I use the Rox elite risers for the fat bars with the risers on the inside of the clamps. I ordered 96mm x 38/40 mm and the fit perfect. I don't think the clamp could have been any wider and fit. I suggest you take the bars off and mount the Rox risers and measure the distance between the bolt holes. That's how I did mine and it was spot on. It took over a week for them to ship...so you may have time to get it changed if you need to.