I’m planning on going from a 65mm stem to a 90mm to try and increase stability on technical climbs – but the one i’m looking at is 17 degrees rise as opposed to my current one which is probably 6deg rise, will this accentuate or lessen the difference?

http://www.brightspoke.com/t/bike-stem-calculator.html

It will lessen the difference. You really want to get the front end lower – both for climbing and keeping weight on the front for cornering.

65-90 that’s quite a jump, I’d try something inbetween, can you borrow a mates to try?

I was happily riding my On One when a pal pointed out my stem was very short and doesnt that make it very twitchy.
No seems OK to me was my reply…

Ever since I cant get out of my head how twitchy it is, felt fine before he said anything.
My heads been messed with.

No wonder they call them ‘A-Head’ fitting.!

Haha, I have this with tyres, they’re fine untill someone tells me theirs are better.

I ran my 456 with a 90mm stem, spolied it a little. But 65mm to 90 isn’t that a big jump, unless you find an 80mm one, but then the difference might not be enough to notice.

I’d just try 90mm, hate it (O-O’s are designed arround small stems, they compensate with longer TT’s), then go back to 65mm (which is still longer than my 50mm on the 456).