CoachingAnswer

WHY DO MY KNEES HURT WHEN CYCLING?

By Anthony WalshRoadman CyclingUpdated 26 May 2026

ANSWER

Cycling knee pain usually comes from one of five position errors: saddle too high (pain behind the knee), saddle too low (pain at the front), cleats misaligned (pain on the medial or lateral side), saddle too far forward or back, or cranks that are too long for your hip flexibility. Most cases resolve with a saddle height change of 5–10mm. A professional bike fit diagnoses which of these is the culprit in under two hours.

KEY TAKEAWAYS

Pain behind the knee: saddle almost certainly too high — drop it 3–5mm and reassess.
Pain at the front of the knee (patella): saddle too low or too far forward.
Pain on the inside or outside of the knee: cleat rotation or float is almost always the cause.
Cranks longer than 170mm create hip impingement and knee load for many cyclists with limited hip flexion.

WHO THIS IS FOR

IS THIS YOU?

The rider with persistent knee ache

Pain that starts on climbs, gets worse in the back half of longer rides, and doesn't resolve with rest alone.

The rider who's just changed their setup

New bike, new cleats, new saddle, or a position change that's introduced pain you didn't have before.

THE ROADMAN VIEW

Knee pain is the most common complaint Anthony hears from amateur cyclists, and almost every time the first fix is the simplest one: saddle height. It's remarkable how few millimetres it takes to create a problem. A saddle sitting 5mm too high can make the leg slightly over-extend at the bottom of the stroke, and over a four-hour ride that's tens of thousands of micro-overstretches of the posterior knee structures.

The cleat angle problem is less obvious but just as common. Most clipless pedal systems give you some rotational float, but if the cleat is set in a rotated position that doesn't match the natural angle your foot wants to sit, the knee is tracking slightly off-axis every single pedal stroke. The pain builds gradually — often in the first few weeks after switching to clipless pedals or after a service that moves the cleats.

If you've checked saddle height and cleat position and the pain persists, consider crank length. Phil Burt made this point clearly when he came on the podcast: many amateur cyclists are riding cranks 10–15mm longer than their hip mobility comfortably allows, which creates repeated hip flexion at the top of the stroke that eventually loads the knee. Shorter cranks are not a luxury — they're sometimes the structural fix.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

Phil BurtFormer Team Sky and British Cycling physiotherapist and bike fitter
The vast majority of knee pain in cyclists is position-related and entirely avoidable. The diagnostic sequence is saddle height first, cleat position second, and then a wider assessment of leg alignment and crank length. Jumping straight to physio before checking position wastes time and money.
Hear it: 5 Bike Fit Mistakes | Roadman Cycling Podcast
Daryl FitzgeraldWorld Tour bike fitter at Science to Sport
Cleat alignment is underrated as a knee pain cause. Riders accept that the cleat position 'feels fine' when it's actually loading a rotational stress on the knee with every stroke. The body adapts for a while, then the pain appears — sometimes months after the real cause.
Hear it: The 1 Bike Fit Change That Costs Cyclists Watts | Roadman Cycling

PRACTICAL APPLICATION

DO THIS WEEK

Locate the pain and adjust saddle height first
Pain behind the knee: lower the saddle 3–5mm. Pain at the front: raise it 3–5mm or push the saddle back 5mm. Make one change at a time, ride 2–3 times to assess. Optimal saddle height gives a 25–35 degree knee bend at the bottom of the pedal stroke — roughly a slight bend, not locked out and not deeply bent.
Check your cleat float and rotation
Stand barefoot and look at the natural angle your feet adopt — toes slightly out is common. Your cleats should roughly replicate that angle. If you use fixed cleats (zero float), switch to a float version first. Most knee-pain cases resolve with 6 degrees of float and a corrected cleat rotation.
Consider crank length if pain persists
If saddle height and cleats don't fix it within four weeks, discuss crank length with a fitter. Riders under 5'8" or with limited hip flexibility often benefit from moving from 172.5mm cranks to 165–170mm. The watts difference is negligible; the knee stress reduction can be significant.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

MISTAKEGoing straight to physio without checking position first.
FIXPhysio treats the symptom; a bike fit addresses the cause. Fix position first — if the pain persists with a correct fit, then see a physio.
MISTAKEMaking multiple changes at once and not knowing which one fixed it.
FIXOne change at a time, three rides between each change. Changing saddle height, cleat angle and crank length simultaneously makes diagnosis impossible.
MISTAKEPushing through knee pain in the hope it resolves on its own.
FIXCycling knee pain from a position error won't resolve while the position error is still there. It will worsen. Stop, assess, fix.

FAQ

FREQUENTLY ASKED QUESTIONS

Is cycling good or bad for knee pain?

Cycling is generally low-impact and often recommended for knee rehabilitation — but only when the position is correct. Cycling in the wrong position can create or aggravate knee problems. The sport itself isn't the issue; the setup is.

Why does my knee only hurt on climbs?

Climbing increases the load on your knee at the bottom of the pedal stroke and shortens the effective stroke at the top. Pain that appears specifically on climbs usually points to saddle height (too high) or limited hip flexion — both of which are amplified when you're pushing bigger watts at a lower cadence.

Can riding at a higher cadence reduce knee pain?

Often yes. A higher cadence (90–100rpm rather than 70–80rpm) reduces the force per pedal stroke, which lowers the load on the knee structures. It's a useful short-term strategy while you address the underlying position cause.

What is cyclist's knee and how do I treat it?

Patellofemoral pain syndrome — pain at the front of the knee — is the most common cycling overuse injury. It's usually caused by saddle position being too low or too far forward. Raise the saddle 3–5mm and push it back 5mm, ride at a higher cadence, and the symptoms typically ease within 2–3 weeks if the position is the cause.

Should I use knee warmers to prevent cycling knee pain?

Keeping the knees warm below 16°C is sensible and reduces stiffness, but knee warmers manage a symptom — they don't fix a position problem. If your knees hurt when riding in warm conditions, the cause is mechanical, not thermal.

RELATED EPISODES

HEAR THE CONVERSATIONS

5 Bike Fit Mistakes | Roadman Cycling Podcast

The 1 Bike Fit Change That Costs Cyclists Watts | Roadman Cycling

I Tried A Bike Fit From Team GB Bike Fitter (Here's What Happened)