Cannondale Hollowgrams

[dave.chippie]

Just wondering if anyone knows more on how Cannondale make their new forged hollowgram cranks? Not like the old 2 piece SI arms but very similar in weight.


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[dave.chippie]

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[Mocs123]

I'm not sure but we've had 3 differnt people in my group crack their holowgram cranks. Cannondale replaced them under warranty no questions asked but my guess is the original design had a design flaw.

[dave.chippie]

Maybe they’ve made them too light, sacrificing longevity


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[Dan Gerous]

The silver ones are an old version, they date from before Cannondale introduced the first generation SuperSix Evo so they're from before 2011, hence the weight being close to the newer mid-range 3D forged model. The newer ones made with the machined 2 pieces bonded construction but with updated shaping and machining are lighter, I weighed my pair of 172.5mm SISL² arms at 263gr.

They're also all generally known to be quite durable, even the bonded models used on road bikes or mountain bikes or cross bikes, Mocs123's group must have bad karma or something!

[Mocs123]

The people I know had bikes from 2015 and 2016 and all three had the spider crank (and were all Synapse Disks). Two of the guys were in their 40's and are fairly strong sprinters, but the third is in his 60's and 150lbs - not putting out lots of watts.

[NiFTY]

I bought a set of sisl2 2nd hand years ago. DS crank had a tiny crack near the crankbolt, seller warrantied it for me. Earlier this year the replacement ds crank developed a small crack in the same area. I have replaced it with a si crankarm. I am 71kg.

[hannawald]

So many cracks, you can easily google it, so hopefully they have changed the design because it is probably the best solution for Cannondale..

[hannawald]

The silver ones are an old version, they date from before Cannondale introduced the first generation SuperSix Evo so they're from before 2011, hence the weight being close to the newer mid-range 3D forged model. The newer ones made with the machined 2 pieces bonded construction but with updated shaping and machining are lighter, I weighed my pair of 172.5mm SISL² arms at 263gr.

They're also all generally known to be quite durable, even the bonded models used on road bikes or mountain bikes or cross bikes, Mocs123's group must have bad karma or something!

Mine cracked as well.

[shoemakerpom2010]

My silver ones cracked also and the Rep replaced them without hesitation with the newer Si. Funny thing is my Magic Motorcycle ones never cracked and they were put thru a beating many times...

[Dan Gerous]

Y'all should stick to Shimano cranks then!

[dolophonic]

mmmn Hollowgrams ! so light and tasty ..alas mine eventually cracked near the spider but i gave them a real kicking ( they were the silver ones)

I also had a Dura Ace crank fail .. it happens.

Im now running SRAM Red and they have been solid.

[Cleaner]

The current Hollowgram SI cranks are a one piece hollow forging. Press materials from the release provide little more detail.

https://www.bikeradar.com/news/cannonda ... offerings/

[dave.chippie]

Cannondale over Shimano for sure-far superior. Yeah I read that Bike Radar article, not a lot of detail on the manufacturing process


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[Dan Gerous]

Cannondale over Shimano for sure-far superior. Yeah I read that Bike Radar article, not a lot of detail on the manufacturing process


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The SI is 3D forged (Cannondale provided more about this process when they introduced a Lefty with a one piece 3D forged lower leg or when they introduced the Lefty stem integrated to the steerer, but basically, I think instead of pressing the metal only in one axis during the forging process, they press the metal in all 3 axis which apparently makes the metal structure stronger), it's made of a single piece and it's the stiffest version of the crank Cannondale ever made and is relatively bomb proof. Definitely an improvement over the old silver Hollowgram that weighs about the same but that is slightly less stiff and perhaps a bit less durable...

The original Hollowgram and later introduced SL and now SISL2 are made of two pieces of CNC-machined alloy, the two halves are keyed longitudinaly to fit into each other and keep it stiff as well. The machining has evolved over the years with more material removed with each lighter iteration, having it made of two halves allows a lot more precision of the internal machining to optimize weight saving without compromising stiffness and, to some degree I guess, durability. That's why the SISL2 is so light and the silver ones with the same construction technique are heavier... but the SISL2 itself has been changed at least once since its introduction, the latest update beefed up the area around the mounting bolt/spider, the area where cracks sometimes appeared.