[Closed] Changing Stems...What will 20mm effect?

Other than what you already said, going from 90 to 70 made my bike easier to lift the front wheel while seated on a climb. Downside, the sense of going over the bars on steep DH comes a lot sooner.

This in on a 115mm HT.

Wozza - Member
Other than what you already said, going from 90 to 70 made my bike easier to lift the front wheel while seated on a climb. Downside, the sense of going over the bars on steep DH comes a lot sooner.

Funny, I've always found the opposite, re. the steep downhill bit. The longer the stem, the more forward a proportion of your weight is, surely?

mmmmmm never thought of the 'over the bars feeling' and lifting the front on a climb, I have issues of it lifting already, maybe 70mm isnt the way to go.

Might be a side effect of the twitchiness of the front I guess.

Twitchyness, now theres a side effect on its own surely.

Any more thoughts?

Anyone gone shorter to 70mm and wish they hadn't?

Downside, the sense of going over the bars on steep DH comes a lot sooner.

Are you doing that "arms straight, arse on the back saddle" thing?

I guess a shorter stem moves you further back, putting less weight on the front wheel which causes less front end grip and disaster.

90mm down to 60mm on my inbred, love it; able to move around the bike more and handles a bit better.

I went from a 90mm to 60mm and it's loads better, more comfortable and just more fun.

Give it a try.

Either MBR, STW or MBUK did an article on the science between stem lengths, and the effect it had on weight position, steering, etc.

I'd like to borrow a shoter stem, to give it a go before i splash out on a nice lightweight one. Put a thread in wanted but haven't heard anything for a few days.

I'll have a search for that article.

Brant - wouldn't say Im doing the arms totally straight, but I feel more comfortable in a 'slightly Stretched out style' but I find it a little awkward clearing my seat comfortably (wedding veg) on the decents.

I have a layback post due to the riding position I mentioned but, maybe this and a shorter stem may put my weight too far back as you suggested.

Which makes me ask whether it is possible, scientifically to be measure for a mountain bike.
I get told, if it feels right it probably is. But Im sure if like me I don't really know what Im looking for, how do you know.......?.....you can get off after a ride and you're not crippled with back pain? 🙁

I did a back-to-back test with 90 mm and 70 mm stems on my bike. 90 mm felt horrid. 70 mm is just fine.

If the front gets too light on the climbs just drop the elbows a bit more and pull your weight forwards on the saddle.

90mm down to 70mm made a big difference on my soul, also switched from 670 to 685mm bars though. Feels more chuckable and planted

Thanks guys should add really that I have a set of Carbon bars that are 660 replacing 685mm.
Think that'll through up a few things maybe.

On of the first things I did with my Wolf Ridge was to swap the 80mm Syncros stem to a 65mm Straitline wedge jobby. The improvement in confidence up front was immediately apparent, especially when paired with 760mm wide bars.

110 to 40 last week. Amazing transformation on the downs. Bit wandery on the ups and lifts on very steep sections but it's easy to compensate for and I'm crap at climbing anyway.

a set of Carbon bars that are 660 replacing 685mm

those days are over. 745+ surely?

Thanks guys should add really that I have a set of Carbon bars that are 660 replacing 685mm.

If you're going to narrower bars and a shorter stem then you'll be going against the stream- perceived wisdom is that you should go to wider bars if you shorten the stem- firstly to keep from cramping yourself up, and secondly, to stop the steering becoming too quick.

745+ haha we have trees here.

I really need to try one and see what happens.......guessing nobody's got one knocking about eh?

If you fit a shorter stem, the easy way to overcome the wanderyness on the climbs (most people forget to do this) is just bend your elbows loads, and lean forwards...

Anyway... Stem length is a real horses for courses thing. What suits one person, may not suit another. And what suits one bike, will not suit another! On one of my bikes, I've just swapped back to a 90mm stem from a 70mm cos with the 70mm on it, it felt too relaxed and lazy! Conversely with the 90mm on, the bike seems to rail into corners and generally feels a lot more eager. This is probably more to do with where my weight is on the bike (lower and further forward with the 90) than anything else, but to me the difference is like night and day!

Conversely, an old bike of mine felt horrid with a 75mm stem on, as soon as I put a 50mm stem on it, it transformed the handling!

Thanks for your experiences mboy, its way too difficult to come to a definitive answer.
I'll have to buy a 70mm and if its a nightmare lose on swapping it later.

vinneyeh, thanks for that. I can see the logic in that for sure. I was going for super light bars and hadn't really thought of the width as a massive difference from 685mm

Quite glad someone asked this question as I've got a stock 100mm 8 degree rise stem from my old aggressor (oversize bar). It always felt kinda long and I had problems with the front wheel lifting on climbs . Ive recently got a 456 frame and thinking of a El Gallo 50 mm stem .
Are the shorter stems predominantly for downhill bikes?.

I'll have to buy a 70mm and if its a nightmare lose on swapping it later.

beg/steal/borrow a 70mm stem for a bit first. There are some cheapo ones out there which you could buy to try, before selling it on, but I'm sure if you ask nicely someone will lend you one for a couple of weeks before you decide if it's for you.

Truvative XR is cheep, and PRO do a cheep one as well, both stood upto all the abuse I could throw at them.

Slack angles = long wheel base = stable

slack angles = slow steering - corect with a shorter stem

short stem = cramped

make top tube longer = longer wheelbase.

Basicly if your frames designed arround it it'll be good, otherwise it's crap.

Exotic stems cheap and light, do it.

I went from 100mm to 80mm then to 45mm on my Giant Trance X which has made my bike much more responsive and better on downhills without hardly compromising climbing ability. I have adjustable travel forks so I can wind them in to keep the front planted on climbs. I just don't get on with that stretched out over the bike position and feel I can do a lot more with the bike with a shorter stem.

You might be able to borrow stems off friends to try out and see what suits you and what kind of riding you want to be doing. Downhill stems are generally very short whilst XC ones are longer.

stanfree - Member
Quite glad someone asked this question as I've got a stock 100mm 8 degree rise stem from my old aggressor (oversize bar). It always felt kinda long and I had problems with the front wheel lifting on climbs . Ive recently got a 456 frame and thinking of a El Gallo 50 mm stem .
Are the shorter stems predominantly for downhill bikes?.

Nah, not really. I haven't used longer than a 55mm stem on an MTB for about 15years now. I'll let you have a shot of my STP next time we're riding together and let you see what you think (it has a 40mm stem)

Cheers GW hopefully get out again soon.

Lend me a 70mm Stem, I'll be gentle 🙁

I just bought the on one 70mm stem for £24

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put it on the HT last night and i love it

I run an 80, 65 and 50mm on my Five (not at the same time, obviously).

It does make quite a difference. The reach is the obvious one (the 50mm makes the Five a little too short) but shorter stems do make steering noticeably quicker (the 50mm is used for bigger/techier/steeper riding).

For most things I find the 70mm is a great length (so to speak) as it's a happy compromise.

I went from 100mm to 60mm, keeping the bars at ~700mm. Much prefer everything about it, although I do care far more about going downwards and cornering fast than I care about going uphill fast. Cost about £12 from eXotic.

I could not be done with any mid point messing about and have gone straight from 90 to 55 stem and from 640 to 680 bars, although not sure if this was a great combo. Early days but after just one ride Easton kit means its way stiffer and my stumpy feels smoother, better balanced and easier on downhills bits. Feel as if i could go up in bar length but don't fancy catching my bars.