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Discussion Starter · #1 ·
I'm going to replace my current 120mm stem and will probably get something closer to 100mm to reduce my reach. Will I notice a dramatic difference in steering? The bike is already a little twitchy and I wouldn't want to increase that.

Thanks.
 

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Do you have a small bike?
Do you feel too stretched out?
 

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Discussion Starter · #5 ·
MR_GRUMPY said:
Do you have a small bike?
Do you feel too stretched out?
My bike isn't small. I'm just noticing over the years that the reach is a little too long for me as I usually have my hands a little bit behind the hoods on the bend of the handlebars.
 

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Yes, you can compensate for too long a top tube, with a shorter stem.
Remember this for your next bike.....Get a shorter top tube (smaller frame)
 

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Discussion Starter · #7 ·
MR_GRUMPY said:
Yes, you can compensate for too long a top tube, with a shorter stem.
Remember this for your next bike.....Get a shorter top tube (smaller frame)
The only problem with getting a shorter top tube would be that I would have a lot of seat post showing which might put me too far behind the BB. My current frame has a seat tube of 58cm C-T I believe and my saddle height is around 79cm. For a while I thought that I should have gotten a bigger frame and shorter stem. What would be your advice? My inseam is about 88 cm.
 

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You'll be in the same position over the BB. The seat post is on the same angle as the seat tube. The only down side of a smaller frame is a shorter head tube, that mught cause you to need more spacers under the stem. This problem can be solved by buying a bike with a shorter than standard top tube. More and more bikes are being designed this way now.
 

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danielc said:
I'm going to replace my current 120mm stem and will probably get something closer to 100mm to reduce my reach. Will I notice a dramatic difference in steering? The bike is already a little twitchy and I wouldn't want to increase that.

Thanks.
Where does this idea come from?

When you were taught to ride, didn't someone mention that when reaching for a bottle, removing arm warmers, etc, you were to grab the bar top - that is, reduce leverage by moving hands closer to the steering axis - to stabilize the steering?

Ever notice that downhill bikes - where twitchiness is definitely NOT desired - have tiny little stems?

20 years ago, a 100 mm stem would have been considered longish, 90 was as close to 'standard' as such things ever get, and if you had a 120 (assuming you could find one) everyone would ask why you didn't buy a bike that fit properly.

Bike geometry has changed somewhat, but not nearly as much as has the tendency to buy too-small bikes to save an ounce and a half.

All you are doing is returning to a more sensible place.


Oh, and my first question has an answer. When these putzes on their too-small bikes put a too-short (and likely too-low) stem on, they increase the proportion of weight being supported by the hands. That additional load reduces fine motor control, and so they tend to over control. In their (lack of) wisdom, they conclude that their poor handling skills (resulting from their poor bike-fitting skills) are the product of some mechanical 'twitchiness', which is simply not true. As applied to an appropriate overall reach, a lower proportion in stem as compared to top tube will result in slower steering.
 

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Discussion Starter · #10 ·
danl1 said:
As applied to an appropriate overall reach, a lower proportion in stem as compared to top tube will result in slower steering.
I thought that when you have a longer stem, your handlebar turning circumference is greater than if you had a shorter stem. The analogy I've heard has been a race car versus a bus steering wheel on your car. You will turn slower with the latter.
 

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People have different shaped bodies. Different configurations will place your body weight in different places on the bike, and alter the emphasis of where the weight is focused. Riding different bikes and stems helps to give an idea of what works. Do what's right for you and don't sweat it.

I have a 90 by choice and design, on a bike I built up with a top tube that is long, also by choice and design.

It fits my long torso/short arms/short legs perfectly and the ride and cornering is as sweet as all get up. I'm constantly amazed by it.

I used to have a shorter top tube bike that gave better standover by conventional reckoning, but even with the longer stem it felt all wrong. (My body weight was too far forward over the front wheel, and on my hands.

Whith the new bike, much happier.
 

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20 years ago I rode a 50 cm Basso with a 52.5 cm top tube with a Cinelli XA 130mm stem. I had no problem getting this stem as they were very common. No one ever commented that I was riding too small a bike. I rode it, raced it and enjoyed it.

Today I ride pretty much the same geometry with my current set up.
 

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I went down from a 100 to a 65 recently for the same reason you are quoting. It's made the bike considerably more comfortable to me. As far as handling goes, it feels crisper to me, but that may be because I'm more comfortable now. With the older stem, the bike felt like it couldn't turn a corner at speed without swinging too wide.
Measure where your hands feel comfortable to the hoods, and order a stem based on that. 20mm might be perfect, but you might need more or less...
 

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danielc said:
I'm going to replace my current 120mm stem and will probably get something closer to 100mm to reduce my reach. Will I notice a dramatic difference in steering? The bike is already a little twitchy and I wouldn't want to increase that.

Thanks.
I could be wrong but I'd think the fork rake and the head tube angle will have much bigger affect on the steering....
 

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If you are shortening the stem so that your hands are further forward on the bar - on the hoods, there should be no difference in handling. Your hands will be in the same basic position in relation to the rest of your body.

I'm curious to know what is making your bike twitchy in the first place.
 

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Ok...

Your frame size is appropriate for your saddle height, if it's 79cm.

Frame size has no effect on your position, relative to the BB. If you get a different frame size, the saddle height would not change. Even if the seat tube angle is different, you would adjust the saddle fore/aft positon to be the same, relative to the BB.

My rough guideline for adequate stem length is knee to arm clearance. If I'm riding in the hooks on a mountain descent, with my upper back nearly horizontal, I don't want my knees hitting my arms when I pedal. A stem that's any longer than it takes to meet that requirement serves no purpose.

As for the steering difference, people can argue all day about the effect on twitchiness, but you'll get used to the change within the first ride. At any decent speed a bike is not steered by turning the bars, like you would at 5-10 mph. At higher speeds, you apply pressure to the right side of the bars, countersteering, to lean the bike to the right and make a tight turn. If you ever ride a motorcycle, you have to figure this out real quick or you'll never get it to turn. The amount the bars are turned is barely discernable.

The main reason most people have too much weight on their hands is a saddle that's too far forward, not properly balancing the rider. With my saddle in the proper position, I'm now using a 12cm drop from the saddle to the bars. I've got no problem at all with excess weight on my hands.
 

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Discussion Starter · #18 ·
rogerstg said:
I'm curious to know what is making your bike twitchy in the first place.
This may be a frame geometry issue but...my compact frame rain bike which is set up very similarly except for a slightly longer effective reach, seems more stable. I can ride no hands sitting up straight much easier than when I'm on my other bike. I also seem to be able to descent more comfortably and take better lines. Keep in mind though that I usually descend on the hoods around here. Both stems are 120mm...go figure!

Thanks for all the input.
 
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