Helpful ReplyHot!Better road vision, & fit, & control: why you want a longer lower stem & custom bars.

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Crit Rider
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2013/10/14 13:00:26 (permalink)

Better road vision, & fit, & control: why you want a longer lower stem & custom bars.

This was a reply to Dan's descending video, but its something I have been wanting to write about for a while. I'll likely add pics and maybe a calculator to it and make it a post on the Bent Up Cycles Blog
 
Dan, and myself, and many others have discovered that as you recline more, you need longer bars, and even a stem will less forward extension. I can get to about 21 degrees with a EM seat on my CA2 with the shortest stem and longest bar that Bacchetta makes. But, the bars are too high for good road vision, and the holding the long bars at the ends, I start to notice a bit of flex. I only notice it at very high power levels trying to keep straight in a pack of criterium racers, but its there. My first change to address this was the longest 2 piece stem Bacchetta makes (107mm forward extension, and custom longer stiffer bar. It solved the stiffness issue, but at a 20 degree seat angle on that bike I wanted the bars lower yet. About this time Rich Pinto was experimenting with this for JT and himself, and then for Kristy as well. Kristy and Rich are below 20 degrees for seat angle and I think JT is still under 10 degrees. 
 
I also remember JK being very particular about his bar height setting up for his 516 miles solo RAAM Q at Sebring. Having the bars at or below shoulder height reduces total frontal surface area. It should be faster, but noone that ai know of has backed this up with data. 
 
Even if you are not that laid back, the lower your bars are the better your forward vision will be. 
  
If you really want to do it right, you want your bars as far forward as possible as your shins slope down to the front. To do this, on a M frame CA2 (or Corsa or Strada with a 12.5" boom), you need a stem with ~6" of forward extension, and of course longer bars to get back to your hands. The bars need to be stiffer too, in order to maintain good steering control no matter how quickly your steering input. Longest stems from Bacchetta, center to center, measured horizonatally: 
  
Old one piece: 95mm  
Newer 2 piece: 107mm 
Pipe and DF stem: 130mm, maybe 140mm depending on manufacturer.
  
A 6 " stem is 152mm long. The limiter to going any longer is your feet, crank length and anything mounted to the front of your bars. The 6" number works well with human sized feet and 170mm cranks on an M frame. I have a L frame, but a GoPro on the front of the bars, so I run a 6" stem now too. Without the GoPro I would want a 7.5" stem (190mm).  I have  bike with a 15.5" boom, on that bike I would want a 9" stem or 7.5" with the camera on the bar. 
  
Mark Power at Power On Cycling can make both for you. I recommend a one piece stem though, as you will be dropping your bars so much that there is not room for the height of a 2 piece. He makes the bars ~26mm all the way back to just before the grip zone, then 22.2mm so you can install controls/grips. You can even get them in U or V shape, and you name the dimensions.  I had mine made slightly V shaped to fit in the back of my car better, but used the same downturn angle and length as Bacchetta. I have my bars horizonatal and my hands are right at shoulder height. AFAIK his bars still come in bare aluminium, so you are on your own for anodizing or powder coating. Mine came out great after anodizing. 
 
The other solution for this is tiller bars. I don't like them. You need to use pistol grip or something similar to keep from adding frontal surface with your forearms. KP has been successful with this on his own bike, and he is very laid back, like close too or at 0 degrees. 
  
I will post pics of my CA2. Kristy has been on this setup for closing on a year, and Rich Pinto is also using Mark's bar and stems on a few bikes.  
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Doc Dan
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/14 21:48:00 (permalink)
First, Jim, let me thank you for providing such a thorough description and analysis of the problem. It was because of the `big honkin' riser' that I wandered into the desert of front wheel drive bikes. Only to return to RWD, i.e., the Bacchettas.
 
Second, I want to put my own thoughts in order before I respond.  
 
JK less than 10 degrees?  
 
 
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biker2381
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/15 05:55:35 (permalink)
JV,
Not trying to hijack your thread.
My thinking is that the tiller (AKA hamster bars..I think) is the faster set up, because it puts your arms closer to your body, and there is less arm or handlebar out there exposed to any crosswind. I doubt that a tiller is as comfortable or easy to control, however.  What do you think???

brian
Ft. Myers, FL
2006 Aero
2004 Strada
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Rich Pinto
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/15 11:50:49 (permalink)
   Dan wrote... "JK less than 10 degrees?"
 
    Dan...IIRC, both borrowed Ti Aero's that Jim Kern used for his 2005 490 mile (just a few seconds short) and his 516 mile RAAM solo performances at Sebring in '05 and '06 had (carbon) seatback angles in the low 20's.  
 
    JV will chime in here, but I believe his overall track 24 hour record of 524 miles (on a borrowed CA2.0) from 2012 had a Euro seat angle also in the low 20's.
 
    Superman and praying mantis arm positions and steering apparatus frontal areas vary *greatly* from setup to setup, there is no way to make blanket statements IME.  I've seen very high and very low frontal versions of both.  
 
      A 1994 Tour Magazine article on bents and uprights in the wind tunnel concluded that the spinning legs in front of the rider are still a baseline aero drag for bents, even those that manage to get most everything else (torso, steering apparatus, arms) behind them.  I found the 1997 "Human Power" review of that article by Dave Wilson, but still looking for the original Tour Mag article that has more of the details. 
 
 
                                                              Rich
post edited by Rich Pinto - 2013/10/15 11:56:19
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roubyred
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/15 14:04:09 (permalink)
Here is a view from my cockpit with the custom riser and bars. 

 
My seat angle is between 14-15 degrees and the bars are probably about 1/2" above my shoulders.
 
The limiter on dropping the bars lower was the clearance between the top of my foot and the underside of my bars.  I maybe could lower them another 1/4" before the part of my shoe just behind my toes rubs the leading underside edge of my bars.
 
I've had this riser & bars combo since just before Sebring last year and love it. Great vision, very stiff, and Rich says it's more aero!
 
As you can see, my riser is black (JV got it anodized), but my bars aren't. I like my signature "Cow Tape"... but the guy that started this thread thinks it belongs back on the cow and off my CA2   I'll have anodized bars within the month and very minimal bar tape for a nice sleek look.  ***I have 3 rolls of the "Blue Cow" cork wrap if anyone is interested.
 
Edit:
Here are a couple more pictures:


post edited by roubyred - 2013/10/15 14:29:25

Kristy
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Corsa "The Stalker"
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Crit Rider
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/15 16:56:18 (permalink)
Here is a pic of the L 700c CA2 I rode at Sebring this year:
 
https://www.dropbox.com/s/5v2qleyew0n3x8s/2013-02-15%2018.22.34.jpg
 
And the bar position on my bike before. 
 
https://www.dropbox.com/s...01.48%20no%20plate.jpg
 
No, thats not my seat position.
 
Rich always seems to find a carbon one for me to use, and its much appreciated. 
Very short stem (70mm?) and a Bacchetta extra long bar, the current one.
Note the high bars, and the position of the camera relative to the Front derailleur post.
The way I set it up, those are about 1/4" from my shins. 
 
Here are pics of my bike with the new bar and stem.
 
https://www.dropbox.com/s...3-10-14%2014.42.42.jpg
https://www.dropbox.com/s...3-10-14%2014.43.24.jpg
https://www.dropbox.com/s...3-10-14%2014.44.02.jpg
https://www.dropbox.com/s...3-10-14%2014.44.16.jpg

Note how much lower the bars are, and how much closer the camera is to the top of the front derailleur post.   ....and guess what, I have about 1" of shin clearance and cannot get the bars any lower with this stem. I either need it bent more, or a one piece. 
post edited by Crit Rider - 2013/10/23 19:15:52
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tojesky
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/15 17:52:37 (permalink)
Crit Rider Here is a pic of the L 700c CA2 I rode at Sebring this year:
https://plus.google.com/u/2/photos?pid=5845385785360528690&oid=102745715384554548369
.........
Here is a pic of my bike with the new bar and stem.
https://plus.google.com/u/0/photos?pid=5934729993009728738&oid=102966771288078855293
Jim, the pictures are not showing up when I click the link, I only get the "no picture" icon.
 
Interesting discussion. I just went from a 90mm to a 60 mm stem to get the bars closer to me.  Kristy's setup looks like it may work for me as well. 
 
Tim


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2013 CA2.0 - 700c
2006 Corsa  (Sold July, 2013)
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Doc Dan
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/15 20:28:26 (permalink)
Rich Pinto
   Dan wrote... "JK less than 10 degrees?"
   Dan...IIRC, both borrowed Ti Aero's that Jim Kern used for his 2005 490 mile (just a few seconds short) and his 516 mile RAAM solo performances at Sebring in '05 and '06 had (carbon) seatback angles in the low 20's.  
   JV will chime in here, but I believe his overall track 24 hour record of 524 miles (on a borrowed CA2.0) from 2012 had a Euro seat angle also in the low 20's.
   Superman and praying mantis arm positions and steering apparatus frontal areas vary *greatly* from setup to setup, there is no way to make blanket statements IME.  I've seen very high and very low frontal versions of both.  
     A 1994 Tour Magazine article on bents and uprights in the wind tunnel concluded that the spinning legs in front of the rider are still a baseline aero drag for bents, even those that manage to get most everything else (torso, steering apparatus, arms) behind them.  I found the 1997 "Human Power" review of that article by Dave Wilson, but still looking for the original Tour Mag article that has more of the details. 
                                                             Rich

 
I'll testify to the spinning legs (or legs in general) constituting a heavy aero drag.  On some of the 6-13 mile consistent 4-12 degree descents out here when I spin out I pick up speed when I close my legs, knee to knee (overlap, in fact), and do all I can to `point' my feet.  
Worrisome when there are crosswinds.
 
Descending I skootch down to decrease frontal surface only to increase leg surface.  I haven't looked at the Garmin in such situations because I'm too busy staying straight and upright on the bike.  
 
On fast switchback descents I pay no attention to aero because I need to a) keep my balance by shifting my torso, b) look for road obstructions, c) feather the brakes.  I rarely exceed 40 mph in these situations.  Which means that quite often I leave motorcycles in the dust :)
 
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/16 17:57:14 (permalink)
tojesky

Crit Rider
Jim, the pictures are not showing up when I click the link, I only get the "no picture" icon.

 
I get the sign up for an upgrade, experience.
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/23 14:06:56 (permalink)
Here's a mock-up of a possible solution that doesn't involve long stems, too low and/or awkward hand position and long flimsy bars.
It's basically a low rise handlebar with a tight bend at the center to improve forward visibility.
It does require a tight bend at the riser/handlebar connection.
The hand grip position can be as high as you want because the lowered riser allows visibility straight ahead.
My mock-up does not interfere with my knees or shins.
Anybody want to build me one?
Here's a Picasa link showing 5 photos.
https://picasaweb.google.com/helendan.cs/Aero

Dan Kluckhuhn
Silver Spring, MD
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Crit Rider
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/23 19:13:37 (permalink)
working links now, and more pics too.  http://www.bacchettaforum../forum2/fb.ashx?m=97692
 
tojesky
Jim, the pictures are not showing up when I click the link, I only get the "no picture" icon.
Interesting discussion. I just went from a 90mm to a 60 mm stem to get the bars closer to me.  Kristy's setup looks like it may work for me as well. 
Tim


post edited by Crit Rider - 2013/10/23 19:15:02
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Bigfoot
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/25 10:41:04 (permalink)
Thanks for posting the pictures JV !!!
This looks like the best solution for Riser and Bars!
I have learned a-long-time-ago that to get-up-to-speed fast - that you need to copy the best.  Bill Gates started his empire that way.....  I'm just sayin'
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Richard4286
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/26 07:49:18 (permalink)
Kristy, do you have a head support or are you using muscles to maintain your head angle?
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roubyred
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/10/26 16:36:42 (permalink)
Hi Richard,
 
There is definitely support under that red mop.
I use AeroDon's ADEM headrest:
http://www.ademhr.com/products/adem2c.html
I can't make it around the block without support for this big coconut! ;-)  Straining your neck and abdominal muscles to keep your head in the right spot also uses precious energy that would be better spent propelling you forward. It may not seem like much extra effort, but hours upon hours adds up. My goal is always to ride as relaxed as possible... the legs are the only body parts that don't get to slack.

Kristy
CA 2
Corsa "The Stalker"
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bentcyclist
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. 2013/10/31 13:19:23 (permalink)
.
post edited by bentcyclist - 2014/03/04 14:30:13
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Dan
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/11/01 10:38:03 (permalink)
Bentcyclist.......................
Could you please elaborate regarding the specific parts and process you used?
Thanks.
Dan

Dan Kluckhuhn
Silver Spring, MD
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johnmwest1
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/11/01 12:48:01 (permalink)
I made about the same mods as Bentcyclist except my handlebars are extra long and don't need the 4" addition.  I am curious where my bars are in relation to JV, and Roubyred, and Bentcyclist.  Since JV and Roubyred are on CA2 with 700 wheels (Same as I am) would you mind taking a few measurements for comparisons?  The distance from ground to center of the crank (Mine measures 37")  and from the ground to the top of the handlebars (Mine measures 42").  Just curious.
Anyone else feel free to measure your set-ups and report.
John
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bentcyclist
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. 2013/11/01 16:14:49 (permalink)
.
post edited by bentcyclist - 2014/03/04 14:30:49
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bentcyclist
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. 2013/11/02 09:17:27 (permalink)
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post edited by bentcyclist - 2014/03/04 14:31:31
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Dan
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Re:Better road vision, & fit, & control: why you want a longer lower stem & custom bars. 2013/11/02 13:26:45 (permalink)
When you all lower your bars by 3 or 4 inches, don't you have low speed turning problems due to the bars being lower than your thighs?
Dan

Dan Kluckhuhn
Silver Spring, MD
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