My bars are a skinny 680mm Monkeylite, & I’m wondering if I moved my grips out say 15-20mm each would it make enough difference to notice?

Plus on the safety side, would it put much strain on the ends of the bars? The grips are tubed all the way through & without end plugs.

Or should I just give Chain Reaction £70 for some 750mm Havens?

PS, I like a decent rise on my bars & the Havens come at 20mm or 40mm.

Flat bars went out of fashion ages ago. 🙂

I have done this before a few times in fact. No issues for me.
Best keep it under say 30mm just to be on the safe side.