cracked cranks are fun.

fooferdoggie

Well-Known Member
I had thought once in awhile I felt my peddle was not quite right but then I checked it was fine. but today when I was sprinting across the street it was really off. checked the peddle seemed fine but tried again really off. I finally found out why the crank arm is cracked. this is on my bosch bike. I wonder if it is the really big peddles for my big feet or that sometimes I can put put 600 to 700 watts for a really short burst or both? I was about 3 miles into my ride home when I found it. only a couple of miles from the ebike shop I bought the bike from. well I went there and told them it was a isis spline and they thought they gave me the right arm out of their junk box. I go back to work as I have a crank puller there. try to take the crank off discover I am missing the washer on stye crank puller so it wont work. lucky I have another shop about 4 blocks from my shop ride there get the crank off and find it is the wrong one. s oI( put it back on and carefully ride home in turbo not putting much pressure on the right crank. of course thats the crank I stand on when starting so its awkward.
I should be able to rise but I wont get a workout now. new arms are like 65.00 but I spent 30.00 for overnight shipping. this is the same arm on our tandem when we crashed look how much it bent. never crashed my regular bike worst case it fell over on that side once.
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fooferdoggie

Well-Known Member
man my left knee is getting tired of doing al later work. even in turbo and only averaging 79 watts thats less then half my usual its getting tired. should have the new cranks tomorrow.
 

Timpo

Well-Known Member
So your crank was hollow? 😲
I wonder why? For weight reduction?

None of my cranks are hollow... I know for a fact because when my crank got stuck on bottom bracket, I had to get an angle grinder and cut them.. on two different occasions.
 

fooferdoggie

Well-Known Member
So your crank was hollow? 😲
I wonder why? For weight reduction?

None of my cranks are hollow... I know for a fact because when my crank got stuck on bottom bracket, I had to get an angle grinder and cut them.. on two different occasions.
no but it has a recess in the back. same with the new ones. it would actually make it stronger I think.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
no but it has a recess in the back. same with the new ones. it would actually make it stronger I think.
Good cranks are hollow (have the recess on their back), for weight reduction. Praxis is the leader in bike cranks.
 

mschwett

Well-Known Member
Region
USA
got them on so Purdy :D should have spent the extra 200 for the carbon fiber ones.

niiiice. i went for the carbon ones on my creo, can't say i could tell the difference lol. very nicely made, satisfying product. installed perfectly.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
i went for the carbon ones on my creo, can't say i could tell the difference lol.
You're going to hate me mschwett for saying that but carbon fibre components are the first thing expected to crack :) What would foofer gain on CF cranks?
 

mschwett

Well-Known Member
Region
USA
You're going to hate me mschwett for saying that but carbon fibre components are the first thing expected to crack :) What would foofer gain on CF cranks?

i'll be pretty proud of myself if i pedal hard enough to crack my cranks!

foofer made the right choice - the weight savings of 116g are certainly not worth it on an eBike.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
i'll be pretty proud of myself if i pedal hard enough to crack my cranks!
Haha! Yet, Steve is a heavy duty rider with great mileage. He has also experienced several crashes. I don't think CF cranks would be the right choice for him!
foofer made the right choice - the weight savings of 116g are certainly not worth it on an eBike.
Especially on a tandem...
 

fooferdoggie

Well-Known Member
You're going to hate me mschwett for saying that but carbon fibre components are the first thing expected to crack :) What would foofer gain on CF cranks?
actually anymore CF is far stronger than aluminum. but its way more then I wanted to spend. I just worked out between our two bikes we spend about 280.00 every 2000 to 3000 miles to ride. since we do about 9000 a year it gets expensive.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
Steve, I don't tell you how you should spend your money. I'm only telling you what CF component brands tell their customers. Buy the darn expensive Specialized CF "Mirror" saddle to learn you better "replace it after 3 years for your own safety". CF frames are not warrantied for lifetime: shall they crack, you can buy a new frame under "Crash Protection" programme and so on.
 

mschwett

Well-Known Member
Region
USA
… CF frames are not warrantied for lifetime: shall they crack, you can buy a new frame under "Crash Protection" programme and so on.
i don’t think that’s true…

  • We stand behind our frames—forever. This means we offer a lifetime warranty to the original owner against structural defects in material or workmanship on ALL models of Specialized-branded frames and forks. This includes seatstays and chainstays on full-suspension bikes.

lots of reports of people (original owner only!) getting their CF frames replaced by specialized.

Yes, I had an excellent experince!
My Tarmac road bike developed a crack at just under 2 years old.
My LBS phoned Spesh the following morning, a new better frame was delivered the day after and it was built up that day!
 

Nomad

Active Member
Steve, I don't tell you how you should spend your money. I'm only telling you what CF component brands tell their customers. Buy the darn expensive Specialized CF "Mirror" saddle to learn you better "replace it after 3 years for your own safety". CF frames are not warrantied for lifetime: shall they crack, you can buy a new frame under "Crash Protection" programme and so on.
I saw that there are some carbon wheels with lifetime warranties but, I must say when I here the word carbon frame the first thing that enter my mind is crack but I have never had a carbon frame.