Egg Beater 4ti Tuning 115gr(carbon spring)/122gr(Ti spring)

Discuss light weight issues concerning mountain bikes & parts.

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by Epic-o


You may have seen the 5.97kg Cannondale Flash that S. Roth presented in the Eurobike (pics 1 and 2)...that bike had a pair of Crank Brothers EB 4ti that weighed 139.2gr. A very nice weight but we still can push the boundaries a bit more.

This is a pic of a disassembled CB EB 4ti already tuned (pic 3) but still a bit "heavy". Basically, we have to modify every single part (weights per pedal).

Normal weight (pic 4)

First, we work with the main wings polishing the body and shaving the combs of the ends of the body (pics 5 and 6). 3.3gr less

The secundary wings have not combs but polishing them we can reduce 0.5gr

The body where the spring is placed is made of Ti and weighs 5.4gr. In we can get an aluminium version(<80kg) that weighs 3.5gr/piece (pics 7 and 8 ). 1.9gr less

This is the main change, the normal spring is made of steel and weighs 11.5gr. Coparni have made a carbon version with an amazing weight of 1.3gr (pics 9 and 10). 10.2gr less

The only part that we haven´t changed is the axle. The normal one is made of Ti6Al4V, weighs 31.5gr with a length of 91.58mm. We can get a Ti6Q2 version in that measures 88mm and weighs 28.65gr (pic 11). We reduce the Q-Factor 7.16mm and 2.85gr

I haven´t found any pic of the bearings of these pedals but I use these of a Speedplay Zero that are about the same size. Changing the bearing body that is made of steel to a plastic one (pics 12 and 13) we reduce 2.5gr

Next, changing the normal bearings to a Full Ceramic version (pics 14 and 15) we reduce 1gr

The only nut of the pedal is made of steel but we can find aluminium security nuts in TorontoCycles. We reduce 1.9gr

Finally, changing the pedal cap to a plastic one we reduce 0.9gr

Total weight, (83-25.1)x2 = 115.8gr
Last edited by Epic-o on Thu Dec 10, 2009 11:35 pm, edited 2 times in total.

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by Epic-o

Last pics...

And a video of the carbon spring:

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by Griswald4x4

WOW! I am really hugely impressed. Crank Bros should take a listen. They could charge a ridiculous amount for those puppies. So could You 8)

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by ResurrectionRacing

That is some seriously hard work... If you did evey part as well as these you would have some silly weight bikes...

Best part for me is not only saving the weight, but these will still work...

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by 1415chris

Great staff

Looks like the easiest way to go under 150g with your 4ti is changing the spring.

Where can you get it from?

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by Epic-o

The spring is still a proto but....

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by Super_fast

The carbon spring looks to be a lot less stiff then the original spring. Clipping in and out seems to go without any force?

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by 1415chris

Watching video clipping in wasn't that hard indeed but the cleat doesn't look new either.

I don't expect to have the same resistance force like steel spring, but if it's enough to ride definitely worth to consider.

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by wadsy

Good effort :shock: :thumbup:

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by GuNKiLLaH

If you can fix It with your hand (VIDEO), It's too soft for riding.
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by Jaker

That's not neccessarily true. I can clip in and out of my EggBeaters with my hand holding my shoe, yet they stay in just fine when I'm riding. The video makes it really difficult to see how much force is being used to clip in. Clipping out is dead easy when you twist the shoe to the side like the video shows.

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by Nicola

carbon springs? uhmm.....where are they "normally" used for??

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by CGT

I too wonder whether carbon springs will work in the long run. Amazing job by the way!

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by DMF

Sure the spring-tension may be ´enough´ for riding... but if you actually rode those pedals in a REAL offroad-situation, stood up and applied the full amount of force in your legs on both the push- and the pull-motion on an uphill section, i seriously doubt that you'd stay clipped-in... it kind of seems that this weight-saving is gonna end up loosing a lot of speed and control, and aren't those two things the main-purpose of actually loosing weight on a bike?

Impressive amount of work put in to the details though! Put I'm thinking the outcome is gonna be that more is lost than gained on this one... But I hope you prove me wrong on this one! :)

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by legsrburnin

This may be old news, but my LBS told me last week that the new Keo road pedals will have a carbon spring (maybe a carbon spindle too, but cant recall if that was true?)

I know it's road stuff, but what it means is that it's functional to a point that a major brand is using them.

Mtb usually follows close behind road once they beef it up a little.
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