If your knees hurt on the bike, check four things in this order: saddle height, cleat angle (if you wear clip-in shoes), the gear you are pushing, and crank length. Fit and technique cause most cycling knee trouble. Pain that comes with swelling, locking or an inability to bear weight is a different matter and needs a clinician, not an adjustment.
Cycling has no impact, so it is gentler on knees than many other aerobic activities. Sheldon Brown, the veteran Harris Cyclery mechanic, still points out that knee injuries do happen, usually because of poor technique or position. That is good news: position and technique are things you can change.
Work through the checks in this order
1. Saddle height
Sheldon Brown lists a saddle that is too low as a common cause of knee problems. A low saddle makes the knee bend more at the top of every pedal stroke, so each revolution loads the joint in a deeper, more crowded position.
Cycling UK gives a simple starting rule. Sit on the bike with the heel of your foot on the pedal, with the crank at its lowest point in line with the seat tube. Your extended leg should be just straight. When you ride with the ball of the foot on the pedal, that leaves a slight bend at the bottom of the stroke. Treat the result as a starting point, not a verdict. Cycling UK notes that fit can only be pinned down approximately by static measurements, and our guide to adjusting saddle height walks through the process in detail.
Do not overcorrect. Cycling UK warns that raising the saddle too far to chase power makes the hips rock, which can hurt your back. Change one thing at a time, ride for a few days, then decide whether the pain has changed.
2. Cleat position and angle
Cleats are the small plates on the sole of clip-in cycling shoes that lock into the pedal. Sheldon Brown explains that each person’s feet rest at a natural angle, whether toes-out or toes-in. On plain pedals the foot simply takes that angle. With cleats, the fitting has to allow it. If it does not, the lower leg is twisted on every stroke, which affects the alignment of the knee joint.
Float softens this problem. Float is the amount the cleat can swivel inside the pedal before it releases. Wikipedia describes why it matters: most people’s legs do not stay in a single plane while pedaling. Many standard road systems offer cleats with a six-degree float. Sheldon Brown notes that most newer clipless pedals have at least some.
For the fore-aft position, Cycling UK reports the accepted theory: line the cleat up with one of the metatarsal joints so it sits under the ball of the foot. Its author admits to being unsure which joint and prefers cleats as far back as they go, so there is no single exact answer. For the side-to-side angle, the same article suggests unclipped, relaxed feet on the pedals as a guide to your natural angle, while noting that a good bike fitter can prevent niggling problems here.
If you are unsure about cleat setup, Cycling UK recommends choosing pedals with plenty of float. Another option is flat pedals. They let you place your foot however you like, which Cycling UK says may instantly solve knee and hip problems caused by incorrectly set cleats.
Safety note: cleat bolts hold your foot to the bike. After any adjustment, tighten them as the manufacturer specifies, and practice clipping in and out while stationary before riding in traffic.
3. The gear you are pushing
Sheldon Brown names riding in too high a gear as a principal cause of knee problems. In practice that means grinding up hills or starting from a stop in a gear that makes each pedal stroke feel heavy. Shift to an easier gear and spin faster. Our explainer on cycling cadence covers how to find a comfortable rhythm.
4. Crank length and knee movement
Longer cranks make the knees bend farther on each stroke, so a bike with cranks longer than you are used to can cause problems. Cycling UK adds that cranks longer than about 10% of your height may give an awkward pedaling action with lots of knee bend.
Also watch your knees. Sheldon Brown says they should travel up and down as you pedal, without sideways motion. Do this check in a quiet place, ideally with a friend filming from behind, rather than looking down in traffic.
Quick symptom guide
| What you notice | Check first |
|---|---|
| Pain builds with riding and your saddle feels low or your knees feel cramped at the top of the stroke | Saddle height |
| Pain began after fitting new clip-in shoes or pedals, or after moving cleats | Cleat angle, then fore-aft position; consider pedals with more float |
| Pain mainly on hills or from a standing start | Gear choice and cadence |
| Pain began on a different bike or after changing cranks | Crank length and overall fit |
The guidance is the same for any bike. On an e-bike, the motor reduces effort but does not change where your knee sits relative to the pedal, so the same checks apply. For a broader fitting overview, see how to fit a bike properly.
When to stop adjusting and see a professional
Adjustments suit mild, fit-related aches. The NHS advises that knee pain which does not improve within a few weeks warrants a visit to a GP. It also lists symptoms that call for urgent advice from NHS 111:
- the knee is very painful, or you cannot move it or put any weight on it;
- the knee is badly swollen or has changed shape;
- the knee locks, gives way or painfully clicks (painless clicking is normal);
- a very high temperature, or feeling hot, cold or shivery, together with redness or heat around the knee, which can be a sign of infection.
Stop riding if any of these appear. The NHS also cautions against self-diagnosing the cause of knee pain, so this page cannot tell you what is wrong. These pointers are from the UK service; elsewhere, use your local urgent-care route. A professional bike fitter can help with persistent fit problems once any medical cause has been addressed.
If you are new to riding, some muscle soreness while your body adapts is normal; our first 30 days of cycling guide sets expectations. Sharp, localized or worsening joint pain is not the same thing.
Sources
- Sheldon Brown (Harris Cyclery): Pain and Numbness
- Cycling UK: How to do your own DIY bike fit
- Wikipedia: Clipless pedals
- NHS: Knee pain
Last reviewed: October 2026.