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Right. Yep. They are completely separate.
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Well, there should have been. It's always about finding the right point between tip and slip, so the two things are intimately connected.
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rear wheel slipping during out of saddle acceleration is def more a problem on the velodrome than on the road bike for me, but I never got fit for the stuff i ride : )
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I'm confused. And not convinced a longer wheelbase wouldn't be better when climbing in slippery conditions.*
- based on gut feeling rather than the physics.
Well, I can see why you're confused, you're not doing mathematics. I cba to do the necessary drawings to explain it to you, but it's not rocket science. As long as you can get the front wheel on the point of lifting, you're getting max traction. If you're standing on the pedals, that's very unlikely so you can just keep shortening the stays until you run out of ideas (curved/split seat tube, flying gate, whatever) because you'll never get them too short. If you're going to sit down, longer stays help because you already have your weight too far back, but you only need to keep lengthening the stays until the front wheel stays on the ground, once you go past that you start losing traction because the front wheel is taking some of the normal load which you really want to be supported by the back wheel.
- based on gut feeling rather than the physics.
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You wouldn't believe the amount of 'engineers' in work that waffle on about how bikes are simple and they know more than you because they have a degree in building bridges, housing developments, or fixing tanks etc... When in fact they are just looking for some one to listen to them waffle that can't walk off or tell them to shut up. Sometimes it is interesting, but most of the time it isn't because it is in no way related to what you are trying to do while they waste your time.
Some times it feels like that here.
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haha
let me trytester: shut the fuck up, thx
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i like tester's contributions on here
he can be annoying because he is generally right, but i appreciate and respect his general technical knowledge
plus he can be more terse and rude than me at times
i'd rather read his accurate and informed posts than the ill reasoned opinions of many other people
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If we had only facts there'd be almost nothing to talk about.
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Well, I can see why you're confused, you're not doing mathematics. I cba to do the necessary drawings to explain it to you, but it's not rocket science. As long as you can get the front wheel on the point of lifting, you're getting max traction. If you're standing on the pedals, that's very unlikely so you can just keep shortening the stays until you run out of ideas (curved/split seat tube, flying gate, whatever) because you'll never get them too short. If you're going to sit down, longer stays help because you already have your weight too far back, but you only need to keep lengthening the stays until the front wheel stays on the ground, once you go past that you start losing traction because the front wheel is taking some of the normal load which you really want to be supported by the back wheel.
Thanks for bothering to explain this. The idea that traction is optimal just as the front wheel lifts (whatever the weight distribution or wheelbase) is new to me – but makes perfect sense.
Repped.
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Did you study Physics or Engineering Tester? Or do you just have a deep passion for it
Also would you care to explain the equation above?Physics to A level, engineering for the love of it.
The equation gives the eventual speed of a rocket in space (no gravity, no aerodynamics) for a given initial speed, structure mass, fuel mass and exhaust velocity. It is a form of the [ame]http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation[/ame]. As such, I use it as punctuation when I use the expression "it's not rocket science"
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I had a gary fisher mtb with genesis geometry (short chainstays, long top tube, short stem). It claimed that it improves climbing and descending.
It's true in wet/slippery conditions and this is why: Your weight is distributed more on your backwheel, and grip(friction) is a result of force (weight) x friction coeficient (nature of the materials in contact).
However your moment of inertia is decreased (perpendicular distance squared x mass) hence more prone to wheelie and fall backwards.
so if you've got an extremely steep hill that's dry: get long chainstay and a steep seat tube, if you've got very slippery hills, get short chainstays or a layback seatpost. -
Superb!
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I had a gary fisher mtb with genesis geometry (short chainstays, long top tube, short stem). It claimed that it improves climbing and descending.
It's true in wet/slippery conditions and this is why: Your weight is distributed more on your backwheel, and grip(friction) is a result of force (weight) x friction coeficient (nature of the materials in contact).
However your moment of inertia is decreased (perpendicular distance squared x mass) hence more prone to wheelie and fall backwards.
so if you've got an extremely steep hill that's dry: get long chainstay and a steep seat tube, if you've got very slippery hills, get short chainstays or a layback seatpost.All makes sense but in reality I won't have two different frames depending on if I think any steep hills are going to be wet or dry. The question is does a frame with a 15mm longer chain-stay length make may difference when actually riding it and not just talking about the theory?
I would just compensate by moving body position around (as I do already) and it is my expectation I wouldn't even notice after a few rides. -
This is all very true, and you can build an excellent bike with physics but there is no guarantee that a bike with great numbers won't ride like a bag of shit. The numbers aren't always right when it comes how a bike feels when you ride it.
A close friend of mine was riding for a team run by a management company that imports custom made carbon bikes from France, as a race bike for last year, because they didn't make one already he asked them to copy the exact geometry and size of his Cannondale Flash 29er from the previous season. They copied it exactly, if you lined it up and measured it, it had all the same measurements. Yet his new bike rode like a shed, nothing like the original. -
COLNAGO Master Olympic Decor
http://2velo.com/wp-content/uploads/2012/11/COLNAGO-Master-Olympic-Decor-3459-1024x685.jpg
http://2velo.com/wp-content/uploads/2012/11/COLNAGO-Master-Olympic-Decor-3460.jpg
http://2velo.com/wp-content/uploads/2012/11/COLNAGO-Master-Olympic-Decor-3508-685x1024.jpg
more PHOTOS
can somebody tell me what is production date of this Colnago master olympic Decor
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@Velocio
As long as the front wheel is pressing on the ground, your CG is too far forward to maximise traction. If longer stays mean your front wheel is skimming the road when you sit and climb, that's an improvement over short stays which would mean the front wheel was coming up to meet you, but that's not an improvement in traction, it's an elimination of tipping over backwards.