# Look Frame Stiffness Comparison Chart



## sirbikealot (Apr 8, 2005)

I've seen many questions regarding stiffness between frames etc so here is a chart from Look outlining the stiffness characteristics of their 2005 models

RIGIDITE COMPARATIF LOOK RELATIVE RIGIDITY

Higher number Equals Stiffer. Un chiffre plus large indique plus de rigidite

Model/	Rear Triangle/ BB/	Steering


KG451 58 157 94

KG461 60 192 118

555 60 192 118

KX Light 61 170 97

KG386 58 160 104

KG481 61 172 100

KG486 70 182 100

585 65 165 95

KG496 Athens	160 220 125


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## blueman (Apr 20, 2005)

I love my kg 461... had no idea it was one of the "stiffest" in their line up. rides like butta.


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## sirbikealot (Apr 8, 2005)

blueman said:


> I love my kg 461... had no idea it was one of the "stiffest" in their line up. rides like butta.


yep when you look at the size of the down and seat tubes they are much larger than any of the other bikes, remeber its custom handmade look carbon so stiffness doesn't mean harshness


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## orange_julius (Jan 24, 2003)

Thanks for posting these numbers. ''Le Cycle'' puts the bikes that they review through the same kind of testing, subjecting the BB, rear triangle and head tube to load and reporting the numbers. I found it very informative. Unfortunately I also found the price of subscribing to Le Cycle somewhat prohibitive in the US ;-).


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## hairscrambled (Nov 18, 2004)

I like my 461 even better now. The guy that said his 555 was a better sprinter than his 461 must have had something else going on.


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## orange_julius (Jan 24, 2003)

*Not just about numbers*



hairscrambled said:


> I like my 461 even better now. The guy that said his 555 was a better sprinter than his 461 must have had something else going on.


A lot of factors can make you a much better or far worse sprinter: fit, position, weight distribution, etc. So I can totally see that a less stiff bike, with better weight distribution, can make somebody a better sprinter. Some people like to rock their bikes more than others, and so on and so forth.


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## RocketDog (Apr 9, 2005)

I find some of these numbers to be quite counter-intuitive. I've always assumed that the 486, 386, and Kx Light would be among the stiffest, particularly in the front end and bottom bracket based on tube size and shape. The 461 is a real surprise. Just goes to show what I can tell about a frame by looking at it. Not much.


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## blueman (Apr 20, 2005)

I think this also goes to show that people make too much out of "stiffness". A lot of the Look bikes that have been raced in the grand tours were probably assumed to be the stiffest most race worthy of the group. I think that these numbers show that comfort on a bike, especially at the tune of six hours a day, probably trumps just a little stiffness. Or, in other words, you don't have to have the stiffest bike to keep up with the big dogs. Sometimes a stiff enough bike that's comfortable is all you need.


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## spookyload (Jan 30, 2004)

Another possible reason for how a bike "feels" in a sprint is the build. Different lateral stiffness on wheels, tire inflation, crank flex, and many other items will make a bike feel different and have nothing to do with a frame.


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## Lactic Acid Racing (Feb 3, 2005)

A flexier frame would release more elastic energy in your dead spot, making your pedal stroke smoother... stiffer doesn't mean better sprinting

...wow, didnt know my 361 (current 451) was so flexy..

btw, my teammate, Jeff Castenmiller is racing Tour de Abitibi right now on his 386, was 20th overall after stage 3, now he's 33rd overall . Next year, we're sending our whole team to Abitibi instead of Team BC and then will have 4 looks racing there


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## blueman (Apr 20, 2005)

I wouldn't count on riding a flexy frame so that it releases energy into your pedal strokes. I agree with the logic of your argument, but think that you might be reaching for a explanation why "flex" is "good".

There doesn't seem to be a benefit in having the frame flex b/c the flex cannot be released into the wheel's rotation which would propel you forward. Instead, lateral flex usually just means the bottom bracket sways back and forth, creating no performance benefit. Some would argue that this eats up the energy you are creating and attempting to get to the wheel through the chain.

I will say that there may be no performance loss with a "flexier" bike... up to a point. Especially for real world performance... and non-pro riders.


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## 6was9 (Jan 28, 2004)

*That's nice to know...*

So now I know that I have the top two stiffest Look frames, 486 & 461, beside their track frame 496.

I'd like to see how C50 and other frames compare as well... it's nice to see the actual numbers.


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## peterpen (May 5, 2004)

6was9 said:


> I'd like to see how C50 and other frames compare as well... it's nice to see the actual numbers.


Umm, but what do these numbers actually represent? I'd like to know how they were generated - or at least the units?  It does seem bizarre that according to these numbers the 585 BB *and* front end are flexier than the 481, especially when much of Look's marketing of the 585 has emphasized how stiff the BB is. According to these numbers, the 585 BB is the flexiest of the entire lineup bar the low-end 386 and 451.


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## RocketDog (Apr 9, 2005)

peterpen said:


> Umm, but what do these numbers actually represent? I'd like to know how they were generated - or at least the units?  It does seem bizarre that according to these numbers the 585 BB *and* front end are flexier than the 481, especially when much of Look's marketing of the 585 has emphasized how stiff the BB is. According to these numbers, the 585 BB is the flexiest of the entire lineup bar the low-end 386 and 451.


It's also nearly a POUND (or more) lighter than almost all the other frames. I've ridden a 585 and found it to be a really superb bike. I own a KX light and really enjoy it. If you look at the stiffness/weight ratio the KX light should be at the very low end of the line.

Bottom line, Look manufactures fabulous bicycles. Top to bottom of the line. I'm guessing by your avatar that you own a 585. Don't let some silly chart detract from your opinion of the bike. Like you said, none of us know anything about how the testing is conducted and what the numbers mean.


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