Whats with the trend for running 50mm stems on bikes used for DH / more aggresive riding? What does it achieve?

More direct steering input and easier to loft front end over obstacles. AFAIK

coz itz kool an awsum innit

its not really a trend – short stems have been in vogue for a decade

It keeps your weight further back, makes the front end easier to lift, and steering more direct

Just had my first ride this morning with the 'short stem/wide bars' set up 😀

The change wasn't that radical, 70 -> 50mm stem and 650 -> 730mm bars saddle moved back about 10mm.

Bike felt more connected to the trail, steering was quick and direct and although I need to fiddle a bit with the stem height and saddle position it felt a lot better than the old set up.

It can be a relatively cheap way to make a significant change to how your bike feels and something I wish I'd played around with ages ago now I've tried it……

my azonic world force stem must be 14 years old, 5lab is correct, it's hardly a trend. in fact it's the oldest piece of kit that i still use.

and with all the clarity that can be expressed on a forum;

short stems: good for handling.

long stems: good for getting your weight over the front wheel to stop you wheely-ing off the back on steep climbs

i suppose the converse could be said of short stems – they're good for getting your weight back if you've got too much weight over the front wheel going down silly steep stuff.

Long stems are 4 Gayerz.

+1 wot scruff saids

So if a rider has a long stem and keeps up with those using a short stem he must be a superb rider then….Thanks… 😆

I find that short stems make me feel more pitched over the bars as my arms feel tucked underneath me..kind of like doinig a pressup with ya hands under ya tummy just feels rong to me..
I seem to get much more power on climbs too with longer stems.

Do the wide bars not take away the sharp steering that the short stem provides..

Do the wide bars not take away the sharp steering that the short stem provides..

Dunno 😉
I'm not that good at 'describing' bike handling and really you steer more with your body/bike position than by turning ther bars (well I do anyway!)
I've always guessed that the wider bars/shorter stem alters the rider/bike geometry in more subtle ways than just by simple leverage at the from wheel.
I find wider bars give me more 'room' to move around the bike on and the short stem/saddle pushed back which although on paper should be wheelytastic, just make the bike just feel more 'lively' and reactive.

Might be good to hear from some of the experts on the whole bike/rider positioning thing…….

Do the wide bars not take away the sharp steering that the short stem provides..

Yes, but that's not a bad thing when you're going fast.

Shorter stem means yr less stretched out and therefore have more space to move your weight around the bike and more capacity to move the bike around underneath you. So, easier to get the front end up for pumping, drops, wheelies etc and also easier to push yourself off the back of the bike for drops and steeps etc etc

easier to push yourself off the back of the bike for drops and steeps etc etc

I thought current wisdom was that 'dropping off the back' wasn't that great when descending 😕

Agree with the 'less stretched out thing' though – I find it far easier to move around the bike with a wide bar/short stem and as the wider bars mean weight is more widely spread around the central axis it needs less movement to effect a change in balance…..

(all IMO of course, I'm far from being a bike handling guru 😳 )

Yes, but that's not a bad thing when you're going fast.

so speed and short stems are a no no then..more for playing

Shorter stem means yr less stretched out and therefore have more space to move your weight

How does making the cock pit shorter give more room to move around.. ❓

Just curious….im quite happy with a long stem bit i seem to be a dying breed..never find the people with short stems leaving me behind, in fact quite the opposit most times..horses for courses and marketing blah i guess

move with the times old man (only joking of course as you may only be 17)

It's to do with geometry too. A long stem on a slack angled bike would steer like a barge. A long stem on a steep bike handles OK though, hence short on slack DH bikes and longer on XC style machines. A short stem on a steep angled bike would be very twitchy and nervous feeling/quick handling depending on your view.

One mans short stem is another mans bargepole……….

I was out with on a ride last wednesday and one of the guys commented on my long stem (90mm) and I laughed as that's the shortest stem on any of my bikes!

Always liked a longer stem, follows on from my 'Old Skool' beginnings I suppose, but anything under 80/90mm feels far too twitchy to me.

NagsNog – Member

How does making the cock pit shorter give more room to move around…

it's not obvious, but there is something behind this:

imagine a really long stretched out bike; the rider cannot move his weight over the back wheel – he's too stretched to move, the rider cannot move forward over the front wheel – he's too stretched to move.

give this rider a shorter stem, and now he's got room to spare – he can move around a bit.

How does making the cock pit shorter give more room to move around

To me it's the fact that the shorter stem lets you bend your arms more and bent arms give more options to move your body weight around than stretched arms.

I still don't get the 'physics' of it though, most of my steering is done with my bars relatively 'un turned' and the bike moves 'with my body' rather than by 'being steered'.
This is all based on riding 'not sitting down' I guess if you're sitting you have more limited options to shift weight and steering is more through the bars……

…and of course, as was said, frame/fork geometry comes into it a lot – I've not ridden enough mtb's to comment other than from my own PoV….

so speed and short stems are a no no then..more for playing

I was talking more about wider bars, I've found going up to 710mm gives much more stability at speed because the steering isn't so twitchy. Think the stem on that bike is 50mm, maybe 60mm.

I rode a demo bike with 635mm bars and a 100mm-ish stem the other week and it was horrible. Weight too far forward and steering twitchy. I couldnt go back.

70mm stem / 685mm bars for me on my 'normal' bike.

Short stems r 4 lamerz wot cant ride.

gives an attack position.

Just switched from a 100mm to a 60mm stem on my Boardman HT Pro. Definitely makes the steering much more responsive, which is a clear pro when dealing with windy singletrack but wouldn't be so good when you're pushing yourself on a long XC race and you're tiring and thus tending to haul unevenly on the bars. So if I do an all-dayer on the South Downs I'd prefer the 100mm stem but for everything else I do (usually just messing around in woodland singletrack or trying and failing on pump tracks) I'm really really liking the change in handling!

I expected it to feel more nervy but it doesn't, which makes sense as nothing about the fork geometry has changed – it's like putting a quicker rack on a car, whilst changing fork angles is more like changing front to rear suspension stiffness (less trail is analogous to more pointy and oversteery balance due to softer front and harder rear suspension).

Way back in the mists of MTB time, people used narrow bars for racing (Because that's all there was) and long stems to keep the steering sensiblem and provide a decent riding position (For racing) Slowly, people realised that narrow bars gave very little leverage (Control) over the steering, so bars got wider, and stems were shortened to keep the steering fast enough. Gradually, over time, top tubes got longer to provide stabilty, stems got even shorter and bars got even wider as people realised there was more to life than racing XC.

Basically

🙂

longer stems are a hangover from mtbs roadie roots

many (american)companies seem to want to spec a nice long stretched out stem for optimal xc climbing ability

fortunately the UK has a more balanced or maybe gravity oriented scene so shorter stem is one of the first things people swap out when they get a new bike

and ime it makes things a lot more responsive, same for wider bars
though all these are dependent on rider height and proportions too

all we need now is to move away from flexy 5mm qr skewers (happening already)
narrow spaced hubs
1" headsets are gone 1 and 1/8th on the way out
disc brakes have weed all over cantis and so on

for some reason the oem speccing monkeys still like their long stems though

I'm pretty certain that my first MTB had quite a short stem and wide riser bars with some sweep to them. It was a 24" wheel Peugeot thing (I was only 9) and the 'stem' was a one piece alloy forged swan-neck which came out of the headset and swept up and forwards to the bars. Not much forwards to it though. That was in '88. My first full-size MTB ('92?) was like ye olde bikes you describe with very narrow flat bars and I guess a long stem (don't remember anything notable about that component).

Were other late '80s bikes like that Peugeot or was it an oddity?

The Boardman bars are 660mm but measure 680mm with the OEM grips as they stick out wider. I can see the benefit to more width but not in my local woods, the trees are already too close!

It's all part of a package, but the whole "don't wide bars cancel it out" doesn't strike me as right, because I'm not going with wide bars for any reason other than that they're the right width for my shoulders and stance. Then, once I'd found the right bar width (680mm for me) I fit out the rest of the cockpit to suit. And that gives me a 60mm stem on the Soul and a 50mm on the Hemlock.

I use the highly scientific approach of going shorter until it becomes a pain to go up hills, then going back up a size 😉

"1" headsets are gone 1 and 1/8th on the way out"

Are they really? Don't see it myself, the rise in funny shaped head-tubes has been exactly matched by the rise in funny-shaped headsets designed to allow us all to still fit standard forks. Tapered and 1.5 steerers are still a rarity and I've seen nothing to suggest that's changing at all myself.