spectastic

Do you actually feel the improvement of BB30 (or PF30) over traditional BSA bottom brackets in pedaling efficiency during hard efforts? or is there proven data that supports the improved stiffness of the shorter, beefier bottom brackets or crank axles?

I know in terms of serviceability, longevity and noise, BSA BB takes it, contrary to what was advertised about the larger BB30, with the fancy bearings, and what not. I'm wondering if the newer bottom brackets have any edge whatsoever over the traditional system, or whether it's just a marketing tool to lower frame manufacturing cost.

smells like bull**** to me

furiousferret

I don't notice a difference, other than BB30 can be finicky and creak. I don't think its smoother, just lighter.

Ygduf

41

topflightpro

Velonews did a test comparing BB30 cranks against non-BB30 and found the BB30 versions did test marginally stiffer.

The other thought is that the larger BBshell that BB30 offers enabled frame builders to construct bigger downtubes, leading to stiffer frames. Of course, that mostly pre-dates the emergence of carbon fiber frames, where BBs can be made any size and shape a frame builder wants.

save10

bb41?

shovelhd

Works great. No BS.

TheKillerPenguin

I like to rag on bb30 for creaking but the truth of the matter is that if you're taking care of your equipment it's totally silent. BB30 is ridiculously simple to service and super cheap to replace when needed. I can only compare it to ISIS spindled giga x pipe stuff and square taper shimano but it is certainly stiffer than both of those.

shovelhd

I went from a GXP Quarq with WM BB30 adapters to a native BB30 SRM and it is noticeably stiffer. That's not a fair comparison, because it should be compared to a native GXP frame, but a direct comparison would not be possible.

mike868y

although my experience is relatively limited, on paper, PF30 should be "the ultimate standard" as it allows you to run basically any crank of your choice with the widely available adapter BBs.

grolby

No personal experience here, but my understanding is that BB30 is pretty good. I hear Specialized doesn't do a great job with the tolerances for PF30, and that leads to a lot of creaking. So things like that could explain some of the problems. I'm not too convinced that my BB really needs to be stiffer, but apparently BB30 will work fine if you pay some attention to what you're doing.

carpediemracing 

Keep in mind the biggest reason for BB30 is to be able to use a wide diameter BB axle. Since it's wide it can be made with aluminum, not heavier Ti or steel. That's where most/all of the savings comes from, from using a lighter BB axle. With a wide diameter aluminum axle you can have a stiff and durable axle that weighs just a few grams.

BB30 is marginally stiffer (it could be much stiffer if the axle was steel or Ti) but much lighter (because aluminum axle). It's hard to compare cranks because many BB30 cranks don't come in a regular English BB version. Velonews found something (FSA?) that came in both I think.

BB30 is also narrow so smaller Q factor (width between pedals). For me that's a big thing and my BB30 cranks are pretty narrow. My Campy cranks before that were narrow also. Cast or heat forged cranks (105, Ultegra, from the old days anyway) are much wider, don't know about current weird configuration arms.

I have BB30 SRMs (two). 573g or something for everything include the computer head. BB, arms, rings, bearings, everything, even a plastic baggie. It's light, it's just as stiff as most anything out there. My Record cranks are 900g or something without the BB (alum arms), I don't remember, but it's a lot compared to the BB30. Helps make up for some not-so-light stuff, like a 250g steel stem or a 1200g frame.

spectastic

found the velo news report on this




based on the deflection data, BB30 does appear to be like 0.5% better, and a little bit lighter too. compounding the two you get 5% improvement in stiffness/weight, which I personally don't really see the point of, considering we're talking about a 30 grams savings on a ~7000 g bike.

I also wonder if the slightly stiffer shaft in BB30 is offset by a slightly longer crank arm.

but I never thought that the axle stiffness would be the limiting factor in cranksets. I wonder if that's why carbon cranks are becoming popular, considering carbon shafts are much stiffer than aluminum.

I still prefer better shifting and easier serviceability over these marginal gains though

Ygduf

What color should I paint my house?

topflightpro

Hot Pink.

topflightpro

The spindle is actually a huge factor in terms of overall crankset stiffness. If you look at the work Fairwheel Bikes has done comparing crankset stiffness and weight, the difference in drive-side and NDS stiffness is amazing. The DuraAce 9000 crank, IIRC, actually had the biggest discrepancy between the two sides, in large part due to the spindle being so long and narrow.

And as has been said, if the bearings are installed properly, there are no problems. I've got more than 50k miles on a set of BB bearings in my Cannondale System 6 without a single creak.

When I bought a Caad 9, I made sure to use Loctite bearing retention compound when installing the BB30 bearings, and I had no issues.

spectastic

shade 41

shovelhd

They forgot Felt, who was one of the first to adopt BB30.

Navy and pink.

spectastic

yea I noticed that too, although according to the test description, the difference between the most flexy and the stiffest crankset is around 1.5 watts at 300W. i guess it's one of those marginal gains that could add up.

spectastic

50 shades of grey. lol

Duke of Kent

When people post stuff like this this, I have to ask: Have you ever tried a truly high end BB30 setup? People will think I'm crazy, but check out something like Enduro's XD-15 ceramic angular contact kit. It is basically what amounts to a cup and cone bearing, in BB30 dimensions, using some magical steel races and ceramic balls.

Given how many people drop 5k+ on race bikes, $200 on a wear item/component that will almost certainly outlast every other part of your bike seems like a pretty decent deal to me. I ride mine through 4 creeks a day, fully submerged and not a peep.

spectastic

huh?

no i've never ridden BB30 before. but dropping $200 on a bottom bracket is crazy. I was able to obtain a completely new drive train (105 crankset, chain, and 11-28 cassette) for $150. that's another thing I like about shimano. meanwhile, I feel like most BB30 compatible cranksets are almost all up in the $300-$400 range,


oh wait, the enduro xd-15 bb is threaded.. I confuse.

tekhna

The thing people always forget to talk about when quoting Fair Wheel's tests is we basically have no idea how that 1.5 watts (or whatever) actually ends up mattering in terms of overall efficiency.

"But those 4.8 Watts go into winding up your crank “spring,” which will spring back with nearly all the energy that was spent winding it up. Some of that spring-back energy probably helps turn the drivetrain while some of it may behave in a negative manner. However, there’s a fair amount of debate about how much energy is returned. The answer to the energy-return question involves kinematic analysis far outside the scope of this article."

TheKillerPenguin

You're comparing apples and oranges. In this context you're comparing entry level 105 to top of the line Sram Red/FSA K-force bb30. Even then though you can hunt around and find them for a lot, lot cheaper than that. Like I paid $180 for my K-Force Light, If you want something comparable to a 105 crank I regularly see the FSA Gossamer on sale for like $65-75

JoesInBoston

Not crazy at all. I got Parlee's PF30 to Shimano 24mm converter cups with Enduro bearings in them. At the time I thought it was ridiculous to spend that much money on metal cups and bearings, but it's been almost 2 years now and they are still smooth as ever. Had the bike out in some pretty monsoon like weather, too. In the past, I've had to replace Shimano Dura-Ace bottom brackets on a yearly basis. Around the same time I got the Parlee cups, I acquired a bike that had a Chris Kind headset. The guy who owned it before me said the headset had been on for like 3 or 4 years. I never had a problem with that headset in the almost 2 years I owned it. Again, in the past, headsets were something that I would replace on a yearly or semi-yearly basis due to indexing or creaking.

There are some parts that truly live up to the (monetary) hype.

shovelhd

Spectastic likes to do this under the guise of conversation. His intentions are made clear in the first post.