Wednesday 9 November 2016

Taking the Short Cranks Challenge

I had pair of old cranks lying about, so I thought I would give them a go.

All steel, with steel, riveted rings.
The "double" steel 152mm crank and cogs weighs a good bit more than my usual 175mm alloy "triple"!
here you can see my 175mm cranks, with the 152 held in front.

the steel 152 crank is slimmer than the 175 crank at the "pedal" end.

You can see the 152mm cranks are steel, because the cadence magnet sticks to the crank arm without ties!
(of course, I put a couple of cable ties on as well, to allow for rotational forces in use).

My 61cm XL bike frame makes the short cranks look even smaller.
The best description I can think of for using such short cranks is taht it feels a bit like running on the spot.

It's all about leg angles.
Leg angle at TDC
The saddle is still set up for 175mm cranks, and it could be argued that I hout move it up about an inch now I have shorter cranks.

Leg angle at BDC.
Angle of straightest leg, just before BDC is very similar.

Update 15 April 2019:
The 152mm cranks had fixed rings of 38t and 48t, and I found the 38t a tad too high for me.
So I got a 145mm pair of cranks with interchangeable rings (110 BCD size, so rimgs are pretty common, and available in grades from plain steel to fancy stuff with pins in them etc. etc.
I've been using them for quite a few months.
Iirc, i used the 145s with a 34/48 pair of rings for a while, then went back to the 175 cranks, then went back down to the 145 cranks again. Anyway, I've been using just the 145mm cranks for quite a few months now. Might be 6 months, might be a year. I haven't really been counting.
Stronglight "Impact" 145mm cranks

Yep, just 145mm long - that's a whole inch shorter than the "standard" crank length of 170mm

On a 60km ride with the 145mm cranks fitted.
(The pic is in the main street in Thame ,Oxfordshire)
Really short cranks tend to lead to a higher cadence (your foot travels less distance per rotation!), and standing on the pedals is less hard than longer cranks.
Each to their own, but short cranks seem to suit me!


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