We finally got a good day in Ames. It's been what's seemed like weeks of rain. Yesterday promised 70 degrees and sunny. So when Paul said he was heading for a 60 mile ride, I had no excuse. I threw on some 42s on my Surly cause I thought it might be a tad mushy. But it ended up being some awesome gravel. It was a bit bumpy in spots, but dry and fast. As always, Paul had a great route picked out. The clouds were high cirrus, the crops were down, and it couldn't be clearer.
We ended up in a great big east then south then west then north loop. There was a little headwind heading south, but not too terrible. And even though it sounds like a boring square loop, there were actually a lot of fun loop, turns, and short hills. I rode out to meet Paul in Gilbert, then, since we had some daylight left, I road back with him for a few extra miles, which ended up to be about 70. On the way back I felt the first bit of lack of food bonking, but nothing too bad. It's funny how you can feel your legs and arms start to get really chilly with the onset of a lack of food bonk. But soon enough I was back and poptarts and a boost took care of it. Actually it's funny, when I get like that, I lay on the ground, nap for about 15 minutes, and that helps the most. I think allowing your body to stop sucking up energy helps a lot. Either way, I feel great today, and if it weren't for a bit of homework, I'd do it again. Thanks again Paul.
10 comments:
It was a perfect day for a ride that is for sure.
Believe it or not, I am feeling great today. Maybe not 100%, but at least 95%!
I can't wait to get on the bike again.
Sounds like a good day's riding. Could be a change in my employment in the future that might allow me to go riding on Saturdays instead of working. This is the type of riding I want to do if so! I went out by myself for about 2 hours today before the weather turned. I noticed that with the crops in the wind is a little more vengeful! No buffer. Also, if you missed #6606 on fixedgeargallery you must look! Later!
Make that 6066!
Hey Greg, that sounds good, hopefully before it gets too cold we can all get a good Saturday ride in.
I took a look at 6066, it's pretty cool what the art guys can do with computer systems these days. I've used Maya a few times, it's not easy to work with. It's got so many features to get lighting and materials just right. Really cool idea the guy has though. I sent my pics in, and haven't seen it show up yet, hopefully soon.
Alex, question:
Could you see any structural problems with chain stays that are pinched (oval cross section positioned) horizontally rather than vertically? On a steel frame that is. It would seem to me that it would provide some additonal vertical compliance (along with hour glass seat stays or some such), but make any lateral movement almost non-exsistent. Same idea as the Ibis currently on your site or Cannondale's Scalpel. Could steel stand the flex, albeit very minor.
As with many engineering questions: it depends:) The ibis design is very good, and it allows for tons of flex to squish the suspension. As a side note "critically damped" is never possible, and pivotless is only a good idea with Ti, not aluminum. I looked at the scalpel, and couldn't tell, is there a pivot? Laterally, a complete carbon fiber box would have been stronger. The pinch doesn't seem to do anything.
If you would pinch the stay, the further you get to the BB, the more flex you'll get. And the more pedal bob you'll get. Don't take the pinch all the way to the BB cause the shear stress on a weld on a horizontal piece would be very high. (Castellano gets away with it because he brings the stays together into one fat wide piece). I would pinch in the middle, then pinch vertically toward the BB. There would be a sweet spot to transition based on your weight and power. I think you have a better chance of getting a good balance by just looking at vertical compliance with the seat stays, and focus on weld strength and lateral/vertical stiffness with the chainstay. But if done correctly, you could create a very nice ride by doing that:)
Forgot one thing, Salsa claims to do this with their Chili con crosso and dos niner. They do it similar to what I described. You might look at them:)
Actually the Dos Niner's chainstays are precisely what I had in mind, only with a non-suspended hourglass seat stay arrangement. Do you think steel could handle the flex like the Scandium? Obviously what I have in mind wouldn't have the range, so maybe flex wouldn't be an issue. Do you think there would be any noticeable benefit over traditional chainstays.
Actually, you probably better read this:
http://www.strongframes.com/material_tech/metallurgy/
That will explain it better than I can. You really shouldn't design it after the dos niner. They claim something good, but executed it poorly with the worst material. Of course steel will flex way more than scandium. (As they say, "have you ever heard of an aluminum spring?") Just cause steel's stronger, doesn't mean it can't flex as much. The %elongation of steel (and Ti) is way better than aluminum (=scandium). It'll also be called modulus of elasticity. Because bike makers get the strength/weight fairly equal in most bikes, the "strength" of steel is not going to create a stiffer ride anymore cause the tubing is thinner, and smaller in diameter. The modulus can be thought of "bend before break". The higher the modulus of elasticity (Young's modulus) the longer the fatigue life too, which is by far the most likely cause of failure (especially at the weld). The dos niner just over compensates with a huge weld, and therefore never actually gets the amount of travel that it claims.
Steel would make this design possible. If you have S bend seat stays, and thin/lightweight steel seatstays, I think you'll be shocked how much more compliant it will be over even your 1x1.
As a side note, that 7 part series is by Scot Nicol, involved with ibis at it's start. Castellano uses Pro Engineer Mechanica
http://www.ptc.com/appserver/mkt/products/home.jsp?k=1183
I've used many similar "Finite Element Analysis (FEA)" packages. It is what most people will use at big companies to determine the stress/strength of things like bike frames.
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