I'm training toward riding my road bike from my house to the ski lifts at baldy. With that in mind, I need to get some compact cranks. I found some for a reasonable price, but they are 165mm. On my mtb bike I've been running 170 and 172.5 and I'm 5'8" with more torso than leg. My inseam is 28". Does anyone have experience with shorter cranks? I know I will lose some of the low gearing because of shorter cranks, but that is only a 4.3% loss going from 172.5 to 165. At the same time will be gaining 12.8% in gearing when going from a 39 to a 34. Total of 8% lower gearing. Any thoughts? thanks in advance.
i have 175's (6'3" rider) and compact gearing. I need all the help I can get to climb to the lifts...
I thought that 165mm are mostly used for DH bikes??? Didn't think people put them on anything else?? But then again i don't ride anything but a DH bike.... shitty CRAP! I just realized i was in the roadie hangout, nevermind....
It'll be a downhill bike once I get to the lifts.:lol: Although I could be like a friend of mine who has his wife pick him up at the top of the road.
I'm in the same situation as you. I'm planning to ride to the lifts on Sunday for the first time. I'm 5'7" and run 170mm on the mtb and 172.5 on my road bike with standard gearing. I was going to buy compact cranks but it cost so much. Luckily I have a rear cassette that has a 28 tooth gear. I found a gearing calculator online and it said my ratio is the same as if I was running a compact crank with a 25 tooth rear gear. I don't think I would want a shorter crank. Spinning it would feel weird. Maybe it would be cheaper to find a taller cassette for the rear.
I an a 30" inseam and rode 165's trying to sort out some knee issues. didn't really mind them but it turned out that narrow Q on a 170 was the fix that worked. I'm genrally a hamster and the 165 was OK for me.
gearing is not angular momentum. Think of this as 7 inch pounds vs 6 inch pounds applying torque on the same fastener. Of course you are talking mm so I should be quoting newtons. The longer lever will be noticed when it becomes all torque in the switchbacks........ Happy trails....yum, I get to fig in newtons
Woe... Do road bikes normally run shorter cranks? And if they do, what is the reasoning behind it? I have never owned a road bike but I'm 5' 8” with a 30” inseam and I have never ran a crank shorter than 175mm. Heck when I used to race BMX when I was 14 I used to run a 187mm crank with a 48t chainring and a 16t freewheel. I was untouchable in the straights
yes, generally shorter. Reasons: less weight, ground clearance, easier to spin fast. Time Trialers will use longer cranks previous factors don't matter.
I guess that makes sense. I suppose since road bikes role better that torque is not as much of an issue as on a MTB.
The reason road cranks are a bit shorter is the rider suppose to spin more instead of mashing gears and more roadies spend the money and time to get fitted with proper crank length. Yes you get more torque with longer cranks but you will have 10mm of extra up and down leg movement if you have cranks that are 5mm longer or your legs need to make 10mm x 3.1415 bigger circle. Or 1.2inch x 80 RPM = 96 inches extra distance for your feet to travel. Of course this does not mean you should get ridiculously short circus monkey bike cranks, get fitted first and ask a professional. So if you are a spinner go with shorter cranks and if you are a masher then go longer. BUT once you learn to spin on a road bike you will actually put out more power/torque than mashing with long cranks. Here are couple of links for crank length calculation(you need shorter cranks than you think): http://www.machinehead-software.co.uk/bike/cranks/cyclist_crank_length_calculator.html http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO
Thanks for the bigger circle comment. For the same force on the pedals each revolution transfers more energy and if you can do it as fast as a shorter crank - more power. Road racers want to spin fast because it recruits the fast twitch muscles needed for a sprint to the finish line or to catch a break-away. Fast twitch muscles tire quickly so for distance riding spinning is not optimal - look at TT riders. To optimize for distance riding (slow twitch) you want longer cranks and more of a masher style. The best length depends upon your size, your muscles, and your goals.
Hey Chupacabra, I finally road up to baldy for the 1st time today. Did it with standard gearing (cranks 172.5) and a 28 tooth rear cog. It was tough but a lot of that had to do with the head wind. I met a guy there that had a 32 tooth rear cog. You just need to find out if your rear derailleur could handle it. I think this could be a cheaper/easier option than changing out your cranks.
Psycle.. Great Job. Quite the accomplishment. That is one tough ride without the headwind. I'm sure I will be in survival mode, if there is a wind it will be hard to get past it. I just paid for the cranks. Hopefully I will have them in hand on Weds. I will give everyoine an update on my perceptions.
