Just put some wider bars on my 29er hardtail , 780mm Spank Oozy , I reckon I need to go shorter than the 90mm Stem that’s on there . Torn between 70mm or 50mm ? Is 70 enough ? Is 50 too much making it too twitchy ?

How wide are your current bars?

I’d try the 70mm first. It’s going to be closer to what you’re used to and wouldn’t make a too massive difference.
As far as I remember I’ve reduced my stem by 10mm when going for a 3cm wider bars and it was spot on!

With stuff like this I buy both (ebay) try each then flog the one I don’t want.

50mm.
Wide bars and short stems work together really well.

tomhoward current bars are 740s . Being a tart I want Thomson ! 2 for sale on PB ATM a 70 and a 50

Buy both, try them, sell the one you don’t use. Unless they are wildly overpriced, you’ll get your money back on a Thomson stem.

50mm.
Wide bars and short stems work together really well.

agree.
Might be a good combination. Riding will change so. First two weeks might be a bit “strange”. But big chances that you will like this setup then and won’t change back to longer stem.

Limit so: going uphill. If you can’t steer any more going very steep you need to change back to longer stem.

Short answer: If you can get both then I would and give them a good try.

Long answer: My most ridden bike of 2017 came with a 100mm stem and 750mm bars. The bike felt ok actually (old school geometry 29er) but as I was at the bottom end of the size chart for this frame size I thought I’d try a 50mm I had in the spares bin. It felt horrible.

I then picked up an 80mm cheap on CRC which was ok but I still wasn’t completely happy.

Finally I bought a 70mm last month and it really made all the difference. It felt SO right from the off.

So worth persisting till you get it right.

The rough guide I remember reading for fitting a wider bar was for every 20mm wider in bar width, reduce the stem 10mm. Not sure how accurate that is but it’s a guide I guess.

When I fitted the 747mm Knuckleball bars to my Wazoo in 2016, I switched to a 35mm Corto stem. But I randomly switched to an old 100mm stem recently and it’s given me more confidence through sweeping corners on the road.

Normal Man that calculation would suggest 70mm as I’ve increased bar width by 40mm

Forget that old bars were 740 new 760 ! I think the issue is backsweep less on the new ones , I’m beginning to think any less than 70 won’t work .

anywhere near Bristol? Got plenty of stems in 50, 55 and 70mm lengths if you want to try one.

If the bars are wider and have less backsweep then you’ll need to go quite a bit shorter.

Beginning to wonder if I should have stuck with Kona bars but wanted to try Vibrocore. AndyL I’m in Somerset!