# Let's talk stem length ...



## DrRoebuck (May 10, 2004)

All things being equal, is there a preferable length? Do different lengths offer different stability, handling, etc.?

Discuss.


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## Len J (Jan 28, 2004)

My persona opinion is that most bikes have an optimal stem length for proper handling. Larger bikes s/b 12-14, med sized bikes 11-12 & smaller bikes 10-11. 

I think these lengths are also aesteticially pleasing......form follows function.

IMO

Len


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## DrRoebuck (May 10, 2004)

Len J said:


> My persona opinion is that most bikes have an optimal stem length for proper handling. Larger bikes s/b 12-14, med sized bikes 11-12 & smaller bikes 10-11.


I agree on the aesthetics.

So, for a 56cm frame, you'd probably be like a 110-120mm stem?


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## mpk1996 (May 11, 2007)

for most frame sizes, if you go much less than 90mm or more than 120mm, it will probably adversely effect handling. if you need anything out of that range, your bike is probably too big/small. that is unless of course you have some odd body size, then maybe a custom bike is in order


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## mpk1996 (May 11, 2007)

for most frame sizes, if you go much less than 90mm or more than 120mm, it will probably adversely effect handling. if you need anything out of that range, your bike is probably too big/small. that is unless of course you have some odd body size, then maybe a custom bike is in order


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## DrRoebuck (May 10, 2004)

You can say that again.


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## tarwheel2 (Jul 7, 2005)

My understanding is that a shorter stem will cause quicker steering, and a longer stem the opposite. I've used stems as short as 8 cm, but have settled on 10 cm as the optimal length for my bikes. Any longer than that, and I feel too stretched out. 

As with stem/handlebar height, I think there are a lot of "style" issues involved. A lot of cyclists seem to gauge their mettle by how low and long their stems are. Personally, I think comfort is the main issue, and whatever stem rise and reach puts your handlebars in the correct position is the way to go. The reach may affect handling, but one way or the other, you adapt pretty quickly.


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## C-40 (Feb 4, 2004)

*the facts...*

Changing stem length from an 80mm to a 120mm only increase the length of the lever arm used to steer by about 15%. The effect on handling is greatly exaggerated. I'll agree that from a looks standpoint, short stems on large frame look kind of odd, but each person has to use what fits them and what they can tolerate from a comfort standpoint.

The larger affect on handling comes from the change in front to rear weight balance caused by moving the saddle fore or aft. Changing stem length, by itself, has little effect on weight balance. It's a common misconception that changing to a longer stem will add a significant amount of weight to the front of the bike.

If you've ever put a scale under the front wheel of a bike, you'll find that torso angle has a significant effect on the weight balance. Changing the stem height will change torso angle more than stem length will.


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## roadfix (Jun 20, 2006)

C-40 said:


> The effect on handling is greatly exaggerated.


100% agreed. Anyway, one can quickly adapt to most any handling changes.


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## Richard (Feb 17, 2006)

I think C-40 is full of bunk. Granted, a plus or minus stem length of more than 2cm from "spec" can adversely affect handling, but nobody is "static" on the saddle, at least on a road or mountain bike.

Fore and aft on the saddle is to position the rider properly over the crank. Stem length is to fine tune the cockpit length, given the geometry of the bike, like seat tube angle. Too short or too long means that the bike doesn't FIT.

I do the professional fitting in our shop, and we don't have a "scale". A couple of "percentage points" on fore and aft balance don't mean squat.


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## Len J (Jan 28, 2004)

*Adapting and......*



roadfix said:


> 100% agreed. Anyway, one can quickly adapt to most any handling changes.


desireing are 2 different things. I have adapted to bad handling bikes, but that doesn't mean either that I liked it or that that is what the designer intended.

A twitchy bike requires much more management that can get very tiring over a several hour ride. Sure I can adapt to it.....but I would still hate it.

YMMV 

Len


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## danl1 (Jul 23, 2005)

Richard said:


> I think C-40 is full of bunk. Granted, a plus or minus stem length of more than 2cm from "spec" can adversely affect handling, but nobody is "static" on the saddle, at least on a road or mountain bike.
> 
> Fore and aft on the saddle is to position the rider properly over the crank. Stem length is to fine tune the cockpit length, given the geometry of the bike, like seat tube angle. Too short or too long means that the bike doesn't FIT.
> 
> I do the professional fitting in our shop, and we don't have a "scale". A couple of "percentage points" on fore and aft balance don't mean squat.


I have some issues with C-40's points, but none that amount to much. 

But you are completely wrong about proper fit. The distance (horizontal and vertical) from the BB to the bars is what positions a person properly over the crank. The saddle is adjusted to get it under a properly-positioned butt. Practically speaking it doesn't happen that way, but the result of a properly performed fitting is exactly that. 

You are correct that an oddly sized stem means the bike doesn't fit, but your understanding of why is lacking. It's the difference between getting someone out the door on what's in stock, as compared to figuring out how they ride, and getting a proper bike underneath them.

Returning to the original discussion, the right size stem is the one that creates proper position and balance. That's the one that will feel and steer (and be) correct. It's not proportional to frame size, it's not an aesthetic decision - it's simply what's correct.

The notion that a shorter stem makes steering 'twitchier' is bunk. If that's the case, why do we teach noobs to put thier hands closer to the stem when reaching for water bottles, etc? Longer ones don't make steering 'slower', either. A stem that's shorter than appropriate will adversely effect steering, as will one that's longer than appropriate. But there are rider-bike combinations where long is appropriate, and others where short is appropriate. That is, it's not 'short' that = twitchy, it's 'wrong' that = twitchy.

And no one has yet asked what the reach of the bars to be used is. It's easy to find 2cm's of reach difference there, and to not think of the two as a system is simply goofy.


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## Henry Chinaski (Feb 3, 2004)

I ride 57 cm c-c bikes. I feel 11cm or 12cm ideal (for me).

I heard Andy Hampsten say that Merckx saw him riding a bike with a 13cm stem when he was with 7-11 and freaked out. He had a custom frame built for him so he could ride with an 11cm stem.


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## Henry Chinaski (Feb 3, 2004)

danl1 said:


> And no one has yet asked what the reach of the bars to be used is. It's easy to find 2cm's of reach difference there, and to not think of the two as a system is simply goofy.


I've always ridden Cinelli 64s, so bars have never been part of the equation for me.


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## Mr. Versatile (Nov 24, 2005)

Think about the way single track vehicles steer once they're underway. They steer by leaning, and that leaning is mostly brought about by exerting sublte pressure on the bars. When you're riding and want to turn, you don't turn the bars. Because the bars aren't actually turned, I find it hard to believe that stem length has any kind of significant effect on bike handling or steering.


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## C-40 (Feb 4, 2004)

*a little harsh..*

You're either misreading or reading between the lines. I agree that saddle fore/aft is to position the rider over the crank, but there's at least a 2cm range that most riders can find useable. A saddle that's too far forward will place too much weight on the hands.

I never said you needed a scale to fit a bike, but when I read post from riders complaining about handling problems, I NEVER read that the front/rear weight balance has been checked. I ride technical mountain descents 3-4 times a week. I never paid any attention to weight balance until I started riding in the mountains and handling became more critical. Very few riders will notice changes to weight balance if they're riding the average rolling to flat terrain and their most challenging corner is a 90 degree on the flat. Negotiating a hairpin at 35+ is another story.

We are talking about stock frames trying to be fit to riders with widely varying proportions and fitness levels. A beginning rider of my exact proportions could not tolerate the reach and 9-10cm drop from the saddle to the handlebars that I use. A beginner would probably have the bars 2-4cm higher and at least one size shorter stem. The majority of weekend warriors I see riding around my area have short, high rise stems. Just because the less fit rider is using a stubby 80-90mm stem doesn't mean the frame doesn't fit, it may well mean that the rider just lacks the fitness to ride in a "normal" (aggressive) road bike position. Of course there are frame models made for the less fit rider, with shorter reach and taller head tubes. That's certainly an option.

Being a short torsoed, long legged rider, I look for frames with the shortest reach (not just TT length), so I can use a 110mm stem, with "standard" 85mm reach bars, if possible. Notice I said REACH not TT length. Reach is the TT length minus saddle setback. In my frame size (51cm c-c), a frame with a 74.5 STA and 52.5cm TT will fit the same as one with a 72.5 STA and 54cm TT. LOOK made frames to both of these dimensions and I've owned both. The only difference in the setup was a no-offset post on the later frame to get the saddle in the same position relative to the BB.


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## Dinosaur (Jan 29, 2004)

Rotating pelvis..........I'm kinda from the old school on bike fit, let you body be the guide. Stem length extends the tt. It takes a certain about of flexibility and torso strength to ride stretched out. Riding in the position rotates the pelvis, which is more comfortable and takes the impact off the lower back. Not everyone feels comfortable in this position. A lot depends on anatomy and geometry of your bike.


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## djg21 (Oct 25, 2003)

mpk1996 said:


> for most frame sizes, if you go much less than 90mm or more than 120mm, it will probably adversely effect handling. if you need anything out of that range, your bike is probably too big/small. that is unless of course you have some odd body size, then maybe a custom bike is in order


 
This (not going longer than 120mm) was true a decade or so ago when aluminum quill stems were the rage. Anything longer than 120mm would flex wildly. With 1 1/8" steerers and the new generation of threadless stems (and even cro-moly quill stems), this isn't really an issue any longer. If you look at the pro peleton, there are a lot of 130mm and 140mm stems being used on relatively small bikes. Focus more on determining the optimal combined length of the toptube and stem for you (find a good bike fitter) and then work from there. By going a touch shorter in the stem, you will still stiffen up the front end a touch, but it won't make a huge difference like it once did.


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## mandovoodoo (Aug 27, 2005)

And the saddle. Some let me rotate pelvis forward more easily. 

Is this sort of valid?: I drop a line directly down from the centerline of the bar at its most forward point, in the bend. I look for that line to cross not very far ahead of the center of the wheel or perhaps up to 2 cm behind it. I hope this is clear. I like the way bikes handle and feel when that's the case. Behind the wheel gives what I think of as an old fashioned road bike feel. More forward gives a snappy, I can muscle it around feel.


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## DrRoebuck (May 10, 2004)

mandovoodoo said:


> And the saddle. Some let me rotate pelvis forward more easily.
> 
> Is this sort of valid?: I drop a line directly down from the centerline of the bar at its most forward point, in the bend. I look for that line to cross not very far ahead of the center of the wheel or perhaps up to 2 cm behind it. I hope this is clear. I like the way bikes handle and feel when that's the case. Behind the wheel gives what I think of as an old fashioned road bike feel. More forward gives a snappy, I can muscle it around feel.


Interesting ... So you measure from the front of the drop?

So, let's say someone was going on Monday to get measured for/order an Indy Fab Factory Lightweight (!). And let's say this person was also getting a new stem. Would the frame-maker typically say "this is what stem we think you should need," or is that something I would figure out when I'm getting the fit dialed in once I get the frame?

I have to order the stem, so I'm hoping to know in advance what size I'll need. After waiting 4+ weeks for the frame, who wants to wait any longer to order a stem?! 

Thanks for all the replies so far.


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## mandovoodoo (Aug 27, 2005)

I measure from the centerline of the bar, not the very front, right in the bend. Generally, the frame makers I've seen working in the old days would know where the saddle and bars were going to end up within a small amount, allowing an appropriate stem to be fitted. Some used measurements, some used a sit on fitting machine.


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## C-40 (Feb 4, 2004)

*questionable....*



mandovoodoo said:


> I measure from the centerline of the bar, not the very front, right in the bend. Generally, the frame makers I've seen working in the old days would know where the saddle and bars were going to end up within a small amount, allowing an appropriate stem to be fitted. Some used measurements, some used a sit on fitting machine.


While this might work for you, it has little validity, IMO. From a geometry standpoint, this would roughly say that for every 3cm increase in frame size and/or headtube + spacers, the stem would need to be 1cm longer, since the stem would move back about 1cm. A more slack HTA would also change the stem length by about 1cm per degree. If two people have the same size frame and one uses no spacers, while the other uses 3cm, the person with more spacers would select a longer stem based on this advice. It would not take into account the riders torso length or ability to tolerate reach. Stem length should be based on what fits the rider.

What I use as a guideline is knee to arm clearance. When I pedal in the drops with my upper back nearly horizontal, I don't want my knees hitting my arms. A lot of riders could not tolerate this much reach while riding on the brake hoods. If you can't, you just have to flare your elbows.


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## Nessism (Feb 6, 2004)

C-40 said:


> What I use as a guideline is knee to arm clearance. When I pedal in the drops with my upper back nearly horizontal, I don't want my knees hitting my arms. A lot of riders could not tolerate this much reach while riding on the brake hoods. If you can't, you just have to flare your elbows.


My bikes are set up similarly; when in the drops my knees have a small clearance to my elbows. If I really try it's possible for my upper arms to hit my knees but it doesn't happen while riding since I almost never get that low on the bike (yes, getting old). 

Once you get into this range of fit it becomes a very personal thing. Many riders, including some professionals, have overlap between their knees and elbows - Sean Kelley was famous for this as was Indurain. Having excessive knee clearance usually means the stem is too long or the rider really likes to be stretched out - again, it a personal thing. No right or wrong answer.


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## mandovoodoo (Aug 27, 2005)

Interesting. My knees lie inside my elbows. I can touch them if I want, but I would have to try. 

That bar position rule of thumb I saw a goodly number of people using years ago. For average sized riders. Really tall and really short are different, of course. It always gave me a 100 to 120 mm stem on a frame on the small side, 

I'll agree that for 3 cm up the stem would need to be 1 cm longer. That seems exactly right. See http://www.prodigalchild.net/Bicycle6.htm and that's what it shows.


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