We are back at it with the pseudoscience. Today we are in the Bike Lab trying to make sense of handlebar widths and stem lengths to help you find the best MTB handlebar and stem combo. The two components are so interconnected it’s tough to talk about one without the other. So, how wide should you run your handlebars? How short is too short when it comes to a stem? How does one affect the other? Stick around to find out.

How we set up the test For the Best MTB Handlebar and Stem Combo

Alright, I’m going to try to make this semi-complex relationship as simple as my little brain can. I’m going to break it down into individual parts to start to understand what each of these things does. This should be easy. Handlebars are what you hold onto, and stems are what keep the handlebars on your bike — Done. I wish it were that easy. There are so many different stem lengths and bar widths, and everyone seems to have an opinion about which is best. I want to dive into how each affects handling, fit, and your bike’s overall ride quality.

I have two of the brand new Enve alloy MTB stems here. One is 35mm long, and the other is 50mm. For me, that’s the practical range of MTB stems. They can’t really get much shorter, and any longer, they are probably a road stem. Both stems have a 31.8mm clamp diameter for the 31.8mm bore Ibis Carbon handlebar I’m using for this test. The Ibis handlebar is unique in that it has two threaded inserts on either end. With both inserts installed, the bar measures 800mm. After testing at 800mm, I’ll remove those inserts to bring the width down to 750mm without having to cut the bar. 

For the test, I’m going to Trailside Bike Park to run multiple laps with each setup. There’s a wide variety of terrain there, making it an excellent place for these back-to-back tests. The things I’m paying attention to are fit, handling, and overall ride feel. Does one setup make the bike feel too small and twitchy? Does another make it big, slow, and sluggish? That’s what I’m going to find out.

Ride Impressions

This was the baseline setup for me. I ride something fairly similar to this on most of my personal bikes. Although, I do like my bars a bit narrower than 800mm. I started with this setup so I could have a good reference point to compare to once I started swapping things out.

Fit – This setup felt pretty comfortable and neutral on my size XL Transition Spur. My riding position both on the climbs and descents felt pretty well centered on the bike. The wider your bars, the closer your chest is going to get to the stem. The short stem kept my position from being too forward on the bike. It also kept the bike from feeling too big. The bars felt roomy but not cumbersome or unmanageable.

Handling – This combo kept the handling speed pretty close to what I’m used to. There are two opposing things happening here. First, the wide bars provide a lot of stability while slowing down the steering a bit. Conversely, the short stem speeds up the steering keeping it from getting too slow. It strikes a pretty good balance between steering stability and speed. The wide bars felt great in rocky sections of trail where the front end tends to get bounced around a bit. They afford you a little more leverage to oppose those forces and keep your front wheel tracking smoothly.

Ride Feel – The bike felt neutral with the short steam and wide handlebar combo. The steering didn’t feel twitchy and it certainly wasn’t slow. The body position was the most centered of all the setups. This is a great combination for aggressive all-mountain riding.

I haven’t used bars this narrow for about as long as I can remember. Initially it felt extremely weird and didn’t give me much confidence dropping into some of the downhill sections.

Fit – The combination of the short stem and wide bars made the bike feel very small. It felt like my elbows were tucked in and my stance on the bike didn’t feel very stable. The short stem kept my weight a little more off the back, especially without the wide bars to counteract the rearward shift. I felt very upright on the bike, especially while climbing. I didn’t notice the rearward shift once I started going downhill, however.

Handling – This setup felt very quick. I wouldn’t quite say it was twitchy, but the steering was much faster than I’m used to. I found myself having to dial back my steering inputs. More than once I oversteered in a corner and almost tucked the front wheel in underneath me. The narrow bars didn’t offer much stability in the rocks and I found it more difficult to keep the front wheel from bouncing around as much. the bike felt much more maneuverable in the air, however. It was easier to turn the bars for extra style points.

Ride Feel – The narrow bars and short stem combo made the bike feel smaller, more lively and very agile in the air. It had the fastest steering and the least stable stance through the rocks. This setup is great for making a big bike feel smaller. I wouldn’t really recommend it for much else unless you use your mountain bike as a full-time dirt jumper.

I’m going to lose a lot of cool points here, but this setup was my favorite for the faster, smoother and flowier parts of my ride. I think it would best suit the majority of riders on the majority of the terrain they ride. Don’t get me wrong, there’s a time and place for more aggressive setups, but the average joe will be better off on something more well-rounded like this. Not all of us are racing enduro, or riding the Whistler Bike Park full time.

Fit – The fit with this combo felt pretty close to the overall fit with the 25mm stem and 800mm bars. Of course my hands felt closer together than with the other combo, but where my weight was on the bike felt very similar. Once turned downhill, my weight felt further forward than with the other setup, but it helped keep traction on the front wheel through corners.

Handling – The steering speed on this setup felt very similar to the short stem and wide bars combo. And, it makes sense. Here we have the narrow bars speeding up the steering, while the long stem slows it down. This combo felt great in the corners with more weight over the front wheel. Again, the narrow bars didn’t offer much stability through bumps and the long stem pulled my weight further forward compounding the effect. If you ride a lot of rocks or steep trails, this might not be the best setup for you — stick with short stem and wide bars.

Ride Feel – This setup also struck a great balance between steering speed and stability. The fit felt very neutral with a slight forward shift for better front wheel traction. I’d recommend this combo for the majority of riders, especially those who don’t consistently ride steep, rough terrain.

If you have a bike that’s two sizes too small, this is a great way to make it feel bigger, while completely destroying the handling and capability. Right out of the gate this setup didn’t work well for me. It made the bike feel way too big. I quickly started feeling a lot of strain through my neck and shoulders.

Fit – This combo made the Spur feel huge. My weight was pulled very far forward with both the long stem and the wide bars. I’d suspect that’s the culprit for the increased strain through my neck and shoulders. Like i’ve said earlier, 800mm bars feel too big to me and the long stem made them feel even worse.

Handling – This was a case of the worst of both worlds for me. The long stem combined with the wide bars slowed the steering down way too much. The Spur is normally a quick, fun and lively bike. This setup completely destroyed that feel. The bike was cumbersome and slow around a corner. The stance from the bars did feel fairly stable, but the forward weight shift was too much and I found myself not being able to get my weight centered well enough on the bike.

Ride Feel – The huge feeling cockpit combined with the slow handling made this combo a flat out “no” for me. It made a fun bike feel like a school bus. I’d only recommend this setup for people that are mostly upper body and are on a bike that’s a little too small. Or, if you only go in straight lines and you like shoulder pain.

the Best MTB Handlebar and Stem Combo Analysis

While testing all the setups, I realized that steering speed simply comes down to how far your hands are from the steering axis. Ready for a physics lesson? Think of your stem and handlebar as levers with your steerer tube as the fulcrum. The longer the lever, the more distance it has to travel to move the weigh on the other side, but the easier it is to move the lever. I’m going to quit here before I get way in over my head with physics. If your right hand moves two inches forward on a 750mm bar, it will turn your wheel a certain amount. Now if you move your right hand two inches forward on an 800mm bar, the wheel will turn less. This explains why the steering on the short stem and narrow bars felt faster than the long stem, wide bar combo. I wanted to make sure I wasn’t totally crazy here, so I measured from the center of the steerer tube to the end of the handlebar with each different setup. The measurement confirmed my hunch.

I also noticed while testing that handlebars had more of an impact on how the bike handled than stem length did. This could have been because there was a 50mm difference between the bars versus the 15mm difference in stems. That’s not the case, however. It turns out that handlebars have a 1:1 effect on the distance from the steerer to the bar end, while stems have a 2:15 effect. In other words, for every 15mm of stem length change, there’s only a 2mm difference in the steerer to bar end measurement. While for every 1mm of handlebar width, there’s a 1mm difference in that same measurement. I did feel that stem length had a bigger impact on body position, however.

Alright, enough with the nerd stuff. What’s the best setup for you? The individual, their bike, and fit are all going to come into play here, but I’m going to go out on a limb and say that most people are probably best off on a 50mm stem with between 760-780mm bars. It’s the most well-rounded and neutral combo. That setup will provide a good balance between steering speed and stability while keeping your weight centered on the bike. The longer stem will help you keep the front wheel weighted on climbs and in corners better than a short stem. The bars will be in the sweet spot for stability and handling. It’s very well suited for a wide variety of terrain, especially faster, smoother flow trails that most people ride.

Not everyone rides groomed smooth dirt. I, for one, don’t really like those kinds of trails. I’d suggest dropping the stem to 35 or 40mm while sticking to 780mm bars for the folks who prefer steep, rough, and rocky trails. I have a hard time recommending 800mm bars for most people, especially those that like their pinkies with the bones intact. Apart from smashing fingers, the wide bars slow the steering down too much and pull your weight further forward.

This test has been very eye-opening for me. If you have the time and resources, I’d recommend going out and trying something similar. The Ibis Carbon Handlebar is a great option for running this test. Those threaded inserts make it really easy to change your bar width. Once you’ve found your number, you can cut the aluminum insert down to the exact length you want. Unfortunately, you’ll have to buy or borrow multiple stems to test that. I don’t know of any adjustable stems, especially any that I’d recommend riding.

Leave a comment below with questions you want answered in the Bike Lab!