Friday, June 07, 2019

Friday News And Views

This Knolly gravel Ti frame was seen as kind of a novelty, but it is seriously cool.
The Knolly Cache Story:

A while back I posted about this new titanium gravel frame from the small but popular company, Knolly. This a company not known for its jumping on trends or for anything other than full suspension mountain bikes. So, at first it was easy to dismiss this as a way to cash in on the gravel trend. Hmm.... Cache- Cash? Interesting...........

Anyway, I filed that away as something I'd likely never hear about again. I mean, I cannot count how many companies send me glowing press releases about some new bicycle only to have that fade into the background noise so fast that it never resurfaces again. Not that the bicycles were, or are bad, but the business being so small, and with certain perceptions of the ridership so firmly held, I never get too excited about anything out of the "left field", as it were. One in a million catches on, but you can pretty much discount most of these deals. The Knolly Cache fell squarely into that mold for me.

Much to Knolly's credit, they have made a PR push on the bike and actually have one of the most informative webpages on a bike I have seen in a while. It's actually interesting, and engaging. I recommend taking a look, even if you don't have any intentions of buying this bike. The frame tech talk alone is worth it. Check it out here.

A "high end" 36"er? Yep! (Image courtesy of Bike Radar)
Fancy-Pants 36"er:

Back ten years ago and more, when Ben Witt told me about this crazy idea for a 36 inch wheeled mountain bike, I thought it was a bit of a fool's errand, to be honest. There was nothing for wheels, and the geometry wasn't dialed in, not to mention what to do with frame design.

Well, of course, Ben pulled it off, and not only that, he had two of these behemoths built. That kind of spurred on a bit of movement in the realm of 36" wheeled mountain bikes. A few builders picked up torches and worked on making the idea legitimate. Then a few companies came around with nothing but 36" wheeled mtb's. Tires and rims got better. Then that seemed "good enough" for quite some time. I never saw much else being developed around those huge hula-hoops.

But that all changed the other day when i came across this "Bike Radar" story about a company that built up a 36"er with front suspension and carbon rims! Not just any ol' carbon rims either, but the high end, Italian made Alchemist rims. Talk about bling! That's crazy stuff right there. And top that off with the upside down MRP suspension fork, and you've got one mighty capable 36"er.

I know Ben Witt is pretty humble about this, but I think you have to tip the cap to him for setting off that big hoop idea in motion back in what? 2006? Anyway, look what they did with that idea now. I'm pretty blown away by this bike, to be honest. It might not be my cup-o-tea, but it sure is cool.

A Wheels Manufacturing T-47 bottom bracket.
Is Press-Fit Finally Going To Die?

In a recent announcement, Trek has confirmed that it is using a T-47(-ish) bottom bracket standard now in the 2020 Crockett cyclo-cross bikes. There is a hint that it may actually go across Trek's entire line of bikes currently using Press-Fit style bottom brackets.

This might be a good time to review why we have Press Fit to begin with. The reasons are "lighter weight" and "ease of manufacturing", but not necessarily both in every case. First- lighter weight: The carbon frame technology had reached a point where eliminating metal interfaces with bearings had become possible. Molded "pockets" took the place of threaded metal inserts. This advanced frame technology into the 'super-light" categories quickly. Then there is the "ease of manufacturing". traditional threaded bottom brackets rely on perfectly parallel surfaces for precise alignment of bearing cups. Threading also is an extra step in machining. This all could be eliminated by simply running a hone through a shell to insure roundness and then pressing in plastic cups which themselves held bearings. the plastic deforms to any out of trueness in the inside diameter of the bottom bracket shell, thus saving money and simplifying manufacturing processes.

So, what's the big deal? Well, problems arose when contamination between the bottom bracket shell and the plastic bearing cups occured and the "squeaky,groaning" noises started driving riders nuts. This was in any frame using those cheap, plastic press in cups. The carbon pockets, most notably on Trek frames, weren't always at the tolerances they should be, and wear over time also showed up, causing Trek to have to manufacture over-size bearings that would press in with a bearing press instead of just being hand-removable parts. Not to mention the ease of which these Press Fit bearings would go bad due to exposure to the elements.

Metal framed users could always opt for one of the expensive "thread-together" solutions, but then Chris King came up with the idea of actually threading these Press Fit bottom bracket shells and they made a cartridge unit that would thread into this. They dubbed it "T-47". This happened about four years ago.

A few other companies picked up on the idea, but it basically was something in the realm of custom, NAHBS type bicycles and no mainstream companies were looking at this, until now. So, why go T-47? Well, it still allows manufacturers to utilize those wide shells to place chain stays outboard as far as possible for maximum frame stiffness and maximum tire clearances. Plus, it gets rid of the problems Press Fit introduced. Sure, it will cause more expense, and in carbon frames cases, heavier weights, but other areas of technology have advanced now to keep the overall weights of bicycles really low, so this won't be that big of an impact anyway in regard to weight.

So, with Trek thinking about making T-47 a spec throughout its line, that may signal a sea change across the industry. Maybe the days of Press Fit bottom brackets are numbered. It will be interesting to watch.

That's it for his week. Keep the rubber side down and have a great bicycling adventure this weekend!

1 comment:

dicky said...

Really good bit about bottom brackets (and what's really wrong with PF) buried in this podcast.