I get this after half hour and can go away if I ride one handed but always comes back. Roadrat with steel disc forks, 32c tyres at 80 psi, short stem for upright position. I’ve got esi thick grips, tried other Foams with no effect. Tried flat bars, carbon risers with no effect.
Any ideas to help?

Same here, try using ERGON grips.

Ergon GP 1 Grips – Worked for me.

I did have some Specialized grips similar to ergons, I’ll see if I still have them. Very rarely get it on mtb.

what’s your saddle angle? if it’s tilted too far forwards it puts more pressure on your hands as you try to stop yourself sliding forwards

32mm tyres at 80psi…?

apologisis if this is a personal question, how much do you weigh?

(i go with 50rear/40front, but i’m a scrawny 12stone and my thumbs explode if i go much higher)

Saddle is tilted forward a little. Tyres are Road tyres, they feel flat under 60 psi.

Get the saddle dead level, drop it a bit if you feel you want to, get the saddle further back on the rails

You mean slide saddle forward on rails Shirley?