Yeah - bar length, stem length, and frame reach all interact. If your existing bike more-or-less fits you, just making the bars wider will pull you forward and potentially make you too stretched out and unable to move your weight around the bike.
For wide bars to really really shine, it usually works best to have a frame with enough reach to use the shortest stem possible. Really short stem and really wide bars compliment each other, but you need a frame with a reach that makes it fit your stature.
The other thing that interacts with all of that is fork offset.
Santa Cruz for example fit their bikes with wide bars these days and 50mm stems. I don't think it's a coincidence that the most common fork offset these days is 49-51mm. Their frame geometry is progressive but not on the extreme end of progressive (their XL frames have the same reach as Kona or Transition or Chromag's large frames, but they are still longer than Ibis or Specialized).
I am 5'11" on a good day and ride an XL santa with a 33mm long stem and 800 bars, basically the geo is similar to a Large Transition or Kona (standover/seat tube length is a little longer but a slammed 150mm dropper work out fine). I did about 10 rides with the stock 50mm stem and as an intermediate rider it felt amazing on flowy trails because, like Cam described, the wide bars pulled me forward into a more agressive cornering position. But, I could tell that my position was not very dynamic. In technical situations where I needed to loft the front wheel quickly, and on steep chutes, it was hard to really shift my weight around. It was stable but not dynamic.
The 33mm stem felt terrible the first 6 rides because I'd gotten into the habit of trying to ride with my weight far rearward since in reality the bike was always pulling me forward before. So - the faster steering due to the shorter stem and lighter front end due to what in reality was actually a more centered riding position, felt super sketchy. It took me a while to manually get my weight forward in the way that the longer stem did automatically. Now that I can do it though it is awesome, because again like Cam was saying - I can have my weight forward, but I have options too. with the shorter stem I can really hang off the back if needed. Climbing is awesome regardless with the long reach, I can sit on the nose of the saddle and really lean over the bars.
The only slight oddity is I think I can feel that the fork offset is greater than my stem length. Interestingly enough now transition is working with lower fork offsets and the fork manufacturers have gotten behind it. I suspect that is why. A lot of bikes need 20mm more reach, 30mm less stem, and wider bars, and reduced fork offset to match the stem.
So in summary, wider bars and shorter stem is good, but it helps if you have a frame with enough reach that a 33-40mm stem doesn't turn it into a knee knocker.
Jan. 2, 2018, 5:30 p.m. - Kenny
Yeah - bar length, stem length, and frame reach all interact. If your existing bike more-or-less fits you, just making the bars wider will pull you forward and potentially make you too stretched out and unable to move your weight around the bike. For wide bars to really really shine, it usually works best to have a frame with enough reach to use the shortest stem possible. Really short stem and really wide bars compliment each other, but you need a frame with a reach that makes it fit your stature. The other thing that interacts with all of that is fork offset. Santa Cruz for example fit their bikes with wide bars these days and 50mm stems. I don't think it's a coincidence that the most common fork offset these days is 49-51mm. Their frame geometry is progressive but not on the extreme end of progressive (their XL frames have the same reach as Kona or Transition or Chromag's large frames, but they are still longer than Ibis or Specialized). I am 5'11" on a good day and ride an XL santa with a 33mm long stem and 800 bars, basically the geo is similar to a Large Transition or Kona (standover/seat tube length is a little longer but a slammed 150mm dropper work out fine). I did about 10 rides with the stock 50mm stem and as an intermediate rider it felt amazing on flowy trails because, like Cam described, the wide bars pulled me forward into a more agressive cornering position. But, I could tell that my position was not very dynamic. In technical situations where I needed to loft the front wheel quickly, and on steep chutes, it was hard to really shift my weight around. It was stable but not dynamic. The 33mm stem felt terrible the first 6 rides because I'd gotten into the habit of trying to ride with my weight far rearward since in reality the bike was always pulling me forward before. So - the faster steering due to the shorter stem and lighter front end due to what in reality was actually a more centered riding position, felt super sketchy. It took me a while to manually get my weight forward in the way that the longer stem did automatically. Now that I can do it though it is awesome, because again like Cam was saying - I can have my weight forward, but I have options too. with the shorter stem I can really hang off the back if needed. Climbing is awesome regardless with the long reach, I can sit on the nose of the saddle and really lean over the bars. The only slight oddity is I think I can feel that the fork offset is greater than my stem length. Interestingly enough now transition is working with lower fork offsets and the fork manufacturers have gotten behind it. I suspect that is why. A lot of bikes need 20mm more reach, 30mm less stem, and wider bars, and reduced fork offset to match the stem. So in summary, wider bars and shorter stem is good, but it helps if you have a frame with enough reach that a 33-40mm stem doesn't turn it into a knee knocker.