MTB Tech Rumors and Innovation

Because PB takes stuff somewhere else and posts it as their own content. This here is a blog, and most people are quite open about their sources. Not the same...

Photo seems to be taken in Queenstown. Would make sense since the whole team moved there for 3 months. Perfect Testing ground for the new Phoenix!!

Yep it definitely is in Queenstown. At skyline 

I'm 175cm and 450mm/45mm stem is perfect for me. 460mm feels a tiny bit long on steep trails. Stack aside.

Saw a prototype shimano caliper on a new sb160 at the capital enduro in Wellington in nz today… didn’t manage to get any photos but was definitely not a normal shimano caliper

Did it say Shimano, or could it be an aftermarket product, like from Cascade Components? 

wheelbased has more deets on the sram cranks 

Looking at these drawings, XTR weights are very possible (about a shade over 500 grams for a crankset). 

What about XTR stiffness (torsional mostly)?

Shimano cranks are hollow forged with XTR going the road way being milled from two pieces and glued together. That means Shimano cranks are hollow sections which is perfect for torsional loads (you know, pressing on the end of the crank via a lever that is the pedal axle and all) and also very good at bending loads (pressing onto the end of the crank, lever present or not - the lever just adds an additional loading case).

The funny thing is that Sram already had hollow forged cranks and moved away from it. Mostly to fully move towards carbon while it seems they are moving away from it with the upcoming X0 based on the leaked pics...

The new Cannondale Habit ridden by Iago 

I like how the new Jekyll rides but Cannondale bikes will be irrelevant to me for as long as they feature that weird offset on the rear hub. Really not something I want to have to deal with.

That's a fair point.  I'd like to think that these new cranksets should be at least as stiff as XTR's since ews factory teams are getting it first.

A curious question would be why go with an alloy crankset now for a (nearly) top-shelf model? 

I wouldn't be surprised if most people can't notice any differences in stiffness between two cranks. Even more so with mountain bikes that have fairly wobbly frames (compared to a hardtail), wobbly wheels, suspension, etc. etc. Could be wrong, but it would be interesting to see how many (few) people could actually notice it without it being pointed out (for example comparing two XTR-like cranks that have different levels of internal milling and look the same on the outside).

Why go with an alloy model? At the face of it I can only point to two factors. Price and impact resistance (considering it's likely X0 will be a bit more gravity oriented than XX). Carbon cranks and handlebars give me the heebie jebbies as they are both very much a single point of failure, as in part of it snapping off gives you a lack support on the bike. It's the same for the head tube, but the headtube to DT/TT joint is not affected by rock strikes (usually) or potentially compromised by overtightened brake levers

That's a great point, Primoz. I don't think almost anyone could tell a difference between cranks, unless we're talking about a complete wet noodle vs. the stiffest crank in the world. I think the biggest differentiator for cranks is strength, both in terms of impact resistance to rocks or the like and also in terms of pure load strength under a big compression like a jump or turn.

I think any crank is going to "feel" like a Saint crank until you land a 50 foot jump to flat. That's when the differences start to show up. That's certainly a moment when years of rock strikes and scratches on your carbon cranks may make their presence known.

One of the first things I noticed after going from carbon cranks to eeWings was the stiffness. Very noticeable, and quite surprising. 

Cranks, bars and rims are the only places on my bikes where I use carbon, because it makes sense from a performance point of view. But titanium cranks oneups the carbon ones. 

I see too many carbon crank failures in my local area to go carbon, Sram being a usual suspect but Raceface also coming up occasionally although they usually de-lam from the spindle where Sram cracks at the pedal.

Id be interested in trying Ti other than the cost of entry. I'm still someone who prefers 24mm spindles for bearing life as well but they might convince me to go 30. 

It sounds like it is time to bring back steel cranks ! Titanium of the poor lol. But with current manufacturing we have to he able to do better than profile style cranks nowadays. It could be cool to see someone offering a steel version of the eewing cranks.

Sounds heavy. And/or weak.

And there’s absolutely nothing wrong with Profile cranks!

If we consider that Ti frame are roughly 40% lighter than Crmo frames, then a "modern" Crmo crank could be 40% heavier than the eewing, which means below 600gr, which if I believe the interballs is below the weight of an XT crank which is announced on Alltricks at 620gr. Even if you consider a 50% penalty from Ti to Crmo you'd be lighter thana Deore crank, not that bad really. 

Not sure it would scale as equally. You need a pedal insert and, most importantly, the axle (and chainring) interface. Those parts could be fairly heavy.

If you do the crank with a fairly big tube, you need to have it very thin to be light enough, which isn't a problem strength wise (steel can have very high tensile strength ratios). This will also give you stiffness. The thin walls will make it very dent prone (think a beverage can situation).

If you go with a smaller cross section tube to be able to make the wall thicker (to cover the issue of denting), it's possible you'll have to make it overly thick to cover the stiffness requirements.

All of this is just eyeballing and throwing out pros and cons, but I'd say there's a very good reason the vast majority of cranks, pocketed out, hollow forged or glued together, is made from aluminium (thick walls required for stiffness and strength, no issue with denting, no issue with weight due to the density of Aluminium). And when done right aluminium actually glues very well. I wonder why more companies don't do that.

https://instagram.com/thanksshimano for some examples why more companies don’t glue their cranks together.

I'm gonna age myself here... Anyone remember the Mrazick brand from back in the 90's? They made a beautiful high chain stay hard tail with classic cruiser curves. They also made a Ti crank set made out of twenty six (I think.) individual pieces all welded together. Just imagine the jig? 

Oh yeah. Magnesium bike frames. There was a local guy when I was a younger wrench who had one, broke it, broke two replacements.

Never saw the cranks in real life.

How many of those are XTR cranks (hope I'm not foreshadowing)? Where's ThanksCannondale or ThanksActofive (or anyone else making two piece cranks)?

Looks like shimano is using a structural 'rear' part and a very thin cosmetic cover over it, that doesn't seem particularly structural. Plus said cover is not afixed by the spindle (though NDS cranks also have problems). Plus there are theories the main issue is moisture (looks like it's happening in Asia more than the rest of the world) possibly oxidizing aluminium. And the glued joint could possibly be designed better (it looks like it's fairly vertical currently).

I think if you made the two halves structurally similar and also strengthened them using the spindle and pedal thread insert (insert the pedal insert from the back so the pedal screwed in compresses the two halves, same for the spindle compressing the two halves once installed into the frame) and made the glued joint stout, there shouldn't be much of a problem. Cannondale has a labyrinth joint that's glued together, but I don't know how Actofive does it.

FWIW, aluminium cars are bonded together, not welded. Gluing aluminium does work when done correctly.

First new find: 

new Saint cranks on brendogs rig?

Second new find: 

Suarez on an alloy proto dh Unno bike?

@SupremeShredder42 taking the idea of spy photos to a new level 

No pics showing?

No pics for me either, just little question mark icons since yesterday. (Mobile site on iPhone) @sspomer feel free to delete this comment once you’ve solved the problem.