frame stiffness quantified?

Discussion in 'Cycling Equipment' started by ebola, Mar 12, 2011.

  1. Eichers

    Eichers New Member

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    Hi ebola, have a look at these wooden frames :)

    http://www.renovobikes.com/ ... they say "It's the smoothest bike you'll ever ride, stealth quiet, lightweight and responsive, stiff as you want. Renovo hollow wood and laminated bamboo frames will forever change your understanding of what a bicycle should be, and how brilliantly these natural materials perform when designed to their strengths."

    I haven't got one or tried one but they look very interesting :)
     


  2. ebola

    ebola New Member

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    Its also about what % of time the components are pristine: ride in the rain and you need to wash the bike more frequently to get a good riding experience. Perhaps I'm subconsciously assuming the squeeky noises are associated with grime particles grinding away at the components which i want to avoid. I take your point that washing it more regularly would help - but I have a very impatient personality.

    Quote:
    If you want a cheap rain bike, get a Giant Defy3 and call it a day. Sora components, about $800, and a comfort based geometry ideal for comfort on longer rides.
    - the mountainbike I have does this job. Perceptions again: for some reason the thing is more appealing in adverse weather, also it allows more traffic-dodging routes. I take your point about bikes surving mud... perhaps I'm subconsciously assuming that a MTB is actually *designed* for mud wheras road is not. Any truth in that?
    Quote: Sorry to sound like a prick but in my opinion, the snobbery of being used to a high end bike is the real issue here.

    Yes I'll admit that.

    Its Dura-Ace.. overkill I know.
    Part of the purchase decision was frame graphics. I understand ebaying bits retroactively could fix that economically.
    The bike DID make me ride more and help me reach a greater fitness peak as part of an overall obsession. (~250 miles/week, i'd love to get back to that level).
    This thread DOES have me considering the downgrade option again or the weirder seasonal part-swap idea .. and I know training wheels are a common option, not being done here due to Campag/Shimano duality which again ebay could fix.
    There are worse vices.
    Quote: proper cleaning after riding in rain will keep your bike in good working order and quite frankly,


    Its also about time. bike maintainance is another chore eating into ones's spare time.
    (a rowing machine would help me more than a winter bike probably)

    Quote: it's winter riding where your bike is picking up the salt thats been put on the roads that would be considered more problematic.


    ok thanks for this info - perhaps you're suggesting I should err toward enjoying the bike in the times when I'm shying away from it (e.g. its rained, there's residual water, or the sky is looking like it might)
     
  3. Motobecane

    Motobecane New Member

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    very cool website, didn't realize wooden bikes were being made in all types!
     
  4. Motobecane

    Motobecane New Member

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    Quote: perhaps I'm subconsciously assuming that a MTB is actually *designed* for mud wheras road is not. Any truth in that?
    A little bit, but not much. MTB Hubs are sealed better, other than that, most of your differences have to do with durability and ability to get over rough terrain, things like 26" wheels(though 29ers are popular mtb's now), wide knobby tires, 22/32/42 tooth cranks to get up mountains. and shifters that are placed on a flat bar and separate from the brake lever so that if you crash you only have to replace a shifter, or a brake lever, not both.

    Honestly, it doesn't take long to clean a bike. If you take a garden hose to it, you will get it done in 5 minutes. some say don't use a spray nozzle because it can actually force water and gunk into areas where the dirt was resting on the surface so just take a regular hose and run water over it. Lets keep in mind, your not PLANNING on riding in the rain, your concern was what it your 30 miles out and it starts raining and you have no choice but to ride back in it. A decent set of cleaning brushes can help get into hard to reach areas and quite frankly, you should WANT to clean your bike once in awhile and use that as an opportunity to inspect your bike in closer detail which you should be doing regularly.

    A bicyclye takes FAR more abuse every time you push a pedal and start putting various forces through it than it does getting a little water splashed on it. The issue is really only if you CONSISTENTLY ride in the rain and never clean your bike off.


    I think it's obvious you've made up your mind that you want another bike to ride in the rain. Consider the bikes direct route something like this is duraace and is $2000
    http://www.bikesdirect.com/products/motobecane/immortal_spirit7900.htm

    OR you can spend a little less and just go with ultegra
    http://www.bikesdirect.com/products/motobecane/immortalforce_10.htm

    BTW, I'm a huge believer in "buy the bike that makes you want to ride it" so i can understand that you wouldn't want to just buy a sora laden bike. heck, I'm constantly updateing little bits and pieces all the time probably subconsciously thinking that each little upgrade will somehow make the bike sooo much better so I have to rush out and go for a ride. I'm just trying to make sure that you understand regardless of what kind of bike you buy, if you ride it in the rain, you need to clean it! or expect to be paying your LBS to do significant overhauls each year which may be fine for you if you've got the money but lack the time.
     
  5. ebola

    ebola New Member

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    Quote:
    Originally Posted by Motobecane .
    Honestly, it doesn't take long to clean a bike. If you take a garden hose to it, you will get it done in 5 minutes.




    Requires 'garden' which I lack. Use of spray indoors requires a Dexter-esque plastic-sheeting living room/bedroom in my rented flat. I'll look into it. Bike cleaning to date has been done in the bathtub which is a little claustrophobic.


    Quote:
    some say don't use a spray nozzle because it can actually force water and gunk into areas where the dirt was resting on the surface so just take a regular hose and run water over it.

    Lets keep in mind, your not PLANNING on riding in the rain, your concern was what it your 30 miles out and it starts raining and you have no choice but to ride back in it. A decent set of cleaning brushes can help get into hard to reach areas and quite frankly, you should WANT to clean your bike once in awhile and use that as an opportunity to inspect your bike in closer detail which you should be doing regularly.

    A bicyclye takes FAR more abuse every time you push a pedal and start putting various forces through it than it does getting a little water splashed on it. The issue is really only if you CONSISTENTLY ride in the rain and never clean your bike off.



    Thanks for the opinions on this. the campag-centaur-wrong-sized-but-rideable-secondary carbon bike got a little bit of drizzle on it today.




    Quote:

    I think it's obvious you've made up your mind that you want another bike to ride in the rain. Consider the bikes direct route something like this is duraace and is $2000
    http://www.bikesdirect.com/products/motobecane/immortal_spirit7900.htm

    $2000 for a DA bike ?! whats the catch.
    I'm in the UK, doubt I can get that here.
     
  6. davereo

    davereo Well-Known Member

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    $2000 for a DA bike ?! whats the catch.
    I'm in the UK, doubt I can get that here.






    BD only ships to the US. Cleaning a bike without a garden hose and shower nozzle can be tedious. You can pour pails of water over your bike outdoors to flush away the road grime then bring it indoors to detail clean. Maybe you could just leave a pail of clean water at your doorstep when you leave for a ride. If you flush your bike as soon as you return you will get most of the crap off before it dries.
     
  7. ebola

    ebola New Member

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    see this is where i'm going wrong with rain then isn't it. Id feel really odd cleaning my bike out in public. Still, dexter manages to dismember corpses indoors leaving no residue, so i'm sure with enough plastic sheeting I can clean a bike without upsetting my landlord.

    wanted, compact bike cleaning invention. robot arm, vacuum nozzle, It can even be pedal powered.

    and we await belt-drives and super-materials that can do hubgears without power loss. or covered cyclepaths (future transport = one way cycle-tubes for collective drafting)
    Or get fit on an indoor rowing machine with PC+big tv providing the sensation of movement.
     
  8. dhk2

    dhk2 Active Member

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    ebola, wouldn't worry about your lack of a hose pipe; bike cleaning is probably over-rated anyway. I think more damage is done with aggressive cleaning than any good it does. High-pressure water and caustic (basic) degreasers can lead to corrosion, particular between steel and aluminum, ie, where most fasteners and bearings are. If your bike components are properly sealed, then riding in the rain shouldn't hurt anything. If they're not, applying more water, detergent and/or cleaning agents to the outside is only going to make things worse.

    My bike is a good example of a lot of the newer designs which aren't sealed well. It uses press-in cartridge bearings in the wheel hubs, covered only by "dust caps". The standard cartridge bearings use "non-contact" face seals, meaning moisture will get inside them. One good rain ride was enough to rust the first pair of front wheel bearings. When I called tech support, they advised me to remove the end caps from the wheel and dry the bearings after a rainy ride so the moisture isn't sitting on them. Good advice, but not something I want to remember after a long, wet ride.

    Ditto for the press-in cartridge BB. These bearings (FSA Megatech) also just have the non-contact face seal rings, behind the end cap spacers. A two-week trip out to NM and CO ruined the last pair, about 500 miles of sand and grit did the deed.

    Weather sealing seemed to be much better on my old Shimano Ultegra hubs and BB bike. Believe these had "real" axle lip seals that did a much better job keeping out the dirt and water, lasting longer as a result. In more than 10 years on that bike, about 20K miles, I recall replacing the BB just once, and never had any service issues at all with the hubs.
     
  9. Motobecane

    Motobecane New Member

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    regarding cleaning, I live in a 5th floor walkup so I can relate to not haveing a garden hose. if I do clean my bike indoors, I have an old beach towel that I put down on the floor and then I either flip the bike upside down or I mount it into my trainer to stand it up and then just a small bucket of soapy water. i don't have any fancy brushes, but there aren't many times I wish I did. I'd say overall i probably spend about 10-15 minutes. if this were after every single ride, I'm sure I'd skip it, but since I don't go out on this bike in the rain all that often it's not a big deal. And considering the infrequency I wash my hardwood floors, spilling anything on the floors isn't too big of a deal.

    To the person who asked about dura ace for $2000 Bikes direct is a no frills, low overhead company. They aren't known for having great customer support and as a result if you don't know your way wrenching around bikes I wouldn't totally recommend going through them but at the same time most lbs will charge you $50 to assemble and then you pay them on a one off basis for any other work. LBS near me are quick to hype up "lifetime free adjustments" but cmon, is it worth paying an extra $1-$2000 for the bike? I don't think so. I have a bikes direct bike with pretty much full ultegra for $1000. your lucky to get a tiagra/105 mix at that price point in an lbs.
     
  10. ebola

    ebola New Member

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    Quote: Originally Posted by dhk2 .
    It uses press-in cartridge bearings in the wheel hubs, covered only by "dust caps". The standard cartridge bearings use "non-contact" face seals, meaning moisture will get inside them. One good rain ride was enough to rust the first pair of front wheel bearings. When I called tech support, they advised me to remove the end caps from the wheel and dry the bearings after a rainy ride so the moisture isn't sitting on them. Good advice, but not something I want to remember after a long, wet ride.

    Ditto for the press-in cartridge BB. These bearings (FSA Megatech) also just have the non-contact face seal rings, behind the end cap spacers. A two-week trip out to NM and CO ruined the last pair, about 500 miles of sand and grit did the deed.


    Next question, which hubs and BB's are best sealed .. best for a winter-trainer. (that veers from my original q/situation though: (1) 'alpha' DA bike good fit, want to keep pristine for special occasions, (2) 'beta' bike is bad-fitting carbon with ok campag-centaur groupset, want to replace the frame to get remaining use out of those components & wheels on days when it *might* rain). Already have 'delta' bike - mountain - which is perceptually more reassuring in bad weather.
     
  11. Eichers

    Eichers New Member

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    Hi ebola, the best BB I have used to date is the Hope (Hollowtech II). The Hope seals are excellent. They keep the outside environment out, the grease inside and fresh, very free spinning, and long wearing. They seem to perform well even with little or no maintenance and they don't seem to squeak.
     
  12. Sleeping menace

    Sleeping menace New Member

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    Actually, I've been dealing a bit with this very subject whilst in the middle of a personal project.
    I'm designing a TT frame, and have, through a combination of CAD/FEA/CFD been refining, and refining.. hopefully working towards a point where I can bring a very competitive frame to market.

    As part of this.. we've been working on a 'deflection matrix' ..against which we measure distortion from static, with loads placed as a rider would whilst in the saddle, out of the saddle.. sprinting..etc..
    Manufacturing tolerances aside.. there are some very interesting differences between frame configurations. Most modern, high quality frames actually flex VERY little in real world usage.
    There's much more flex in wheels, bars, and cranks than in frames, but there are very real distortions that happen to every frame when being put under rider power.
    To test the model we were working with, we did a cad model of an existing frame we had around the shop, approximating it as closely as possible.. and looked as the simulation results, vs fixing the frame to a jig, and using a hydraulic ram and a bit of clunky funky measuring.. putting the same pressures.. and measuring the deflections. So far.. the results have been fantastic...better than we'd hoped.
    We're going to continue to refine as we go.. and one nice aspect of using all open source software is that we have the source in front of us.. to add on and make changes as suits.

    If you're interested in the subject, and painfully bored.. I'm beginning to document the project as I go.. on my blog.. and somewhat in twitter..


    ........................ http://anotherdooratthe.endoftheinternet.org Cycle related blog entries, including a few 5 minute reviews: http://anotherdooratthe.endoftheinternet.org/category/cycling/
     
  13. dhk2

    dhk2 Active Member

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    ebola, don't know much about current BBs other than my Megatech/ISIS. Chris King claims to have a well-sealed BB designed with ability to use a grease gun via an adapter tool. They come with a 5 yr warranty, if that means anything. My guess is that with regular re-greasing, this one would last a long time. Might be the best choice for extreme condition use. There are probably other BBs that are designed for long life in adverse conditions. However, when you consider cost, it may be cheaper in the long run to use Shimano BBs and just replace them more often.
     
  14. ebola

    ebola New Member

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    Wow... How many buzzwords can you grab my attention with in one post :) Nice to know i'm on the right forum.

    r.e. Open Source FEA - Can you give me links ? Does it run under linux ?
    Does it produce any graphical / animated visualizations ? Are there interesting datasets available.

    Do you use GPGPU e.g cude/opengl to run the FEA simulations. I am a games-tech programmer by trade but am curious about GPGPU for serious engineering/scientific applications. How compute intensive is it.

    Can you recommend any books on serious engineering simulation maths/programming (my education is in physics rather than compsci, but haven't used it in my career, only simple arcadey simulation for driving games)

    Very interested to hear how close your FEA can get to real world measurements... generally how well does that work.

    .. can you reverse engineer rival frames ? etc.

    Is the FEA adapted to deal with the directional nature of carbon ?

    What sort of tools do you use to build the FEA meshes.
    All of this fascinates me.

    And back to the original question ... do you have any quantitative measurements of the various bike frames out there for frame recomendations at various price points.(inc alu)


    Quote:
    Originally Posted by Sleeping menace .
    There's much more flex in wheels, bars, and cranks than in frames,
    So perhaps you're suggesting upgrades in high end components are worthwhile.. and also for mid range bike, there might be more in the decision about say Ultegra+Alu versus 105+carbon ? And thanks to KLabs & dhk2 for the BB recomendations.
     
  15. Motobecane

    Motobecane New Member

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    i agree, shimano bottom brackets are very cheap. For a guy obsessed with durace, $30 bottom bracket is no big deal.
     
  16. Eichers

    Eichers New Member

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    Hi ebola, fwiw I believe that the following is true ...

    1. Ultegra cassette will last longer than a DA cassette
    2. Ultegra crankset is stiffer than a DA crankset. In fact the Ultegra crankset might be the stiffest crankset on the market, maybe?
    3. DA chain will last longer than a Ultegra chain
    4. DA RD, FD & STI is better than a Ultegra RD, FD & STI
    5. DA brakes are better than Ultegra brakes
    6. Electric Ultegra is coming, I believe this year, and will be about the same price as the mechanical DA (unofficially)
     
  17. Sleeping menace

    Sleeping menace New Member

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    HI,.
    um.. the answers to many of your questions are in my blog.. dunno if you've gone there and had a look around.. but quite a bit is there under the Time Trial Frame project section..

    However, quick answers to a few of your questions:

    Running on Linux : Yes.. is the short answer. I use the toolsets in CAE Linux for much of the work. I also use Impact (a java based FEA program which runs on Linux, Solaris..etc.. personally I run it on Solaris using Javaparty.. and tag-team all 16 CPU's in the blade server together.. works quite well.

    The work is quite compute intensive.. after all, it's ALL math.. We've experimented a bit with CUDA.. so far.. it's not shown itself worth running towards, but it's still young and I'm sure will improve/mature with time. The workstation I do the most work on is actually a single CPU 6core AMD Phenom, overclocked to 3.725GHz per core.. which does very well for itself. It also crunches through Mersenne prime searches pretty quick for my GIMPS participation.

    As far as reverse engineering a rival frame.
    We did do one..as a lab rat.. to see how far off our 'deflection matrix' was.. and to fine tune our calculations a bit. As it turned out..we were off.. but only slightly, and within a fairly tight window of the actual measured figures.. We were able to get our hands on 3 of the frames.. (identical cept for colour).. and there were some variances..which you have to attribute to manufacturing variances.. as well as them having been subjected to differing kinds of uses. Very interesting to note..that the one brand new frame we found (NOS.. on Ebay)..actually deflected more under identical loads, than the others.. which seemed to exhibit a bit of work-hardening. This was very slight by the way.. and we really didn't have a large enough sample set to say it as fact.. but it pointed us in that direction.

    Our materials model for carbon..is constantly evolving as we go..
    we were able to get some really good data from manufacturers.... and a bit more from some of our own testing.. (keep in mind this is all being done out of our own pockets.. so it's not as if we have a 3million euro lab set up.) We did buy a couple frames specifically to cut up and test on, and as well..we've made a few pieces .. again.. specificially to cut up and test.. we've got a data set which is ..good.. .. far from perfect..but good.. and the results are accurate within a very reasonable window, given the nature of carbon fibre, resin, and the skill of those doing lay up..

    No..we have not assembled a database of existing frames on the market. We did enough with one model of frame to get a working dataset and reference point for measurement that we can build on it. I've been expending my time/energy with my own frame design.. and borrowing heavily what I've learned from this experimentation.. I'll be putting up some sanitised drawings and photos as the project gets further along.. .. and too, I will explain a bit of the logic as to some of the decisions we made design wise.. With what you've expressed, you may find this quite interesting..

    BTW: this is NOT an ad for my blogsite.. there are no ads.. I don't make any money.. its just there as a sounding board for my various alter-egos.. and as a place to share info with people of similar interests.

    Leave me a comment on the blog (they're all screened by me before being posted) ..with your email addy..I'll kick some info over to you..and answer your questions in a bit more detail than I'd prefer to do here..

    There's also a twitter button there. if you want to keep up on the day to day adventures of this project..


    ........................ http://anotherdooratthe.endoftheinternet.org Cycle related blog entries, including a few 5 minute reviews: http://anotherdooratthe.endoftheinternet.org/category/cycling/
     
  18. Sleeping menace

    Sleeping menace New Member

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    +1 on Ultegra cassette lasting longer
    dunno on the cranks.. I'm not a fan of shimano cranks/bottom brackets at all
    DA chain will last longer, but neither will last as long, or is as light as a KMC X10SL which is about the best chain out there..
    DA rear mechs are fragile.. They're a great race piece, but not for the weekend warrior who also wants to just put on miles. Ultegra is slightly heavier as a rear mech, but can be lightened with jockey wheels and a titaninum bolt for short money.. and will last 2x as long a a DA any day.
    DA brakes are OK..but the Token Accura brakes (AKA Planet X Lightweight CNC) are cheaper, lighter, and have at least as good stopping power.
    ... am not going to comment on electric ultegra..

    in closing.. having said all this about Shimano.. .. within a month or so.. I'll be running SRAM end to end.... with the KMC chain.. .. :)


    ........................ http://anotherdooratthe.endoftheinternet.org Cycle related blog entries, including a few 5 minute reviews: http://anotherdooratthe.endoftheinternet.org/category/cycling/
     
  19. Eichers

    Eichers New Member

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    Hi Sleeping menace, what is your comparision of the BB30 BB and the Hollowtech II BB :)
     
  20. Sleeping menace

    Sleeping menace New Member

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    sorry, screwed up a bit..see other reply..
     
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