Left sit bone slipping off saddle

[willhub]

I had a bike fit at Pedal Precision in Manchester.

Bike was changed only slightly.

I was given exercises to help stability.
I was told I had a functional leg lengths discrepancy.

In 2015 I was given a shim however this was angled to tip my ankle to the left on my leg food.

The consensus on leg length says it's impossible to get an exact indication of leg length discrepancy without an MRI scan because it can be a lot of other things giving the effect, so as a result I've never managed to get an exact indication in mm of any leg length discrepancy.

I have about 8mm worth of shims (combination of 2mm shims and 1mm shims) also have one that is angled.

When I tried shimming the left side this slip on the saddle didn't go away.

 

[PaulSB]

@willhub it may well be impossible to determine the exact leg length difference. It's definitely possible to determine it to an extent, in my case sufficient to correct pronation, largely eliminate hip pain, eliminate a tendency to pull right and change my saddle position.

My GP and three podiatrists, one private, two NHS, have diagnosed it and I can see for myself. Was your bike fit guy suitably qualified to provide a diagnosis?

In my view slipping off the saddle can only result from your overall position on the bike.

 

[willhub]

I've been to Pedal Precision where the guy I expect would be and also bike fit in 2015 was Cyclefit precision, they're only based in London now.

I can't really afford to go for another bike fit or put money on it any more, my partner won't let me especially with a baby due.

I'm sat waiting to see a physio about my back but I don't think I can tell them about leg length and bike fit they'd just fall asleep especially with it been on the NHS.

I'm going to try a 10cm stem because if I move my seat back 1.7cm I can't see that been any detriment it should be better re balance. Then the 10cm stem.

That would give a reach of 66.7cm, 7mm further than it is now, the 2mm can be adjusted for so I think 66.5 is closest I can get. Reason I want to try this is I'm wondering if my arm angle is wrong at 67cm as currently with the seat pushed as far forward with a setback from BB of 5cm and the reach at 5cm I feel like it's a better position over the bars.

Perhaps shorter stem would help handling too?

Or should I leave it as it is and mess with shims again? I'm just trying everything but it's so draining, loosing time for riding, 3 hours faffing last night that could have been a 60 mile ride if I could actually ride comfy.

 

[willhub]

I'm been referred at the doctor's he wants to check me out further as has suspicious of Rhumatoid Spondyloarthritis and also to be checked for HLA.B27 which my mum and uncle has, doesn't effect my mum but ours my uncle in a wheelchair when it seems to occur.

Hopefully I don't have either but wonder of either could explain on the bike issues

 

[wonderloaf]

Before were you so unstable the bike could not be kept straight without using too much effort that effectively leads to aches and pains?

I could move the cleat forward on my left shoe but I can't imagine miss matched clears would feel right ?

To be honest they're exactly even right now but I always feel my left foot is at a different fore/aft to my right

Moving the cleat did feel strange at first but I don't notice it much now, especially when riding on a flat road. However when I get out of the saddle on a hill that's when I do notice the difference, but this is better than having an unhappy buttock!

 

[willhub]

I've moved the cleat from "3" to "5" on my left shoe and kept the cleat as far back ony right foot at "3", I'm sure it felt a bit more stable and straight.

I've added a further movement from "5" to "5.5" and will see how this works.

That's a clear different of around 8mm further forward on the left leg

 

[willhub]

RESULTS:

6mm further forward cleat on left shoe effectively lowering saddle for that leg.

Much more stable, better acceleration, better stopping, better more stable power.

Still not perfect, unsure if I should add a shim or move even further forward or just persevere until bike fit on 29th.

 

[OldShep]

I've even tried to ensure I'm balanced and moved the saddle all the way back as far as it'll go, I still get numb hands, now I've moved saddle as close to my 4cm setback from BB from 2015 bike fit but I can only get to 5cm.

Are you a small person? That’s less than half of my set back I’m 6‘

 

[willhub]

Are you a small person? That’s less than half of my set back I’m 6‘

I'm 5ft 10.

Setback is approx 5.5cm currently. 8cm setback would 100% be too much for me.

What is your inseam measurement?

 

[OldShep]

I'm 5ft 10.

Setback is approx 5.5cm currently. 8cm setback would 100% be too much for me.

What is your inseam measurement?

Can’t remember exactly but with the book at crotch method think it’s somewhere between 33-34. Set back IMO is more akin to your balance point than getting KoS. When you say you’ve numb hands then it sounds like you’re leaning in them and need your saddle back.

 

[willhub]

Possibility, did have it as far back as it could go and still got numb hands, now it's as farforward and still get same amount of numb hands.

Your inseam is about 3cm more than mine so you've got longer legs

 

[OldShep]

Possibility, did have it as far back as it could go and still got numb hands, now it's as farforward and still get same amount of numb hands.

Your inseam is about 3cm more than mine so you've got longer legs

Which in turn means that it’s possible you have a longer body in relation to your legs. To balance that longer trunk and take away weight from your hands you have to stick more of it out the back.
Stand against a wall and bend forward see how far you get before falling. Next step forward away from the wall and repeat. See the result when your bum can stick out.

 

[willhub]

Which in turn means that it’s possible you have a longer body in relation to your legs. To balance that longer trunk and take away weight from your hands you have to stick more of it out the back.
Stand against a wall and bend forward see how far you get before falling. Next step forward away from the wall and repeat. See the result when your bum can stick out.

Just tried that and it's about the same amount of bend :s

 

[willhub]

I have made a few vids on YouTube of my position, changed it a bit since then but maybe the various videos will shed some light ?


View: https://youtu.be/1BqHEOvnkes

 

[PaulSB]

Clearly it's all personal, and therefore subjective, opinion. My position is somewhat different and I would want to do the following:

• Move the saddle forward so that in the six o'clock position there is a straight line between the centre of my hip and my heel
• Extend the leg more in the six o'clock position
• Move the foot further forward on the pedal

The combination of these would give a more upright position and a flatter back. I would start with the saddle height and position first.