Bike sizing / science/ geometry is a big blind spot for me. I can’t seem to translate numbers on a web page to knowing how a bike will fit or ride.

So, I bought a new bike in March and I’m really enjoying it for the most part. However, I am encountering an issue when I have to shift my weight back on it. I notice this most when I’m cornering on a descent.  I don’t so much steer the bike as slightly lift and move the front wheel as my weight seems to be so far back. I find this unnerving. If I try to compensate by moving my weight forward, I feel very thrown over the bars and generally unstable.

I had a coaching day recently where the coach said the bike was just a shade small for me. I like the bike I have but the distributor reckons the next size up would be too large (at 6′ 2″ I’m right on the margin of L and XL).

So, is it top tube length, chainstay length, plain size or just my riding style? I have limited test ride options where I live.

Bar height or width? Stem length?

The problem is that it’s hard to take any of the numbers you mention in isolation as they all interact. To me it sounds like your bike could be longer or wider bars or longer stem etc or possibly it’s a position issue and your weight is too far back.

sorry but it’s you.

You’re basically attempting to manual turns because you’re scared to be far enough forwards to weight your front tyre.

Ignore all the comments you’re bound to get about your bike and simply take it out and learn to corner it properly.

ignoring the bluntness above.

When you get your weight forward are you too low or how do you feel like you are going over the bars?

Could be bars/stem too low or a bit too short for where you are comfortable

What was the coach’s thoughts apart from a bit too small?

Long (and low) bikes are supposed to help make it possible to have your weight in the right front/back position whilst having more OTB stability.  Theoretical considerations support this.  I have only gone “a bit longer” rather than full long and I couldn’t say I have noticed this, but I like it anyway.

2 suggestions, as well as agreeing with mike above, but we really need to know the ‘style’ of bike.

1 – no dropper post? modern long bikes even on the xc trail end of the spectrum need you to be low and central, basically where the seat is. dangling off the back because the saddle is in your chest could lead to the feeling you are describing. my trail/enduro bike I physically cannot get behind the saddle at full pedaling height, unless I’m wearing lycra. and then my arms are pretty much locked straight and useless for steering.

2 – fork set up – under pressured fork or too linear a spring rate, could lead to this scary pitching forward feeling that results when you attempt to do it ‘right’. will be worst on a longer travel hardtail as the whole bike will be diving forwards.

The bike is an Intense Recluse.

Coach really wanted me to work on my attack position but that’s what makes me feel unnerved. Bringing my torso lower magnifies the over the bars feeling. Keeping my chin plumb with the top cap as coached just makes the bike feel really unstable.

Bar is 760mm with a 20 degree rise.

Do you disagree with the coaches advice or is it just fear holding you back from fully committing to it?

Seriously. go out and actively practice cornering with your weight further forwards/centred. Once you’ve pracaticed enough and gotten more used to the position you’ll realise it’s not anywhere near as unstable as you think it is.
What do you mean by “I have limited test ride options where I live.I have limited test ride options where I live.”
You can practice basic cornering and weight distribution anywhere.

It’s not a short bike by any means

+1 on working on the ready/attack position. Go and spend a few hours on easy trails and keep body position as your main focus. Stop regularly, think about the section you have just ridden specifically in relation to body position, then go do some more. It will all drop into place, the time it takes depends on the rider and the bike and the terrain.

are you moving you feet? getting the outside foot a bit lower to get the weight through that pedal? It’s amazing how much grip getting the weight through the outside pedal can get you with a bit of weight over the front and being slightly offset to the outside and front can get you. Different corners require more and less of this, you’ve got to judge each and move around. But you need to be loose and move about as required, it’s not a one size fits all thing.

Thanks for all the thoughts. Practice it is then.

The reference to test rides was in relation to demo bikes in case a change of bike was needed.

In my opinion, if you are on the top end of a large, the shorter reach (compared to a longer bike) bike will be exaggerating the OTB and manualling feeling.

I liken it to having your feet closer together and leaning forwards and backwards, the closer they are the less stable you are, move them apart and you’d be more stable.

I believe better riders can ride a shorter bike as they have the skill to finely judge the weight shifts to get the best balance, and be able to use there weight to manual and move the bike around. I’m not a great rider so feel more comfortable on a longer bike as the margin for error is greater.

Good comments (mostly) above. The “attack” position is a weird one to get used to as you’re dropping your chest and head whilst keeping your legs relatively straight. Particularly when you’re going down the steeps. Bottom line though is you need to keep weight over the front wheel in order to retain control of the bike. Otherwise you will wheelie into a tree (or somesuch), washout or go A over T off the back of the bike. You can compensate a bit by dropping your heels so that you have more weight behind the bb. At the end of the day it’s about practising riding that position on easy terrain until you’re comfortable with it and then applying it on more “gnarly” stuff. Hanging your arse over the back wheel is probably the most common mistake bikers make. In my case it led to me hitting a jump with no way to push weight back when the bike caught the lip and rotated forward, leading to me landing on my head and costing me teeth and an awful lot of additional pain!

Also worth thinking about pumping into corners, essentially pushing with heels through pedals and arms (emphasis on inside arm, ie left on a lefthander) through handlebars as you ride through the corner. Pushes weight through the wheels giving more grip and (particularly on an FS) can pop you out of the corner giving you greater exit speed.

Advice on pedal position relative to corner is good as well. On flat corners (no berm) you want the outside pedal dropped (also reduces risk of pedal strikes). Less so the more banked up the corner is.

Advice applies regardless of whether the bike is too bid/small/perfectly sized