Which Crankset+Chainring will fit my frame crank?

[rg12]

Hey Guys,

I got this Chinese enduro ebike frame that comes with a crank (or is it called the bottom bracket?), anyway
it's got that middle section already in so I just need the crank arms, pedals and chainring.
I want to order from eBay but most I find are mostly those hollow center shimano like crank arms that come with a 4 bolt chainring.
Which one do I need? and I also need to know which pedal thread will fit because I noticed that there isn't just one standard...

 

[wturber]

Hey Guys,

I got this Chinese enduro ebike frame that comes with a crank (or is it called the bottom bracket?), anyway
it's got that middle section already in so I just need the crank arms, pedals and chainring.
I want to order from eBay but most I find are mostly those hollow center shimano like crank arms that come with a 4 bolt chainring.
Which one do I need? and I also need to know which pedal thread will fit because I noticed that there isn't just one standard...

You need to figure out what kind of bottom bracket you have. The key item you'll need to know is what kind of spindle your bottom bracket has. Once you know that, you can start looking for cranks that match the bottom bracket and chain rings that will mount to the crank you pick. There are multiple standards for bottom brackets and for chain rings.

Post a close-up pick of your bottom bracket and someone here who knows these things in more detail than I do, will probably be able to tell you what you've got. If your frame is new and came with the bottom bracket installed, maybe the bottom bracket type is documented.

 

[rg12]

It's not near me right now but I remember that it has a square thingy to connect the pedal arms to...

 

[dogman dan]

Then you need square taper type crank. Easy to find, they still use square taper on the less expensive bikes.



Likely you want to pick one from an mtb, rather than a road bike. A road bike crank might rub the frame, since the pedals are set narrower on road bikes.

 

[d8veh]

It would be better to show a photo of it so that we can give exact sdvice instead of general advice,

 

[rg12]

Ok, I got the frame and the crank has a square crank that is 13*13mm and has a screw hole in the middle.
Can someone help me with an eBay link to a set of crank arms, chainring and pedals that will fit it?

 

[wturber]

Ok, I got the frame and the crank has a square crank that is 13*13mm and has a screw hole in the middle.
Can someone help me with an eBay link to a set of crank arms, chain ring and pedals that will fit it?

Sounds like you have a square taper spindle in your bottom bracket. Take a look at this page to make sure. If that looks like your spindle then you will know what to go shopping for.

https://sheldonbrown.com/bbtaper.html

 

[rg12]

Thanks alot, that helped!
Now the problem is finding a set of crank arms that have a single chainring (since it's for a singlespeed (ebike)) that doesn't cost $100 (el cheapo)
any ideas? I also prefer a relatively small chainring because the big ones are ugly as hell.

 

[Chalo]

You don't choose a chainring because you like how its size looks. You choose it on the basis of the gearing range you need. What's the highest speed you want to pedal at? What are the sprocket sizes you have in back?

Ignore all this if you don't pedal. Heck, don't even put a chainring and chain on your bike if you don't pedal.

 

[rg12]

You don't choose a chainring because you like how its size looks. You choose it on the basis of the gearing range you need. What's the highest speed you want to pedal at? What are the sprocket sizes you have in back?

Ignore all this if you don't pedal. Heck, don't even put a chainring and chain on your bike if you don't pedal.

I know it changes the gearing, I have a single speed 16T in the back and no one really pedals with these high powered ebikes.
I just hate those big looking chainrings.
The ones on downhill bikes are very cool since they are a single chainring and a small diameter.
But I need something cheap for a square taper.
I thought about something like $20-$30 for a set of crank arms and a chainring (something simple and black).

 

[wturber]

This looks like what you are asking for. Though I have no idea if it is what you "need."

Heck. It even comes with its own bottom bracket.

http://www.ebay.com/itm/Aluminum-Fixie-Single-Speed-Track-Crankset-170mm-42T-Square-Taper-BB-NEW-/391890554081?epid=1993199518&hash=item5b3e7f4ce1:g:U-QAAOSwNgdZnFgU

Hey. Maybe spice things up with some cool colors.
http://www.ebay.com/itm/Alloy-44T-170mm-Fixed-Gear-Bike-Crankset-Single-Speed-Bicycle-Chain-Wheel-Riding/222435199509?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D43628%26meid%3D0c89f7daf416487e8c9c2bc05f8f6d37%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D372085209519&_trksid=p2047675.c100005.m1851

 

[rg12]

Thanks alot man!

 

[wturber]

Thanks alot man!

No problem. I have no idea if a $30 crank is strong enough to deal with a guy doing motocross stuff on an e-bike. It may be plenty strong. But personally, I'd spend the extra money on a name brand crank (used even) if I was jumping my bike on hills and the like. But you asked for a $30 crank ... so there ya go.

 

[Chalo]

I have no idea if a $30 crank is strong enough to deal with a guy doing motocross stuff on an e-bike.

The crank is probably fine. What breaks those-- very infrequently-- is high-cycle fatigue from tens of thousands of miles of vigorous pedaling. I don't think we have anyone like that in present company. It's far more common to ruin a crank like that by letting it become loose on the spindle and thus wallowing out the square hole.

It's the square taper bottom bracket spindle that's at significant risk of breaking. I've snapped off two of them (one time at the cost of my front teeth) on normal pedal bikes, with quality name brand BBs. I generally avoid square taper BBs now. I accept one on my BBS02, because that's the only way I get to have a BBS02. And because I pedal less forcefully when I ride it than I do a regular bike.

I think things like jumping a bike and doing wheelies are dumb and juvenile even when a small adult does them, but they're even dumber when a big man (me for instance) does them. But if I felt dumb enough to do them, I sure wouldn't use a square taper crank for that.

 

[wturber]

I have no idea if a $30 crank is strong enough to deal with a guy doing motocross stuff on an e-bike.

The crank is probably fine. What breaks those-- very infrequently-- is high-cycle fatigue from tens of thousands of miles of vigorous pedaling. <snip>

Good. I wouldn't want to recommend something that is likely to precipitate injury. I'm using a square taper right now on my bike. But I'm an average height guy who weighs 160 lbs (and moving down). So I doubt I'll break mine. I never did on my Trek1400.

I doubt the OP is interested in doing the additional research and work on the BB size/thread, but a similar combo that comes with an ISIS spindle might be better for him. He doesn't have to use the square taper Bottom Bracket that the bike came with.

 

[rg12]

I rarely even make one turn with my pedals...as long as they are bolted firmly I don't think I will have any trouble.

 

[wturber]

I rarely even make one turn with my pedals...as long as they are bolted firmly I don't think I will have any trouble.

My concern was their strength as a platform to stand (or jump and land) on. But Chalo seems to think they will be fine and I think he has a lot of experience in seeing what fails and doesn't fail on bicycles. So yeah. You are probably fine with this.