90 or 100.

and, actually for anyone who says it makes a difference: it doesn't. It never will. You get used to it and you adapt. People who believe that it does might as well take a seat next to the people who still think that Carbon will spontaneously explode in a fireball.

The total wheel base of your frameset and particulars of the fork have a bigger impact on the handling than your stem ever will.

_________________
Exp001

This is only half of the equation right? Bars come in various reaches from about 70 to about 90. FWIW, I'm a smaller guy and run a 90mm stem on an average reach bar of about 80mm.

It does make Difference. The longer the stem the longer the lever arm. Also changes your balance on the bike. How big the difference is relative to other things and whether and how you adapt is another question.

Sent from my HTC One X using Tapatalk 2

_________________
----
power2max

Wheel base would make a bigger difference. You can only adapt so much with that, but ultimately that's bigger factor.

_________________
Exp001

Well, I started with 110 some time ago, changed to 120 for a short while and 'been running on 130 -6° for a year now, and I like it. I've switched a few times between 120 and 130 but I like 130 more
I have a small reach handlebar.
I'm 183 and frame size 56.

My knowledge comes from people who design and build bikes for a living. I now am lucky enough to test ride them (hopefully for a living too).

Talking in absolutes, especially in cycling, is a pretty big call to make.


*just to be clear, not at all saying it makes bikes unrideable. It does however make a difference.

_________________
Baum Ristretto, Baum Mondrian Corretto & the '89 Merckx! | "If you could eat it in one sitting, hold your line." | twitter.com/Tinea_Pedis

Best post of the day.

You are absolutely right there, I shouldn't have stated an absolute.



Ditto, actually. Maybe not on the scale of Baum, but they're frame makers and designers as well. One of them works for Specialized... okay, so he's on the scale larger than Baum, the other two are local builders. The verdict, by all accounts, is that stem length might make someone think one build is sluggish vs. another, but it really becomes a moot factor that the body adjusts to. The body & brain won't be able to adjust what determine's the frames properties though: wheel base. If the bike is longer, particularly if the fork has a lot of offset, it will tend to feel "sluggish" compared to one with a smaller wheel base or shorter rake, which will veer towards being called "twitchy". Change stem lengths and there might be a temporary change in feedback from the rider until a few miles in when they figure out how to steer with the new position of their hands relative to the steering tube, but that still does not affect the bike's wheel base itself. Smaller bikes: better handling (see also "nimble around corners"). Longer bikes: more stability (see also "sluggish around corners")

A good metaphor would be this:
F1 Driver. Same engine, Same driver, Same level of aero, same width of car, Same steering interface. Yeah?
-Shorter wheelbase, driver will say "very nimble, twitchy response"
-lengthen that sucker out to a limo and the driver will say "sluggish in turning"

If you keep the wheelbase the same and just adjust the radius of the steering wheel (same affect as length of stem: more/less distance/effort needed to rotate), the driver may say something at first but will adjust to what they have there and, in the end, the comments on the vehicle will be as they were before the change (for the most part).

It's the wheelbase that is a larger factor.

Back to the bicycle world:
Take a touring frame vs. a race frame down the same descent. It really doesn't matter what length of stem you are riding on either one: the touring bike will have a longer wheelbase and be, by comparison, sluggish, and the race bike will be, by comparison, nimble/twitchy. Switch riders, the bike will handle the same. Sure one rider might be stretched out on a stem too long for them, but the handling of the bike will be the same regardless of the rider.

That's what my contacts say. I'm honestly interested in what Baum has to say about wheelbase being a factor compared to length of stem.

_________________
Exp001

Well, we've got Nick Crumpton and Parlee on this board often enough, let's see what they have to say.

_________________
Exp001

Completely agree w/ prendrefeu.

But to answer the original question - 110. Also switched from -6 to -10 degrees and did not notice much of difference.

Riddle me this Batman: why are DH stems so short? Keep the weight back on the rear wheel?

_________________
Fear is healthy, panic can be deadly

110mm and -6 degrees for me. I doubt you notice +/- 10mm either side of what fits you as fas as bike handling goes.

Sent from my HTC One XL using Tapatalk 2

_________________
N+1 It Never Stops

I agree with prendrefeu. When turning lets say downhill at 60 kph I bank my bike like a motorbike. So the wheelbase will matter in this situation. But when turning tight corners or making a u turn that's the time I use my bars

I use 100 mm

_________________
Cervelo R2.5
Cervelo P2c
Cervelo R3
Parlee Z3
Parlee TT

I agree also, makes little difference. I have a 90 on one bike and 100 on the other and they both have the same relative geometry.
I actually feel as if the 90 is currently too short but do feel it is stiffer. I actually have different bars on the two bikes with a lot more reach in the bars on the bike with the 100.
I ride both and don't feel any difference in steering between them.

yes. or more accurately, to keep the weight evenly distributed when the trail pointing down. on those bikes, and any big-hit type, on flat ground, i feel like i really need to load up the front wheel when entering a corner or itll just wash out.

my stems- 110,-6 on my road bike, 110,-17 on my mtb.

Baum's (and others I've spoken to, bike fitters as well as ) thinking is in relation to weight distribution and weight over the front wheel axle.

There is then pairing that with a suitable rake.


Was lucky enough to have my 595 geo copied but with 10mm out of the top tube and added to the tem. Wheel base the same. Felt more stable on the bike with the longer stem as opposed to the 595. Everything else was exactly the same.


With your touring bike example, you'll find they actually tend to have a great BB drop - which really makes them a stable rocket going downhill. Again, we know this as we've done 'touring' type bikes (not a huge wheelbase as panniers weren't wanted, just a rear rack) and they were unreal to take down a decent.


Not saying stem length is the be all and end all, however (for me at least) there is a difference. And is only one part of the bigger picture.

_________________
Baum Ristretto, Baum Mondrian Corretto & the '89 Merckx! | "If you could eat it in one sitting, hold your line." | twitter.com/Tinea_Pedis