Threaded stem help please!

[KJMUNC]

Having only started wrenching my own bikes during the era of threadless stems, I've never had to figure out my fit with a threaded stem. I just picked up a De Rosa Primato from another forumite and now I'd like to get it right the first time and avoid doing the stem dance of swapping out multiple sizes.

All things held equal, if I'm running a 110 threadless stem with a 60.5 TT now, should I expect to run a 110 quill stem on a bike with the same TT length? I know seat angles and stack height will be other factors to account for, but is there anything I'm missing or need to account for when measuring for fit with a threaded stem?

[Too Tall]

OK ok I admit to being quite the dsylexic however stems are measured the same regardless. The "issue" ,if any, might be how to achieve a satisfactory height....no...wait...not a problem 'cause you can set it where you want to :)

Hope that helps.

[DRZRM]

Hey Kerry,

I may have a Ti stem that will work for you (I think it is a 120 Ibis), maybe we can do a swap for that front wheel? Give me a call.

Zach

[Grant McLean]

All things held equal, if I'm running a 110 threadless stem with a 60.5 TT now, should I expect to run a 110 quill stem on a bike with the same TT length? I know seat angles and stack height will be other factors to account for, but is there anything I'm missing or need to account for when measuring for fit with a threaded stem?

The correct answer depends on the angle of your threadless stem.

A 110 stem x 80' rise will put the handlebars as far away from you as a 120
stem with a -17 angle. (most quill stems are level with the ground, and are
73' or -17)

There's some Pythagorean Theorem happening in there...
and the 80' stem has the shorter distance between two points.


g

[T-Crush]

I've found the graphic below (from the Habanero site) useful.

[Grant McLean]

When looking at the chart, keep in mind that modern ahead
stems are sold based on their "extension", not their "reach"
(you can see on the diagram these are not the same result,
unless your stem extension is horizontal.)

It was a simplier time when all stems had the same angle!

g

[KJMUNC]

I believe I was overthinking the issue, as obviously the measurement of stem length is the same but the stem angle and height will dictate the overall reach. I managed to dig up an old Cinelli stem from my parts bin and will monkey around with it to get a baseline fit before making a decision on a final stem. Thanks for the diagrams and advice!

[michael white]

quill length is crucial too. If you have any reason to think you like the bars anywhere close to saddle level, best get a Nitto Technomic or a Salsa 90 or 105 degree.
traditional italian stems with 135 quills don't work for everyone, esp. since frame sizes seem to have shrunk.
Rivendell has lots to say on all this.

[KJMUNC]

Michael, that's the only thing I'm concerned about, but will check with the Cinelli and see how much room I have to play with. I can usually tolerate a good bit of drop so I'm not too concerned. Additionally (and luckily) the De Rosa has an tall headtube (20.7) to go along with a 62cm C-C seat-tube so I won't have to try and make up too much rise on the stem height.

[RPS]

It was a simplier time when all stems had the same angle!IMO the math can be made much simpler by converting stems to true horizontal reach.

[KJMUNC]

So the Cinelli has a quill of 13.5....is that pretty standard length? That leaves me with about 8cm to play with before I hit the "min insertion" mark.

Is there a rule of thumb as to how much quill needs to be in the headset (or is the min insertion mark a legitimate guide?)

[Grant McLean]

So the Cinelli has a quill of 13.5....is that pretty standard length? That leaves me with about 8cm to play with before I hit the "min insertion" mark.

Is there a rule of thumb as to how much quill needs to be in the headset (or is the min insertion mark a legitimate guide?)

yup, stick to within a few mm's of the minimun line

g

[Grant McLean]

IMO the math can be made much simpler by converting stems to true horizontal reach.

i totally agree.

the standard system of markings should be simply rise and run.
what does '10 degrees' mean to the average person? nothing!

g

[KJMUNC]

Agreed....rise/run would be much more clear. I just took measurements from the two threadless bikes I have and plugged 'n chugged for stem length, height, and stem/stack height combo so I can find the right headset too. Looks like a 110 stem is going to fit the bill....anybody got a cool black one they want to get rid of??

Now we'll see how far off I am when theory meets practice on my build next week!

[RPS]

i totally agree.

the standard system of markings should be simply rise and run.
what does '10 degrees' mean to the average person? nothing!

gAbsolutely; to me it means very little until I convert it to something I can use. If rated based on a 73 degree head angle, it would not be any different than the old "7" stem. And differences in true horizontal reach (I guess you call it run) based on bikes ranging from 72 to 74 degrees (which cover most all road bikes) is insignificant.

Even rise due to head tube angles, which is affected far more than horizontal reach, are still very small -- like one thin spacer.

[weisan]

Looks like a 110 stem is going to fit the bill....anybody got a cool black one they want to get rid of??


I don't but maybe you can check into this one:
http://www.bicycletires.com/tek9.asp?pg=products&specific=jnkseopok

The front removable plate makes for easy removal of handlebars, swapping out stuff. I used it on the steel ritchey and like it. ebay might show up cheaper.