Crank length >175mm?

[Chad Minnaar]

I know the topic of crank size has been discussed in length and I get the theory behind it, however I'm looking for RESPONSES ONLY FROM CYCLISTS WHO HAVE ACTUALLY USED CRANKS LONGER THAN 175mm.

My inside leg measurement is 93cm and according to some charts I should be using a crank 180-185mm.

Has anyone moved to a 177.5 or 180mm crankset and what feedback can you offer me?

 

 

 

 

 

[popcorn_skollie]

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[The Guy in Pink]

I use a 180mm crank on my road bike, using the logic that as my strength declins with age I can still create the torque but at lower cadence. Finding 180mm cranks is more difficult - unless like me you enjoy Campy Record.

according to the chart above the 185mm crank is right.

I certainly enjoy the longer crank which I can still spin at over 110 cadence when I want.

[Super J]

I ride 180mm on me road bike and 200mm on me TT rig, I dont think its so much about leg length but more about your power out put and cadence, but saying that, I am over 2 meters tall..... Now here is my logic behind this...... taller people obviously have longer legs, and carry more muscle mass, and this also causes a reduction in leg speed as there is a greater range of motion that the legs travel.... just look at track sprinters, the short guy take rapid short strides while the taller runner take a much slower but longer stride, you never see a Giraffe prancing about like a Springbok...but due to the extra muscle mass and leverage the taller rider can exert more power.... much the same as motor sport where they increase a pistons conrod length or "stroke" for more compression and power, but inturn this reduces the revs. So I think you have to look at your own riding style, whether you tend to spin or grind a gear, and take it from there but dont try force yourself into a riding style that your body isnt natural at! I am the common laughing stock in PTA rides when everyone is riding along at 90 rpm and I sit comfortable at 60rpm, and then we hit a climb and these guys go through the gears to get their cadence up while I still sit in the same gear at the same speed, the problem I have is when there are rapid jumps or attacks, i cannot mach the increase in speed as fast as the spinners, but there is **** when I get that gear going....... Hope this helps a little.

[Trackmonster]

One of the guys who rides with us has a 180 crank and a 175. He says the 180 puts a bit more pressure on his knees and prefers the 175. He is 6ft5. I do agree with the longer crank for taller riders but I am 6ft 4 and still ride 175 with no problems. I race track sprints on 167.5 and have even used 165, but that was way too tight to spin such small circles. I will stick with the 175 as they seem fine. To go out and buy 180 and then find the 175 were better is a waste of money.

[Long Wheel Base]

I often ride on the front of a tandem and converted our ride to 180mm up front and 175mm at the back. found it made a difference. even did kremetart with that set up and climbed that first and last hill just fine. gearing we running is 44 and 56 tooth blades with either a 23-11 or 27-11 cluster depending obviously on terrain. I'm 182cm tall so according to that chart I should ride shorter but I much prefer the longer crank on the tandem. I do however ride a 175mm non compact on my single bike. But like it was said before its difficult to get longer cranks. My 180mm is a old model dura-ace TT crank.

[montyzuma]

I have an inside leg measurement of 95cm and after thinking about the logic of longer cranks for longer legs etc I changed to 180 cranks. I got really painful quads for a while on long rides, and dropped to 177.5's which worked well for me for a few years. Eventually finding them was just too much hassle (Shimano don't even offer them in the new XTR any more) and I've gone back to 175's. I don't notice any great difference in power output or cadence, but when I do ride the 177.5's on my old MTB from time to time I do get painful quads on long rides

Edited October 8, 2014 by montyzuma

[JA-Q001]

Ok, I was one of those asking you to search for the other info first, but let me contribute here as well.

 

First off, what do you hope to achieve with the longer cranks?

I have made an excel table that I will attach, this will show you all the mechanical changes while riding.

 

Now, I assume you are asking this for your mtb, so some things you should consider when going longer:

Your saddle height will drop, but because the distance between TDC and BDC has increased by 20mm (Assuming you change from 175 to 185) you will probably be keeping your bars on the same height in order that you dont feel your knees are touching your chin. This will change your body position to be more upright.

Then, because your pedal is no 10mm lower, you also increase the chances of hitting your pedal on rocks.

 

Please feel free to play around with numbers in the table. If you want any extra info, then I can add it in.

 

Ok, I cant get the excel file to attach, anyone that can help with that?

 

 

[Mellow]

It basically all relates back to your femur length and your position on the bike. Tall riders can gain a lot of power with the extended leverage and also on the pull.

 

Just look after your knees

[Chad Minnaar]

Thanks everyone for your contributions, that was a big response in 12 hours. I forgot to mention that this is for my road bike and according to my riding style of leaning toward grinding over spinning then I think I'll try a 177.5 which is not too much of a drastic change from my 175mm. Thanks again