Stem length and handling

Discussion in 'Road Cycling' started by Uawadall, Jul 25, 2016.

  1. Uawadall

    Uawadall Well-Known Member

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    I've been steadily changing my Cannondale Synapse from an endurance bike to a speedier set up. Raised and changed the saddle,dropped the handlebars, new wheels, swapped the compact for a standard,etc...Most likely, my last adjustment will be changing the stem angle and length. My current stem is a 31.8, 6 deg angle and is 110mm. I will be getting a new stem thats -17 degree angle and 120mm. Besides getting lower, I have long arms and was feeling kind of cramped for space.


    My question is, how much does stem size and angle affect bike handling? Also, how often if ever do you adjust or change the stem and handlebars on your bike?
     
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  2. CAMPYBOB

    CAMPYBOB Well-Known Member

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    I've never heard of a pro rider picking himself up off the deck and cursing the length of his 130-140 MM stem as the culprit.

    Once in motion and at speed the front wheel just isn't turned very much to steer the bike. With the current trend being to ride a frame size or two smaller than...well...smaller than what we used to ride and to what was once considered a proper fit a 100 MM stem is definitely for those with shorter arms. 120 MM might be the new 100 and it's nothing to see racers on 130's and 140's, pro and amateur alike. 'Low & Long' is still the king if you got the flexibility and can develop your power while on those drops.

    And 'handling' also factors in position on the bike, weight distribution, wheelbase length, frame angles, fork rake & trail, bottom bracket drop and rider size/weight.

    The same goes for cranks. 170 MM was the road standard for decades. Now, even the midget Narrow Quintana uses a 172.5 and 175's are used by guys 5' 6" and up all the time.

    Handlebars did seem to narrow down for a couple of years for the .0004% aero advantage that added, but lately I've been seeing a trend backs towards more 42's and 44's in the reviewed pro bikes. Again, it's all dependent on rider preferences, but it's fun trying to keep up with who's on first...who's on second.
     
  3. cyclintom

    cyclintom Well-Known Member

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    It is extremely easy to get stems too long. Pros do not use long stems on their racing bikes to achieve a flat posture on the bike because they have to sit up and peer around corners and over the people in front.

    Stem length is where in a tuck your elbows do not strike your knees.
     
  4. CAMPYBOB

    CAMPYBOB Well-Known Member

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    WTF???

    See over people in the front? Is that just before or right after the 30-bike stack up that occurred for no reason?

    Most pro's use 120, 130, 140 or even longer stems. Wiggins uses a 143 IIRC.

    Additionally, their saddle-to-stem drop measurements are often huge. At 35 MPH for hour after hour aerodynamics are everything.

    The above can be in addition to top tube lengths that are longer than on public sale production models.

    Hitting elbows? A lot of the pro's went to bars two sizes more narrow than the old normal standard just to gain even more aero Watts. The last thing any rider seeking speed is concerned about is getting a knee into an elbow.

    Spend a few months reading the pro bike reviews on Cycling News if you don't believe me.

    Check out Nibali's Spesh:
    http://www.cyclingnews.com/features/vincenzo-nibalis-tour-de-france-specialized-s-works-tarmac/

    Or Bennet's Bianchi:
    http://www.cyclingnews.com/features/george-bennetts-bianchi-oltre-xr4-at-the-tour-de-france/

    Or Matthew's Scott:
    http://www.cyclingnews.com/features/michael-matthews-tour-stage-winning-scott-foil/

    Or Rolland's SooperSix:
    http://www.cyclingnews.com/features/pierre-rollands-custom-cannondale-supersix-evo-hi-mod/

    You won't find a 120 in that bunch and that's just the last four road bikes from the Tour that got reviewed.
     
  5. cyclintom

    cyclintom Well-Known Member

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  6. BrianNystrom

    BrianNystrom Member

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    While the above is true, it's also true that in the current carbon frame era, most riders are on stock frames regardless of their body proportions, as it's too expensive to create tooling for one-off frames. However, what they do has little bearing on most of us who aren't getting paid to ride.

    Getting back to the original poster's question, the general rule of thumb for bike fitting is that:
    • The frame size is proportional to leg length (This is the least critical dimension, since seatpost length can make up for a short seat tube, as is commonly done with frames with sloping top tubes)
    • The top tube length is proportional to torso length
    • The stem length is proportional to arm length
    So in a case like mine, where I have long arms and legs relative to my torso length, I ride a large frame (~59 cm) with a relatively short top tube (57.5 cm) and a long stem (13 cm). This assumes a seat tube angle of 72.5 degrees, which is pretty common on frames of this size. Changes in that angle will affect the length of the top tube required in order to achieve the same position relative to the bottom bracket. Over the years, those measurements have remained constant, but I've raised my bars ~5cm compared to where they were back in my racing days. I'm also riding wider bars (44 cm vs. 41 cm), as I find them more comfortable and also advantageous when climbing out of the saddle.

    As for the effect of stem length on handling, the biggest difference is that it changes your weight distribution on the bike. Lengthening it will bring you closer to 50:50 weight distribution (mine was 48% front /52% rear when I was racing). Lowering the bars has the same effect. This benefits the handling, as the increased weight on the front wheel also increases front-end grip, improving cornering if you have the skill to utilize it.

    Regarding the Synapse, it's designed for a slightly more upright position, so the deeper drop stem is a good choice in order to get a lower position. Keep in mind that the Synapse is designed as an endurance bike (and a fine one at that), so it's not going to provide the same level of performance (handling, lateral/torsional stiffness) that you'd get from a racing design like the SuperSix or SuperSix Evo. If you plan to get into racing or you're just really serious about performance, you may eventually want to get a different frame. So, keep the old parts from your Synapse, as you may end up with both racing and endurance bikes for different rides.
     
    #6 BrianNystrom, Jul 31, 2016
    Last edited: Jul 31, 2016
  7. cyclintom

    cyclintom Well-Known Member

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    Brian, as you say professional racers are using stock frames. So where does that leave you and your top tube proportional to the length of your torso and the stem length being proportional to your arm length? We know that sprinters tend to have longer torsos and climbers tend to have shorter. Arm length tends to be proportional to leg length though there are some remarkable exceptions.

    Since racers use smaller bikes to obtain a slight weight advantage, the play racer on the street sees these super long stems and believes that is the correct way to fit a bike.

    That is what I meant when I said it was easy to get a stem too long. Going up one size of bike these days depending on make can give you a centimeter and a half difference in top tube length. Sticking one of those 13 cm stems on there to look like a pro can set you so far forward that you have far too much weight on the front half of the bike. Not to mention back and neck pain.

    One of the things I'm observing on this group is that we have a lot of very experienced riders like yourself that tend to forget that beginners tend to hang on your every word while you take things for granted because of your vast experience that they miss completely.
     
  8. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Of course body geometry is a big determining factor in choosing a frame size, saddle setback, bar reach and drop, stem length and crank arm length...and a whole bunch of other position tuning details. NO ONE is arguing otherwise.

    Hip rotation, general flexibility, chosen handlebars, stem spacer setup ALL enter in the equation. As I originally stated, when it comes to speed and aero, long AND low are king. Aero rules in the world of going fast. In order to get aero, trialing out a longer stem or deleting stem spacers is how it's done.

    And I 'think' the OP mentioned his stem was already slammed or close to it (with today's tall'ish head tubes on many models, almost a necessity for even 'midget arms' to get more aero) and his steerer tube is already cut. Does that sound like a guy worried about neck pain or brain cancer caused by a stem length change?

    However, the OP has many, many miles on his current rig, is riding at advanced speed and mileage (he is NOT a rookie fresh off his Schwinn LeTour or Sears Free Spirit). He IS seeking more speed and a more aggressive position on the bike in order to achieve that speed requirement. And to that I say, "Good for him!".

    The most difficult thing to do with your training is...to CHANGE it!

    He asked, plainly, if the increased stem length is going to adversely affect handling.

    Frankly and truthfully...it is NOT. Tu capisci?

    Frame sizing, in general, has been on a trend towards 'smaller' for well over a decade. Back in the day a 90 MM-100 MM stem was max. That usually yields a cramped fit to the 'average' body type (if there is such a thing) and typical fits today start at 100 MM and often exceed that by over an inch.

    As far as pro's riding stock frames, many, if not most, of them do. Many do not. Just off the top of my head:

    Tom Boonen: Longer than stock top tube. Experienced lower back problems with stock geometry.
    Lance Pharmstrong rode a 58 CM TREK in order to get the top tube length he needed.
    Little Damiano Cunego used a custom TT length.

    Too pressed for time to Google from BikeRadar, Cycling News, etc.

    I really don't get it. It's not like the OP is tossing his old stem in the trash and can't bolt it back on if a longer one doesn't work for him. Spending $30-$50 on an experiment in your bike position is chump change. And there's always eBay and Craigslist if it doesn't work out.

    Here's a little quality information from someone other than Campybob on stem length:



    [​IMG]
    How does stem length affect a bike’s steering and handling?
    by Matt Wikstrom

    March 30, 2015



    TECH SUPPORTED BY
    Today’s marketplace provides a wide variety of stem lengths and angles, allowing riders enormous flexibility for fine-tuning their reach to the handlebars. While comfort and an effective position trumps all other considerations, Matt Wikstrom takes a closer look at the influence of stem length on the steering and handling of a road bike.

    Almost since the invention of the safety bicycle, the handlebar stem has served as a crucial point of adjustment. While the earliest designs offered negligible reach, longer, adjustable versions soon emerged.

    Marshall “Major” Taylor is credited with the invention of the first adjustable bicycle stem at the close of the 19th century. The design employed a sliding clamp on a protruding length: the handlebars could thus be adjusted fore and aft to suit the size of the rider. Taylor used the stem to great effect, winning a multitude of races, first in the US and then throughout Europe.

    [​IMG]

    Taylor’s “outrigger” eventually gave way to sturdier one-piece designs and ever since then riders have adjusted their handlebar reach by fitting stems of different lengths. Nowadays, there is a choice of stems as short as 50mm and as long 150mm with a variety of angles for fine-tuning the position of the handlebars.

    Such adjustability allows a rider to consider a variety of frame sizes and geometries. But the question arises: can a stem be too long or too short for a bike? And is there an ideal length?

    No simple formula
    Custom framebuilders are perhaps the best source of information on the matter of stem length. After all, they are in the business of building bikes that provide an ideal fit for their clients, and part of that process involves determining the best stem length for each frame they build.

    When I put the question of stem length to Steven Jaegher of Jaegher in Belgium he said, “We try to keep stem length within certain margins in relation to the frame size to keep a nice balance handling wise. Compensating a wrong frame length by mounting a short or very long stem is never a good idea.”

    Richard Craddock of Craddock Cycles based in the UK expressed a similar view, “In general I find the best balance is a medium length stem. Of course, all this depends on your position and whether you have a frame with the right top tube length to allow you to achieve that position with a medium length stem.”

    [​IMG]

    For Tom Kellogg of Spectrum Cycles in the US, one of the most important considerations is the rider’s reach, which he refers to as ‘cockpit length’.

    “It comes down to the cockpit length not rider height. Longer cockpit riders should have longer stem/bar reach combinations,” Kellogg said. “And the more aggressively a bike will be ridden, the (somewhat) longer the stem. Full on race bikes should have longer stems than touring bikes, all other things being equal, in order to get more weight on the front wheel.”

    The importance of the bike’s purpose is something that also stands out for Ryan Moody at Baum Cycles. “Stem length will vary with the design of the bike. It must also address the rider’s comfort, biomechanics, performance needs, and the steering and handling of the bike. Deciding on the best stem length depends on the rider’s priorities for each because a relaxed position compromises performance, and it’s not always possible to achieve ideal biomechanics.”

    Gererally speaking, longer stems belong on racing bikes for tried and true reasons. As I have patiently explained above. If some touron wants to run a 70 MM stem or someone has a horrible back (as do I and my 'long stem' causes me no problems while cleaning a bathtub kills it), let them. No one is saying the world has to subscribe to 'go fast' advice, but if one wants speed there ARE accepted means to go about it.
     
    RD1000 likes this.
  9. Uawadall

    Uawadall Well-Known Member

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    You make some very valid points. I started to understand the pro's and cons to my bike a few months after purchasing it. I would have bought a racier geometry if I would have known then what I know now. I really have no complaints about it though, I go plenty fast and have toyed with it enough to know my positional and gearing preferences for my next ride. The thought of racing has crossed my mind, but just being a fast recreational rider is the current plan.

    I plan on buying a second racier bike sometime next year and will mod this to better suit endurance/climbing days. I'll keep in mind the importance of keeping old parts. Thanks for the input!
     
  10. BrianNystrom

    BrianNystrom Member

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    It sounds like you're just going through the normal growth curve of someone who is discovering the performance side of cycling. You also seem to be making measured, intelligent choices in your modifications. The bottom line is that you own a great bike that was likely an ideal selection based on what kind of riding you thought you would be doing when you bought it. I'm sure that there are many people here who've gone through a few bikes before they learned exactly what they needed, which may also be a "stable" of steeds for various purposes. There's the old saying that the perfect number of bikes is "n + 1". As we evolve as riders, our needs and desires change and we purchase equipment to suit those changes. Cycling is a journey, not a destination. I hope you enjoy it for decades to come.
     
  11. BrianNystrom

    BrianNystrom Member

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    One of the reasons that you see some seemingly odd configurations on pro's bikes is that they are forced into riding frames that aren't ideal for them. In a given frame size (based on seat tube length), a range of 3 cm in top tube lengths among brands is not uncommon. While this offers consumers more options to find a good fit, it can put pros in a tough situation, since they must ride their sponsor's bikes. It's not like in previous decades where frames were similar enough that a coat of paint could disguise a custom bike or that a manufacturer could just braze/weld up custom frames for team riders. Even aside from the fact that custom carbon frames would be hideously expensive for my bike companies, UCI rules that require pro's bikes to be available for sale to the public seem to be having an impact, too. For example, Cancellara's custom classics bike is now an option in the Trek line. Specialized has made some long top tube frames for riders like Boonen and Sagan, though I don't know if you can actually order one or not.

    I don't think that it's possible to make generalizations about sprinters proportions any more than you can say that they're typically tall or short. Just compare Mark Cavendish and Caleb Ewan with Andre Greipel and Marcel Kittel.

    You make a valid point about beginners wanting to emulate pros, which is typical in any sport. Back when I was in the bike biz, I used to see it all the time; people would come into the shop with preconceived notions about what they wanted, which was often a long way from what they actually needed. IMO, one of the most important jobs for shop personnel (or for people like us on forums, for that matter) is to educate newer riders about their options and the pros and cons of each, then guide them to making appropriate decisions. It isn't always possible and it doesn't always work, but that's life.

    BTW, I sincerely hope that no one is hanging on my every word. That could be dangerous! ;)
     
  12. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Nope. I hang on no one's words. And I am not trying to be argumentative just to be belligerent or come off as some sort of intarwebz 'expert'. That bullshit was boring 25 years ago.

    I am a great believer in thinking people are not really stupid and quite often know exactly what they need or at least what they want to try out.

    For shits & giggles I just pulled up the Wilier (the brand I'm currently riding) Cento Uno frame geometry. The effective top tube length ranges from 51.3 Cm to 58.6 Cm. That's a 7.3 Cm spread (2.87").

    For more shits & giggles I pulled up my TREK Emonda Winter beater's specs. The ETT length ranges from 51.3 Cm to 61.0 Cm. A 9.7 Spread (3.82"!!!).

    Accordingly, we could all, in theory, be on a 90 MM stem...

    The Reach & Stack measurements were correspondingly large in their spread. Hmmm...

    I'm not tryin' to prove anyone right or wrong here, but even within a chosen fit there is far more involved than passing off what works as 'getting the look' or trying to emulate anyone. What works is...what works.

    If taking a guy off a 54 with a 140 MM stem and sitting him on a 60 with a 90 MM stem worked as well or better...wouldn't you think we would see a mix of both fits...'somewhere' in the go fast crowd?

    Smaller frames are certainly not chosen for weight advantages. Most 60 Cm frames can be built up with Ultegra and meet UCI minimums and if we're talking USCF/UASC almost any size can be built to weight weenie specs and come up pounds lighter than the UCI would allow on a starting line (not that I've seen scales at the local crits, but even the USCF has to follow UCI rules in most cases).

    Although minor lateral, torsional and vertical deflection number changes might be noticed as frame sizes change, the fact is you can buy a super stiff frame in any size and a piece of limp spaghetti in any size in any of the popular frame materials. Hydro-formed ultra-alloy this or 100T Toray that or any possible mix and match can achieve almost any desired result while keeping weight near the legal target.

    AFAIK the trend to short'ish is for aero setup...and maybe a dash of overall handling thrown in for good measure.

    If I did not say it up top and even if I did allow me to repeat myself: There is nothing wrong or 'incorrect' about rider 'X' tooling around on a short stem or a bike with one of those funky stem riser adapters. His money. His choice.

    However, if a rider is striving for speed he damned well better study the pros. Study the pictures (especially profile pictures). Study the videos. Not just one guy or two. Study all you can find. Study the local riders in the Tuesday Evening World Championships. See what works and what fails.

    The disclaimer: Anyone following my words as Holy Gospel will be lead down the One True Path of Righteous Knowledge...er...Ok...maybe not!

    The other disclaimer: If it looks stupid and works, it's not stupid.
     
  13. RD1000

    RD1000 New Member

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    Wow, very comprehensive Bob
    I am currently developing an adjustable stem that has angle and stem length adjustment.
    Would you like to see a couple of 3-D design image photos?
    I would really like feedback...
    Thanks
    Rich
     
  14. jeremyrundle

    jeremyrundle New Member

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  15. RD1000

    RD1000 New Member

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    Thanks 20170408_111340.jpg 20170408_110328.jpg
    Thx Jeremy
    Your bar stem looks very substantial/strong .....!
    Here's two photos of my 3D designs..
    (Calling it SY-STEM (copyright))
    US utility patent obtained with more pending of the parts that cannot be seen.
    Some recent feedback advised 4 bolt bar clamp is best, may need water seal at the telescoping clamp annulus, oval tube section or bead and groove for extra stability, maybe greater range of telescoping adjustment....
    Tried rotating images 90 degrees on here, no joy...
    Cheers
    Rich
    20170408_111340.jpg 20170408_110328.jpg
     
  16. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Interesting.

    Adjustable length track stem were all the rage dating from the turn of the last century (early 1900's) up through about the 1960's. There are already several adjustable angle / rise stems on the market. Sales are probably fairly low, but there are several bikes I know of that come with that type of stem as OEM spec.

    Whoever gave you the 4-bolt bar clamp advice gave you good advice. Much less creaking as opposed to the 2-bolt designs and most of the 3-bolt clamp designs.

    Good luck with your product!
     
  17. RD1000

    RD1000 New Member

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    Great
    Thanks Bob
    Apologies - I jumped the gun posting before you replied...
    Thanks for the 4 bolt clamp confirmation.
    With some design mods hope it will be a product that is accepted / desired world wide. Will get a working prototype made first and it will have to prove itself in use..!
    Need a lot more feedback first.....please feel free to distribute to as many of your contacts as possible.
    Cheers
    Rich
     
  18. RD1000

    RD1000 New Member

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    Thanks Bob
    The grey image model does have a flat on the underside of the telescoping sections that can't be seen in that view - apologies just checked latest design.
    That should lock them in position and no movement or creaking...!
    Will get design mods done to provide access to the headset bearing cap bolt ASAP and re post.
    Propose one model with telescoping and rotation and another without telescoping in various stem lengths....cheaper...
    Cheers
    Rich
     
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