One of the great things about working in the cycle industry is actually seeing what’s beneath the covers and outer casings of the products we all use everyday, often without a thought. At the Eurobike show there were lots of instances of this, with Shimano showing a cut-away 7900 chainset and Trek cutting up a Madone.

Shimano 7900 Chainset Cut-Away

 

This cut-away 7900 chainset shows perfectly the Hollow-Tech II technology along with the hollow outer chainring which gives the crank its ‘ting’.The technology here is clear to see, quite how they do it is beyond us (moulded I think). The loss of material from the inside allows a low weight while the material lost has been lost strategically to provide strength and stiffness.Of course it’s not as light as carbon, but Shimano seem to be sticking with alloy down here and it seems to be working! There aren’t many bad reviews the 7900 group and the shifting is superb.

7900 cut-away

he making of SRAMs XX cassette

On the SRAM stand was a great insight into how they produce the XX cassette. I know this is from the dark side but as an engineering process this is quite amazing.

The cassette starts as shown on the left, a 4.8kg solid block of billet steel.

The making of an XX cassette

Stage 2 : The profile discs are CNC-machined to give this:

Weight is now down to 2.3kg

Stage 2

Stage 3: The cogs are CNC-machined over an hour:

Weight is now 219g

Stage 3

Another hour of machining the holes and the cassette is complete.

Weight: 126.07g!

From a block initially weighing 4.8kg this is quite an achievement and its no wonder XX is now the bench-mark XC-race groupset.

Finished!

Something which caught our eye was this huge front plate on the PRO stem and bars. As modelled by Mark Cavendish it’s designed to resist all types of flex and going by looks we’d certainly trust it. We didn’t take our rulers but the front plate is massive, holding onto more bar than normal and being wider helps the bars to resist flex also. One for all the budding sprinters out there!

Probably not the lightest but it won't flex!

Something which caught our eye was this huge front plate on the PRO stem and bars. As modelled by Mark Cavendish it’s designed to resist all types of flex and going by looks we’d certainly trust it. We didn’t take our rulers but the front plate is massive, holding onto more bar than normal and being wider helps the bars to resist flex also. One for all the budding sprinters out there!

Probably not the lightest but it won't flex!

Probably not the lightest but it won’t flex!

Trek Madone Cut-Through

On Trek’s stand was a cut-through Madone frame. Showing clearly just how far they are pushing the boundaries with carbon frames (as are all the manufacturers) the carbon here is wafer thin.According to a certain boffin here at PBK a tube, if increased in diameter by a factor of two has an increase in stiffness of 16 times the original, while allowing the walls to be thinner! Which explains why everyone has gone ‘oversize’ with frames. Frames today will be right on the boundary between ultimate stiffness and the ability to resist flying stones and debris from tyre.

Frame cut-through

One last picture is off the Look stand. Their 1-piece all carbon chainset here is cut in half to show the varying thickness of the walls. With computers being heavily used the design has been tailored to provide strength where needed and then cut weight where no stress is applied. A very fancy chainset for some very fancy bikes

Look all carbon chainset



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