36". Control vs speed 150mm vs 125mm cranks

Hey all… Appriaciate your inputs here…

Having just migrated from 29" Nimbus with 125mm cranks 1 week ago to new Nimbus Nightrider 36" … I started on the 36" with 125mm cranks and after several UPDs and the odd stack, felt maybe best to go with the 150s on the 36"

… Where I ride is mostly flat and predominant footpath / shared cycle way with a footpath ramps and bumps and some road but lots of pedestrian traffic kids and dogs. Thus a 36" wheel “out of control” could do more damage to the unsuspecting pedestrian vs a 29"…
After only riding 12Km on the 150mm, I can sense the reduction in speed.

Thus thinking the greater control achieved via 150cranks with downside being less speed may be the more practical approach. … At the end of the day my 40km per week riding is more about enjoying the experience vs “speed” … Thus wanting to sanity check the logic of switching back to 150s on the 36" in the interest of minimising risk to ususpecting pedestrian or to lesser extent myself. 1) Is it “mythical” that 150mm cranks will increase control ?
2) And just how much speed will be compromised vs the 125s. ??
3) is it easier to freemount 150mm on a 36" vs 125mm cranks. ??..
Anything else in context, do throw in your two bobs worth.
Thanx Jimmy

I’ve been in a similar situation as you! I started with 125s then went to 100’s for flat footpath. Recently I got t a pair of 150s to go gravel grinding with and it is by far my favorite size. A lot more control and stability. You do lose some speed but given the control,factor it is more comfortable to start cranking faster so you definitely still will go fast if not faster in some terrains! If you have a square taper hub and like Q factor keep in mind the coker cranks there inexpensive and very nice!

you definitely want to keep a 36er in control around pedestrians.

You’ll learn to control the 36er more and more as you spend more time on it. I don’t think even 125s compromise control as long as you are able to use your momentum effectively. A 36er just doesn’t ride like a small wheel, and you have to throw your weight around on it a lot more. Short cranks compromise maneuverability only through loss of leverage, but not directly.

I would start with longer cranks (150s) until you’ve put some days/weeks on it, and then move down when you’re comfy with it. For me, long cranks compromise not only speed (at least a few mph) but also comfort. More leg motion causes more chaffing of the leg, and for longer rides, less leg movement will just be more comfy.

It’s definitely easier to mount a 36er with 150s rather than 125s, not only because you have more leverage if you don’t get the mount perfect, but because the pedals are lower to the ground.

In any case, I am perfectly comfortable using 110s around town, and then hop on the sidewalks and do a little weaving on downtown sidewalks at low speed. It’s doable, but you need to give yourself time to develop those skills. If you ride bike paths primarily, you’re likely going to see a pretty substantial speed increase from the short cranks, because you can keep that top speed for longer. If you’re riding around a downtown area and tackling obstacles pretty regularly, the short cranks don’t provide much/any benefit.

Overall, I don’t think you’ll see a huge loss of speed with longer cranks. If you like riding longer cranks, and the leverage and security that gives you, do it! I would also consider 138s as a happy medium.

In a strictly mathematical/mechanical terms 150 mm cranks will exert 20% more torque to the wheel for the same pedal pressure when compared to 125 mm cranks. The wheel would also spin 20% slower for the same pedal velocity.

So yes if foot speed is your limiting factor you will be riding slower but with more control.

With 150s you’ll have a LOT more control than with 125s. Until you get used to it, it’s like night and day. The slower you go or downhill and/or more balancing you have to do around pedestrians the more you notice it.

Depends. Honestly, after switching to 125s it took me months to beat my fastest time with 150s on my 14km commute. The difference was of course that with 150s I almost never had to dismount and remounted quickly, whereas with the 125s I was dismounting 2-3 times and then often needing to walk to a pole to remount. I didn’t really track it, but I would say if you’re traveling less than 10km (6 miles) then it makes almost no difference in your actual travel time. On my 14km commute I feel way faster with 114s than with 125s or 150s, although my true average is virtually the same. If you get better with the 150s you may feel like you’re limiting yourself, but it’s pretty small. The 20% saskatchewanian noted is in theory only and it takes LOTS of practice to realize that potential.

Yes! Again a HUGE difference. When I fist got my 36er I was up maybe 80% freemounting with 150s within a few weeks, but on 125s it took me months to get to maybe 50%… Not only do the short cranks require more control, but the shorter cranks require a higher seat so you’re propelling yourself up a lot higher. I’m 6’1", so I can practically step onto the 36er with 150s, but with 125s I have to go up an extra inch and with 100s 2 inches. The difference is very noticeable.

My recommendation would be to try the 150s until you’re pretty consistent at freemounting and handling slow-speed stuff and then go down to 125s or so, and then again maybe go shorter if need be. That being said, changing it up is also very helpful: After riding for a few weeks with shorter cranks, it will then feel so easy when you go back up (e.g. for me now after riding 100s for a few months (twice actually), I feel pretty comfortable on 114s and the 125s feel like massive control (and slow unfortunately)).

Edit: I just read juggleaddict’s post again and I agree with almost everything. My answers are similar.

Yeah, I think a lot of the difference is in comfort rather than speed. When I switched from 137s to 127s I noticed a big increase in comfort over long distances.

Don’t forget about the 137/138s. They’re a good compromise between 150 and 125 and pretty good for road riding (150 is just too long for road riding IMHO).

I think everyone else has covered this well. You will experience more control with the 150s. I started with 150s when I learned to ride my 36er, and thought it was great getting comfortable on those. I put a lot of miles on with 150s before switching to 127s.

I clocked myself over the course of 10 miles with 150s vs. 127s. I gained 2 mph when I switched to 127s. It took a few rides to really get comfortable on the 127s, but I feel like I’m flying on the 127s.

I didn’t notice much of a difference in freemounting, but I do a rolling mount on the 36er. The momentum from the rolling mount is probably why I didn’t experience a big difference in mounting between the two sizes.

Appreciate the insights here Juggleaddict. Sounds like i’m making the right call for now.the 110s amongst civilians raise the eyebrows … Impressive … Jimmy

Appreciate your pragmatic guidance MUCFreerider… Again validating my thoughts.

Personally, i’d avoid riding my 36" around pedestrians with kids. I Almost ran over a toddler once. The little guy didn’t see any danger and i could not jump off in front because i would land on top off him, i could not jump off the back because the wheel might hit him and i could not go sideways because i would hit others. Luckily his mom snatched him away in time.