3

My first road bike, and the bars feel a little low and a little close. What would be the effects of switching to a stem that is 10-20mm longer, and either the same angle so the bars are slightly higher, or angled slightly up so the bars are more noticeably higher?

Is there a formula for moving bars away and up to maintain comfort/reach, similar to when moving your saddle up/down after change the fore/aft position, or is it just based on rider perception?

I guess I’ve always thought of an aerodynamic position as being about getting low down, but stretching out must achieve a similar end and help to get horizontal forearms, a flatter back etc?

edit – this has come from me feeling like I could stretch out more on the hoods and still be comfortable, and the drops feeling too low to maintain a comfortable position without feeling it in the lower back. I have 86cm inseam and ride a 60cm bike, but long upper body and arms hence thinking of a longer stem.

  • 4
    As a general comment, plenty of cyclists do engage in fitting by trial and error, probably with some influence from people we ride with or people on the Internet. You can also pay for a professional fit, but you probably want to search a bit and ask around. Bike stores may offer these services, or some fitters may practice independently from stores. As to the trial and error bit, if you have buddies, you could ask to borrow a stem in your desired length. Some riders may have accumulated excess stems. – Weiwen Ng Nov 4 '19 at 18:50
  • 1
    When I purchased my first "real" frame, it was several cm too "small" for me, so I got a long seat post and stem. While I was low on the bike and generally comfortable (no back issues in my early 20s!), my neck got sore from looking up for an hour or more for each ride. It seems my neck never got used to holding my head up, either, as that was always an issue on that bike. – FreeMan Nov 4 '19 at 20:27
  • Looks like you've managed to make two accounts on SE, the Wilskt account is the original on SE by many years (but has only recently joined Bicycles), and the GoldmanT account is completely new. You can get them merged by following the instructions at bicycles.stackexchange.com/help/merging-accounts If you'd posted from the same account, then your edits would not have gone to the approval queue. – Criggie Nov 6 '19 at 7:57
6

There is no magic formula for handlebar position, so some experimentation is necessary.

If you feel your hand should be further forward, get a longer stem. Think about where your hand want to be on the drops and decide if you will go 1cm or 2cm longer.

You can experiment with bar height. If you have spacers on the steerer you can move the stem up and down. If you want the bar higher still you can flip the stem.

By the way, many riders find the drops uncomfortable for long periods of time. Spending time in the drops, stretching and core strength exercises help.

With regard to handling a longer stem moves mass forward which makes the bike a little more stable and slows steering due to the longer radius between contact points on the bars and the steering axis.

| improve this answer | |
  • Thanks for this, makes sense. I guess a follow-on would be what is the difference between a 600mm top tube with a 100mm stem, and a 580mm top tube with a 120mm stem - would it just be handling and responsiveness, as the rider position should essentially be the same for both scenarios? – GoldmanT Nov 4 '19 at 13:51
  • @GoldmanT See update to answer. Moving the front wheel backward but keeping the rider in the same position has both stabilizing an de-stabilizing effects. Mass more over front wheel and longer stem stabilize things, but a shorter wheelbase steers faster. – Argenti Apparatus Nov 4 '19 at 16:01
  • 1
    A shorter stem makes the steering more nervous. – Carel Nov 4 '19 at 16:08
  • With a traditional steel frame the rule of the thumb was that if you put your elbow against the nose of a correctly positioned (!) saddle the tip of the middle finger should touch the handlebar +- 1cm. It has to do with body geometry. – Carel Nov 4 '19 at 19:14
  • Best advice I've seen online about bike fitting- peterwhitecycles.com/fitting.php – Fred the Magic Wonder Dog Nov 6 '19 at 16:29
1

With basic trigonometry you can calculate the horizontal and vertical distance that your stem adds to your reach and stack and then see how a different stem would change things.

The horizontal distance is length * cosine(angle), vertical is length * sin(angle)

Example:

length in mm             100  110   
angle in degrees           7   40   
reach in mm               99   84      -15
stack in mm               12   71       59

So changing from a 100mm, 7 degree stem to 110mm, 40 degree would bring your hands 15mm closer and raise them almost 6cm.

Here's a Google Sheets spreadsheet that will do this. Make a copy so you can edit or download as Excel

Then you could do another triangle for your butt, shoulders and hands to see how much your shoulders would go up or down with different stack and reach, but that's going to be a long story and you might be able to get an idea from the above and sitting on your bike and seeing what 20 mm further out or up would do for you. Get the stem you think will work and iterate.

Note that if you make extreme changes, your riding position will change and you may need a different seat.

From your description it sounds like your frame may be a bit short for you. Perhaps you are tall.

| improve this answer | |
  • 1
    Thanks for the link, that’s a useful thing to play around with. I had edited some measurements into the OP but apparently they don’t appear until reviewed – I have a fairly usual inside leg of 860mm so ride a 60cm frame, but I’m 196cm tall with a sternal notch of 163cm and 76cm arms, so all upper body, hence feeling that I could do with a longer stem. The current one is 110mm with -6 degree angle, so think I’ll try a 130mm with the same angle. I guess I could flip the current one to see what difference a bit of extra height makes, and maybe flip the new stem or buy a zero degree stem. – GoldmanT Nov 5 '19 at 9:29
  • The spreadsheet is set to readonly, but if you have a Google account you make a copy or otherwise you can download it and should be able to edit locally. – Michiel Nov 6 '19 at 22:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.