Mountain Bike Reviews Forum banner
1 - 20 of 20 Posts

·
Lets RIDE!
Joined
·
1,548 Posts
Discussion Starter · #1 ·
Given 2 stem arrangements that put the bars at about the same position......say, a 40° stem mounted without spacers, and a 0° stem with about 2" of spacers under it......are there advantages/disadvantages to either set-up? Seems to me the 40° set-up would be the lighter and stronger choice.

Also, I sometimes see stems with spacers above them......any reason for that, other than maybe to allow a little extra steerer height for future stem changes?

Jim
 

·
local trails rider
Joined
·
12,300 Posts
JimZinVT said:
stems with spacers above them......any reason for that, other than maybe to allow a little extra steerer height for future stem changes?
Three more reasons:

- to keep fork steerer tube long for resale value (long enough to fit any bike)
- still not decided how high you want the bar
- too lazy to get the extra cut off.
 

·
Registered
Joined
·
6,762 Posts
Lighter and stronger,.....

not really. It takes the same amount of material to make a 110mm 40 degree stem as it does to make a 110mm 0 degree.

The problem is that stem angle not only changes the height of your hands it also changes the position of your hands either forward or backward. With that radical of a difference it would be almost impossble to keep your hands in exactly the same position both vertically and horizontally. So lets say you go from a 100mm 0 degree stem with 2 inches of spacers, to a 100mm 40 degree stem with 0 spacers. That would put your hand position 6mm higher than the 0 degree stem, but a full 44mm (1 3/4") further back!

Going with the higher rise stem will change your riding position on the bike as compared to the 0 rise stem. The thing is there are no clear cut advantages or disadvantages to going either way. What is advantage to one rider and riding style is disadvantage to the other.

Moving your hand position rearward but at the same height will force a more upright riding position. This is an advantage for descending as it lightens the front end and moves your center of gravity rearward. You'd be able to do steeper descents without moving behind the saddle. But it is a huge disadvantage when climbing for the same reasons because in climbing you need to do the exact oposite, weight the front more and unweight the rear. So it would require considerably more forward lean to keep the front end down on steep climbs. There is an optimum position for your upper body in relation to your legs when seated on the bike that will allow you to put the maximum power into the pedal stroke with out moving. If you are leaning to far forward due to hand position you are out of that zone, if to upright it's the same. So this could be a disadvantage for both extremes depending on frame geometry and fit.

Then we come to handling. The flat stem will put your hands further forward and give the bike a bit quicker response to your hand movements. The closer the bars (and your hands) are to being directly over the front axel, the quicker the bike will respond to bar input. But it will be less stable both descending and at speed. The further back your bar and hands are from the vertical line of the front axel the slower the bike will respond to bar input, but it will be more stable descending and at high speeds.

The bottom line is, there is no "strength" advantage given two stems of the same design, but different rises. A 40 degree stem would likely see less stress placed on it as you would hardly put any pressure on it in comparison to the 0 degree stem due to the radically more upright riding position, but that's about it. The advantages and disadvantages to either stem come from riding style, bike geometry, and preference. Like I said, what is advantage to one rider and riding style is disadvantage to another. And I didn't even tough on personal preference! That's whole other kettle of fish! :thumbsup:

Good Dirt
 

·
Registered
Joined
·
2,822 Posts
Say, you want the bar in the same place reach wise, but higher.

here's a spreadsheet... more or less what I think you're talking about. Otherwise, read what Squash says;)

The 160x40 stem has the same reach as a 90x5 stem, but almost 4" higher. Yes, these do exist, a guy on ebay sells some Kore in this configuration (great for dropbar mtb's BTW:D).

I like to leave my steerers long for 3 reasons-
(1) stem changes (dialing in cockpit setup or just need a new stem) - stems can have very different stack heights & you may need extra steerer to fit different stems.
(2) switch to different bike w/ different headtube length & cockpit setup.
(3) resale value

Aesthetically, I prefer to have a higher rise stem compared to a bunch of spacers under a stem.
 

Attachments

·
Registered
Joined
·
1,811 Posts
I wrestle with this same issue. I have four stems and four handlebars and keep swapping things around to seek out that perfect blend of reach, height, weight, and yes, looks. My search continues. :incazzato:
 

·
401
Joined
·
71 Posts
I have a question sorta related to this ... I want to flip my stem to see if I couldn't get a better angle on it. I was told I can do this (it's a Thomson Elite).

My question is ... do I need to pull the cap off the head set (Chris King) in order to do the flip? I'm kinda a novice with the head set stuff.

MH
 

·
Registered
Joined
·
1,147 Posts
MiguelH said:
My question is ... do I need to pull the cap off the head set (Chris King) in order to do the flip? I'm kinda a novice with the head set stuff.
Yes, if I'm reading you right. You have to remove the top cap (on top of the stem).

The top cap is there to clamp the stem to the headset and/or spacers, and when tightened provides preload to the headset bearings.
 

·
Lets RIDE!
Joined
·
1,548 Posts
Discussion Starter · #8 · (Edited)
Squash said:
It takes the same amount of material to make a 110mm 40 degree stem as it does to make a 110mm 0 degree.
True, the stems are about the same weight.....but but with the 40° stem I can cut off a healthy chunk of my steerer tube and loose all the spacers, so it's lighter.

Squash said:
The problem is that stem angle not only changes the height of your hands it also changes the position of your hands either forward or backward. So lets say you go from a 100mm 0 degree stem with 2 inches of spacers, to a 100mm 40 degree stem with 0 spacers. That would put your hand position 6mm higher than the 0 degree stem, but a full 44mm (1 3/4") further back!
I guess I wasn't completely clear in my initial post. The stems would not be the same length. If we take your 100mm 40° stem example, but compare that to, say, a 60mm 0° stem on a taller steerer, we're close to having the same handlebar location.

I'm not looking to exactly duplicate the bar location of my 40° stem. I was just curious if there was a functional or structural reason to go one way or the other. Or if I was in danger of not looking cool. :cool:

Squash said:
Moving your hand position rearward but at the same height will force a more upright riding position. This is an advantage for descending ................But it is a huge disadvantage when climbing for the same reasons.

Then we come to handling. The closer the bars (and your hands) are to being directly over the front axel, the quicker the bike will respond to bar input. But it will be less stable both descending and at speed. The further back your bar and hands are from the vertical line of the front axel the slower the bike will respond to bar input, but it will be more stable descending and at high speeds.
THAT is the best, most concise explanation of the effects of stem length I have ever read. Thank you! :thumbsup: Somebody write that down someplace!

I'm not set in my decision to use the 40° stem....this is a new build, and that just happens to be the stem I had lying around. It seems to put me in a comfortable position, but I won't know until I get out and ride it.......we're still rippin' through the trees on our snowboards up here. :yesnod:
 

·
Registered
Joined
·
123 Posts
So it's not just me

Vecsus said:
I wrestle with this same issue. I have four stems and four handlebars and keep swapping things around to seek out that perfect blend of reach, height, weight, and yes, looks. My search continues. :incazzato:
:) I thought I was the only one being driven crazy by the handlebar/stem dilemma. I bought a ne Jamis Dakota Elite a month back and am still trying different stems on it and last week added the Easton MonkeyLites..I think I'm almost there. Just waiting for the Thomson Elite 100mm, 17 degree stem to come in, to replace the 110mm pictured below.
http://home.comcast.net/~nikon-d80/Nikon-D80-images/Jamis_XC_6821w.jpg
and a picture of how it arrived home after switching from 120mm to 90mm 5 degree rise with flat handlebars before it left the LBS.
http://home.comcast.net/~nikon-d80/Nikon-D80-images/Jamis_DakotaElite_6722w.jpg
 

·
Lets RIDE!
Joined
·
1,548 Posts
Discussion Starter · #10 ·
logbiter said:
Say, you want the bar in the same place reach wise, but higher. here's a spreadsheet...
logbiter, is there someplace I can find a working version of that stem position spreadsheet? I googled it but came up with a dead link.

logbiter said:
Aesthetically, I prefer to have a higher rise stem compared to a bunch of spacers under a stem.
I'm with you there, bro. Especially when it's a stack of mismatched spacers!
 

·
Advanced Slacker
Joined
·
15,333 Posts
HikerToo said:
:) I thought I was the only one being driven crazy by the handlebar/stem dilemma. I bought a ne Jamis Dakota Elite a month back and am still trying different stems on it and last week added the Easton MonkeyLites..
Me to. The reason I never spend over $15 on a stem is that I am constantly playing around with it. I have a whole mess of cheap stems that I use to dial in the fit, and once I find it, I just leave the one that works on there.
 

·
local trails rider
Joined
·
12,300 Posts
lyndonchen said:
The top cap is there to clamp the stem to the headset and/or spacers, and when tightened provides preload to the headset bearings.
To be more accurate...

The top cap sets the tension. The bolts on the stem hold it.
After the stem is tightened on the fork steerer, you could remove the top cap and the head set should stay put OK (not that I'd really want to remove it).
 

·
Registered
Joined
·
6,762 Posts
Gentlemen....

for those of you that want a stem calc spreadsheet I've got one stored on my computer. Drop me a PM with your email address and I'll shoot it to you. It is a useful tool.

Good Dirt
 

·
Registered
Joined
·
6,762 Posts
I see a little clearer now....

"I'm not set in my decision to use the 40° stem....this is a new build, and that just happens to be the stem I had lying around. It seems to put me in a comfortable position, but I won't know until I get out and ride it.......we're still rippin' through the trees on our snowboards up here."

There's no real structural difference other than stiffness, and that' is usually a function of design shape, difference in materials used, etc. Functional I already covered in my first post. Yes you'd save a bit of weight with no spacers and a bit less steerer tube. But before doing that I'd want to try both stems. The reasson being is as you stated, you won't really know until you get it out and ride it! So leave the steerer tube long and run spacers above and below the stem so you can adjust the clamp height and run different stem combinations if you can. First determine where you want your bar height in relation to the top of the seat. Usually 1 to 2" below for XC, Even with the seat for Trail and AM, and 1 to 2" above (sometimes more) for DH, Freeride, and Jump. This is just a rule of thumb to start out with, not a hard and fast rule. Then tweak that by moving the stem up or down the steerer by moving spacers. Only when you have it dialed to your liking should you cut the steerer. What you end up with will depend on your preferences.

As far as a 100x40 stem vs a 60x0 you're pretty close in your estimation. The forward position change would be right around +6mm with the 60x0 as compared to the 100x40, but the height would change a full -19mm with the 60x0. In my experience as little as 10mm, while it may not make for dramatic changes in handling and doesn't look like much on paper, it can make a huge difference in the way the bike feels and rides, and how comfortable you are during the process. And that's the key.

That's the reason that I never cut a steerer tube to size on a new build to begin with. I use the method above. Pick the stem I want to use, set the bar height in the area that I "think" will work with the new ride, but leave 25 to 30mm of spacers above and below that point so that I can experiment with it. It sometimes takes a month or more to get it dialed, and it looks goofy while your doing it with spacers all over the place. But once your done you have it set up so the bike fits, feels, and performs the way you want it to. Then you can make your final cut on the steerer.

Good Dirt
 

·
Registered
Joined
·
2,822 Posts
JimZinVT said:
logbiter, is there someplace I can find a working version of that stem position spreadsheet? I googled it but came up with a dead link.

I'm with you there, bro. Especially when it's a stack of mismatched spacers!
here it is...:thumbsup:
I've posted it on some threads a while back. Keep in mind, this one is fairly simple, it doesn't take into acct stack height of different stems, which affects reach & rise.
If you really want to geek out w/ some excel spreadsheets, check out clary's bike comparator page.
 

Attachments

·
Lets RIDE!
Joined
·
1,548 Posts
Discussion Starter · #16 ·
Squash said:
So leave the steerer tube long and run spacers above and below the stem so you can adjust the clamp height and run different stem combinations if you can.
That's exactly how I set it up....the "tall" stem is on, with close to 2" of spacers above. Looks pretty foolish, but I'm not cutting until I have it dialed. Now I just need a little more snow to melt so I can ride!
 

·
Registered
Joined
·
2 Posts
Hi, seems that I'm not the only one dealing with this. What about trying with an adjustable angle stem? are they only for trial and error or can I get one of those for riding? I never saw anyone using those. What's the reason? could they brake or fail?
Thanks.
Angel
 

·
Registered
Joined
·
10,039 Posts
alas214 said:
Hi, seems that I'm not the only one dealing with this. What about trying with an adjustable angle stem? are they only for trial and error or can I get one of those for riding? I never saw anyone using those. What's the reason? could they brake or fail?
Thanks.
Angel
Most adjustable stems are not really designed for mountain biking
 

·
Advanced Slacker
Joined
·
15,333 Posts
alas214 said:
Hi, seems that I'm not the only one dealing with this. What about trying with an adjustable angle stem? are they only for trial and error or can I get one of those for riding? I never saw anyone using those. What's the reason? could they brake or fail?
Thanks.
Angel
Yeah, they are not going to be as stiff or strong as a solid stem. I'm sure they would be OK for you to find a position that you like. However, with a couple of cheap stems of different lengths and some spacers, you can achieve a whole lot of possible bar positions.
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top