Help deciding quill stem angle
 

I can choose between 2 quill stems, as I have to replace the one on my old Marin - converted for cyclotourism. My bike:

https://s27.postimg.org/98qv4lfer/IMG_0885.jpg

Negative stem:
http://granadadistribution.com/3471-...o-1-silver.jpg

Positive stem:
http://www.joggen-online.de/sportart...K-83467655.jpg


Is there a particular reason to put on another positive stem? As I prefer the look of the negative one, but I admit I see vintage MTBs only coming with positive stems. Is there a steering control advantage that might favor positive stems? Keep in mind i'm only going on tarmac and white roads with this bike.

Putting a negative rise stem on your bike is going to give you a larger saddle to bar drop. That drop may be too uncomfortable to ride. There is a reason almost all mountain bikes comes with the stems they do.

It's just a matter of your riding position. It looks like you already have the seat up pretty high, and as far forward as it will go, so I suspect you will want the taller stem; but it really depends on the posture you're trying to achieve.

On a road bike the positive stem looks a bit out of place, but they do accomplish the goal of getting the bars up higher if you need it. On a mountain bike they are the normal rise in order to help in weight transfer while on a trail. The negative rise will put more weight on your hands.

In principle and assuming both can place the bar where you want, the positive stem could be lighter because it goes from the steerer tube directly to the bar clamp. A traditional negative stem goes up and backwards before saying "Oh, I need to be over there" and going forward to the bar. However the positive stem can't be lowered any further whereas the negative stem can be raised or lowered to its limits if you wish.

I'm going to be negative here. Go negative. The positive stem looks dorky. That's what really matters, izzn't?

I agree with everyone else's recommendation so far.

The positive "dirt" stem just looks right, and puts your bar at the correct height.

Not recommending this for you, but throwing it out - the only reason to ever go to a negative stem on an upright bike is for short-reach using a tall quill like like a Technomic.

http://img.photobucket.com/albums/v7.../aP3180021.jpg

Negative works for me.

http://imagizer.imageshack.us/v2/102...0/834/gv99.jpg

http://imagizer.imageshack.us/v2/102...0/818/fd9a.jpg

the tall Technomic also gives you an easy-reach bell mount.

http://img.photobucket.com/albums/v7...aaPA180005.jpg

Your bike has a long stem, just want to mention that you should keep the current length in mind when looking for an alternative. As mentioned, a 7 quill stem will seriously drop the bars down lower than they are. If you like where the bars are now, in both extension and height, then you shouldnt go near a 7 quill stem.
The stems you posted as examples are hopefully just examples as neither will be nearly long enough to replicate the current setup...assuming thats what you like.

You should go with the stem that gets your bars to the right height for your riding position. On that bike, I doubt a negative angle would accomplish this unless you use a really long quill like a Nitto Technomic. You also have aesthetics to consider and my personal opinion is a positive angle stem would look much better on that bike than a negative angle with a lot of exposed quill.

Positive angles were used on mountain bikes to achieve desired bar height on a frame with lower standover height. You wanted lower standover height to better navigate off road.

So I guess it's more a stylistic matter that *all* late '80 and early '90 MTB stems pointed upwards, since a negative stem doesn't seem to hamper control.

Maybe I was looking too much into this, trying to find some esoteric point which is not. Probably the logic behind positive stems in vintage MTBs was only to differentiate them from roadies... road -> negative because wind is bad, off-road-> positive because... well comfort & relax.

This is very interesting.

I agree with [MENTION=403744]plonz[/MENTION] assessment. My road bikes range between 58 and 60 with an option of 61. No MTB is equivalent and my RockHopper is a 20.5" (~52), a larger frame than you typically see.

It's all on where you want your handlebar height and reach to be.

steering at 72~73 degrees, , 90 is straight up.

so, a 17 degree drop = a horizontal extension

computer-bike guy made a tool to calculate this : http://yojimg.net/bike/web_tools/stem.php

a Zero angle stem has a rise to it, on the bike .

You putting different handle bars on ? you can tour on it as is, maybe swap to a grip/bar end like ergon
http://www.ergon-bike.com/en/product.html?a=griffe




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By the way for Cycle touring It will include packing the bike in a Box to get to or return from places ..

So consider how the bars will come Off .. open face stems and perhaps even a quill to threadless conversion and an open face stem may serve you better ,

than either of those you pictured..




...

Not stylistic, but by design. As mentioned, it gets the bars up to a universally good height. The quill stem's ability to rise/drop in the steerer tube will help refine the overall height fit.

Positive stems are normal for MTBs because those bikes are normally sized smaller, with the assumption that you'll raise your handlebars up high. You don't want to go on a rough trail with only an inch of standover height.