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Master of Disaster
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Discussion Starter · #1 · (Edited)
I'm riding a size-Large hardtail XC 29er with a 120mm stem and a 620mm (24.4in) wide, 25mm rise handlebar. I recently demoed a full-squish 26er with a shorter stem and 690mm bar and really liked the quicker steering.

I'm just guessing here but am I correct that a 100mm stem would quicken the steering on my bike? Any downsides?

My thinking is that with a 100mm stem and bar about 670mm wide (plus or minus 10mm), I'd have better and faster control of the front end. I've read some magazine testers complaining about the narrow bars common on budget bikes. Seems to me that 620mm is on the narrow side for optimum control (though 690mm seemed like a tight squeeze between the trees! LOL.). TIA.
 

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Rider and Wrench
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Clones123 said:
I'm riding a size-Large hardtail XC 29er with a 120mm stem and a 620mm (24.4in), 2.5-inch riser handlebar. I recently demoed a full-squish 26er with a shorter stem and 690mm bar and really liked the quicker steering.

I'm just guessing here but am I correct that a 100mm stem would quicken the steering on my bike? Any downsides?

My thinking is that with a 100m stem and bar about 670mm wide (plus or minus 10mm), I'd have better and faster control of the front end. I've read some magazine testers complaining about the narrow bars common on budget bikes. Seems to me that 620mm is on the narrow side for optimum control (though 690mm seemed like a tight squeeze between the trees! LOL.). TIA.
You are on the right track as far as a shorter stem/longer bar combo being able to offer a bit more control/leverage - nice thing is the wider bars help keep your reach feeling ok if you shorten up the stem (as well as reducing your stem's rise can help reduce the effects of going with a shorter stem)
Bar width is a personal preference for sure but 635-690 mm wide bars paired with 80-110mm stem for most trail/XC riding is a good start-. I run a bit different combo on each bike- 90mm w/ 635 bars on one and 100mm with 685 bars on the other - mostly because of top tube length but I also like a bit wider bars on my SS... it seems you have been reading a bit of MBA as I recall almost every test mentions bar width as an issue...
 

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Master of Disaster
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Discussion Starter · #4 ·
knottshore said:
it seems you have been reading a bit of MBA as I recall almost every test mentions bar width as an issue...
I could have sworn it was MBR instead but I flipped through some recent issues and it was actually What Mountain Bike that got me onto the issue of shorter stems and wider bars.

When I rode motorcycles it was the Brit magazines that were by far the best. Same with mountain bikes now - Mountain Bike Rider, Mountain Biking UK and What Mountain Bike each have awesome content (blunted somewhat by a fair amount of UK-specific content). Thing is, these foreign magazines are hideously expensive in the USA - like $10 an issue at a newstand.

Not to highjack my own thread but what is it with the Brits anyway? They've got crap weather, insanely high prices and rampant bike theft and yet they ride bikes (both motor and pedal powered) as though their Island is some kind of biker's paradise. I admire the spirit - I just don't understand it. Kudos to you Brits and your mags!
 

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Rider and Wrench
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Clones123 said:
I could have sworn it was MBR instead but I flipped through some recent issues and it was actually What Mountain Bike that got me onto the issue of shorter stems and wider bars.

When I rode motorcycles it was the Brit magazines that were by far the best. Same with mountain bikes now - Mountain Bike Rider, Mountain Biking UK and What Mountain Bike each have awesome content (blunted somewhat by a fair amount of UK-specific content). Thing is, these foreign magazines are hideously expensive in the USA - like $10 an issue at a newstand.

Not to highjack my own thread but what is it with the Brits anyway? They've got crap weather, insanely high prices and rampant bike theft and yet they ride bikes (both motor and pedal powered) as though their Island is some kind of biker's paradise. I admire the spirit - I just don't understand it. Kudos to you Brits and your mags!
I agree WMB and MBUK are great mags- tought to find sometimes and like you said $10 bucks pop! Ouch- grreat info though and no @ss kissing to anyone- just telling it as they see it.
 

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singletrack bound
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I think you may be feeling the difference in wheel size...29" HT to 26" squish. The 26" would probably have quicker steering characteristics all components being equal.

Stem and bar will have the same kind of effect too! I think you will see a difference running the 100mm stem over the 120 on the 29er. :D
 

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Snapper
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Short and wide

Shorten that stem mate and reap the difference in handling. Hell l used to run 120/110mm stems with 690mm bar. More allround position rather than long and low for XC. I have been able to reduce (overtime) my stem to 90mm and bar increased to 750mms. going to try a 70mm stem. Love the increased control in technical terrian and have learnt to shift weight forward for the steep climbs. Ride Jones and Blacksheep bars on other rigs which l like but not for everyone.
 

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Master of Disaster
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Discussion Starter · #8 ·
johnd663 said:
I have been able to reduce (overtime) my stem to 90mm and bar increased to 750mms.
750mm?! Whoa. I didn't know they made bars that wide. At least not for sale in North America. I'm pretty sure that standard spacing between pine trees in Georgia is less than 750mm (or at least it seems like it). Now, down in Melbourne no doubt a lot of things are different...

Like, is "Foster's" really "Austrailian for beer" like they claim on TV? :p
 

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Snapper
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Damn straight

Clones123 said:
750mm?! Whoa. I didn't know they made bars that wide. At least not for sale in North America. I'm pretty sure that standard spacing between pine trees in Georgia is less than 750mm (or at least it seems like it). Now, down in Melbourne no doubt a lot of things are different...

Like, is "Foster's" really "Austrailian for beer" like they claim on TV? :p
Foster Australian for beer, hell no, that stuff is cat piss that is only for export........ we dont drink it here....... send it overseas to prop up your cat piss beer market. There are many misconceptions about Australia floating around but we do train kangaroos to deliever mail in the outback and koalas kill more Aussies than White Sharks.
Everyone here rides really wide bars. So much so that trails are built exactly 780mm wide for clearance or we learn to mono through trees while turning bars. Look at Sam Hill, Graves, Chris Kovorac (spelling), Rennie, Cadel and sick Mick. They all got good at riding downhill by learning to commute with really wide bars, hungover on Fosters smuggled in from US while avoiding koalas that drop from the surrounding trees and buildings and gauge out the riders eyes. Bit like the Johnny Cash sond "Boy named SUe" but instead once the trainer wheels come off the really wide bars go on and fend for yourself kid.
Now l imagine things are alittle different here in Melbourne to North America. We have 8 of the top ten most deadly snakes on the planet, 6 of the worlds killer spiders and the koalas. If you want to ride a bike around here you have to be fast. Then add to that the fact that mountain bikers are like Gods / Godesses to the opposite sex and it is not uncommon to be ambushed by a bevie of beauties while riding to the shop. MTBer are often abducted and held as sex slaves for catwalk models who devour their prey like the Mountain Devil Roo native to the area.
So if you want to get fast ......... chuck on some wide bars, an Australia Wallabies jersey and some extra iron tablets and go ride. Just watch out for the drop bears and swimsuit models.
Riding in terror
Always
JD
 

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Back on topic I am a big fan of shorter stems I bought a 60mm to put on a Voodoo hardtail it's now on its third frame a Gunnar. A friend picked up a Salsa that came with a 120 he didn't really like the way it handled I think he's down to a 90 now. I put him in touch with a shop that I like to use the guy always keeps some extra stems on hand to allow for test rides until you figure out what works best. When I had a custom build done at this same shop they put me on a trainer to figure out a base line for stem length. When sitting in a comfortable position where are the bars in relation to the front axle. This is just a starting point but I find that if the bars are in front of the axle it feels like you will go over easier. If the bar covers the axle or is just behind it I feel I get a better ride.
 

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Its got what plants crave
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You are using 2.5" riser bars on an XC bike? That probably explains the crappy handling right there. Is the frame too small for you?
 

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Master of Disaster
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Discussion Starter · #12 ·
Doh! 25mm riser bars is what I should have written. Fer cryin' out loud - I'm surprised no one else questioned that. Hardtail beach cruiser anyone?

Here's a photo of the bike when it was still new. I've since inverted the stem to get the bars pretty much level with the seat. Perhaps "XC bike" (race?) doesn't descibe the bike as well to some as "Trail bike" would. Flat bars would be below seat height even with positive angle on the stem. I'd happily move to low-rise (10mm) bars but most of the bars I've seen for sale are either flat or 25mm rise.

 

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Master of Disaster
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Discussion Starter · #13 ·
AZTtripper said:
I find that if the bars are in front of the axle it feels like you will go over easier. If the bar covers the axle or is just behind it I feel I get a better ride.
I hadn't thought much about the bar's position relative to the front axle but, now that you mention it, I have been over the bars several times in the past two months!

Perhaps a shorter stem would lead to less wear on my helmet, eh?
 

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650b me
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@johnd663:

If everyone in Australia is as funny as you, I gotta get down there for a visit! Thanks for the laugh!

(OP, sorry for the highjack)
 

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I'm trying to understand these claims from a physics point of view. A shorter stem gives you more control? quicker steering? Twitchier? More stable?

WHY?
Please discuss:
 

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smilinsteve said:
I'm trying to understand these claims from a physics point of view. A shorter stem gives you more control? quicker steering? Twitchier? More stable?

WHY?
Please discuss:
c=2Pi * r where r is the radius (or stem length) and c is the circumference of the circle (or arc of the stem). Longer stem = more arc to cover.

<this sounded better in my head than it looks in this post>:skep:
 

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noah19692000 said:
c=2Pi * r where r is the radius (or stem length) and c is the circumference of the circle (or arc of the stem). Longer stem = more arc to cover.

<this sounded better in my head than it looks in this post>:skep:
More arc to cover, yes. So more hand movement for a given tire movement. (Good or bad?)
On the flip side, longer lever to resist forces that try to turn your wheel.
I think this is a good beginning to the analysis. Please continue...
 

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noah19692000 said:
c=2Pi * r where r is the radius (or stem length) and c is the circumference of the circle (or arc of the stem). Longer stem = more arc to cover.

<this sounded better in my head than it looks in this post>:skep:
Hey when I look at your post, it doesn't contain a sentence that appears when I quote your post, which is:
this sounded better in my head than it looks in this post
Why is it not visible except when quoting? And then when I post with your quote on there, it doesn't show up????

Is it the > symbols?
 

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noah19692000 said:
c=2Pi * r where r is the radius (or stem length) and c is the circumference of the circle (or arc of the stem). Longer stem = more arc to cover.

<this sounded better in my head than it looks in this post>:skep:
Test test

Sill not there!
:confused:
 
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