Crank Length

[Mountie]

Hi I’m looking at purchasing a set of carbon cranks from Praxis for my 2018 Expert Levo, does anyone know the stock crank length 170mm or 165mm? Or has anyone tried these cranks yet?

Thanks

 

[NSFRACING28]

Hi I’m looking at purchasing a set of carbon cranks from Praxis for my 2018 Expert Levo, does anyone know the stock crank length 170mm or 165mm? Or has anyone tried these cranks yet?

Thanks

Not sure if you managed to find any but here is my experience. 20 mins of riding from brand new, 2019 s-works. First minor pedal strike.

 

[Mountie]

Not sure if you managed to find any but here is my experience. 20 mins of riding from brand new, 2019 s-works. First minor pedal strike. View attachment 14670View attachment 14671View attachment 14672

Thank you so much and sorry that happened hopefully they give you your money back.

 

[NSFRACING28]

Thank you so much and sorry that happened hopefully they give you your money back.

Sadly no, Praxis stated no manufacturing fault. Personally, if that is the case, I cannot see how they can be fit for purpose. I have replaced them with alloy and will not put carbon cranks back on. Pretty poor for a $15,000 bike.

 

[Mountie]

Sadly no, Praxis stated no manufacturing fault. Personally, if that is the case, I cannot see how they can be fit for purpose. I have replaced them with alloy and will not put carbon cranks back on. Pretty poor for a $15,000 bike.

I was going to order Monday, I thought they must be a durable as the stock aluminium arms but I guess not. Thanks for saving me some money specially is Praxis won’t stand behind their products no interest in a company that takes the money and runs. Again, sorry this has happened to you.

 

[deanphoto]

Hi I’m looking at purchasing a set of carbon cranks from Praxis for my 2018 Expert Levo, does anyone know the stock crank length 170mm or 165mm? Or has anyone tried these cranks yet?

Thanks

I wouldn’t bother.

 

[Mountie]

View attachment 14674

View attachment 14675

I wouldn’t bother.

Another set?

 

[Mountie]

i dont see the logic behind putting cf cranks on a 45 lb bike w a motor. aside from bling factor

They are totally cool and every gram you save extends your range and cool factor. I was about to buy them but this has stopped me totally in my tracks. When they break they also look very sharp wouldn’t want to get speared by carbon shards in a big off.

 

[Mountie]

whats the difference in grams like 50 grams total? you can shed more weight by taking a piss.

Lol true, but it is fun making a machine as efficient as possible.

 

[NSFRACING28]

and to add insult to injury (at least financial), when the pedal wasnt there on my next down stroke, I ended up going over the handlebars. In a funny/not funny slow speed crash. The resulting damage to the bike, helmet and smashed Apple watch was way more than the cost of the cranks (Specialized agreed to cover the cost of the Helmet as a goodwill) However, the CSU on the forks was damaged and needed to be replaced. The LBS ordered the new one and when it arrived it was for E-bike specific forks. All good you would think!? But No, the Fox Factory Forks on my 15k bike, although advertised as E-bike specific, and marked on the leg as E-bike specific are actually not. They are the standard ones with 1mm tube thickness. LBS then had to order another one as the internal piston and valving was for the standard leg. So how about a warranty failure if they have decided that E-bike specific forks are necessary? What about premature failure? I will be very interested to hear what Specialized Customer Care comment about that. Anyone else had this?

 

[Mikerb]

I use carbon products a lot in my other sport of Windsurfing......mast boom and board. You need to know what you are buying...what modulus carbon, what cloth makeup....e.g UD/Biaxial, what epoxy, what layup, what manufacturer. Carbon composites are rarely just carbon. Carbon components can be lighter and stiffer than other fabrications however the main benefit is speed of reflex. Its main weakness is impact resistance. I can see no real benefit in using carbon for a crank. In fact I would not buy carbon for any part of a mountain bike!! Road bike....maybe, but after any sort of crash you could not guarantee terminal ....often unseen...damage.

 

[HORSPWR]

They are totally cool and every gram you save extends your range and cool factor. I was about to buy them but this has stopped me totally in my tracks. When they break they also look very sharp wouldn’t want to get speared by carbon shards in a big off.

Or have to pedal 20 ks home with one leg!

 

[TMS]

I have hitted SW carbon cranks to rocks very hard several times. No problems so far. I don't know how much experience Mikerb have carbon mtb frames and parts. I've had zero issues with carbon frames, cranks, seatposts, handlebars or rims since 2013. So I think carbon is fine. However, looks that Praxis cranks could be the first exception.

 

[Mikerb]

I have hitted SW carbon cranks to rocks very hard several times. No problems so far. I don't know how much experience Mikerb have carbon mtb frames and parts. I've had zero issues with carbon frames, cranks, seatposts, handlebars or rims since 2013. So I think carbon is fine. However, looks that Praxis cranks could be the first exception.

None for the reasons I stated but 30+ years windsurfing where I have seen both success and dismal failure of carbon components.

 

[Tetsugaku]

They are totally cool and every gram you save extends your range and cool factor. I was about to buy them but this has stopped me totally in my tracks. When they break they also look very sharp wouldn’t want to get speared by carbon shards in a big off.

Having a poo before you ride would give you more range mate

 

[Mikerb]

You can make carbon composite more impact resistant by using a biax weave with kevlar but that is hard to lay up other than as a flat surface so usually added to a composite in small vulnerable sections. Strange with the broken crank pics There was no obvious laminate layers almost as if they were moulded using epoxy with micro fibres rather than a composite lay up.

 

[HORSPWR]

You can make carbon composite more impact resistant by using a biax weave with kevlar but that is hard to lay up other than as a flat surface so usually added to a composite in small vulnerable sections. Strange with the broken crank pics There was no obvious laminate layers almost as if they were moulded using epoxy with micro fibres rather than a composite lay up.

Composite lay up will always be stronger followed by inpreg.

 

[Mikerb]

The pics of broken cranks show that they are constructed using a foam core machined to shape then layed up with carbon and epoxy wetted and then vacuum wrapped. I assume the metal parts are bonded in after it is cured. I saw one video of Race Face making carbon cranks and it said they use UD cloth.....ok its the lightest and very stiff but only in one direction and very brittle...it would not be my choice of cloth. The video did not inspire much confidence in carbon cranks for me. About the only real gain is that carbon does not suffer from repetitive stress fatique like ally and it can be lighter. Weight saving on a small component is marginal however. Carbon has nowhere near the same impact resistance as ally. Ally will deform/dent, carbon snaps. Any impact that fractures the weave can be invisible but will lead to failure. Not for me!