Neophyte Knee Pain Fix?

Discussion in 'Race Series (V1.x, V2.x, V20)' started by Winded Lowrider, Aug 12, 2017.

  1. Looking for expert advice on knee pain riding the Vendetta V20.

    So far I have 386 miles on the V20. Steering, general bike position, neck rest, bottle mount, lights and bag mount issues have been adequately fixed for now. I feel like I can ride it now in a fairly relaxed manner.

    The V is fast, but (so far) not as fast as my Zox low racer. It's not an apples to apples comparison , The Zox has a faired rear wheel and it's been fine tuned to fit me. On the V I have not reached 30 mph in an 800 meter sprint yet ( that's possible on my Zox). Partly it's my lack of confidence on the bike.

    Applying power/torque to the pedals has started to hurt my knees ( top inner) slightly. I don't want that to continue. Generally I do not experience knee pain while cycling... so something likely needs adjustment.

    Should I start with:

    1) Moving my cleats back
    2) Moving the boom ( out, in, up?)
    3) Switching to oval chainrings ( expensive!)
    4) Shorter crank arms ( expensive and I tried them on my Zox and don't like them)
    5) other things I'm not aware of?

    I appreciate your opinions/help
    -Brad
     
  2. Lief

    Lief Guru Schmuru

    Hey Brad, both knees?
    Roughly equally?

    I had inner knee pain several bikes ago - it was "supposedly" to be resolved with shims on my cleats that let my feet stay at a slight angle of approach to the pedal-spindle.
    It was because of moderate bowleggedness.

    So - some factors there are perhaps - pedal extenders if your hips are wide? (Is that q-gmfactor?) or cleat shims like I got, or even pedals with more float? What are you running?

    Not an expert but in/out on the boom might be just front/back of knee generally speaking.

    Another thought/ after only 360 miles you are still getting the hang of high-wattage input to the steering and you are staying too stiff in the legs to compensate? Might not be enough time for that much sustained power at a slightly different position (from your Zox)?
     
    super slim likes this.
  3. Lief:

    Hip width is normal
    My feet are super flat ( enough to end my running/track aspirations)
    Foot issues are a constant battle for me. Knee issues not so much. Technically I'm a "compensating pronator" meaning my feet pronate but my knees remain relatively straight. In 45 years of cycling my knees have not hurt.

    Cranks are 170 mm now, My legs are 33 inch inseam which should be a good fit. I would consider 165mm cranks if that solved the problem.
    I'm thinking the 90 degree angle is the issue, which you pointed out earlier . That correlates with my zox position and what my Taji teacher preaches about healthy knee habits ( Knee Beyond Toes = Bad).
     
  4. Running crank bros candy 2 pedals ( some float) and shimano w-i-d-e mountain shoes which have been a good solution for my foot pain issues.
     
  5. Correction crank is 165mm already! (news to me) So cruzbike new bike setup may be aware of this issue?
     
    Lief likes this.
  6. Both knees: sprinting and hill climbing. I thought my knees would hurt today after they hurt during my ride yesterday ( 25 miles flat) but so far, so good today ( rest day)
     
  7. ratz

    ratz Wielder of the Rubber Mallet

    Top of knee= boom too short
    Inside of knew = cleat misalignment or a need for more float
    Crank brothers = spring to align cleat

    I would move the boom out 5mm
    Consider Hacked Frog pedals to retain walkable show you are accustomed to.

    See the v20 build diary for a "Tangent" on how to hack the frogs.
    http://cruzbike.com/forum/threads/vendetta-v20-build-diary-2016.10189/page-2#post-119653

    Check with @Rick Youngblood for the importance of protecting the knees and for feedback on the frogs versus the other options. The ease of the frogs should help with your v20 confidence too.
     
  8. Ratz: Thanks for the input!
    Mostly top of knee pain...

    Boom out 5mm, I will try that. I brought it in a bit during the last position adjustment. I used the classic "Bare heels on pedals, spin pedals backwards, no rocking in the hips" method to get close and micro-adjusted from there.

    Plenty of play in the pedals. Don't see the need for another pedal system ( yet). Does the MBB format REQUIRE more play for some reason?
     
  9. ratz

    ratz Wielder of the Rubber Mallet

    Nope not MBB specific; just most people underestimate the effect of return to center springs on your knees; without the downward force of body weight the pedal that spring gets to impart more torque on your knees than it should. HArd to explain until you have bad knees then it’s very obvious
     
  10. Bill K

    Bill K Well-Known Member

    I have a couple pair of the Frog pedals that I do not use (don't like them, switched back to spd's).
    I could loan you a pair if you want to try them out (your profile says Woodinville, and I ride the Burke Gilman /Sammamish river trail to work 3-4 days a week so it should be easy to get a set to you if you are interested).

    I'm no expert but adjusting the boom for "bare heels on pedals" would not work for me. The boom would be too close, which would cause pain at the top of the knee cap. I go with "heel on pedals", but wearing my cycling shoes.
     
    PeteClark and Lief like this.
  11. Lief

    Lief Guru Schmuru

    Side note: I rode Silvio 1.0 for years before getting V20 - and when I did I pushed so hard on 172.5 pedals that I over stressed my knees pretty much immediately.

    You, Brad, are wise to notice and try to correct this early.
     
  12. Pushed the boom out 5mm. Moved my cleats back 5mm ( I was thinking of doing this anyway for my chronic plantar fasciitis)
    So hopefully today I can get out for another ride to test the new position...

    Sat on my Zox just to compare positions and man -o-man that bike is way more comfortable than the V. Even with the thin foam pad on the plywood seat. I wonder if the ventisit pad is in my future? I surely appreciate the Zox more now. It's a fast accelerating, comfortable flat land speed machine.
     
  13. I see from other threads that some have mounted a thor seat to get a better fit. That is interesting and frustrating. I mounted a thor seat on my Ran stratus XC and I like it. Good upper back support seems to benefit power output but at a slight aerodynamic cost.
     
  14. Short test ride yesterday. NO KNEE ISSUES! and I hit 30mph ( wind aided) for the first time on level ground....so now I'd say the V is roughly equivalent in speed to the ZOX but its a very different bike. The zox winds up/accelerates quickly ( and loses speed quickly). Lots of power is lost in the zox boom pulley system. The Zox is more aero. The V is rock solid in terms of power transfer. The big wheels spin up more slowly but retain their speed much longer. The big wheels do better on rough pavement. As I slowly master the V steering I can put more power to the pedals. Cadence is notice ably slower for me on the V. Like 75-85rpm. On the ZOX its 85-95. On a DF I used to spin 110+....
     
  15. LarryOz

    LarryOz Zen MBB Master

    Eventually your cadence will pick up as you grow more comfortable with the V-drivetrain. I ride at around 100 rpm very comfortably for hours. 30+mph in <400 meters from a standing start entirely do-able. Post a pic of the Zox - I am very curious!

    p.s. I am a huge advocate of making sure you knees do not bend more than 90 degrees on your backstroke. Play with boom length and crank length to get it right will yield benefits in the future. Good Luck!
     
    DavidCH and super slim like this.
  16. The ZOX 20 Z-frame is a fast bike, but it is not a versatile bike. It does not climb well. It does not play well with DF bikes. It does not like rough roads. In a flat windy time trial on smooth pavement it is in the same league as a baron or similar low racer. The ZOX 26 solves some of the issues, but is slightly less aero. I bought the V because I want to climb hills again and go on group rides!
    STP 2010X.jpg BradZoxRearView.jpg
     
    super slim likes this.
  17. DavidCH

    DavidCH In thought; expanding the paradigm of traversity

    The zox will be slow when you get shortened cranks. With your cleats positioned back with the right adjustment the pain in the knees will be no more. I have sensitive knees. And all the above posts will help for sure. The shorter cranks will make you more aero and the less of the necessity to go with oval chainrings. Even so I still have Oval chainrings :rolleyes:
     
  18. DavidCH:

    Knee pain has vanished after moving the boom out (Very slightly) and the cleats back.

    I am NOT a fan of short cranks, tried them on the Zox. At 6' tall with a 33 inch inseam 170-165 mm cranks fit me well. I AM a fan of Oval Chainrings and I WILL upgrade those when funding becomes available.

    Now I'm considering seat options. Upgrade to a thor seat? Upgrade to a ventisit pad? IMO, the stock seat is the least well designed part of the Cruzbike V. Its too flat, needs a slight rise near the top to position my neck and shoulders comfortably. Most other seats do that.

    I'm a designer, so I look with a critical eye, not trying to be negative.
     
    Gary123 likes this.

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