How to measure MTB stem

[AliShah2020]

Hi all,

I'm learning how to upgrade my bike myself and fairly new to biking.

Can I please ask, is this the correct way to measure the stem and does this mean my stem is 55mm? Or is it 60mm?

I'm looking to shorten the stem, as the long reach hurts my elbow joints during long commutes. Otherwise my bike is sublime.

Many thanks for your input! 😊❤️🙏🏼

 

[dan_bo]

I'd call that a 55 but 55 is a funny size cos they normally come in 10mm increments so I'd call that a 60.

If that makes sense.

 

[fossyant]

It's 6cm I think as your ruler looks to have moved - the end isn't flush to the ruler. Measure centre to centre.

You could go a little shorter. There are also other factors, including top tube length and head angle. New bikes are a lot longer by design.

 

[TempleDancer]

Looks like a 60mm to me too. You could also try rotating the bars back slightly before replacing the stem and/or consider cutting them down if they are particularly wide.

Most of my discomfort when I used to ride MTB was from bar width and sweep rather the reach, and generally I'd be out of the saddle more often than not. Though if you are commuting then i guess that may not be the case.

 

[Cycleops]

If you go much shorter the steering will start to feel twitchy. I’d rather consider changing/altering the bars before doing that. You could also try moving the saddle further forward.
Is the bike a bit big for you?

 

[AliShah2020]

I love this forum, all you guys and gals are very helpful and supportive so a big thank you!!!

@dan_bo yes I am with you! That's why I was a bit confused too! Thanks for input

@fossyant I measured a bit crooked so as not to cover the bolt head with the measuring tape so I could show the forum where the bolt was 😊😎

@TempleDancer Thanks for your input. I rotated the bars a few weeks ago. I still feel there is room for improvement, every time I hit a bump in the road my elbows (despite keeping them slightly bent) are still quite straight due to reach issues and they absorb the impact. I had inflammation in my elbows for a week and it made me realise I need to address this issue.

@Cycleops Good observation mister! I am in between frame sizes. I am 5"10, a size M frame felt small and would need a longer stem, a size L frame feels better for me and more stable at high speed.

I moved the saddle forward and that has helped with no ill effects to my knees. It has also taken the strain off my elbows (although this could be improved more) as my arms are still relatively straight(ish).

My son has a Boardman MHT 8.6 (size M) which feels very agile, but the bars feel too close to my body. He has a shorter stem as per photo with 29er wheels (my wheels are 27.5). I was hoping a 35mm stem would be perfect for me? I don't think dropping from a 60mm down to 45mm will have enough improvement and I may regret not getting the 35mm stem (as this allows the saddle adjustment for a larger range of adjustment).

Please see pic of my bikes stem vs my sons bike stem.

I did not find his bike twitchy, baring in mind I am an urban commuter living in the city of London so this bike is more for road commute/fun with style. I did find my larger frame more stable when going down hills. I am envious of his 29ers though lol they carry good speed!!!

 

[vickster]

Hi all,

I'm learning how to upgrade my bike myself and fairly new to biking.

Can I please ask, is this the correct way to measure the stem and does this mean my stem is 55mm? Or is it 60mm?

I'm looking to shorten the stem, as the long reach hurts my elbow joints during long commutes. Otherwise my bike is sublime.

Many thanks for your input! 😊❤🙏🏼

Maybe you would also benefit from a narrower handlebar?

 

[AliShah2020]

@vickster you may well be right. Problem is I'm so used to them that they feel luxurious and sublime.

I've approached the problem incrementally:
1. Rotate handlebars
2. Adjust saddle forwards
3. Replace stem (just placed an order for 35mm and 45mm stem to compare the two)
4. Cut handlebars or replace (last option).

 

[TempleDancer]

Sounds like you're approaching it the right way. I usually run shorter stems on my MTBs as I prefer livelier handling anyway and if you are primarily commuting, as you say, I doubt you will notice an undue level of twitchiness.

 

[AliShah2020]

@TempleDancer I like to get things right, and within budget (without costly mistakes hopefully). I needed reassurance I have approached the problem the right way. Thank you very much for the input 😊

 

[iluvmybike]

If you go much shorter the steering will start to feel twitchy. I’d rather consider changing/altering the bars before doing that. You could also try moving the saddle further forward.
Is the bike a bit big for you?

Modern mtbs have muc shorter stems than was de riguer a few years back - this is compensated for by having really wide bars and helps with tight turns

 

[fossyant]

Modern mtbs have muc shorter stems than was de riguer a few years back - this is compensated for by having really wide bars and helps with tight turns

Correct, and that the geometry is much more slack at the front. Nobody goes 'narrower' on MTB bars, ever !

 

[Cycleops]

Correct, and that the geometry is much more slack at the front. Nobody goes 'narrower' on MTB bars, ever !

Not even for commuting in London?

 

[fossyant]

Not even for commuting in London?

I'd expect them to be around 700-740mm already which aren't 'wide'.

Personally he's better off leaving it be and keep up the riding. Don't forget you can move your hands around quite a bit on MTB bars as the grips are usually around 130mm. Could move his brake levers in a little more to use inner edge of grips.

No point going shorter stem tbh. They aren't road bikes, believe you me. Leave as is for commuting as it's not the right tool for the job anyway. Just spending for spending sake over 20mm on an already short stem.

 

[Drago]

I did not find his bike twitchy, baring in mind I am an urban commuter living in the city of London so this bike is more for road commute/fun with style. I did find my larger frame more stable when going down hills. I am envious of his 29ers though lol they carry good speed!!!

Sounds like you're approaching it the right way. I usually run shorter stems on my MTBs as I prefer livelier handling anyway and if you are primarily commuting, as you say, I doubt you will notice an undue level of twitchiness.

A change in stem length will not make a bike more or less twitchy. The fundamental handling characteristics remain totally unaltered, and for every degree of steering input the bike will respond identically regardless of stem length.

Reducing the head angle will make it twitchier. Shortening the offset, and therefore the trail measurement, will make it twitchier. Shortening a stem will not.

Changing the stem length changes only the feel, or more accurately the perceived feedback. Shortening a stem makes the same difference to the actual steering behaviour as changing the steering wheel on a car would - none at all.