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Discussion Starter · #1 ·
Since the search function is broken, can anyone expound on the theory and how the practical difference is in the real world for long top tube/short stem vs. short top tube/longer stem combo?

I currently have a shorter/longer combo (17¨ MC 29er with a 23.7 tt and 120mm stem). I´ve been contemplating how a longer/short setup would work in comparison.
 

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I'm really liking the long TT,shorty-stem setup. Sorry I can't justify it, other than it feels right.
 

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In theory a shorter stem is supposed to make the handling more twitchy. The only place where I have made a direct comparison is on my road bike - I've been playing with the setup on it a little more and decided to go with a larger drop, and so had to switch stems. Went with a massive switch - 110mm to 60mm. Yeah, it is a little more nervous in handling, but nothing I didnt get used to in one ride.

On an MTB, I *love* my long TT/short stem. After my discussion with a couple of other fellas on the EMD9 thread, I was thinking about why. I think I like the way my body is positioned on a bike with a longer TT - I am more "between" the wheels as opposed to being in the front. This feels a lot better to me on fast downhills - I feel better positioned. Plus the longer wheelbase restores adds to the stability.

I switched from a shorter TT/long stem on my 26er to the opposite on my EMD9, and so far, have been thrilled to bits with the result. I ride mostly XC trails - not a lot of technical stuff and no jumps/drops and felt significantly better on downhills with this setup. As for climbing, worked well enough to climb the Himalayas in Bhutan.

V.
 

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also interested...

Being someone who can get away with riding a med or a large, this question is of interest to me as well.

vkalia, do you ever get the sense that the long TT,short stem combo feels a bit truckish or does the steering with the short stem make up for the larger frame feel?
 

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The shorter stem makes lofting the front end easier as well, which can be a chore on steep climbs as the front end takes more effort to keep weighted. On the other hand this can be good on technical climbs where you need to loft the front wheel over obstacles.

I like a top tube somewhere in between most manufacturer's mediums and larges, but given the choice I will go for the large and a 70mm stem.

But there are other factors that matter too, like effective seat tube angle. I like that to be relatively slack without making the reach too long.
 

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suffer fest said:
vkalia, do you ever get the sense that the long TT,short stem combo feels a bit truckish or does the steering with the short stem make up for the larger frame feel?
Well, I have never ridden one of those 22lb racing hardtails so I cannot say how it compares to such bikes. But to me, the bigger frame is a good blend of stability and responsiveness.

It still turns pretty much along the same radius/speeds as before, but perhaps feels a little "heavier" while turning, if that makes any sense. My old bike (which was a 26er, which also affects the perceptions) would feel a lot more nimble on the turn. This one starts into the turn with equal agility, but feels more solid when the rear makes the turn, even though it is the same line and I am carrying more or less the same speed. Some of it is the larger frame, some of it is the larger wheels. Sorry, I am not sure how to describe it any better.

But the larger frame is still very responsive at small/sudden course corrections - there, the small stem really helps.

It is hard to make a good comparison on how a smaller frame with a longer stem would handle, as handling of a 26er is obviously going to be quite different. But I am quite happy with the balance between handling and agility with the bigger frame.

MS is right though - on really steep climbs, it is easy to pull the front wheel up, which makes climbing a little harder. But it is easy to adjust to it - I simply move up a little further to the front of the saddle, which restores the balance. It did take me a couple of rides to get the hang of where to best position my butt.

V.
 

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i should prolly put it in my sig, since i seem to bring it up so often, but don't forget the role of handlebar width in the above discussion.

wide bars (700+ mm for example) will often make a short stem feel just right. wide bars will also help make a shorter top tube feel more roomy.
 

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This really gets into personal preference fast. Typically I run a longer tt bike with a straight post and short stem. I picked up a SC Heckler this spring and was forced to go the other route due to limited tt length of their XL. The main differences are in switchbacks and quick maneuvers. The longer frame is not as nimble. The truck analogy isn't a bad starting reference. A long tt bike even with a shorter stem will corner like an F150 in the parking lot. The longer stem on a shorter bike is more like maneuvering a compact truck. You can get used to either, it is just a matter of which you prefer to drive ;)
 

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Discussion Starter · #11 ·
vkalia and MS... thanks.

My only frame of reference was my old GT Avalanche 26er. And I mean old. It had a longer top tube than was typical on most of its competitors frames of that time. Prior to having that, I rode a friend's Mongoose that was way to small for me, but felt really nimble. I thought it was the smaller frame that gave it that feel.

When I got the GT, I always felt way to stretched out, but it had a longer stem. Once I switched up to a shorter stem, I experienced the things you describe. Clearly, that was just changing stem length on the same frame, but it was dramatic (from a 130 to a 90). So it's not really the same. But I did have the long top/short stem thing going in the end and liked it.

So when going to a 29er, I thought going to a smaller frame would be the answer. Then it took a longer stem to get the reach right. Now the 29er feels like I'm driving a truck again. I didn't think it was necessarily the wheels alone.

The TT/stem has to play in it somewhere. (along with other angles, but most of the bikes I've had have similar seat tube angles). I had that truck-ish feeling with the 26er that went away when the TT/stem difference went the other way. It's just that because it was the same frame with a stem change clouded that assessment.

I have a friend with a XL Redline D660. I might persuade him with beer to let me try a short stem on it and adjust the seat height and see what that feels like. I'm guessing I'll like the quicker, more intuitive (for me) steering.

Time will tell. :)
 

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suffer fest said:
Being someone who can get away with riding a med or a large, this question is of interest to me as well.

vkalia, do you ever get the sense that the long TT,short stem combo feels a bit truckish or does the steering with the short stem make up for the larger frame feel?
It seems to be unanimous. A 1" longer wheelbase is more stable and a stem that is 1" shorter (25mm) more than makes up for the very little difference in how a 1" longer wheelbase steers. From my experience, a longer TT (wheelbase) with a shorter stem not only steers much quicker, but it handles the downhills much better. There is no comparo.
I wish dw would get a fukin clue and stop shrinking every bike he gets a hold of.
 

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I ride rigid, with an 100mm stem. To me it's the perfect compromise between enough weight on the front wheel, and decent leverage to hoist that front wheel.

While I think this is fairly personal, like a lot of things, I think a short stem is used by most to overcome lack of skills in technical/steep descents. If you ride ride in areas where you have long chill uphills, and raucous knarly descents that go on and on, sure, short stems make a bit of sense on cross country bike. That said, what's the trade off? Personally, again, I think feel is lost. The best tracking, carving bikes I have ever had were bikes with stems at least 100mm and slightly shorter top tubes (my old Fat Chance, being a prime example). If you go back a ways, like the early 90's everyone rode 135s. Those bikes just railed, like your roady rails. Something to do with weighting that front wheel. The combination of front weighting and slower steering is really kind of nice in flowly riding. Ya' just lean a bit more and... carve. Of course I may just be suffering from all those performance dehancing substances I enjoyed while riding in the 80's and 90's.
 

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olapiquena said:
While I think this is fairly personal, like a lot of things, I think a short stem is used by most to overcome lack of skills in technical/steep descents. .
Funny, I say the same thing about 29er riders.

olapiquena said:
Personally, again, I think feel is lost. The best tracking, carving bikes I have ever had were bikes with stems at least 100mm and slightly shorter top tubes (my old Fat Chance, being a prime example). If you go back a ways, like the early 90's everyone rode 135s. Those bikes just railed, like your roady rails. Something to do with weighting that front wheel. The combination of front weighting and slower steering is really kind of nice in flowly riding. Ya' just lean a bit more and... carve. Of course I may just be suffering from all those performance dehancing substances I enjoyed while riding in the 80's and 90's.
You must keep in mind that this is the 29er forum. Those examples are of 26er bikes. 29ers have steeper HAs so you should run a shorter stem in order to keep the same amount of weight on the front tire.
I run a 100mm stem on my new XXL Sultan and this is the shortest stem by far I have ridden to date. If the TT was a bit longer I would have gone to 90mm. BTW, this bike rails the corners and steers quicker than any 26er I have ever ridden....mostly because of the too long 135mm stem that was required on the 26er bikes of old.
 

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Discussion Starter · #15 ·
yogiprophet said:
It seems to be unanimous. A 1" longer wheelbase is more stable and a stem that is 1" shorter (25mm) more than makes up for the very little difference in how a 1" longer wheelbase steers. From my experience, a longer TT (wheelbase) with a shorter stem not only steers much quicker, but it handles the downhills much better. There is no comparo.
I wish dw would get a fukin clue and stop shrinking every bike he gets a hold of.
This makes sense to me and something I will explore further. Even though the end reach might be the same, the steerer tube is roughly an inch closer to the rider. I think (perhaps incorrectly) that moving that steerer tube out might bring more stability even in the low-speed technical stuff as well.

PS -- who is dw???
 

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There's truth to both arguments. Weighting the front wheel is just as important in mountain biking as is unweighting it--especially in racing.

Personally I like the handling with a bar about 26 inches wide with a 90mm stem for all around cross country riding and some racing. But I tend to shy away from extreme handling traits in most aspects of bike setup. So I dislike 50mm stems and ultra wide bars almost as much as I hate 22 inch bars and 120mm stems.
 

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racerdave said:
PS -- who is dw???
dave weigel is the creator of the dw-link rear suspension. He is also known for steering bike makers into making their bikes shorter...everything he touches shrinks. Rumor has it that the poor guy can't even find his weiner anymore when he need to pee.
 

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If you were in Utah, I'd definitely would like to lend you my bike and switch back and forth. I have a large Monocog and wonder how the ride would differ on a medium. I'd like to try out a few trails to see what the difference would be.
 

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yogiprophet said:
It seems to be unanimous. A 1" longer wheelbase is more stable and a stem that is 1" shorter (25mm) more than makes up for the very little difference in how a 1" longer wheelbase steers. From my experience, a longer TT (wheelbase) with a shorter stem not only steers much quicker, but it handles the downhills much better. There is no comparo.
I wish dw would get a fukin clue and stop shrinking every bike he gets a hold of.
I will take the other position.

For me the important thing is where my hands are in relation to the front axle (and the front axle in relation to the BB). This sets my weight on the front end the way I prefer.

If you go strictly by total reach of the TT/stem (and bar) (and given the same HTA), a long TT/short stem puts the front axle further forward relative to the rider than a short TT/long stem. Add in the HTA and a slack head tube pushes the axle even further forward than a steeper HTA.

IME when the axle is too far forward, no matter what the HTA, TT or stem length, The bike will not corner well. I intentionally use "corner" rather than "turn".

Cornering is how the bike moves through the curve. Tracking, front/rear grip, holding the intended line. Too little weight on the front and it drifts out and requires more steering input (understeer) or even washes out. Too much weight forward and the rear wheel may drift out more than wanted (oversteer) or the front wheel can tuck under and you high side/endo.

Turning is the initial turn in or just the simple input to maintain a "straight" line. Lighten the front end and it is "quick" and easy to change direction--intended or not. Some call it "twitchy", some wandering. More weight can stabilize the steering and improve the tracking.

You need to find the balance where the tracking/turn in is easy and accurate and the bike carves the curves.

My overall fit/position allows me to easily shift my weight as needed for the situation--up, down, flat--in or out of the saddle. This, of course, requires looking at the whole bike/rider geometry and not just a couple of isolated dimensions. I do not change my fit/position for wheel size, though the steering geometry does need to be adjusted to match the choosen fork and wheel.

To comment on DW, it seems his preferences are similar to mine. Moving the weight forward (balanced IMO) makes the fork more active along with the other things I have outlined. He is looking at the total performance of the bike/rider/suspension/terrain interaction.

If you want pure DH performance shifting the weight back makes sense as the bike is functional "steeper", and more forward on the descents. Not what I want for an all-round trail bike, though.
 

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Discussion Starter · #20 ·
p nut said:
If you were in Utah, I'd definitely would like to lend you my bike and switch back and forth. I have a large Monocog and wonder how the ride would differ on a medium. I'd like to try out a few trails to see what the difference would be.
I´d be more than happy to do that because it would mean 1) I lived in Utah (gorgeous and tons of great riding), and 2) we could do the comparo.

Alas, I live in Wisconsin. Could be worse places to be, however.

It will complicate the ride swap though. :)
 
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