Knee Issues?

[piston9]

Hey Everyone, looking for some experience\advice...

I'm considering a V20, but unsure about dropping all that $$ over some previous issues. I currently ride an Ice VTX, and Love it - but I'd love to lean again, and also get more speed still .

In the past (7ish years ago now) I had a sofrider. I enjoyed it, but my knees were getting sore, and at the time I attributed it to the MBB - with constant changing angles for the knees. The V20 obviously has different angles\experience to the early cruzbikes.

Has anyone experienced this? Debunked it? Any advice?

Last bit of context - I used to commute on it - which involved a lot of sharp corners (streets, paths, etc). This will be more fitness\long rides, so probably less of that if anything. Still, on the fence - if I could find a well priced used one, but it seems flying pigs are easier to find! I'd probably have to sell the VTX to fully spec up a new one the way I wanted, and then there is no going back....

Thanks in advance
Drewe

 

[KiwiGuy]

Hey Drewe

What length cranks did you have on the Sofrider? I used to run 172.5 mm on my Specialized Roubaix and Volae Club. When I ran into problems with knee pain a friend who was a trained bike fitter recommended I move to shorter cranks.

As a result, I moved to 165 mm cranks when I bought my V20. Problem solved. I've had no further knee pain.

 

[LarryOz]

I had the same experience when I got my first Cruzbike. I went from 170's down to 150's - knee pain gone. There is really no downside to shorter cranks: You legs and knees move less distance - so no flailing around, Better aero, quicker spin-up, lighter weight if you count those grams. easier to spin faster (which also helps knee pain since you are not pushing as hard when you spin faster. I love them and even ride 140's now on my new V20C.

 

[ccf]

I’ve also found that shorter cranks are easier on my knees. But keep in mind that you need a larger cassette with shorter cranks to keep the force required to climb steep hills reasonable.

 

[chicorider]

Ditto what the others have said, to which I will add the importance of finding the best place for the bottom bracket--neither too far out nor too far in. Even with short cranks, if the bb is too far in or out, you will most likely experience pain. But get that spot just right, combined with the most suitable crank arm length (I run 160mm), and you can spin pain-free all day. But it can be a fiddly, trial-and-error process of making small adjustments over a period of time until you find "THE spot."

 

[piston9]

Thanks all, it sounds like I just need to jump in and work hard - it took me 6 months or so to get the VTX perfect, so....

 

[Frito Bandito]

No knee pain here, but I too went from 172.5mm to 165mm and all is well. Another thing to consider is the pedals. I use Shimano 105 SPD pedals and loosened the clipping mechanism to the 2nd to last clip. This lets the cleat on my shoe rotate a few degrees ever so slightly without unclipping, and super easy to unclip when stopping. I don't have problems with them unclipping under heavy power, but I can see how that would be a possibility if rotating the heel out too far.

 

[Don1]

After running 165 for a year, I've moved to 170 mtb cranks. Just a little more leverage climbing mountains. Other benefits of mtb cranks. Wider q factor. And with the 104bcd I use 30-50 chainwheels with a 11-36 cassette which is way lighter than a 34-50 road crank with a 11-40/42 cassette.....

 

[Randyc3]

Started off with 165s on my S40, then moved to 162.5s which feels better on the knees. For pedals I was fitted with speedplay zeros with long spindles on my DF. I carried these over to my S40 since the q-factor is the same.

 

[vosadrian]

I run 155 cranks and want to try 145. As Larry says, there is no real negative of short cranks. About the only negative is if you have to grind up something slow in your shortest gear, the torque is less so you need more leg force... but you can account for that with gear selection.

I do find my knees get more of a workout on the recumbent than my DF. I do get sore knees... but mainly the muscles above the knees. Seems to be that I use these muscle more than on DF. I don't think it has anything to do with the MBB. I think on a V20, which is made for speed, you rarely do large steering angles, and certainly not under power. Once you are in the V20 zone going fast, the steering angles are minimal and unlikely to cause knee issues.

 

[Jeffers]

I do find my knees get more of a workout on the recumbent than my DF. I do get sore knees... but mainly the muscles above the knees. Seems to be that I use these muscle more than on DF. I don't think it has anything to do with the MBB.

I don't believe it has anything to do with MBB either, because my muscles above the knees can get sore as well on my RWD low racer.
But I have found another way to lessen the load on my knees.
If I open my hip angle more, it lessens the load on my knees.
Unfortunately most bikes don't have as much hip angle adjustability as the Performer low racer and the only option then is going to a shorter crank.

 

[Beano]

I find something that helps are pedals with a lot of float, Speedplay are the best ime.

 

[LarryOz]

Ditto what the others have said, to which I will add the importance of finding the best place for the bottom bracket--neither too far out nor too far in. Even with short cranks, if the bb is too far in or out, you will most likely experience pain. But get that spot just right, combined with the most suitable crank arm length (I run 160mm), and you can spin pain-free all day. But it can be a fiddly, trial-and-error process of making small adjustments over a period of time until you find "THE spot."

One of the reasons to get shorter cranks is to not have you knees bending so much. Once you go shorter you need to adjust the BB so that on your back-stroke you don't bend you knee much past 90-100 degrees. I think 90 degrees is perfect and what I shoot for. Any greater bend than that and knee pain happens for me. Plus there is no really power there anyway when the knee is bent much beyond 90-100 degrees when you start to push. So best to already be at that point when the pedal comes around again waiting for you to push it again.

 

[cruzKurt]

One of the reasons to get shorter cranks is to not have you knees bending so much. Once you go shorter you need to adjust the BB so that on your back-stroke you don't bend you knee much past 90-100 degrees. I think 90 degrees is perfect and what I shoot for. Any greater bend than that and knee pain happens for me. Plus there is no really power there anyway when the knee is bent much beyond 90-100 degrees when you start to push. So best to already be at that point when the pedal comes around again waiting for you to push it again.

Larry, do you think oval chainrings figure into this conversation about knee bend. I am building a v20 frame up and considering oval chainrings with my shorter cranks.

 

[bladderhead]

How different is the S40 from the V20? On my S40 I am always in carparks and pedestrian places, going through gates and barriers. No knee problems. I think the leg bends sideways at the hip. I have 130 cranks. I climb slowly, but I get there, with 51t cog and 38t chainwheel. I can go really slow in a straight line, below 4mph. Is the V20 as stable as this? Low gears is what you need if you have short cranks.

 

[LarryOz]

Larry, do you think oval chainrings figure into this conversation about knee bend. I am building a v20 frame up and considering oval chainrings with my shorter cranks.

I have ridden with Q-rings for most of the last 5-6 years. They do not really affect the motion of the legs as that is determined by the center of the BB. It will be the same with or without.

 

[LarryOz]

The only difference I have noted between V20 and S40 is that the S40 is a little easier to balance due to its higher seat angle. Eventually your body learns to deal with it though. There are many people that can ride the V20 with no hands and go very slow without loosing their balance. But if you are riding the S40 a lot and then switch over the V20 you will probably have a slight learning curve. Plus some people are just more gifted at balancing than others. Me - not so much unfortunately.

How different is the S40 from the V20? On my S40 I am always in carparks and pedestrian places, going through gates and barriers. No knee problems. I think the leg bends sideways at the hip. I have 130 cranks. I climb slowly, but I get there, with 51t cog and 38t chainwheel. I can go really slow in a straight line, below 4mph. Is the V20 as stable as this? Low gears is what you need if you have short cranks.

 

[Jeffers]

Hi Larry,
I've had a question I've wanted to ask for a while.
Is your preferred hip angle 146 degrees measured in this way?
I ask because after a lot of experimentation I've found my best to be high 146 to low 147 degrees.
Narrower than 146 degrees puts stress on my knees. And more open than 147 degrees I feel my power begin to drop.
Thanks,

 

[LarryOz]

Hi Larry,
I've had a question I've wanted to ask for a while.
Is your preferred hip angle 146 degrees measured in this way?
I ask because after a lot of experimentation I've found my best to be high 146 to low 147 degrees.
Narrower than 146 degrees puts stress on my knees. And more open than 147 degrees I feel my power begin to drop.
Thanks,

Hi Jeffers,
Yes I believe this to be what seems best to me. I have never measured it this way - Pretty cool overlay. What program are you using to do this?
This is my absolute fastest bike I have ever ridden. I did almost 32 mph at Charlotte Motor Speedway in a 10-mile TT. It was awesome. I tried to do a sub 50 min 25K there too - and crashed due to the wind. I had both wheel fully covered when that happened. It is a bullet - but a must is no wind for it to be safe. Would never ride in on a road with car and truck traffic - dead wish.
Larry

 

[Jeffers]

Here's the online protractor I use.

https://www.ginifab.com/feeds/angle_measurement/

And here's my current bike geometry measured the same way.