Bottom Bracket Preference by Team Sky Mechanics

[Rebel_Biker]

Article is old but I am always coming across articles as I research frames for the shop.

I found the BB discussion interesting.

"One anachronistic detail is the use of an Italian-threaded bottom bracket. Pinarello says Sky’s mechanics requested a threaded system for maintenance and reliability purposes. As for Italian versus British threading, Pinarello says (we’re not making this up) Italian is stiffer."

http://www.bicycling.com/bikes-gear/bikes-and-gear-features/first-ride-pinarello-dogma-f8/page/0/1

[Cicli]

Probably the mostaccioli.

[Shortsocks]

I do know that Italian is a pain In the ass, for my Pinarello, because all of the cool after market Gold BB's are all English. And my LBS never keeps the italian BB's in stock. But they are stiffer?! COOL.....:banana:

[sandyrs]

Obviously they prefer the italian standard. It's far superior

[Black Dog]

Stiffer sure. :rolleyes: no way for them to measure that. None.

[Steve in SLO]

"Stiffer" in Italian must mean "We have lots of these left in the parts bin"

[Rebel_Biker]

I don't think the Sky mechanics cared if it was Italian threaded. They just did not want the press fit option.

I wonder if some of the manufactures that really want the wider BB could develop a recessed BSA threaded option.

[AngryScientist]

i only own threaded BB bikes, and concede that i have never worked on a bike with pressed bearings in the BB, but i have to believe for a pro team, that has to keep a bike in tip top shape for stage races, etc threaded has got to be easier. i dont blame them. long live the threaded BB!

[peanutgallery]

Finally, proof that press fit bb's have been forced upon us. It was all just a scam to sell a myriad of adapter kits:)

[mtechnica]

Well the Italian shell is 2mm wider than the British one so maybe it is marginally stiffer in theory. Still bb30 seems to work fine for most people as does bsa

[bigbill]

I like threaded bottom brackets because the parts that have clearances can be replaced quickly and easily. If I was team mechanic and my rider was complaining about a creaking bb, I could swap it all out in 20 minutes.

[11.4]

I see Tater's hand in all this.

[eddief]

well you know.

[oldpotatoe]

Obviously they prefer the italian standard. It's far superior

Obviously, why the consternation?

[ScottM]

In addition to being wider, the standard Italian bottom bracket has a larger diameter. The larger dimensions will make the bottom bracket stiffer. Of course, this additional stiffness should not be noticeable as it is unlikely to yield when installed in a typical frame.

Scott

[soulspinner]

Well the Italian shell is 2mm wider than the British one so maybe it is marginally stiffer in theory. Still bb30 seems to work fine for most people as does bsa

this...2mm could make a measurable diff, no?

[oldpotatoe]

In addition to being wider, the standard Italian bottom bracket has a larger diameter. The larger dimensions will make the bottom bracket stiffer. Of course, this additional stiffness should not be noticeable as it is unlikely to yield when installed in a typical frame.

Scott

Of course but 'press' BBs mirror what happened when forks/shocks went to thread less. Painted as a performance advantage but really just easier(cheaper) for frame/fork makers. Easier to weld fat tubes to fat tubes, also why integrated/insert type HS' came to be.

[Grant McLean]

In addition to being wider, the standard Italian bottom bracket has a larger diameter. The larger dimensions will make the bottom bracket stiffer. Of course, this additional stiffness should not be noticeable as it is unlikely to yield when installed in a typical frame.

Scott

Setting aside the fact an English cup is 34.8mm in diameter and an Italian
thread one is just 36mm, I don't see how the diameter of the cup itself has any
impact on stiffness.

Diameter of the bottom bracket axle would, depending on the material,
as does the interface between the axle and the arm. But I think the
person from sky is just exhibiting marketing-speak in typical fact free
style.

-g

[Mark McM]

Setting aside the fact an English cup is 34.8mm in diameter and an Italian
thread one is just 36mm, I don't see how the diameter of the cup itself has any
impact on stiffness.

Well, with the larger threads, a slightly larger diameter shell could be used, which would slightly frame increase stiffness at the shell. In addition, the slightly wider shell would may allow slightly fatter frame tubes/chain stays to be used, also theoretically increasing frame stiffness. Finally, the wider shell can potentially allow a slightly wider bearing stance, slightly increasing stiffness of the spindle.

Of course all these improvements would be marginal at best, and is more of an academic exercise than a practical one.

[soulspinner]

Well, with the larger threads, a slightly larger diameter shell could be used, which would slightly frame increase stiffness at the shell. In addition, the slightly wider shell would may allow slightly fatter frame tubes/chain stays to be used, also theoretically increasing frame stiffness. Finally, the wider shell can potentially allow a slightly wider bearing stance, slightly increasing stiffness of the spindle.

Of course all these improvements would be marginal at best, and is more of an academic exercise than a practical one.

Thats what I was thinking, and any stiffness increase with pros that need it would be welcome, it would seem.

[Grant McLean]

Well, with the larger threads, a slightly larger diameter shell could be used, which would slightly frame increase stiffness at the shell. In addition, the slightly wider shell would may allow slightly fatter frame tubes/chain stays to be used, also theoretically increasing frame stiffness. Finally, the wider shell can potentially allow a slightly wider bearing stance, slightly increasing stiffness of the spindle.

Of course all these improvements would be marginal at best, and is more of an academic exercise than a practical one.

Are you familiar at all with the frame being discussed?
In a carbon frame like this pinarello, there is no actual bb shell,
The entire area of the frame flows all the tubes together.
The inside diameter of the cups is not a factor.

http://roadbikeaction.com/wp-content/contentimages/2014/Maloney/Pinarello/XIMG_0011.jpg

[carpediemracing]

I like threaded bottom brackets because the parts that have clearances can be replaced quickly and easily. If I was team mechanic and my rider was complaining about a creaking bb, I could swap it all out in 20 minutes.

Probably much quicker than that unless you're working on the bike while it's on the roof of the team car in the caravan. But yeah, that's the real reason I think. That and trying to put together 30 or 50 bikes etc.

As far as Italian vs English, whatever.

Threaded is nice because it's consistent and doesn't require much finesse. With a cartridge bearing BB just don't cross thread and you're basically fine. I have a GXP crank (track bike) but have been on BB30 for a number of years. When I installed the GXP crank I was like, "Wait, that's it?". Based on my err "non-eliteness" I realize now that I should have gotten ENglish BBs for simplicity sake. I committed to BB30 SRMs so kinda stuck for a bit.

When Shimano first came out with the cartridge BB I happened to have a chance to watch an Italian mechanic work on Shimano equipped bikes. Because I look like I might be someone from Shimano, and because I was watching so intently, he kept looking at me and doing more work on the bike. He even removed the cartridge BB, wiped it very carefully, then reinstalled it. I realize now that he was probably scared that I would report to Shimano if he didn't do something or didn't look thorough. I still remember the look on his face as he carefully wiped the cartridge BB, the whole time looking at me like "What the hell else does he want me to do?".

It was Gatorade and he was working on Dirk De Wolf's bike. The wheels were so out of true - they were truing based on not hitting the frame, so figure 5-8 mm range both laterally and vertically - that even I'd have thrown them out but apparently they were using last rate stuff in the US for DuPont. I think the guy could have rebuilt the wheel in the time he spent "working" on the bike.

This is before I inadvertently harassed the mechanic. Bugno's bike.
https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xpa1/v/t1.0-9/10649518_10152901583163824_2679366060518398400_n.j pg?oh=13857a896d44480874c5722651c4dfb2&oe=5555AB71&__gda__=1435383911_497273c992342ed0cec874dc9d67157 3

[nate2351]

Funny enough, last time the Pina rep was by our shop he pointed out that the Italian threading could also be used to help identify counterfeits. He claimed they haven't found a Chinarello with Italian thread yet.

[Mark McM]

Are you familiar at all with the frame being discussed?
In a carbon frame like this pinarello, there is no actual bb shell,
The entire area of the frame flows all the tubes together.
The inside diameter of the cups is not a factor.

http://roadbikeaction.com/wp-content/contentimages/2014/Maloney/Pinarello/XIMG_0011.jpg

There's obviously still a shell - it just may not be a continuous piece of metal. And the width of that "shell" is limited by the BB standard. Does not increasing the width of a carbon structure (the "shell") also not increase the potential width of the structures that emerge from it (tubes and stays), and does this not potentially lead to increased stiffness? And does not increasing the width of the bearing stance still increase the stiffness of the spindle?

As I said, potential stiffness increases for Italian vs. ISO threads are marginal at best, and is mostly an academic exercise.

[Ti Designs]

I can't believe that people here would dare to question what someone from team Sky says.

[Grant McLean]

sometimes i'm not sure why i bother...

-g

[rnhood]

Easy Grant, we always value your contributions here. You bring an element of reality to the forum so don't run off.

[RudAwkning]

https://www.youtube.com/watch?v=K_Gtb1kElRk

[giordana93]

https://www.youtube.com/watch?v=K_Gtb1kElRk

just to add to the levity: you do know today is mardi gras day and that Brennan's had been closed for a long time until just recently.... and that on mardi gras day, (at least in the old carnavalesque tradition), the king's fool became king for a day (in other words, we must believe both the old italian mechanics and the technocrat-marketing experts; and of course stiffer is alway better)

http://imgick.nola.com/home/nola-media/width700/img/tpphotos/photo/2015/02/17/-4c2da592b5b9b353.JPG


http://www.mardigras.com/#/0


carry on

[soulspinner]

Are you familiar at all with the frame being discussed?
In a carbon frame like this pinarello, there is no actual bb shell,
The entire area of the frame flows all the tubes together.
The inside diameter of the cups is not a factor.

http://roadbikeaction.com/wp-content/contentimages/2014/Maloney/Pinarello/XIMG_0011.jpg

makes sense.....

[Mark McM]

makes sense.....

Not really...

While I think we all understand that the difference between 70 mm and 68 mm BB width is nearly inconsequential, I don't know why we are arguing about whether a wider BB stance can potentially produce a stiffer frame.

One needs only to look at why MTBs increased their ISO (British) threaded BBs from 68 mm to 73 mm. A 73mm BB uses the same thread and same spindle diameter as a 68 mm BB, so bother? They did this so that they could attach fatter tubes to the BB shell, for increased strength and stiffness. The extra 5mm was deemed a worthwhile change that it has become nearly standard for threaded BB MTBs. Likewise, even with a monocoque carbon frame, increasing the width at the BB can allow the frame to be wider at the BB, resulting in an increase in stiffness. Granted, the 2mm change in width from ISO to Italian isn't much, and the increase may not be worthwhile in the greater scheme of things, but that doesn't mean that there is zero stiffness change.

[sandyrs]

Not really...

While I think we all understand that the difference between 70 mm and 68 mm BB width is nearly inconsequential, I don't know why we are arguing about whether a wider BB stance can potentially produce a stiffer frame.

One needs only to look at why MTBs increased their ISO (British) threaded BBs from 68 mm to 73 mm. A 73mm BB uses the same thread and same spindle diameter as a 68 mm BB, so bother? They did this so that they could attach fatter tubes to the BB shell, for increased strength and stiffness. The extra 5mm was deemed a worthwhile change that it has become nearly standard for threaded BB MTBs. Likewise, even with a monocoque carbon frame, increasing the width at the BB can allow the frame to be wider at the BB, resulting in an increase in stiffness. Granted, the 2mm change in width from ISO to Italian isn't much, and the increase may not be worthwhile in the greater scheme of things, but that doesn't mean that there is zero stiffness change.

I thought the change in MTB shell width was to match the change to 135mm rear spacing.

[Mark McM]

I thought the change in MTB shell width was to match the change to 135mm rear spacing.

Not necssary. Adjusting the chain line can be done by increasing spindle length (not shell width) and/or crank spider offset. There are plenty of bikes with 135 mm rear axles and 68 mm BB shells.

[giordana93]

of course it had nothing to do with 2.5" tires needing more clearance at the bb shell. jeez

[11.4]

of course it had nothing to do with 2.5" tires needing more clearance at the bb shell. jeez

Jeez, Giord, of course not. You just make the chain stays a couple inches longer so the wheel isn't squeezed into the tight spot right at the bottom bracket. Those are all wanker frames anyway.

[El Chaba]

I wouldn't be at all surprised if the "Italian thread bb's are stiffer" comment wasn't made entirely tongue in cheek.....