I am setting up an MTB for the Mrs. She has a back problem so I need to set the handlebar quite high. Is it better to use a riser stem of say 30 degrees, or just keep the steerer tube long and fit a regular stem. Will the handling be different? Is one option better than the other?

Both options fine.

Although bear in mind that sometimes lower handlebars can actually stop back pain.

All much of a muchness. Long steerer/high rise steerer/big riser bar – if the grips are in the same place it *should* feel the same.

A few spacers, mid rise stem, mid rise bar looks most balanced.

Keep the steerer long and then that way you can experiment with different heights of bar.

A longer steerer will bring the bars back towards the saddle. See my pic – ok, I have a very slack head angle, but had I mounted the stem directly on the headset, then it would have been about an inch further forward.

Untitled by davetheblade, on Flickr

When I built up my wife’s 1st mtb, it had a 10 degree 90mm stem.

It soon ended up with a 20 degree stem but with a 70mm length as she wanted a more upright position.

It’s worth while maybe reducing the reach slightly as well as the bar height.

Thanks for those thoughts. I think I’ll experiment with the stems I have (both 6 degree rise, 60mm and 80mm) and a bunch of spacers. May just get a cheep high rise stem to add to the experiment.

Like the picture above from TheArtistFormerlyKnownAsSTR with a slack head tube, more spacers and longer steerer tube will bring the stem clamp behind the headset. I wasn’t sure if that would make a difference to the steering or stress/leverage on the steerer tube (I have 50mm of spacers on there at the moment).