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Cycle Snack said:
Is there any other cons on 180 mm cranks (as opposed to 175s) than possibly weight and perhaps more pedal strikes that I am not thinking about?
This subject has been hammered over the years; suggest you do a search. You'll find a ton of info.

Pedal strikes are caused by a too-low BB, not too-long cranks. If your cranks are the right length for your legs but you're suffering too many pedal strikes, then you need a new frame with a higher BB, not shorter (ie: wrong size) cranks.

Most people choose to resist this notion because they don't want to consider fixing the root of the problem (a new frame is expensive and they may like their current one). Regardless, it is truth.

--sParty
 

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SSOD
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It could be just two different riding positions, but I have 180's on my Bianchi Muss, 17.5 frame, that I bought used to try out a rigid bike. I hit roots/ rocks all the time when pedaling uphill over rough terrain. I also have a Bianchi Wuss, 17.5 frame, with 175's on it, which are what fit me for that bike, and I still have pedal strikes occasionally but with less frequency it seems. Could be alot of other factors but that's just my experience with the two sizes.
 

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Sparticus said:
This subject has been hammered over the years; suggest you do a search. You'll find a ton of info.

Pedal strikes are caused by a too-low BB, not too-long cranks. If your cranks are the right length for your legs but you're suffering too many pedal strikes, then you need a new frame with a higher BB, not shorter (ie: wrong size) cranks.

Most people choose to resist this notion because they don't want to consider fixing the root of the problem (a new frame is expensive and they may like their current one). Regardless, it is truth.

--sParty
I'm not sure I get your logic on this one.

So let's take a On One Inbred 29er for example. If you get pedal strikes by using 180mm or longer cranks it is the fault of the frame, and not the length of the crank arms??

So someone who would need to use 180 or longer cranks should have a frame that has a 13.5" or so bottom bracket height?? :confused:

Doesn't add up.

I'd say you just have to deal with pedal strikes if you want to use a particular frame. It is not the fault of the frame/nor of the crank length per se. Just a factor you have to deal with based on one's normal riding terrain, their crank length of choice and a frames bottom bracket height.

No real "wrong" part in the equation IMHO.
 

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MMcG said:
I'm not sure I get your logic on this one.

So let's take a On One Inbred 29er for example. If you get pedal strikes by using 180mm or longer cranks it is the fault of the frame, and not the length of the crank arms??

So someone who would need to use 180 or longer cranks should have a frame that has a 13.5" or so bottom bracket height?? :confused:

Doesn't add up.

I'd say you just have to deal with pedal strikes if you want to use a particular frame. It is not the fault of the frame/nor of the crank length per se. Just a factor you have to deal with based on one's normal riding terrain, their crank length of choice and a frames bottom bracket height.

No real "wrong" part in the equation IMHO.
My Inbred 29er does have a 13.5" BB with a taller 100mm fork and big tires though ;)

I don't think Sparty is saying that "just dealing with it" isn't the easiest or cheapest solution, but that if you want to do what it takes to make it right you shouldn't compromise the proper fit of longer crank arms when you can compromise the slight difference in handling without compromising fit.
 

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MMcG said:
I'm not sure I get your logic on this one.

So let's take a On One Inbred 29er for example. If you get pedal strikes by using 180mm or longer cranks it is the fault of the frame, and not the length of the crank arms??

So someone who would need to use 180 or longer cranks should have a frame that has a 13.5" or so bottom bracket height?? :confused:

Doesn't add up.

I'd say you just have to deal with pedal strikes if you want to use a particular frame. It is not the fault of the frame/nor of the crank length per se. Just a factor you have to deal with based on one's normal riding terrain, their crank length of choice and a frames bottom bracket height.

No real "wrong" part in the equation IMHO.
Boomn gets my point.

Crank length is another facet of proper bike fit. Bottom bracket height is not. Make your bike fit you correctly first, build the frame around those parameters.

As for BB height and its affect on handling, that's another topic altogether. I've owned literally dozens of frames in my riding "career" (road bikes since ~1970, mtn bikes since 1985) and could mount a compelling argument for high BBs handling just as well as low BBs (at least on mtn bikes) despite the common belief that a bike with a low BB handles better. Personally I don't believe this whatsoever.

Ironic that you mentioned an On-One Inbred 29er in your example above. I ride that exact bike and employ 195mm cranks on it. One reason I chose this frame was it's relatively high BB. I've also discovered that the human brain is amazing at learning to take everything into account subconsciously. When I first moved to "extreme-length" cranks on production frames back around the turn of the century, I'd hit my pedals on the ground often. After a few months it hardly ever happened. I believe this automatic ability becomes intuitive for those willing to persevere.

Another skill that one seems to acquire when employing long cranks on a frame with "standard" BB height is not freaking out whenever the pedal bumps into something. Initially this was disconcerting to me... but after a while I got to where I practically didn't notice it whenever it happened. I generally shrug it off and keep pedaling.

BB height is not something that frame manufacturers want to factor into frame sizing. Some people like 170mm cranks, some 180mm, etc. regardless of leg length. This is fine, and frame manufacturers don't want the expense of offering two different BB heights in their XL frames for those tall riders who value cranks longer than 175mm or 180mm. In the bicycle industry, this is considered one of the reasons that custom frame builders exist. Can't exactly blame production frame manufacturers for embracing this attitude.

--sParty
 

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Longer cranks = bigger circle to be turning with your legs. Not sure if that's a big issue for you, but it's certainly something to keep in mind.
 

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Somewhere on this forum there is a thread that claims that shorter cranks are better for SS. Regardless, I don't think that crank length matters all that much. My single speed mountain bike has 180mm cranks, my cyclocross bike has 175mm cranks, and my road single speed/fixed has 170mm cranks. It's really just a matter of preference. Here's another "con" for 180mm cranks - there are a lot fewer cranks to choose from compared to 175mm cranks.
 

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ballbuster
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The root of the problem....

Sparticus said:
This subject has been hammered over the years; suggest you do a search. You'll find a ton of info.

Pedal strikes are caused by a too-low BB, not too-long cranks. If your cranks are the right length for your legs but you're suffering too many pedal strikes, then you need a new frame with a higher BB, not shorter (ie: wrong size) cranks.

Most people choose to resist this notion because they don't want to consider fixing the root of the problem (a new frame is expensive and they may like their current one). Regardless, it is truth.

--sParty
... with pedal strikes is poor pedaling technique.

I love low bottom brackets, and long cranks. Yes I pedal strike from time to time, but I blame the rider, not the equipment.

Me: Singular Swift with 180mm M952 XTRs with Jericho SufferRing. EBB in the push-down position. Rails rollercoaster singletrack like a mufugger. Love this setup. I don't really have long legs, but I love the extra torque, but you do give up a bit of 'spin'. Like Sparty said... it really doesn't make a huge difference, but I like it.

 
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