Cycling UK Forum

I do notice the difference and prefer 170mm over 175mm, but it's not night and day. As far as ground clearance goes, I doubt that it will be dangerous. If your BB is already quite low you might have to be a little careful. Just try and see, I'd say. One of my most used bikes has quite a low BB and I have got pedal strike a few times with 170mm cranks. You just have to be a bit mindful of pedalling while leaning sharply, nothing that can't be accommodated for while riding. Again, the same for toe overlap/heel strike, not a huge difference but you might have to consider it.

Yes, having just fitted a 175mm chainset that I already had and found it intolerable to ride compared to my usual 170mm. Needless to say, I have just ordered an XD2 touring triple chainset from Spa today, in the correct length. Sometimes you just can't avoid these things.

10mm difference between up and down.
In theory, with the longer crank, you should lower the saddle 5mm to suit your leg length.
That means your knee has to bend more to accept 10mm higher at top of crank turns.
May or may not bother you.
My road bikes are 170 and 175 on my MTB. I don't notice any difference.
(Not done any serious mounting biking for years though so old knees might complain now.)
I did once fit some 165's to a road bike and it always "seemed" more tiring to pedal.

Firstly, it will depend on how fussy, even sub consciously, you are. If you are good to go there then only time will tell if you are going to feel any effects, good or bad. Too individual for a reply from someone else I think.

Yes, I definitely notice the difference between 175 and 170mm, and I prefer the (170 or less), @ 5'10" tall 1.78m with 33 inseam. I have a number of road and touring bikes, some with 175, others with 172.5 others with 170 and I dont know them
all in my head, or in advance of going for a ride, which bike has which crank length. Sometimes after riding for a while I can feel the extra size of the circle my knees are doing, and at the end of a long ride and I stop and check what the crank arms are, and its the 175's. I prefer shorter cranks and so do my knees. I have 2 bikes with 167.5 and they are definitely noticeably smaller circles and l am moving to them as my preferred crank length...
Like 'Q' factor or tread, if you prefer a narrower pedal tread, you immediately notice riding a bike with wider Q factor. YMMV.

Yes, covers all the bases.

sorry meant the pinkbike review (linked in the thread) covers all the bases

Cyckelgalen wrote: ↑9 Aug 2024, 12:59pm But I wonder, with shorter cranks, your joints move through a smaller angular range, but you lose leverage, mechanical advantage, which means that those ageing joints will have to exert higher forces on the cranks and suffer accordingly.

No, you just use slightly lower gears and spin slightly faster. When years ago I (5’6” tall) switched from 170 to 165, I no longer suffered knee pain in my damaged knee, and my average speed increased - a bonus that I didn’t expect.