negative degree vs positive degree stem?

Question

Hi guys, what are the effects when using a negative degree stem and a positive degree stem on a bike? Thank you!

Answer 1

I really don't understand the need for a negative degree stem setup. The only explanation is to accomodate road bike riders who sit and spin in the adult fetal postion. For them bike fit is critical, and having a negative degree stem might be helpful to some riders as they try to dial in that perfect fit.



Having too long of a stem or one that causes you to reach too low for your handlebars is a bad thing as far as body postion goes. You want to be able to ride with heavy feet and light hands. If you have to support the entire weight of your upper body with your hands, then your bike is not set up right.

Answer 2

Correction: What John M. forgot about was the angle of the head tube. On this bike with a 54cm frame size, the head angle is 71.0°. http://www.raleighusa.com/bikes-road-fitness-cadent-cadent-2



As you can see from the illustration, the angle on the stem is pointing slightly up. Flip the stem over & it would point straight out - flat.



Here's another example but on a road bike. From the stock internet photo of a 2012 Giant Defy 5, the stem points straight forward - flat. http://www.giant-bicycles.com/_generated/_generated_us/bikes/models/images/2000/2012/Defy_5_triple.jpg



That same bike but with the stem flipped over gives roughly a 6 to 7° RISE. I know...it's my bike in the photo below.

Answer 3

Straight stems are zero deg. A pos deg stem raises the bar and a neg one lovers it. You can turn a 6 deg pos stem upside down and make it a neg 6 deg.



Edit:

The question was about stems not head tubes.

Answer 4

I agree with answer #2. Here's my 2013 Fuji Sportif 1.7C. http://archive.fujibikes.com/archivebikes.php?prodid=2351&prodname=Sportif%201.7%20C&modelyear=2013



Here's the same bike with the stem flipped over. https://www.flickr.com/photos/94629318@N06/8613659417/sizes/l/



Angle of the head tube makes the stem straight in one position & rise a little flipped over.