Long TT short stems?

[stephenmarklay]

I am curious with all of the different style of bikes now available with varying TT measurements (Gravel grinders, adventure) and the fact that MTB bikes have migrated to shorter stems and long TT what are you guys doing?

I have always run thought about 10cm to 12cm stem meant that your TT was ‘’about right” if the your fit was good (comfy for your purpose.)

However, I am wondering if that is just convention. I have a cheap 1990 hybrid Schwinn that I have been commuting with and today I did a 30 ride about half gravel. It did better than I would have expected. It has a 56cm seat tube and 60 cm TT. The stem is this goofy looking 30 degree riser so the true extension must be 7-8cm. It is super stable and made grinding a no brainer.

So are long TT and short stems the new trend but perhaps not new thinking?

[wallymann]

i think for MTBs and grinders, the longer TT is more about handling/balance when traction is sketchy.

longer TT means you'll tend to have a longer front-center, with the front-wheel more "out in front" instead of right under your nose. when a front wheel is more heavily loaded and traction is light, when the front end goes it tends to go quicker with undesireable results. stretching out the front-end and lightening the loading makes the front-end somewhat more forgiving.

there's nothing new about it, but fisher's "genesis" geometry was a recent effort to actively market it as "something new".

[fiataccompli]

shorter torso & longer legs puts me on the short end of the traditional "ok" stem length spectrum of road bikes often. Funny, I was thinking the other day of putting a 85mm stem WTB post up. The geometry/handling explanation above makes perfect sense to me.

[CiclistiCliff]

Shifter shapes and bar reach can also affect stem length, making some bikes look very odd. Shimano's 105 hydro shifters are so long most customers are dropping to 2cm shorter stems as bike manufacturers spec the same stem length no latter what hood shape/lenghth is like.

[stephenmarklay]

Shifter shapes and bar reach can also affect stem length, making some bikes look very odd. Shimano's 105 hydro shifters are so long most customers are dropping to 2cm shorter stems as bike manufacturers spec the same stem length no latter what hood shape/lenghth is like.

Yeah that makes sense.

[stephenmarklay]

i think for MTBs and grinders, the longer TT is more about handling/balance when traction is sketchy.

longer TT means you'll tend to have a longer front-center, with the front-wheel more "out in front" instead of right under your nose. when a front wheel is more heavily loaded and traction is light, when the front end goes it tends to go quicker with undesireable results. stretching out the front-end and lightening the loading makes the front-end somewhat more forgiving.

there's nothing new about it, but fisher's "genesis" geometry was a recent effort to actively market it as "something new".

That’s kind of what I figured.

[bmeryman]

The trend toward longer TTs and shorter stems on mountain bikes has been accompanied by (or followed) wide bars. Somewhat by necessity. But there's certainly something to be said for the quicker steering response of a shorter stem. If you're interested in reading a whole manifesto on the merits of short stems, check out Pacenti's here: http://pdent.pacenticycledesign.com/

It's definitely an aspect of bicycle geometry that I think will see more widespread attention in the coming years. More than just mountain bikes, I mean. I'm curious to see what happens. I'd like to do some experimentation myself with different cockpit setups.

[carpediemracing]

I'll post a counter-thought.

I understand and acknowledge that for off road a shorter stem works for me, although I haven't had much time on such a bike (Bontrager or similar). With my long torso + short legs I've always run a 15 cm stem and it looks 5-8 cm too short. On steep descents (I never did drop off per se) I always felt uncomfortable, too far forward. Definitely more of a chance of a header.

On the other hand, on the road, I want more weight on the front wheel. In turns I'm always looking to move forward, weight the front end more. This is for mainly flat or slightly downhill corners at speed. For uphill, I don't go fast enough for it to make a difference.

Based on pictures of my (custom) bikes it seems that I like the drops to be over or just in front of the front axle.

To be fair I got unnerved the first time I did a long steep/switchback descent with my longer custom frame bikes. The descent is the steeper one off of Palomar, which for me is a 35 minute descent and 2 hour ascent. After the first time I was fine. I'll point out that the Palomar ride was one of the first ones on the custom frame, and I was getting used to the extra 5-6 cm in effective length. In fact it unnerved me that when climbing/not-sprinting out of the saddle my thigh didn't hit my bars on every pedal stroke. This was something I experienced since day one, about 27 years prior, and at first I regularly had these mini-panic attacks that my bars or stem had become detached from the steerer (because no bar brush on my thigh).

[David Tollefson]

This only applies to bikes I've built for myself, but I've gone to 70mm stems for anything off-pavement, and 90 on-pavement. I like the feel of the long and slack front end. My crit days are long behind me.

[benb]

I have an 80mm stem on my All City Space Horse. I've rode it with a 70mm stem too. I ride this bike in the dirt quite a bit.

I needed to do this to make it fit. I have a 58cm frame, it's too long. The next size down is 55 and would have needed a lot of games to get an acceptable drop to the bars. When I ride it on the road I can't discern any bad behavior at all at speed even with the 70mm stem. My gut feeling is the roadie claim of needing the longest stem possible is more fashion than physics. In fact this bike I had more trouble with high speed stability with the longer stems. (I rode it with 110mm and 100mm stems for a long time.)

It pretty much works fine everywhere I would just say it still isn't as good as a bike that would have had a more ideal geometry. If anything lets it down it's really tight singletrack stuff where it's really just the wrong bike. It does great on gravel & sweeping dirt trails that aren't super rough and twisty.

My MTB has a 61.3cm effective TT, it's an older bike. I have two stems IIRC that I have run on it, one is a +6 degree 110mm stem and the other is a +17 deg x 100mm stem. It is definitely better with the shorter stem. Front wheel is more predictable. For whatever reason that bike will change lines in the blink of an eye compared to the All City.

I am tall with a shorter relative torso, I've never really used a stem longer than 100mm on any of my road bikes for the most part. 56cm TT with a 100mm stem is about perfect even though my saddle height is just shy of 78cm.

[zap]

Shifter shapes and bar reach can also affect stem length, making some bikes look very odd. Shimano's 105 hydro shifters are so long most customers are dropping to 2cm shorter stems as bike manufacturers spec the same stem length no latter what hood shape/lenghth is like.

In many cases, short reach handlebars offset the long hoods.

[fiataccompli]

Maybe it's my torso, maybe it's more modern hood shapes, but I've trended towards converting everything I ride regularly to "compact" short reach bars.


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[carpediemracing]

I am tall with a shorter relative torso, I've never really used a stem longer than 100mm on any of my road bikes for the most part. 56cm TT with a 100mm stem is about perfect even though my saddle height is just shy of 78cm.

My saddle height is 67.5 cm so about 10 cm shorter than you.

My TT is 56.5 cm (with a 75.5 deg STA so it's pushed forward a bit) and I run a 145 mm stem.

[carpediemracing]

Maybe it's my torso, maybe it's more modern hood shapes, but I've trended towards converting everything I ride regularly to "compact" short reach bars.

Not directed at you in particular but I'm wondering, are people going to compact bars to reduce reach? Is that one of the "benefits"? In other words are people riding bikes that are too long or too aggressively dropped up front?

Or is it shape, bar design, etc.?

When I went to compact bars it was a big deal to get the reach/drop the same as before. Is everyone going with 3 cm longer, 3 cm more drop stems, which is typical when going from a 11 cm reach / 15 cm drop regular bar to an 8 cm reach / 12 cm drop bar?

[ColonelJLloyd]

Same boat. My saddle height is 80cm (170mm cranks) and there are very few frames I've had on which I needed a stem longer than 10cm. I use randonneur bars on a lot of bikes and a Deda Deep Drop on my go-fast. Lots of modern drop bars have really short reach (probably to compensate for evolving integrated shifter design). There are just several variables. The bars I ride have ~12cm reach and 13cm drop as opposed to the 8-10cm reach of compact drops.

All things equal I'd rather have a longer TT and shorter stem (within reason) as I've never felt comfortable with my hands and the weight they're supporting being (or at least feeling like they're) ahead of the front axle. But I have three vertebrae fused together in my lumbar so I don't now and will never have an aggressive fit. I'm just not flexible enough for that.

<snip>

I am tall with a shorter relative torso, I've never really used a stem longer than 100mm on any of my road bikes for the most part. 56cm TT with a 100mm stem is about perfect even though my saddle height is just shy of 78cm.