I am shopping for a new stem to match the dimensions of my existing stem -- an IRD A4 road stem. I have seen it advertised as a +5 degree rise. Whatever that is, I want the same rise, which looks slightly higher than flat when flipped.

Other stems I have seen advertise crap like 80 degree rise or 84 degree rise.

Far as I can tell, most head tubes are around 74 degrees, so if a stem is 5 degrees down, I can see how it would be about 80 degrees from vertical, so maybe that is waht they mean, but I don't want to rely on this assumption.

So please explain stem rise.

Thanks!

A 0 degree rise is the same as 90 degree rise. So if your +5 degree stem is flipped to the lower position, -5 degrees, that would be the same as an 85 degree stem.

Check out this website and see if that helps. It's a little confusing because there are a couple ways to measure it.

https://www.cyclingnews.com/tech/fix/?id=roadposition

Thanks.

The stem I am trying to match is advertised as "Rises 5° and 15° (flip flop able)"

How can that be? This doesn't make any sense based on the above 2 answers (which I am sure are correct, just that they all use different standards).

So what angle would I be looking for when shopping online? I see alot of stems that say 10 degree (like the THompson Elite).

Thanks

WNC is right on the money, just be aware that there are a variety of angles, 20, 17, 15, 10, 7, 5,... probably other custom angles depending on the company. And most stems are "flip flop" or reversible, meaning you can mount it up, or upside down, which explains the + / - thing. The other way a stem is advertised is in relation to being perpendicular to the steerer (90). A 5 degree stem flipped up (+) is 95, flipped down -5, is 85. Same thing with +/-17, flipped up +17, it's 107 degree's, flipped down -17, it's 73. That high school trig is finaly coming in handy eh?lol

I prefer the traditional racing style of 17 degree's since most bikes my size have 73 degree headtube's so with a 17 degree stem flipped down the stem is parallel with the ground. Makes stem mounted computers a little easier to see if you're out of the saddle.

Those are probably the 2 angles the stem is available in that the seller has in stock.

Thanks guys.

Yeah, I have a mechanical engineering degree, and I can tell you the trigonometry and other math doesn't come in handy when manufacturers and retailers use non-standard terminology, funky reference points, and non-stated assumptions about head-tube angle to specify their stems. Very confusing.

But I think with your combined input I will be able to make my purchase decision.

Thanks