Mountain Bike Reviews Forum banner
1 - 20 of 22 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
Im doin once a while minor jumps (2-3 feet) with my bike but my crankset keep breaking
Its a hardtail bike so that could explain why it keeps breaking apart but im still pretty sure that if i put some better crank in it'll do the job
The problem is that i have absolutly not idea of what a great crankset is

Any suggestions of what crankset i should buy?
 

·
Old man on a bike
Joined
·
12,395 Posts
What exactly is breaking? What's your budget? My favorite value crank right now is the Shimano LX M582, Jenson has it for $99.
 

·
Registered
Joined
·
373 Posts
hmm yeah i mean idk whats breaking exactly, but if your actually snapping the crankarms or something serious, i also would reccomend the truvativ husslefelt
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #4 ·
Its actualy the square shape inside the arm that's causing troubles
After a while it gets deformed, the screw get loose and the arm eventualy fall off
 

·
Old man on a bike
Joined
·
12,395 Posts
easybiker said:
Its actualy the square shape inside the arm that's causing troubles
After a while it gets deformed, the screw get loose and the arm eventualy fall off
That's more likely a problem from poor installation, not a fault of the crank itself. Square tapers work great when installed properly. Once they're deformed, though, it is time for a new crank. The nice thing about the crank I mentioned is it comes with a new bottom bracket as well. If you just try to buy a new square taper crank you'll have to make sure it works with your current square taper bottom bracket spindle length.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #6 ·
That's more likely a problem from poor installation, not a fault of the crank itself. Square tapers work great when installed properly.
I dont think its the installation the problem 'cause the first time the crankset broke (i'm at my 3rd one right now:madman: ) its the guy at the bike shop who changed it and it didnt make a difference. Even more when i changed it, i replaced it by the same model
And what do you call a good installation???:confused:
 

·
Bicyclochondriac.
Joined
·
14,907 Posts
easybiker said:
I dont think its the installation the problem 'cause the first time the crankset broke (i'm at my 3rd one right now:madman: ) its the guy at the bike shop who changed it and it didnt make a difference. Even more when i changed it, i replaced it by the same model
And what do you call a good installation???:confused:
What crankset do you have now?
 

·
Underskilled
Joined
·
4,749 Posts
I think SLX is the cheapest cranks rated for abuse.

I used Raceface Atlas and it has taken 3 years to break, but has lifetime warranty =-)
Just to put this in perspective I have broken EVERYTHING else on my bike, the cranks was the last to go, EVERYTHING.
 

·
Banned
Joined
·
2,665 Posts
Are the spindles on the BB sound? Seems to me if you keep experiencing the same failure, the crank-spindle interface is compromised. My guess is your crank bolt is coming loose, followed by damage to your crank (and maybe the spindle too).

FWIW, I had a crank bolt come loose on a ride, on my (at the time) 15-yr-old Stumpjumper. A little Blue Loctite prevented that from happening again.

edit: To be clear, don't take that to mean "put your damaged crank back on your possibly damaged spindle and use Blue Loctite"
 

·
Bicyclochondriac.
Joined
·
14,907 Posts
easybiker said:
I cant remember the exact model but i know its an unexpensive shimano
It doesnt really matter because now its dead
If it did not matter, I would not have asked in the first place. Do you want help with this or not?

Anyway, it does matter what you have now, because knowing what does not work will help determine what will. If it is a very low end, budget/entry level crankset, then simple buying any half decent set could solve the problem, but if you are breaking a set of quality square taper cranks, then you may need something for freeride-specific.

Also, do not dismiss improper installation. It is possible that the problem is with the bb spindle at the bb/crank interface being deformed, and that is often due to improper intallation (specifically, the torque on the crank bolt). Once that is deformed, putting a new crank on is just going to damage the new crank at the interface. Based on the limited info you are giving, I am going with a deformed bb interface as the source of your problems, and that is either a factory defect or improper installation.

Really, any halfway decent set of xc cranks nowadays should handle an occasional 2-3 foot drop with no problem unless you are very heavy (something else you have not let us know yet). The suggestion of the LX cranks for $99 sounds like a great idea to me:thumbsup:
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #12 ·
kapusta said:
Also, do not dismiss improper installation. It is possible that the problem is with the bb spindle at the bb/crank interface being deformed
So basically if the bb interface is the problem i gotta change the whole crankset?

Sorry for the "limited informations" i gave you
My budget is around 100-150$ and im not super heavy so i think i'll buy the Shimano LX
except if you have a better suggestion
 

·
Probably drunk right now
Joined
·
6,753 Posts
No...

easybiker said:
So basically if the bb interface is the problem i gotta change the whole crankset?

Sorry for the "limited informations" i gave you
My budget is around 100-150$ and im not super heavy so i think i'll buy the Shimano LX
except if you have a better suggestion
What he's saying based on what you told us:

1. You're rounding out the inteface between the crank arm and the bottom bracket.

2. You've replaced the crank arm 3 times for the same problem.

3. You really shouldn't be having this problem.

4. You never mention replacing the bottom bracket.

5. You still haven't answered the questions asked.

It sounds like improper installation because it seems like your bottom bracket needs replaced. If your shop has replaced the crank 3 times and each time you have the same problem and they haven't suggested a $30 bottom bracket replacement, shame on your shop.
 

·
Bicyclochondriac.
Joined
·
14,907 Posts
easybiker said:
So basically if the bb interface is the problem i gotta change the whole crankset?
[/QUOTE
Yes, if the bb spindle is deformed, then you need to replace the bb, and if it has already damaged the current crank arm, then that also should be replaced.

Sorry for the "limited informations" i gave you
My budget is around 100-150$ and im not super heavy so i think i'll buy the Shimano LX
except if you have a better suggestion]
Yes, that sounds like a good idea:thumbsup: It even comes with the required bb.

FWIW, I agree with the comment made that your shop really screwed up not replacing the bb after the 2nd arm fell off. That should have been a heads up that there was definitely a problem with the crank/bb interface.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #16 ·
Ok the LX seems to be the most suitable for mu budget (100-150$)
But i remember when i previously searched on the inter for a crankset that there're 2 types of shape on the last gear (the one facing the inside of the bike)
One is curved and the other is not
Will that be a problem?:confused:

To be clear, don't take that to mean "put your damaged crank back on your possibly damaged spindle and use Blue Loctite"
For the blue loctite, i already tired a similar product and it didnt work:(
It only stopped the "squeeking" sound
 

·
Old man on a bike
Joined
·
12,395 Posts
easybiker said:
Ok the LX seems to be the most suitable for mu budget (100-150$)
But i remember when i previously searched on the inter for a crankset that there're 2 types of shape on the last gear (the one facing the inside of the bike)
One is curved and the other is not
Will that be a problem?:confused:

For the blue loctite, i already tired a similar product and it didnt work:(
It only stopped the "squeeking" sound
Two types of shape for a granny ring? There's different sizes, in terms of tooth count, but they're all round.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #18 ·
Bikinfoolferlife said:
Two types of shape for a granny ring? There's different sizes, in terms of tooth count, but they're all round.
Yeah thanx man i knew about that:thumbsup:
What i mean is the shape of the last gear will modify the distance between the crank and the bike

Also something i forgot to ask:
The speed? This LX is a 7, 8 or 9 speed?
It think my bike is 7
 

·
Old man on a bike
Joined
·
12,395 Posts
easybiker said:
Yeah thanx man i knew about that:thumbsup:
What i mean is the shape of the last gear will modify the distance between the crank and the bike

Also something i forgot to ask:
The speed? This LX is a 7, 8 or 9 speed?
It think my bike is 7
Are you thinking about chainline? It's not the shape of the gear, it's the specific setup of the crank/bb. An external crank is typically 50mm chainline, older square tapers more likely 47.5mm; the change is not likely going to be noticeable but possible. The LX is a "9 speed" but it'll work fine with your 7 or 8 speed chain.
 
1 - 20 of 22 Posts
Top