Stack and reach for neck issues, help me understand.

hello so I have had long term neck issues and now have bugling discs in c5;6 & 7, this results in a interesting array of issues for the riding of bikes long term.

My most comfortable bike is a stooge with a 420 reach and 632 stack it also has a headtube length of 130mm….used with a 780bar problem is it is rigid and I cannot cope with the impact on or off road.
The full suspension option is a Nicolai g13 with a reach of 510 a stack of 619 with a headtube of 130mm bars are 780 with a 30mm stem. Reach and seat tube angle seem ok It places too much pressure on my hands and neck as it is low, I have flung on a 25mm riser and that has not made a difference.
So the headtube length is same as stooge but stack is much lower…..for my next bike should I be looking at the stack height to get a more upright feel or reach or what to some degree mimic the stooge?

Well straight away the Nicolai has a much longer reach, nearly 10cm longer which is not insignificant.

Longer reach means more stretched out riding position which means potential for strain on lower back, as well as neck as you’ll be craning it more in order to be able to see straight ahead.

As a basic principle stack height will dictate the extent to which you are bending down to the bars and reach how much you’re stretching forward.

So a sit up and beg style Dutch bike will have very high stack and very short reach.

I’m surprised at the extent of reach difference between the Nicolai and the Stooge. I know Nicolai are loooong, but are they both the same frame size?

Regardless if I was you I’d be looking for a much shorter reach than the Nicolai and a bit more stack too..

I don’t know if my anecdote will help you understand, it hasn’t helped me to understand.
Anyway, I had a bike fit done a month ago for my (road bike) riding where I get a sore neck going up onto the base of my skull.
I was really expecting the reach to stay the same, and the stack to increase, however, the end result has been to move the bars closer and lower, and I’m no longer in pain. I don’t think it proves much except for the fact that what works for one person doesn’t work for the next.

Thanks for the replies, with stem length factored in and seat angle the length difference feels minimal it is the lowness of the Nicolai….which I wanted to try as it may have helped in essence closer and lower.

So is it stack heights need to understand?

Can you not get a FS with the same reach and bar height of your Stooge? If those are the numbers you’re comfortable with it would make sense to duplicate them. I understand that it’s quite expensive to replace a Nicolai. Maybe move the saddle forward on the rails to shorten the Reach, but I would be trying to replicate what you already have as near as possible.

Bang as many spacers underneath as you can to try to bring the bar up into a more ‘sit up and beg’ position to try out. ProTaper do some very high rise bars which might help.
I’m sure the longer Reach is also quite an important factor as it’ll have you stretched out a bit more than before.

Or run a longer fork to raise it up

This should explain it

This may sound slightly squiffy but bear with me. I had cervical neck pain begin on a short ride and then become exacerbated with more rides. This was on a CX bike I’d ridden 000’s miles on. I tried raising the stem, changing to a +17’ stem, shorter stem; all one at a time and still no difference. I did some reading and one aspect that popped up was saddle angle. So I tilted my saddle nose up a little. Night and day in terms of neck issues.
The slightly nose down of the saddle previously had been loading my arms-shoulders-neck up little by little. By nosing up more of the weight of me is being taken by my buns and legs. When I say nose up a little I mean the nose is now ~5mm higher than previously. I’d recommend trying it.

is it comfortable sat down or stood up?

I have some (less significant) back issues and found a new longer reach bike with a steeper seattube (and thus a shorter ett) was less stretched in feel than my old bike. reach is just moving your feet back, and can actually reduce the angle you’re bending in the middle if the ett stays the same.

Try more stem spacers and maybe a reach reducing headset as it’s almost 100mm longer. ProTaper make some high rise bars that are nice to ride if you need more height.

I have flung on a 25mm riser and that has not made a difference.

If you mean you added a 25mm rise bar and you’ve not run them any more swept back you’ve actually made the bike longer, to bring the bars closer you need to raise the stem. I’d try the old bars with some spacers under the stem.

There’s no doubt that a low stack means you’re bending down more to the bars. Consequently more strain on neck as having to ‘look up’ more to see straight ahead and more weight on shoulders/neck too.

Reach being the horizontal difference between bb and top of head tube, it’s really about how much of the length of the top tube is in front of the bb. So you can have a bike with a very steep seat-tube angle (say 78° or so) that has a long reach but comparatively short top tube (I believe the Stif Squatch is one of these).

In your position I’d be looking for a bike with a high stack a shorter than extreme reach and a shortish top tube (all for the given frame size). A more upright position means less strain on neck/shoulders as well as on the lower back. A Nicolai doesn’t answer to any of the above.

The advice about saddle angle is good too

Took me a day but found a diagram which explains what I said better