Short Stems = Twitchiness. Discuss

bartman100

I have a 57cm frame with some Deda Zero 100 compact bars and a Planet X 90mm stem.

I specifically didn't want a longer stem as I wanted to reign in a little over stretch. However, I do notice (I think) a little twitchyness, especially when descending. I know this is probably a side effect of a short stem, and probably need to experiment with a longer one. But a couple of questions:-

1. Does short stem necessarily = twitchy responsive steering, or is it more complicated
2. What's in a stem anyway? surely this is a bike part it is worth skimping on cost for? Or are they more vital than I understand.

Cheers!

sungod

degree of twitchiness depends on the overall geometry of frame and forks, not just the stem

stems need to be safe first, and stiff second, imho a stem that flexes is annoying

if you change the stem, you also need to consider the angle, aside from stem length, a different angle will also affect position

there's a calculator here...

http://yojimg.net/bike/web_tools/stem.php

rake

as said some bikes are more twitchy. some could do 40 no handed.

majormantra

The twitchness of shorter stems on road bikes is great exaggerated IMO. My commuter has a 90mm stem and my race bike has a 130mm and neither feels ridiculously fast or slow in steering.

The best stems are both light and stiff and more expensive ones are sometimes cooler looking. At shorter lengths like 90mm variations in stiffness will be less noticeable though.

FWIW (not much) the 3T Arx Pro seems like one of the best compromises between weight, looks, stiffness and price to me.

centimani

sungod wrote:

degree of twitchiness depends on the overall geometry of frame and forks, not just the stem
stems need to be safe first, and stiff second, imho a stem that flexes is annoying

if you change the stem, you also need to consider the angle, aside from stem length, a different angle will also affect position

there's a calculator here...

http://yojimg.net/bike/web_tools/stem.php

Thats interesting. I nearly messed myself when i realised what i'd done with a bike build...
Ribble Sportive, because the geometry didn't exactly match my Bianchi, i measured just about every tube, size etc etc, then came to the conclusion i wanted a 70mm stem to retain seat to bars distance etc etc. 70mm, thats bloomin short...but i didnt give it thought when i ordered it.
Then i thought about it and worried it'd be as twitchy as a twitchy thing....but its not.
Full carbon bars and stem, tall headtube (taller than the Bianchi) and i find i can sit with one hand on the drops, other arm free...its all pretty stable. Yes, it may be a tad twitchier than the Bianchi...maybe , i'm really not sure, but that tells me its certainly not that noticeable.

TBF, the bikes very comfortable, but i think the 70mm stem appears to leave my knees closer to the bars when out of the saddle. But perhaps it was always that way on my old bike..i may be over analysing it all, i'm not sure.

But anyway...if a 70 mm stem feels 'ok' in a non scientific way, i can;t see a 90mm can be that bad.

Edited to say...personally, i can't stand 'lazy' steering. I like to ride in traffic and move around a lot, i like a bike that responds instantly. I have a winter hack thats comfortable but 'lazy' , absolutely useless for responsiveness. Gimme a twitchy bike any day.

juankerr

MajorMantra wrote:

The twitchness of shorter stems on road bikes is great exaggerated IMO

Yeah, I've gone up and down in 15mil increments on a road bike and two mountain bikes and the increase in twitchyness that some people warn against simply wasn't there.

styxd

Short stems make the steering quicker. Its a fact. You'll also get used to it so it probably wont become a poblem.

I dont like short stems on a road bike - not only do they look wank, its harder to get more weight right over the front when cornering and your knees tend to get close to the bars when climbing out of the saddle.