Crank length, changing from 175 mm to 165 mm

[dickyknees]

Has anyone replaced their 175 mm cranks with 165 mm?

I ask as I'm being advised that 175 mm cranks are too long for me, I just had a bike fit. I am 182 cm tall.

Has anyone got pros or cons for doing this?

Thanks

 

[Ming the Merciless]

I’m 184 and run 175s on one of my bikes and 172.5 on another. Dropping to 165 is quite out of the norm, why are they suggesting that?

 

[GuyBoden]

"When I first met Bradley Wiggins he was riding 177.5mm length cranks, but for the Rio Olympics team pursuit he rode 165mm [Wiggins won gold]. He was on similar for his Hour record. That wasn’t by chance – it was planned – and if it can work for someone who has won the Tour de France, it might be worth you considering."

Good luck on your hour record attempt.

 

[T4tomo]

I’m 184 and run 175s on one of my bikes and 172.5 on another. Dropping to 165 is quite out of the norm, why are they suggesting that?

maybe its for his dicky knees?

 

[cougie uk]

Due to me spotting a crack in my Mavic crank before a ride I had to transfer an old one on.

I ended up with 172.5 on the chainset side and 167.5 on the other.

Completely forgot about it and rode it like that for months if not years.

How and where you sit on the saddle, how you bend your ankle and knee makes a huge difference.

Would I spend money if it wasn't s problem for me?
Probably not.

 

[MichaelW2]

At 182cm/5'11" you are bang on average size so any of the medium sized cranks will work. Given that medium ranges from 165 to 175, then basically any crank will work but personal preferance in cadence, pedalling force and joint flexibility, leg length can narrow it down.
Consider such a choice fortunate, small riders are all using extra long cranks and tall riders are using extra small, in relation to limb size.

 

[Milkfloat]

At 6'4" most of my bikes are 175mm, however I have some at 172.5 and my track bike is 165mm. I can tell I am riding different bikes, but cannot really tell which cranks. I would only change crank length if getting a new bike or have a medical problem.

 

[Darius_Jedburgh]

At the level of most, if not all, on here there is not going to be a major difference in performance whatever length of cranks are fitted.
Anyone who claims to be able to tell the difference without a bank of performance monitoring equipment will be too busy training for their next pro race to bother with us lot.

 

[Once a Wheeler]

Tour and Giro winner Marco Pantani:

Following an accident he had one leg slightly deformed or shorter than the other and consequently rode with different length right and left cranks. I think it just makes the point: find what is comfortable for you and stick with it. As a climber, the difference in moment must have been noticeable between the two sides but I am not aware of him thinking it was of any significance other than personal comfort.

 

[Darius_Jedburgh]

Of course Pantani had a little help from sources that are not easily available to recreational cyclists. And Riis, and Ulrich, and Virenque, and Armstrong and.......

 

[iluvmybike]

If you were 5ft 3ins I could understand dropping to 165 cranks but at your height it seems odd - unless you have very short legs and a very long body? I'm 5ft 4 ins and ride 170mm cranks. It will make your gearing feel slightly different.

 

[dickyknees]

Thanks for the feedback.

I have bought a new bike and having new replacement knees so a bike fit was in order.

I started having lower back pain with the new bike which I think I’ve solved that by reverting to the my old saddle.

It transpires that my hips are not as flexible as they used to be and to make the pedalling action easier shorter cranks would help.

 

[Twilkes]

I went from 175mm to 170mm simply because the cranks I could order weren't available in 175mm. I pretty much notice no difference, 6ft5 and 34" inside leg, but I'm more of a spinner than a grinder (>85rpm) which is meant to favour the shorter cranks. The only time I feel like it might be different is when climbing out of the saddle and it feels like the pedal stroke/travel is quite short, by the time I'm stood on the pedal and it goes down it's already at the bottom of its circle, I doubt that 175mm would make much difference to this though.

 

[Sharky]

Olde English cranks used to be 6.5" and that was probably the norm in those days. Track riders I think use 165mm to allow for the banked track.

Now me - I am 5' 9", and ride with150mm cranks. It helps to open up the hip angle and reduce the knee angle. The reduced leverage with the cranks is just a myth as you compensate by using a lower gear. Cadence goes up and gives you a more lively ride.

Loads of studies out there listing the pros and cons.

 

[boydj]

The shorter cranks will reduce the amount of bend in the knees and hips. Just how much that will help depends on how bad your knees are. On the other hand, you are plenty tall enough to be using the 175 cranks, and your new knees and the muscles supporting them will benefit from the exercise. I'd hold off changing for a while unless you are experiencing problems with the current setup.