I've lowered my bars 10mm to stop the front lifting when climbing (to counteract a longer fork) and I'm planning on getting some new bars, with the same rise as the current ones as it's working well.
BUT it got me thinking...
I'm sure I've seen something in the past that says high rise bars ≠ the same effect as moving the stem up. Can anyone explain the physics behind it? Surely either way would move my hands up by the same amount and move my weight back in the same way etc.
I've already written thousands of words on this subject. Basically, I like high bars especially on modern LLS bikes because everything has grown except stack height and most bikes have tiny head tubes.
Currently on 30mm high Burgtec because the bike with 40mm Fatbars got nicked. Gonna get some 40's again. I wish there were more choice though. I'm still trying to avoid 35mm stem clamps.
TLDR: stem spacers look whack- high bars look cool as
Raising your stem moves the bars backwards as a function of head angle.
Increasing the bar rise instead results in a bar that moves up but not backwards, or effectively further forward than a raised stem.
Increasing the bar rise also moves the hands further forward in relation to the steering axis, somewhat similar to what a longer stem would achieve.
So a higher bar will put you more upright but maintain a bit more weight over the front wheel than a higher stem. We're talking a few mm.
That's before you've played with roll, which should match the sweep to your shoulders but can also fine tune the reach.
Basically it's complicated, only way to find out if try.
Just imagine exaggerating the adjustment, if your head angle was 45° and you added 100mm of stem spacers, it would massively move your bars backwards as well as upwards. Just using high rise bars in that scenario would not reduce effective reach.
Obviously in reality you don't have such slack angles and big adjustments but it will be the same idea but to a lesser extent.
If you align your bar rise with your head angle then swapping spacers for extra bar rise puts your hands in exactly the same place. If you align your bar rise vertically then extra rise also gives you the steering feel of a longer stem (and the extra effective reach of a longer stem).
My bikes both have the same 40mm rise Renthals. On one the bars are rolled back closer to the head angle, on the other they’re closer to vertical. I’ve done that because I prefer the quicker steering feel from having them rolled back (shorter effective stem length) and vice versa.
30mm of spacers puts your bars around 12mm back with a 64/5° head angle, so going from 20mm rise to 40mm for example saves you taking 8mm out of your reach with spacers given that the bar roll is set the same, obviously the higher the rise the more range of adjustment is available by rolling the bar but if you have a sweep preference your bar roll will roughly be the same regardless of rise.
There can’t be a free lunch here
The effect of the extra rise, on the bars, would be the same as spacers and a slightly longer stem
If you get a high rise bar, you can get fore and aft adjustment with a minimal change in sweep angles (there is still change, but you get a good few mm reach before anything significant happens with sweep.). This is cheaper and more convenient than swapping in different length stems.
The position with a low stem (no spacers) and a high rise bar is more or less the same as you'd get with a longer stem, more spacers and a low rise bar. Of course, fashion dictates that long stems are naff and spacers are naff, so stick to modern principles and have all the benefits of actually being in the right position on your bike without the fashion police coming to get you.
Jack Moir had just swapped from running loads of spacers for a Renthal riser bar. Maybe ask him?
Sidebar question: does a higher rise bar have more flex, as the leverage is higher, grip further in a straight line from the clamp, it may be minimal in reality, princess and pea stuff
I’m sure I’ve seen something in the past that says high rise bars ≠ the same effect as moving the stem up. Can anyone explain the physics behind it? Surely either way would move my hands up by the same amount and move my weight back in the same way etc.
If the bars place your hands in the same place, there will be no effect. Different bars have different sweep and rotating riser bars forward or backwards will move your hands forward or backwards so you need to take account of that.
Enduro magazine article titled "the right handlebar rise - all you need to know" pretty much covers everything. Basically buying the same bar in different rises and set up the same way using the printed on set up lines will move the bar height up or down in a vertical line.
On this site you can play with geometry, spacers, bar rise, bar roll etc and to comparisons
Thanks, that all makes sense.
I think the thing that has thrown me before was that someone had to tried to say that even with your hands in the exact same position there would be a difference. Which contradicts this
If the bars place your hands in the same place, there will be no effect.
Which seems much more plausible 🙂
This seems a good exploration although the topic is slightly different.
IIRC lots of spacer's isn't recommended as you start twisting the steerer tube in odd ways. It also looks awful compared to a slammed stem and high rise bars.
I've currently got a slammed stem and Stooge Moto Bars on my Escarpe, it's the muts nuts.
There's definitely a point where things are too high and the front end loses all grip while cornering, and lower is definitely faster for aero reasons as well.
on modern LLS bikes because everything has grown except stack height and most bikes have tiny head tubes.
+1, a lot of people you see out on the trails just don't look comfortable with their arms stretched out in front of them. It might work if you have the core strength for it, but it's not working for the average weekend warrior.
I think the thing that has thrown me before was that someone had to tried to say that even with your hands in the exact same position there would be a difference. Which contradicts this
If the bars place your hands in the same place, there will be no effect.
Which seems much more plausible 🙂
If your hands are in exactly the same place there will be no difference, problem is that adding a 10mm headset spacer does not put your hands in the same place as buying a set of bars with 10mm more rise, the headset spacers will move your hands back by a small amount in comparison as the steerer tube is not pointing straight up.
This seems a good exploration although the topic is slightly different.
Seth high raise stem
Highway to the danger zone.
https://www.pinkbike.com/news/exploring-the-relationship-between-handlebar-vs-stem-length.html
thols2
Full Member
This seems a good exploration although the topic is slightly different.Seth high raise stem
Highway to the danger zone.> https://www.pinkbike.com/news/exploring-the-relationship-between-handlebar-vs-stem-length.html
Interesting, I've tried Jones-ey bars in the past and hated them as they put my hands behind the steering axis, my exact remark was "feels like riding a motorbike, but with none of the stability" because as he points out motorbike bars are behind the steerer axis as well so your hands sweep differently, motorbikes (to me anyway) feel more like you sweep them sideways rather than turn the bars.
First ride on the Stooges last weekend and the front end tucked under on a fast but tight berm, it didn't do it again but I'm now wondering if their sweep is pushing them back beyond that theoretical 15-20mm optimum. It only did it once though and otherwise they feel great.
I've also been experimenting with a 70mm stem on my SS Scandal as I'm not convinced by the weight distribution when clipped in, it's fine on flats but having my feet that 10mm or so back on clips seems to do all sorts of weirdness to the handling, there's a sudden lack of any confidence in the front wheel, similar to what happens if the bars have too much rise. It's like the longer "reach" needed a longer stem.
