Stem Length

[Hacienda71]

Can anyone enlighten me as to the benefits of short versus long stem length on a mtb?
I have a 2004 Stumpjumper Fsr Expert acquired from a mate who has upgraded. The stem length on it is 120mm with 6 degrees of lift. Whilst I can ride it comfortably I do feel quite pitched forward on descents. This may be due to me being technically not that sound, but I do wonder if a shorter stem would help.

 

[fossyant]

No expert here. I'm pitched forward on my old MTB but it was set up close to the road bike. Less stem reduces twitchy handling. I'm just crap at technical descents

 

[Cubist]

A better combination if its twitchy on descents would be wider bars and shorter stem. A wider bar gives you more options to get hunched over the bars to get weight over the front on corners, and get your weight more over the centre of gravity. That stumpy has a steepish front end by modern standards, and will feel a bit lairy facing downwards. Shortening the stem will increase steering input required, so a wider bar will give you more leverage. 120 is very long indeed, but I'm not sure you would necessarily benefit by from an ultra short stem. On One do a superb CNC stem for just under 20 quid, and my suggestion would be to try a 70 or 80 mm married to a pair of their unbelievably cheap El Guo Ancho bars. You can get something like a 760 and cut it down a bit if it's too wide.
http://www.on-one.co.uk/i/q/HBELGUANB/el-guapo-ancho-b-handlebar

A bit of rise with that geometry wouldn't come amiss either. If you were feeling flush they do their awesome Knuckleball carbon bars for less than 40 quid.

 

[dan_bo]

Just ride your bike.

 

[Hacienda71]

Just ride your bike.

Gotta keep up with the boy!

 

[dan_bo]

Gotta keep up with the boy!

I know. Dem kids get fast dont they.

Might have a 100mm job in the back of the shed if you want it.

 

[Cubist]

And I've got a 710 or. 750 bar you can use if you want to experiment, and a 70mm stem.

 

[GrumpyGregry]

A better combination if its twitchy on descents would be wider bars and shorter stem. A wider bar gives you more options to get hunched over the bars to get weight over the front on corners, and get your weight more over the centre of gravity. That stumpy has a steepish front end by modern standards, and will feel a bit lairy facing downwards. Shortening the stem will increase steering input required, so a wider bar will give you more leverage. 120 is very long indeed, but I'm not sure you would necessarily benefit by from an ultra short stem. On One do a superb CNC stem for just under 20 quid, and my suggestion would be to try a 70 or 80 mm married to a pair of their unbelievably cheap El Guo Ancho bars. You can get something like a 760 and cut it down a bit if it's too wide.
http://www.on-one.co.uk/i/q/HBELGUANB/el-guapo-ancho-b-handlebar

A bit of rise with that geometry wouldn't come amiss either. If you were feeling flush they do their awesome Knuckleball carbon bars for less than 40 quid.

^This. Everything you need to know is in that post.

 

[Hacienda71]

Thanks for the kind offers @dan_bo and @Cubist ,most appreciated. Dan if you are up for a blast around Clayton Vale in the next couple of weeks I may take you up on the offer as a starting point for fiddling with the setup. I am not sure of my bar width but will check it later. They are certainly wider than the ones on my son's Giant but riding road bikes most of the time mean that I have no idea if they are wide or narrow.

 

[dan_bo]

Thanks for the kind offers @dan_bo and @Cubist ,most appreciated. Dan if you are up for a blast around Clayton Vale in the next couple of weeks I may take you up on the offer as a starting point for fiddling with the setup. I am not sure of my bar width but will check it later. They are certainly wider than the ones on my son's Giant but riding road bikes most of the time mean that I have no idea if they are wide or narrow.

Nice one. Do you have a set of lights?

 

[Hacienda71]

I've got a solarstorm u2 x2 and a u2 x3. Have never ridden in t dark on single track though.

 

[I like Skol]

Be careful when messing with this geometry thing! I replaced a 130mm stem with a 110mm stem when rebuilding my Zaskar as I thought the fashion for shorter stems might actually have some substance to it. I'm not convinced it was a good move in handling terms but do sometimes think the cockpit is a bit cramped now. My (unknowledgeable and unscientific) theory for this is that the current bikes with next to no stem length must be correspondingly longer in the top tube dept? This means a bike designed for a long stem will be crap with a short one and vice-versa.

On the other hand, if you have a free, loan stem to experiment with then go for it. I am kicking myself as the 130mm version of my stem is no longer available and all the alternatives are considerably more expensive

 

[GrumpyGregry]

would that I was so sensitive and perceptive, and my senses so scientifically calibrated, that a change of 20mm in a stem, especially when the resulting replacement stem is still a long one, would make such a noticeable difference.

Makes me glad to be an insensate and unperceptive luddite

 

[Cubist]

Be careful when messing with this geometry thing! I replaced a 130mm stem with a 110mm stem when rebuilding my Zaskar as I thought the fashion for shorter stems might actually have some substance to it. I'm not convinced it was a good move in handling terms but do sometimes think the cockpit is a bit cramped now. My (unknowledgeable and unscientific) theory for this is that the current bikes with next to no stem length must be correspondingly longer in the top tube dept? This means a bike designed for a long stem will be crap with a short one and vice-versa.

On the other hand, if you have a free, loan stem to experiment with then go for it. I am kicking myself as the 130mm version of my stem is no longer available and all the alternatives are considerably more expensive

Which is why wider bars were my suggestion.Did you put wider bars on? Shorten the stem with narrow bars and you simply make steering more difficult.

@Hacienda71 You are welcome to come over and try any number of different combinations of stem and bar widths, it's only an hour or so from leafy Cheshire, and there are some good little spots for you to try the combinations out. I have 710, 720, 740, 750 and 780mm bars, plus 50, 60 and 70mm stems to go at.

 

[Jody]

I have 710, 720, 740, 750 and 780mm bars, plus 50, 60 and 70mm stems to go at.

Just been looking at the On One stems and they look like decent kit. Light and hopefully strong. Might have a punt on a 50mm and see if it livens the steering up.