Mountain Bike Reviews Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
496 Posts
Discussion Starter · #1 ·
What frame options with kinda geo. One thing i love about my 26" HT is the more aggresive geo, with more lean forward and less upright feel. Been thinking about a DOS or a El, and am thinking running a 80 mill fork would give this feel, but the better option would a frame around 100 but with the agressive geo. Does it exsist non-custom?
 

·
Uncle
Joined
·
4,388 Posts
The simple answer is in the HT angle. Many (most?) 29ers out there have a 72 deg HT angle, which is fairly steep, and can be set up fairly aggressively with the proper cockpit arrangement (short fork, flat bars, neg. rise stem, etc.) Some folks find this on the twitchy side, but at least from what you've posted here, it's the kind of feel you're after.

Kona, Spot, GF, Raleigh and a few others have slacker HT angles. Pretty much all others that come to my memory-limited mind are in the 72deg range.
 

·
Registered
Joined
·
821 Posts
How tall are you? It is about saddle height vs. fork length plus head tube length vs. stem/handlebar setup.

(I do not think HT angle has any influence. On steering: Yes. On the range of possible positions on the bike: No.)


If you are very tall, you should be able to get lots of saddle-bar drop with a 100mm fork, a reasonably sized head tube, a down turned stem and a flatbar.

At the other extreme, if you are small, the only way to achieve any saddle-bar drop at all is a shorter fork, frame designed with a short head tube, low stack headset, no spacers under the stem, a down turned stem and a flatbar.

What you can do is search for a frame that most of all is the correct size for you and the short head tube, low stack 'hidden' headset and a 80mm fork that can be set to 100mm too (RS, Fox). If you find your handlebar sits too low, you can allways add a handlebar with rize, travel to the fork, spacers under the stem (if you did not cut the steerer tube too much) and turn the stem upwards.

So, the question on your answer depends on your saddle height and the amount of saddle-bar drop you want, but think twice: There are possible downsides to a low and forward position. Get it too low and bike handling will suffer. Get it too far forward and your leaning on your arms a lot and there is a risk of lower back issues.

Get fit on a bike by a good fitter!
 

·
Registered
Joined
·
760 Posts
There are two ways to get a more aggressive XC riding position. I will bring up Lance and his Leadville bike again. You don't need a handlebar well below the saddle to achieve a stretched out position. LA doesn't. You need a large bike with a long top tube and long stem. Head tube angle and even steerer tube length can be worked around...even with 100mm fork stroke. I ride this way in fact..not much drop but stretched out which I prefer for high speed XC riding. My nominal position with hands in the middle of the grips is with a back angle of 45 degrees in profile which btw is a std. road bike position on the hoods.
45 degree back angle with slightly bent arms on a mountain bike used to be the standard and for me it still works the best and same for my road bike which many believe should be set up the same as a XC mountain bike albeit with very different top tube length ~4-6mm longer for mtb due to backswept handlebars. (hood position on a drop bar is 80mm in front of stem clamp center depending on the bar shape) If I ride with a shorter cockpit, I not only lose power but am less comfortable and feel cramped...spine is more in compression and gets pile drived more, more weight on the saddle etc.
 

·
Registered
Joined
·
1,367 Posts
I am starting to toy with this right now and would like to get to about 1 inch saddle to handlebar drop, and similar to the simialr to advice of above and going to be getting multiple headset spacers, and trying a 0 degree stem vs the 6 my bike came with might also try to flop for negative 6 but that seems extreme, but will probably try just to see. Also when i get the new stem I think I will try to get one 10-20 mm longer and move my seat up this might also help with climbs.

I am not buying new handlebars yet but might see later.

By the way I am 5'7 riding a small GT Zaskar 9r any adice would be taken. Not doing this because I dont like the bike now just really trying to fine tune at this point, currently have handlebars sit about one inch higher then seat and I have the seat far back, I have thought maybe i needed a medium frame but I really like the standover clearance and the ETT seems good where I am at so longer stem emans moving seat forward.
 

·
Registered
Joined
·
496 Posts
Discussion Starter · #9 ·
Thanks for the input. I think I have a few ideas. I understand the "twitchy" and back issues replies. But I am familiar with that. This is what I am used to riding on my 26" bikes, and the one thing that keeps me away from a true 29" HT is the position. It seems most 29er frames have a extremely sloping TT to help with stand over issues, and on the different 29ers I have ridden and borrowed I can't get the saddle high enough to find my normal leg extension I'm used to, and the saddle to bar drop I like. There is only so much seat post you can have before it gets unsafe. I am 6' even barefoot, with a pant inseam of 30," I guess normal build.

To get the dimensions I want, I'm thinking I may need to go custom, or stick with another 26" build.
 

·
Registered
Joined
·
2,710 Posts
I don't think this would be so hard to achieve on a 29er. Most 29er have a relatively longer top tube than a 26er, to avoid toe clip overlap among other things. This will help get you stretched out. They also will have a taller front end, but most have quite short head tubes to make up for that.

I'd suggest an '08 or earlier Mamasita. Those had long top tubes (longer than the Dos Niner), a steep head angle, and a not so severely sloping top tube.
 

·
Registered
Joined
·
10,039 Posts
jmadams13 said:
Thanks for the input. I think I have a few ideas. I understand the "twitchy" and back issues replies. But I am familiar with that. This is what I am used to riding on my 26" bikes, and the one thing that keeps me away from a true 29" HT is the position. It seems most 29er frames have a extremely sloping TT to help with stand over issues, and on the different 29ers I have ridden and borrowed I can't get the saddle high enough to find my normal leg extension I'm used to, and the saddle to bar drop I like. There is only so much seat post you can have before it gets unsafe. I am 6' even barefoot, with a pant inseam of 30," I guess normal build.

To get the dimensions I want, I'm thinking I may need to go custom, or stick with another 26" build.
What bikes in what sizes have you tried? There is no reason you shouldn't be able to get the full saddle height that you need. Most large size 29ers have ~19" seat tubes, regardless of top tube slope. In fact, the slope can be deceiving compared to what you know on 26" bikes because the fork height means they have to slope up to a higher position up front

Bar drop relative to your proper saddle height is another issue and it will never be the same on a 29er as a 26er. A 29er fork is typically around 30mm longer than a 26er fork of the same travel, and the whole front end is sitting on a hub 1.5 inches higher off the ground. So even an 80mm 29er fork setup will still be taller than a 100mm 26er setup. Getting a large amount of bar drop can be hard and can take a careful selection of parts, depending on the length of the headtube
 

·
Ride to the ride.
Joined
·
360 Posts
Less upright, more agressive xc oriented geo?

Is the aggressive rider the one climbing at 3 mph up a steep incline, dripping sweat, balanced on the anaerobic tightrope? Or the one plowing through a pile of toaster-sized scree leading to a drop?

Most of the aggressive riders I know ride very upright.

Yes. I'm being a snit.

I come from the long, low reach school or riding. But I'm being reformed. (Very, very slowly.) It is possible that I go faster and with more control now that I sit up more -- stiff headwind excepted.

I don't think that a 29er bike excludes you from an XC position. My friends were happy to mock my Fisher HiFi position. Flip the stem downward for more of that.

I've had a chance to go back and forth between "XC" position and more upright positions over the last couple years -- usually with a corresponding slight slackening in bike angles. Each time my personal conclusion was that I was WAY more in control when sitting up. And had way more fun. And I didn't feel any faster leaning over. (I ride for "feel" not for clocks, so... take that as you will.)

Here's a little observation I shared (per 26" bikes, but more per position):
http://forums.mtbr.com/showthread.php?t=573837

I'm only half-reformed on my position. My new Rumblefish is more upright than about any bike I've ridden, and I still have more reach than my peers. I'm still mocked for my long reach. But it's a higher long reach. And not as long.

So... Just sayin'. If that's what you want your bike to be like, I see no reason you can't have it on a 29er. But, hmm. Maybe there's something to all this evolution... And it probably all depends on where and what you ride.

--Greg
 

·
Registered
Joined
·
173 Posts
Im running a -17 degree thomson stem on my Niner to get the handlebars lower. Ritchey also makes a -17 degree stem, but it is flexier although lighter than the thomson. I am able to run about a 3 inch drop which works pretty well, on my 26 inch bikes I ran about a 4 inch drop, but the 3 inch feels good on the 29er.
 

·
Rider and Wrench
Joined
·
1,478 Posts
jmadams13 said:
Thanks for the input. I think I have a few ideas. I understand the "twitchy" and back issues replies. But I am familiar with that. This is what I am used to riding on my 26" bikes, and the one thing that keeps me away from a true 29" HT is the position. It seems most 29er frames have a extremely sloping TT to help with stand over issues, and on the different 29ers I have ridden and borrowed I can't get the saddle high enough to find my normal leg extension I'm used to, and the saddle to bar drop I like. There is only so much seat post you can have before it gets unsafe. I am 6' even barefoot, with a pant inseam of 30," I guess normal build.

To get the dimensions I want, I'm thinking I may need to go custom, or stick with another 26" build.
I am just under 5' 10" and have a ~29-30" inseam (Just an observation but you would probably like a large 19-20" frame as you may have relatively long torso/arms which helps account for your feel of a "shorter/relaxed position) and have ridden a number of different 29er's and each is as different as any 26" bikes I have owned form race oriented HT's to fairly lax 5" F/S.

Over the past few years the "up-right" position has become much more popular for "aggressive" riding in the sense of rough/technical trails so that the rider can move around a bit more. I am guessing you are looking to dublicate the "aggressive" race geo of many 26" HT's. I am not sure what 29ers you have been trying out but just like the 26" bikes there are some 29er HT's that lean toward a "race" geo vs a "trail" or whatever one wants to call it???? Some 29ers also feel like you ride almost "in the bike while others are more "on" the bike-

The feel you are looking for is not just seat drop, top tube, head tube etc... it is a bit of a combo of them all- Ironically the HT geo on a current 29er is pretty close to older "twitchy" 26 race wippet bikes- I have been surprised how much the "stretched" feel you seem to want can be achived by running a bit wider bars (at least wider than the 22" guys on your current bike....;) ) I run a few different widths on 29ers depending on the bikes geo/stem/top tube length- anywhere from 22-23 1/2" is what I ride-
 

·
Registered
Joined
·
82 Posts
dirtrider7 said:
...You need a large bike with a long top tube and long stem..not much drop but stretched out which I prefer for high speed XC riding. My nominal position with hands in the middle of the grips is with a back angle of 45 degrees in profile which btw is a std. road bike position on the hoods...If I ride with a shorter cockpit, I not only lose power but am less comfortable and feel cramped...spine is more in compression and gets pile drived more, more weight on the saddle etc.
This could well be the most intelligent and informative post about riding position I have ever seen on mtbr.
 
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top