Crank length

13 rider

Guru
Location
leicester
My Shimano Ultegra crank has suffered a hollowtech failure and is in the process of being replaced under warrentry. As you know there is a supply shortage of parts ,My options are wait for the correct part 172.5mm crank set delivery was March 22 now December 21 ,2 contribute to an upgrade to Dura ace 172.5mm about £100 ,3 Ultegra 175mm crank set available now
I think I'm going for the 175mm cranks ,My question is will I notice any difference once I lower the saddle 2.5mm. I genuinely believe if the Lbs put them on and altered the saddle without telling me I doubt I would notice
Any thoughts
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
You'll not notice. I ride 170 road, and 175 MTB (that's how they came) - same saddle heights. And I'm 5'9"
 

Soltydog

Legendary Member
Location
near Hornsea
Minimal difference, depends how sensitive you are to change. But why lower the saddle? It would create a 5mm difference at the top of the pedal stroke & that could be more noticeable. I'm not sure myself, just trying to think logically which at 10pm on a Saturday night probably isn't a good idea :laugh:
 
Minimal difference, depends how sensitive you are to change. But why lower the saddle? It would create a 5mm difference at the top of the pedal stroke & that could be more noticeable. I'm not sure myself, just trying to think logically which at 10pm on a Saturday night probably isn't a good idea :laugh:
Excuse my ignorance. Why would it create a 5mm difference ? The top stroke peddle is only 2.5mm closer to his foot therefore
the op is right with just a 2.5mm adjustment.
 

neil_merseyside

Veteran
Location
Wirral
Saddle stays in same place doesn't it as no crank alters the seat to bb axle distance, you will pedal different size circles and at the top it will be 2.5 up and the bottom 2.5 down, but if you shift it up or down that 2.5mm then you make the 5mm on the opposite side?
 

cougie uk

Über Member
You'd not notice and I'd not bother changing the saddle height either. You move round in the saddle and alter angles on the knee and ankle so your change is minimal.
 
OP
13 rider

13 rider

Guru
Location
leicester
Thanks for all the replies ,@Soltydog certainly got me thinking about the distance at the top of the circle I had only considered the bottom of it
But I been a bit forgotful ,I my left crank has a power meter and is of course 172.5mm so it looks like option 1 and 2 .
 

si_c

Guru
Location
Wirral
You could get a 105 crankset, they are functionally identical to the Ultegra ones, and they don't have the failure mode common to Ultegra.

I wouldn't change the crank length myself, shorter maybe but longer no, just because I'm used to the position and I know it's correct.
 
OP
13 rider

13 rider

Guru
Location
leicester
You could get a 105 crankset, they are functionally identical to the Ultegra ones, and they don't have the failure mode common to Ultegra.

I wouldn't change the crank length myself, shorter maybe but longer no, just because I'm used to the position and I know it's correct.
As it's being changed under warranty I don't won't to go for a lesser ( although perfectly acceptable) alternative so have ruled out 105 for now unless wait time is extended
 
OP
13 rider

13 rider

Guru
Location
leicester
I would be tempted to wait for the replacement, but buy a used crankset in the meantime. When the replacement arrives, just sell it.
Thankfully I have a second crank set fitted so still riding the bike . The crank failed on holiday and a Lbs in Oswestry the Bike works did me a massive favour and got me up and running the same day with a second hand set . My cycling ocd is tested as I have a left hand black crank and silver chain set
 
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