Knee pain on new trike

[Monkreadusuk]

Morning all,

I've recently started riding a kmx tadpole trike on my commute of a small 7.5 miles each way. However I've noticed discomfort in my knees, mainly my right, when cycling.

I've tried pointing my toes in, out and moved my seat a bit closer to the pedals but still no luck. When I had my DF bike fit I was told that my right knee has a tendency to oscillate when I'm peddling but this was resolved by a foot bed sole in my shoes and the cleat angled in slightly. This doesn't seem to be working on the trike though.

I try to keep spinning up hills but even in the easiest gear I can't spin fast at more than 4mph

Looking for any ideas on how to resolve this.

Many thanks

 

[ianrauk]

I had exactly the same problem, even with the right knee.
I tried all sorts of configurations to cure it. Boom further out, boom further in. Different seat positions. Different type of pedals. Foot beds in shoes.
But nothing worked. After 70 miles I would be in agony.
In the end I gave up and sold the bent. (which I hugely regret)

Sorry I can't be of more help.

 

[byegad]

Try moving the cleats on your shoes all the way back toward the centre of your feet. and feel free to alter boom length 0.5cm at a time. I'd go for slightly shorter than may seem intuitive. Also consciously spin rather than mash the pedals.

 

[PaulM]

KMX trikes come with 170 mm cranks. What's your leg length. Try switching to 150mm cranks - big difference in knee stress with the shorter cranks.

EDIT: If you change to shorter cranks you need to move the boom out by the same amount - so by 20mm if switching from 170mm to 150mm. The idea is that you can pedal with less knee bend.

 

[arallsopp]

A few things I found helped when starting out.

1. Keep an eye on your cadence. Less than 70 was bad for me. I found it very hard to judge, so ended up fashioning a cadence monitor out of a cheap cycle computer (magnet taped to crank arm, sensor zip tied to boom). Keep the head unit in view. When it drops below 70rpm, change down. (I didn't have cadence mode on my computer, so faked it using a custom wheelsize and an arbitrary number I shouldn't drop below).
2. My right knee tended to track inward at the top of the pedal stroke. I attached a zip tie (no big surprise there) to the boom with the long tail left pointing at my knee. Every time I snagged my lycra on it, I consciously moved my knee outwards. Soon enough I learned to avoid it subconsciously, with the benefit that my pedal stroke is now straight.
3. Pedals with float. I use time atac pedals. Lots of wiggle room there, so my foot tends to end up where it wants to be rather than pinned into a position that mightn't be good for it.
4. See if you can find out what part of riding it is that stresses your knee. It might be where you rest it when freewheeling. It might be the jerk it gets when you shift gear. It might be only the few times when you pull away from lights. If you can isolate it, you can probably avoid it.
5. If you've been cycling uprights for a while, you might find your leg muscles are stronger than your knees. Knees will generally be strong enough to lift you, but not much more. On an upright, you can't push more than your bodyweight, so it doesn't need thinking about. On a bent, you can push way more than your own weight, so you've got to be really aware of gears when stopping and starting off.

Hope you manage to find a way around it.

 

[Scoosh]

I'm currently off riding, as I have been getting similar knee pain.

I had also noticed my right knee tending to 'lean in' towards the boom - much as described by @arallsopp above. I now spend part of each day lying on a physiofoam roller trying to loosen my ITB, which is rather too tight … . It hurts a bit.

The physio reckons I can try riding a bit when I want to … just as the weather turns to full autumn.

 

[steveindenmark]

I had a similar problem on a DF and went onto flats for a couple of months and it cured it. If you are using spds I would find another way of securing the pedals to your feet and get rid of yhe clips.

 

[Monkreadusuk]

It's mainly when going up hills, just can't get that cadence high enough. May look at a cheap cadence sensor to keep track of it.

Thanks for all the advice

 

[Tigerbiten]

It's mainly when going up hills, just can't get that cadence high enough. May look at a cheap cadence sensor to keep track of it.

Are you running out of gears or just not changing down enough ??
If it's just not changing down enough then the trick I use is to not work on cadence but to work on how much pressure you feel on the bottom of your feet.
Once you get in the habit of keeping it low no matter what, you can spin at 60-70 rpm without putting a lot of strain on your knees.
The downside is you do go uphill slower because you're not thinking speed but how little effort can I use.

 

[Monkreadusuk]

Are you running out of gears or just not changing down enough ??
If it's just not changing down enough then the trick I use is to not work on cadence but to work on how much pressure you feel on the bottom of your feet.
Once you get in the habit of keeping it low no matter what, you can spin at 60-70 rpm without putting a lot of strain on your knees.
The downside is you do go uphill slower because you're not thinking speed but how little effort can I use.

It's not having enough gears I think. I change down and spin at 4mph up the hill in lowest gear

 

[SatNavSaysStraightOn]

I'm also having a similar problem. and it is one of the reasons I am also off my trike. I have found that shortening the boom more than I should helped me. Cadence isn't an issue with me because I don't have the strength in my legs to use power to get me up anything: I can only spin (being partially paralysed).

I've also adjusted the seat position to try to help which it seems to have done. But I'm also looking at the pedal width on mine. I think I need some spacers because I'm conscious that my shoes are as far apart as they can be and seen to want to be further apart

 

[FrankCrank]

....yep, gotta keep spinning, not mashing. I use 140 mm crank arms too, much debate as to their merits on recumbents, but to me they seem an obvious choice.

I live in a flat area, but can trigger knee pain just by mashing up a hump-back bridge, need to change down early and keep spinning - becomes second nature after a while.........

 

[DaddyPaddey]

If you have shorter cranks doesn't that mean that it makes the pedalling harder as you have less leverage?

 

[PaulM]

Not as much as you might think. This is because you are gain more time in the high torque part of the crank revolution where the knee is less bent. If you go from 170mm cranks to 150mm cranks then you may want to drop the gearing by a couple of teeth on the chain ring, but see how it goes. It only matters if you run out of gears at the bottom end.

 

[Monkreadusuk]

After fitting a makeshift cadence sensor, it would appear my average rpm is about 70 on my commute to work.