Shorter Cranks ?

[miss_undaztood]

Hello, newbie here so be gentle !

Just bought my bike, a Saracen Mantra Pro 2010, (wanted a white one and the price seemed good I thought ), which as yet I have only just built up and adjusted etc, havent actually used in anger yet.

But, when sitting on the bike I feel the cranks are too long and would like to fit shorter ones.

Having a look on tinternet its not a simple job of buy shorter Shimano cranks and changing them, theres all manner of "stuff" going on there and cranks only seem to come in 2 lengths, 170mm and 175mm, not much difference, but in loads of different fittings.

I was thinking more about 150mm would suit me as i`m only 5`4 tall, 27" inside leg measurement.

So, help !!!!!

CJ.

 

[RecordAceFromNew]

Before jumping into conclusion, perhaps it would be helpful to check your bike fit first? The best is to go to a competent retailer, if not I would suggest this and reading this.

Unusually short cranks are available from inexpensive children models (such as this) to expensive specialist models (such as those by TA). The problem of the latter is that they can cost not much less than the bike. The thing to bear in mind though is changing the chainset usually requires changing the bottom bracket at the same time to ensure the chainline is not signfiicantly altered - otherwise you will encounter problems with your front gear shifts.

Hope it helps.

 

[miss_undaztood]

Hi, thanks for the welcome and the help

I doubt i`m "bike fit", or any fit, hence why I got the bike to get some excercise and get fitter.

The reason I feel the cranks are too long isn`t due to my unfitness levels, its because they "feel" physically too long.
Its like walking up a flight of stairs but 3 steps at a time in each stride.

I just figured that if you can buy frames in different sizes, alter seats and bars, all to suit the rider, that surely the crank length would be different for different folks too depending on their inside leg measurement. Longer cranks for longer legs, shorter ones for stumpies like me

CJ.

 

[GrasB]

You may be to far back on the saddle compared to the bottom bracket for your upper body position. This then feels like you're having to lift your knees up very high which leads to feeling you're like stepping up multiple stairs at the same time.

 

[Crackle]

Record Ace didn't mean fit as in fit but fit as in setup, have you checked the bike is set up correctly for you. As Grasb says as well, having your seat and bars set up correctly will make a difference.

5'4" isn't so small and I would think most crank lengths would be fine. Cadence and gear selection will also play a part and it would be interesting to know whether you spin the cranks quickly or whether you spin them slowly. You might already know this but you should select your gears to keep your cadence/ spinning even and don't worry about speed in the beginning. You should also aim to choose a gear which allows you to spin the cranks at about 60 - 80 rpm. Eventually, spinning faster might be more beneficial but one step at a time.

 

[Angelfishsolo]

The reason I feel the cranks are too long isn`t due to my unfitness levels, its because they "feel" physically too long.
Its like walking up a flight of stairs but 3 steps at a time in each stride.

It sounds as though your seat is too high.

 

[RecordAceFromNew]

I just figured that if you can buy frames in different sizes, alter seats and bars, all to suit the rider, that surely the crank length would be different for different folks too depending on their inside leg measurement. Longer cranks for longer legs, shorter ones for stumpies like me

You might want to take a look at this average height statistics. It seems if a female at 5' 4" is a stumpy then half are!

I also don't think 27" inside leg is short for a lady. Your ergonomic issue, if any, likely lies elsewhere.

 

[snailracer]

I have a 29" inside leg, and as an experiment, I once grafted a set of 140mm kids' cranks onto my bike. My pedalling style changed to be a bit more "spinny", but, after a few weeks to adapt, it felt fairly natural and my overall speeds were the same as before. After a few months, I put the original 175mm cranks back on and, after a few weeks to re-adapt, the 175mm cranks felt natural again.

I suggest you give it a bit more time before going to the trouble and expense of non-standard cranks.

 

[Deleted member 1258]

Like snailracer I'm a 29" inside leg, on my fixed I have 165 cranks and on my geared bike I have 172.5 cranks, on the road I can't tell the difference between the two, the advantage I get with shorter cranks on the fixed is that they make spinning downhill easier. As others have said you need to get your bikefit sorted first and then start looking at changing componants.

 

[miss_undaztood]

Hi guys, thanks for the replies.

I guess I need to adjust the bike as best I can just now then see how I get on when I use it more.
I`ll keep in mind what you`ve all said, and have had a look at bikefit stuff too, which makes sense.

Hopefully I just need to get used to it having not been on a bike for years, well not one without an engine anyways ! Or, learn to cycle in platform



CJ.