165mm Cranks For The Hoods?

happycrank(s)

Hello All,

I have a Giant Defy 2 Aluxx SL (frame) with 4600 Tiagra, it's 3 years old and with general wear to cables and the drivetrain, I've decided to treat myself and upgrade the entire groupset to 105 5800.

The only real choice I have to make is the length of the cranks, I currently have 172.5mm cranks on a compact with a 12-28 cassette, my height is 5'9'' and inseam is 81cm (31.5 inches). According to GCN (using their maths equation) and most other sources I should be using 165mm cranks.

I'm in my mid 40's and spend most of my time on the hoods, but having done some reading about shorter cranks and their benefits, greater comfort and a higher cadence etc.

My question is are these benefits only really useful for the younger aero rider or would I benefit from them while riding mainly on the hoods.

I'm grateful for any insights,

Rob

svetty

I have 31 inch inseam and ride 172..5 on all my bikes.
Having read all sorts for and against long cranks and short ones I have concluded that you get used to whatever you use. Having said that for your height 165 is pretty short - not sure I'd recommend as short as that - 170 probably best.

mrb123

You probably won't notice much difference. 165 to 170 for your height but don't expect much change or benefit.

dj58

I also have a Aluxx Defy, medium frame, and have inseam of 32". My bike came with 172.5mm cranks, I swopped them for 170mm cranks as that is what I had been riding for the past 30yrs and wanted the same on my road bike. In hindsight I should have gone straight to 165mm cranks, which I now have and prefer, also cured the toe overlap with the front wheel, which was nice.

They help me spin up the climbs keeping a higher cadence, compared to the 170mm, it's all personal preference of course, and depends on how sensitive you are to subtle changes. I don't think it matters that you ride mainly on the hoods, though try top of the bars for seated spinning up the climbs and hooks of the drops for descending.

cadseen

I can notice the difference in 172.5 to 170.00, not everyone can. I used to have 172.5 but due to shrinking height due to age and possibly loosing flexibility I now feel more comfortable on the slighty shorter cranks. Also an advantage of going shorter is that you can higher your saddle by same amount and have more clearance between legs and chest/abdomen.

Strange how things come about though, nearly 50 years ago when i was riding, standard crank length was 6.5inch (165mm) Only tall people used any larger.

Bobbinogs

I have posted this before but it always makes good reading:
http://bikedynamics.co.uk/FitGuidecranks.htm

keezx

cadseen wrote:

I can notice the difference in 172.5 to 170.00, not everyone can. I used to have 172.5 but due to shrinking height due to age and possibly loosing flexibility I now feel more comfortable on the slighty shorter cranks.

Shrinking height only affects your back, not your legs...

cycleclinic

I am 6ft1 i have cranks from 165mm to 177.5mm and barely notice difference.

Depending on how you analyse this ideal crank length could as low as 145mm but we have all settled on 165mm to 175mm for a reason it works. What ever you pick you will get used to it. Longer cranks does have an impact on cleat position though so 170mm is probably about right.

cougie

It wont make any difference. And the hoods is irrelevant.

happycrank(s)

Hello All,

Some interesting comments and opinion seems to be divided.

I'm busy right now but will be able to give a full response tomorrow night after work.

Regards

Rob

bernithebiker

I'm firmly in the shorter cranks is better (for most) camp.

Every single rider I've met or advised to go shorter has been positive about changing to shorter.

One female client recently, in her 40's, about 5'6 ,was on 172.5's. (And this after a so called 'pro' bike fit!) Going to 165's has changed her cycling experience completely, far more comfortable and efficient.

hsiaolc

I am 5 7 and it was recommenced to me to use 165 and I have been using 165 since.

I think you should be on the 170. But go with what you feel like.

zefs

I saw a benefit on my injury so I would recommend the 165mm ones. They are also easier on the knees when climbing:
viewtopic.php?f=40013&t=13070280

happycrank(s)

Hello All,

Firstly, I would like to thank everyone for taking the time and effort to post their replies.

I've noticed a pattern on this site and some of the others that I've viewed on the subject.

And it is that some riders say that after they've switched to 165mm cranks they did not notice any or much of a difference, others say they did notice some difference and it has been generally a positive one.

There's an inference that can be made from the last sentence, simply it is that nobody actually speaks negatively about shorter cranks. Has anyone offered up (anywhere) an opinion that they will slow you down or cause damage to the rider?

Even those with a negative tinge to there opinions are at worst only saying that there is not a difference to be noticed.

With the above in mind I have nothing to lose by trying them.

If they work for me I'll have all or some of the benefits mentioned (here and elsewhere) or opposite to this, I won't notice much of a difference (not the end of the world for me).

happycrank(s)

Forgot to add that I will go straight to 165mm and not 170mm, I feel 172.5 is just to close to 170mm.

I've seen a Tiagra 4700 50/34, going for a decent price.

The equivalent 105 5800 version is over £45 more, with the only real difference between the pair being weight (120g), stiffness will be the same (surely?).