Originally Posted by mkatz

I've looked! unfortunately (for me) I've been able to locate online only a few, short reviews. I'm interested in the Helix because it appears to have a relatively compact folded size with relatively light weight and "reasonable" diameter wheels. It also appeals to my sense of engineering aesthetics. The problem is that I'm old (73 ) with an old man's neck which requires me to seek out a relatively upright riding position and I'm wondering how the geometry of the Helix might fit my needs with or without bar +/or stem replacement (if such is even feasible). All thoughts appreciated!

Originally Posted by Robmac123

It will depend a lot on your height. I’m about 5’11” and I like my seat high so my legs are well stretched out due to knee issues. I lean forward a little, but it’s still comfortable for me. I’m definitely not perfectly upright. If my wife rides it her riding position is much more upright, but she’s 5’5” and has the saddle pretty low. Folding bikes I’ve had before the handlebar tube was telescopic and I could get the bars high enough to give me an upright position even with the seat fairly high. I had a cheapo Citizen 20” bike that had a big comfy seat and a huge amount of adjustment in the bars. That bike was like riding an armchair, but it made for a very inefficient and slow ride.

With Helix you don’t have that telescoping adjustment so the stem height is fixed. You should be able to change the stem for one with extra rise, it doesn’t look to be part of the securing mechanism, you’d just have to remove the knob on the top and it should come right off. The handlebar tube that the stem clamps onto seems to be 1-1/8”/28.6mm which I’m pretty sure is a fairly standard size. The problem with adding rise in the stem is that it normally adds reach/effective toptube length also, so you can end up back where you started in terms of being upright.
Adding riser bars is another way to get a more upright position. I have some on mine. They only added about 2” of rise but that made a big difference to me. I have them raked slightly back towards me also, so it may have reduced the effective top tube length by an inch as well as adding 2” to the height. Bars with that extra rise didn’t affect the folded size, but a riser stem would likely add to the width of the folded bike a little, if that matters to you, as it will stick out further as well as up. If you added much more rise I think you’d have to swap out the brake/gear cables for longer. If I remember when I fitted mine I thought that was around about the limit for the cables.

I would look a the helix promotional video and the few other reviews on YouTube to get an idea of the riding position. If you pause it with a side on view you get a pretty decent idea, even though you’re guessing the riders height.
if you want any measurements I’m happy to take them for you.