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Is it Possible to Bent a Crank Spindle in a Nasty Crash?

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Is it Possible to Bent a Crank Spindle in a Nasty Crash?

Old 01-10-20, 02:21 AM
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SuperPershing
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Is it Possible to Bent a Crank Spindle in a Nasty Crash?

Is it Possible to Bent a Crank Spindle in Crashing?



Because im going to buy a new Crank which is a Vision Track Crankset and its Spindle is forged 7075 30mm. And currently i have a Sram Omnium with a CroMo Spindle which is Damn Strong. But i was skeptical becuase on the picture above, is a Bent Crank but not from a Crash. But since im planning to Switch to a Softer Spindle material, I'm afraid that i might bent or damage the spindle when i crash in a Race (I will soon race in a Fixed Gear Bike) Since its a Weaker Material than the CroMo Steel


Spindle of a Sram Omnium, 24mm CroMo

Spindle of a Vision Track Crankset, 30mm Forged 7075-T6 Alu
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Old 01-10-20, 05:45 AM
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Anything is Possible. If you Crash hard enough to Bent your Crank, you may be Off the Bike for awhile. Try to not Take Anyone with you When you Crash.
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Old 01-10-20, 07:47 AM
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That bent spindle is odd. How were the bearings removed?
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Old 01-10-20, 09:34 AM
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I'm no expert but I would think if you crashed and bent that "spindle" like that you've probably got bigger problems than just a bent spindle.
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Old 01-10-20, 09:35 AM
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The "bent" spindle looks to me to be more of a twisted one. The splined end seems to still be coaxial with the rest of the spindle and the ripple has a angular nature to it. I'll bet a beer that it was overloaded in a test jig, note the complete lack of bearing seat wear or and marks/dirt on the splines or threads.

I've seen FAR more bent arms then BB axles, by a huge factor more. But I do have to note that when going after race grade stuff how one races and how one values replacements (or pays for them) really determines if a race light choice is the best choice. Andy
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Old 01-10-20, 09:57 AM
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From Bike Rumor web site . I think you can rest easier now, unless you can put over 1,600 pounds of pressure on your cranks.

Shown above and below is the GXP spindle after it’s been subjected to SRAM’s stress test. The GXP spindle is steel, and when pressure is applied to both crankarms, the spindle will twist and bend before the cranks are affected. The GXP spindle deforms to the point where it will bind up in the bottom bracket at about 1,655 pounds of pressure. Essentially, your bike will become unrideable before you’re ever going to break one of the crankarms.
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Old 01-10-20, 10:35 AM
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Originally Posted by SuperPershing View Post
...
But since im planning to Switch to a Softer Spindle material, I'm afraid that i might bent or damage the spindle when i crash in a Race (I will soon race in a Fixed Gear Bike) Since its a Weaker Material than the CroMo Steel...
Clue: Material "softness" is not material strength and material strength is not structural strength. Unless you're prepared to re-engineer your bike from first principles, maybe pick a manufacturer to trust.
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Old 01-10-20, 10:48 AM
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You're over thinking things
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Old 01-10-20, 11:46 AM
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Anything's possible, I've seen BB cups shatter and square taper TI or hollow steel BB snap though usually due to a construction flaw leaving a stress riser. I've not heard of hollow spindles just breaking and I'm glad to see that the pic posted was from a testing machine. I've seen plenty of bent arms from impacts where the spindle was good and I'd be more worried of a crank failing before a modern spindle. Any respectable brand should be over-engineered to be safe enough for the power output of professional level riders and more then safe; also, just don't crash.
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Old 01-10-20, 01:31 PM
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Originally Posted by Moe Zhoost View Post
From Bike Rumor web site . I think you can rest easier now, unless you can put over 1,600 pounds of pressure on your cranks.
So OP lifted pic from Bike Rumor and either didn't read the article or posted a fake "concern." Lame
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Old 01-11-20, 06:07 AM
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"But i was skeptical becuase on the picture above, is a Bent Crank but not from a Crash." I said not from a crash and this was on a forum of testing the spindle. Its just a Reference/Imagination picture duh
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Old 01-11-20, 06:08 AM
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Unfortunately, Yes i do
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Old 01-11-20, 06:09 AM
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Its from a Test sorry, i just used it for reference
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Old 01-11-20, 10:13 AM
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Originally Posted by SuperPershing View Post
...
I'm afraid that i might bent or damage the spindle when i crash in a Race...
You're asking the wrong question. Anything and everything used in racing is expendable from the first moment.
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Old 01-11-20, 10:55 AM
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Originally Posted by AnkleWork View Post
You're asking the wrong question. Anything and everything used in racing is expendable from the first moment.
Including the racer.....
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Old 01-11-20, 09:36 PM
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Agreed that racing means anything is expendable. However there are shades of grey in equipment choices and finishing is more important then dropping out when leading because of a mechanical. Andy
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Old 01-12-20, 12:07 AM
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Originally Posted by Andrew R Stewart View Post
Agreed that racing means anything is expendable. However there are shades of grey in equipment choices and finishing is more important then dropping out when leading because of a mechanical. Andy
"...when i crash in a Race..."
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Old 01-12-20, 08:15 AM
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What's the difference to the rider's goal, placing well in the race, if the bike broke because of or separate of an accident? Andy
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Old 01-12-20, 08:27 AM
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racing in a fixed gear series is pretty much going to guarantee in bent and scraped human parts, I'd be a lot more concerned about that....
Pedal-strike-a-rama
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