Stem length

[Caerus]

How does one know what stem length to use? I have a spare FSA stem(OS 90) which I have from a previous upgrade( Giant Trance). I currently have a 130mm and it weighs as much a small elephant.

 

So is there a way to check that this will work for me on my GT Avalanche, my LBS said I should measure my top tube(570mm, I measured from centre of headset along the toptube to the centre of the downtube) Are there any other measurments I need to give myself a rough idea(ie height, arm lengh etc).

 

I do realise that my seat may need to move back as well. I am also looking at a new seatpost. I never had much hassle with my old set up except the odd lower back pain, I never had a proper setup done, the bike was used mainly for commuting. Since upgrading to be able to take it offroad now, it doesn't seem to handle like it should, just doesn't seem that responsive.

 

Many thanks

[Iwan Kemp]

Shorter stem: big steering influence, some weight distribution

Moving saddle: big weight distribution, big influence on pedaling efficiency

 

Lets say TT is 595 and stem is 100mm (fair lengths on XC Med). This will give you effective reach of 695mm. Moving your saddle 10mm back WILL NOT negate effect of going 10mm shorter on your stem.

 

To set your bike up properly:

1. Set sag

2. Set saddle height

3. Check sag especially if big changes were made

4. Set saddle for/aft

5. Check reach. This CANNOT be adjusted other than by swapping your stem. Flipping the stem so it's angled up or down will have an effect on reach (down = longer reach and vice versa) but this will also influence weight distribution. Big time. Eg: Angled up will raise your upper body, thus moving your weight towards the rear of the bike. Technical climbs will be tougher.

6. Check spacers

7. Check everything again

[Iwan Kemp]

I do realise that my seat may need to move back as well. I am also looking at a new seatpost. I never had much hassle with my old set up except the odd lower back pain, I never had a proper setup done, the bike was used mainly for commuting. Since upgrading to be able to take it offroad now, it doesn't seem to handle like it should, just doesn't seem that responsive.

 

Many thanks

 

Do yourself a favor and have the bike setup properly.

 

How tall are you?

What size bike do you ride?

What bike do you ride?

 

 

 

[Barend de Arend]

Was wondering whether a 10mm (1 cm) reduction in my stem length would make a difference and whether it is possible to compensate by moving my saddle 10mm (1 cm) back<img src="https://assets.bikehub.co.za/legacy_images/smilies/smiley5.gif" height="17" width="17" border="0" align="absmiddle" alt="Confused" /> I had a 120mm stem and now acquired a 110mm stem.

 

You're not telling us why you want to use a shorter stem.

 

If it's for back pain, don't change your saddle. In fact, don't change your saddle. Or don't change your saddle. And don't change your cleats 10 mm to compensate either.

[Caerus]

Do yourself a favor and have the bike setup properly.

 

How tall are you?

What size bike do you ride?

What bike do you ride?

 

 

 

 

 

Im 1.82, and this is for my hardtail GT Avalanche 0.5 which is a large.

[AndreZA]

You NEVER adjust a saddle to fit reach. The norm is a 100mm on a 54-58 (M) frame and shorter for smaller frames and longer for bigger. YOu can also adjust reach by fitting different handle bars. Compact (shallow bend) bar's reach is shorter but only on the drops. So if you ride with your hands on the top alot, a stem is the answer.

[Iwan Kemp]

Disclaimer: the next comment is based on averages and might not work 100% for you

 

For your height and size bike a 110 - 120mm stem should do. Even 120mm is getting on the long side of things, but could work.

 

Coming down from 130mm on that bike will make a huge difference. Night and day. Much better steering, better control on descents and less strain on your back & shoulders.

(Side note: GT Avalanche is a MTB so there won't be any riding on the drops.)