Tech Stem angle

Apr 22, 2014
41
8
18
Shibuya
#1
It's driving me nuts every time.
When fine tuning threadless stem angle it is really frustrating to find the perfect angle so it does not feel a little left or right when riding and takes more time than all the technical job. Maybe I don't know some trick?
How do you set up your stem angles?
 

kiwisimon

Maximum Pace
Dec 14, 2006
2,681
494
103
Japan
#3
Measure from the front of your saddle (presuming it's straight) to the bars on both sides They should be the same. You have a dominant eye( either left or right) so don't think the perception of the bars being not straight when you are riding is fact. If you don't have a long measure just use a taut string. Check your brake levers are positioned evenly as well.
 

Sibreen

Maximum Pace
Jul 23, 2010
564
242
63
Hanno, Saitama
#5
Measure from the front of your saddle (presuming it's straight) to the bars on both sides They should be the same. You have a dominant eye( either left or right) so don't think the perception of the bars being not straight when you are riding is fact. If you don't have a long measure just use a taut string. Check your brake levers are positioned evenly as well.
Presumably the wheel would have to be absolutely straight for this to work. But, how do you get the wheel straight?
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#6
We all have one arm slightly longer than the other, so you might find that could be causing the issue. If you are looking for the perfect alignment to the frame the simple way of doing it is to find a quiet flat road and then ride up and down a few times no handed, keep an eye on the tracking of the stem and adjust accordingly - keep tweaking it till you get it right.
 

kiwisimon

Maximum Pace
Dec 14, 2006
2,681
494
103
Japan
#7
Presumably the wheel would have to be absolutely straight for this to work. But, how do you get the wheel straight?
bike in a stand, front wheel or back wheel on the ground, straight line string from the back of the back wheel to front of the front wheel, a string line works well. Or go to a
straight piece of curb and use the curb as a guide.
 
Apr 22, 2014
41
8
18
Shibuya
#8
If you take the front wheel off and turn your bike upside down, you can use a wall to ensure the fork and handlebar are straight. It works best when the levers are out of the way or not yet installed.
Thank you for the suggestion! I'd like not to remove levers though. :)

@Kumachan - maybe your frame isn't straight and your bike is tracking like a crab?
Huh, so THAT is what "Assymetrical" means on the frame? :D

We all have one arm slightly longer than the other, so you might find that could be causing the issue. If you are looking for the perfect alignment to the frame the simple way of doing it is to find a quiet flat road and then ride up and down a few times no handed, keep an eye on the tracking of the stem and adjust accordingly - keep tweaking it till you get it right.
In fact I am just paranoid. Sometimes when the alignment is not absolutely perfect I look at the stem and find it looking slightly different way than the wheel. And as people say "you can't unsee it". Thank you for suggestion, the one without hands (hopefully won't go into without teeth) sounds very reasonable!
 

bawbag

Maximum Pace
Mar 20, 2013
430
244
63
Tokyo
#9
Ride to the top of a hill. Ride back down in a Jesus Christ pose while checking the bars. Adjust at the bottom of the hill. Listen to the Soundgarden song. Ride back up. Fine tune on the second descent.
 

zenbiker

Maximum Pace
Mar 4, 2008
802
228
63
Chofu
#10
We all have one arm slightly longer than the other, so you might find that could be causing the issue. If you are looking for the perfect alignment to the frame the simple way of doing it is to find a quiet flat road and then ride up and down a few times no handed, keep an eye on the tracking of the stem and adjust accordingly - keep tweaking it till you get it right.
Thank you for the suggestion! I'd like not to remove levers though. :)



Huh, so THAT is what "Assymetrical" means on the frame? :D



In fact I am just paranoid. Sometimes when the alignment is not absolutely perfect I look at the stem and find it looking slightly different way than the wheel. And as people say "you can't unsee it". Thank you for suggestion, the one without hands (hopefully won't go into without teeth) sounds very reasonable!
Sounds reasonable until you figure in the camber of the road!
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#11
Sounds reasonable until you figure in the camber of the road!
Thus why I said "Find a flat piece of road."

The bike will always track true when riding no handed and you'll see if the stem is out of align.

There was a famous pro rider that would argue to hell and back regarding this same issue and it really was a case of him being so sensitive to the arm length difference that the mech had to set the angle of the stem off by 2mm to compensate this.

The only sure way to get it perfectly lined up is to have a bike mount where the fork and BB area are locked in to place for working on then rune a straight edge along the frame to the stem and adjust accordingly - although again this will not take in to account any biological abnormalities (which are normal :) ).
 

undftd1984

Speeding Up
Jul 26, 2013
62
16
38
Honolulu
#12
I usually pull the front wheel off, put the dropouts/fork against a door sill, and line the bar up parallel to the sill by sighting from above the handle bars. it usually works unless you're running something fancy that doesn't have a flat top and slopes downward, or some super curvy track bars.
 
Likes: Robert

zenbiker

Maximum Pace
Mar 4, 2008
802
228
63
Chofu
#14
Thus why I said "Find a flat piece of road."

The bike will always track true when riding no handed and you'll see if the stem is out of align.

There was a famous pro rider that would argue to hell and back regarding this same issue and it really was a case of him being so sensitive to the arm length difference that the mech had to set the angle of the stem off by 2mm to compensate this.

The only sure way to get it perfectly lined up is to have a bike mount where the fork and BB area are locked in to place for working on then rune a straight edge along the frame to the stem and adjust accordingly - although again this will not take in to account any biological abnormalities (which are normal :) ).
True, but they tend to not build flat roads..... something to do with rain.
I have a big T on the garage floor. Line the wheels on the up line and stet the bars on the cross.
If I do it by eye, I usually ride about 200m down the street before stopping to get the tools out!
 
Apr 22, 2014
41
8
18
Shibuya
#17
I usually pull the front wheel off, put the dropouts/fork against a door sill, and line the bar up parallel to the sill by sighting from above the handle bars. it usually works unless you're running something fancy that doesn't have a flat top and slopes downward, or some super curvy track bars.
Amazingly simple and smart method. Thank you!
 
Aug 27, 2012
581
234
73
London, UK
www.macrophotofly.com
#20
Been noticing since I changed my stem a few weeks back that my left leg has occasionally been brushing the upright water bottle which is odd given I'm right leg dominant. On the trainer this morning and noticed it was brushing the sweat hammock too. A small adjustment of the front wheel stand (to very slightly off-centre to the left) fixed it - therefore I'm guessing my stem must be off by a couple of degrees to the right - not visible but enough.