There is a trend, especially with CF racing frames, towards new BB standards like BB30, BB90, and BBright. This limits ones ability to swap parts around. For instance, having invested in a Quarq power meter that fits the threaded BB of my steel Gunnar, I find that my desire to be able to move the Quarq to a racing frame is limiting my N+1 choices. Of the bikes I'm currently considering, only one (Specialized Tarmac) is available with a threaded BB. There is a similar trend towards tapered head tubes. Both trends are based on eliminating flex, or at least making that flex elimination easier to accomplish.

So my question, to those of you who have experienced both the old and the new technologies, is: How much difference does it make?

Especially given I'm a big, 200 pound (well, actually 199.3 pounds now!) guy, should I bite the bullet and go with an oversized BB, reconfiguring my Quarq, or, (ga$p), buying another one?

I like my Tarmac. I believe it is race worthy and I would buy it all over again.

And I take yours has a threaded BB, Jet? Tarmacs come in a variety of flavors, many of which use an Oversized BB.

There are adapters available for your existing Hollowtech or GXP crank.

I'm looking, and finding a lot of adapters, but so far nothing that is GXP <> BB90 (Trek Madone)

Ahhh..., I would contact Trek.

^^^^ Great looking bike!^^^^^

It's an external threaded BB.

thanks... makes me want to say "I'm Batman"

Man, I gotta learn the lingo. I thought Oversized Bottom Brackets was going to be a tribute to Queen's "Fat-Bottomed Girls."

Is that the bike that now has the PT?

The PT is in the hub of my training wheels that I can also use on my Roubaix and TT bike while training and in C races. Those 58cm tubular wheels are my Sunday-go-to-meeting wheels.

Wot's a PT?

PT = Power Tap hub power meter

I guess your saying you do not have an external threaded BB.
Isn't a Quarq pm mounted in spider of crank?

I have a 2011 Trek Madone w/BB90. I had my SRAM RED Compact Crank (BCD 110) from my old bike (which used a GXP external BB) re-installed to the Madone using required a BB90 BB kit. I chose the Enduro one with hybrid ceramic bearings.

thanks.

So this connects to a cyclocomputer, and replaces the old magnet on the spoke kind of thing?

It is a sophisticated cycle computer that measures power generated by the rider in watts. The hub has strain gauges and other internal bits that measures torque, speed, distance, watts, time and estimates cadence and sends the info wireless onto the CPU. I purchased the cadence sensor to get real cadence. Instead of training by heart rate I train using established power zones that are similar to heart rate zones but are more accurate because power generated is consistent where HR can vary due to heat, fatigue and other factors. I had to do specific testing to determine the lactate threshold heart rate and average watts produced over a specific time frame to generate the data needed to establish the power training zones. It reads complicated, and to me it is, which is why I invest in a coach and spend my time riding and following directions.

On the one hand, I gotta confess these oversized bottom brackets look pretty badass on a lot of new bikes...the sheer size of some of them conveys a solidity/rigidity that, in theory at least, suggests some sort of perfomance benefit.

On the other hand, the puny normal-sized bottom bracket on my TIG-welded steel Strong frame is so freakin' solid I can't imagine anything else being perceptibly more rigid, or offering any perceptible performance gains.

I know, "Failures Of Imagination Are Not Insights Into Necessity", yadda-yadda-yadda.

I understand where you are coming from Bob. In my case, with the wide and stiff bottom on my Tarmac I have never jumped on the pedals up a hill or sprint and had the chain rub the derailleur. Every effort seems to go into the wheels. My 1999 stiff aluminum Cannondale would rub quite heavily and my early-70's 531 steel Super Course would need constant trimming. If anything, it just feels good to have the bike respond to every effort the moment it’s made.

I'll second that!
Very nice

I have an external threaded BB on the current bike, but might not on the new one. And yes, the Quarq unit is mounted in the spider.

This is good to hear, as it is exactly what I'm considering. I have a SRAM RED S975 (S975=Quarq) GXP standard crank on my bike, and one of the bikes I'm considering is the Madone. I had heard of the Enduro adapters, as Cervelo also references them (for their BBright BB). I just haven't been able to find the right one online. I'm trying to make sure there are no surprises when I pull the N+1 trigger, and want to be knowledgeable before I even start talking to the LBS. I'm currently considering the Madone, the Tarmac, and Cervelo Rx, and I'm fortunate that we have an LBS carrying all three, and that LBS has a relationship (spelled d-i-s-c-o-u-n-t) with my coach.

Me too. I'm trying to get my mind around the science and data, because that's just the kind of guy I am, but it truly is overwhelming. I've been gradually reading "Training and Racing with a Power Meter", which is the bible on the subject, digesting it slowly like a time-release protein powder. I'll finally be doing my threshold test a few weeks from now, when there is a break in my racing schedule.

I'm glad I don't race, just ride!

To quote a great old commercial: "Try it; you'll like it."

Seems [Afaik], BB30 moved the frame width out to re internalize the External bearing stuff.

external stuff was compelled by Shimano, etc, jumping on the patent expiration
of Bullseye, tube attached to the right crank arm design.

the original design used needle and ball bearings , to fit in a normal 1.37" threaded shell..