wide shell width and a wide crank diameter (therefore a wide shell diameter). Because of that, BB386EVO is in theory superior.  As said before, because of the terrible frame tolerances within the cycling industry, pressfit is less ideal with noisy creacking and poor alignment as disadvantages. 
This is where T47 wanted to offer a solution as having a threaded interface and still be able to use larger bearings (either in the frame or outside the frame).
For 24mm axles, I would dare to state it doesn't matter that much, but for 29/30mm spindles (DUB) it's beneficial to be able to place the bearings outboard.

Now, will you notice the difference: I would doubt so. For example, I can't notice the difference in stiffness between shimano (nylon cups) and metal cups which I would expect to give a big difference in feeling.

[jonathanf2]

if you're bonding in an alloy sleeve because you can't make the carbon shell to tolerance, you're already so far from the ideal you might as well put threads on there and make final assembly easier

Actually an alloy sleeve for BB86 is easier. For example there are different width thread attachments for both BB68 and T47. The same bearing press I use for BB86 can be used for external headset cups. Removal of BB is easy with just a rubber mallet and BB cup removal tool. T47 is all over the place with no standard diameter threads and external + internal cups configurations.

Also I’m guessing sleeved BB86 frames would have less issues with delamination. There is no torquing on BB threads. Lastly non-sleeved bb86 frames can be problematic if using thread together BBs. If you’re not paying attention you could easily crack the BB shell. I know some on this forum can attest to that mistake.

[Toru]

First time posting here.
Beside performance there is also reliability to consider.
Aluminum and carbon are an active pari, so I guess in many cases why T47 or other bonded aluminum cups get delaminated is due to galvanic corrosion. One would need water/humidity for the process to happen. I’m someone who lives at a nordic country, they use here salt on bike paths in winter, so that makes it even worse. I like pressfit because there is less components, though it is annoying to get rid of squeaky BB 

[rsw42]

IMHO there's more than just one answer to that question.

In a world where all of the framests are true to the standards: Something like BB30 where the bearings are directly pressed into the frame wins.
In a world where there's only little variability on the frames: Pressfit with cup like bb86 or bb386 will be best choice for beeing lighter etc (see all the other things above)
From a maintenance point: Threaded BBs are so much nicer to work with, especially if your customers don't care about there stuff at all until it's way too late.
For all of the points: Bigger bearings will be more reliable since the balls can be bigger.

Especially the last point makes BB86 one of the worst systems imho. Having too many people around racing on 30mm spindles in a 41mm shell. The BBs just can't hold up as long.

If I'd have the choice - I'd go for BB386 anytime - you've got the plastic cups to mitigate bad QC, you'll have more reliabilty than with BB86, you wont have the threads and all the potential problems with debonding, seizing, etc.

As for flex - I believe that you probably feel more flex from the frame around the BB-Area. Where the Down-tube meets the BB-Shell. They'll call it "engineered compliance" and ask a premium for it soon

[offspring_fan]

I absolutely don't buy the argument that pressfit makes a material improvement to drivetrain stiffness, or that outboard BBs put more stress on the bearings.

I would, except that outboard BBs have the bearings very well supported by aluminium bearing cups.

Given the large depth of threads in BB cups relative to their total length, and the minimal width of the external portion (c. 10mm per side), I just can't see how the degree of flex occurring beyond the plane of the frame's bottom bracket is material.

[adam900710]

I'd say yes and no.

Yes for the 86.6mm width, no for the 24mm only spindle option and in the real world there are way more important things like tolerance (thus possibility to creak), only support 24mm spindle, and frameset availability.

With all that said, what works for you is always the best.

And unfortunately BB86 doesn't always work for me. I had 2022 model TCR adv pro frameset, which unfortunately has a pretty bad BB, there is even a big void inside the driven side BB wall.

[patliean1]

Peak Torque just dropped a video earlier today and gives his opinion about T47 68 outboard. Funny timing...

6:00 mark

The GRAVEL race bike you've not heard of - Voice Velo GMajor Review

https://youtu.be/Awgg4kULqb8?si=8foGZgV4UkEemG5D

[Hendie]

I have both T47 and Press Fit (PF4186).

The simplicity and weight of press fit is vastly superior to T47...  But I find the 41mm shell to a problem, I use dub standard cranks.  My ideal solution is 386 with the 46mm shell.