Booster

[carnagr]

Lately I've noticed my booster (Salsa Carbon, on a Simtra) has been flexing quite a bit. I like my brake to be fucking stiff, and every other part of it is damned expensive, so it's a waste of all my money if my brake is mushy because I have a shitty booster.

I want to hear what boosters are stiff as fuck. Has anyone tried one of those 74Kingz boosters from tarty? They're damned expensive, so they must have something going for them...

[besham]

I also have a flexy booster. Until you find a new one, try to "preload" the booster. Tighten one bolt then pull and strech the booster as hard as you can while someone else tightens the other bolt. It takes two people to do it right but works very well. Good luck

[myergin]

my mother fucking booster is mother fucking stiff!

[carnagr]

Forgot to mention it's vees.

[carnagr]

my mother fucking booster is mother fucking stiff!

What motherfucking booster do you motherfucking run?

[SpeedyS]

My homemade mother fucking booster is super fucking stiff and it's made from 8mm 6061 mother fucking aluminum.:naughty:

[Darren]

Hey Curtis, My fucking Echo booster is pretty Fucking stiff, and it was Damned cheap! I used to run an RB which was Damned good looking, but the echo is a Fucking lot stiffer. good luck. fuck.

[heatsink]

It's a shame it's not a 4 bolt one you're looking for:

http://www.heatsinkbikes.com/content/Boosters/goldbooster.jpg

One day I'll get a Vees version of this sorted out! Getting there....

Steve

[Total Uni]

1) Make one

2) Use steel, stiffer,wont fatigue.

[CoppellStereo]

i thought steel was flexier than aluminum?:dunno:

[Total Uni]

I dont know what you mean about "Flexier" But this should give you a good idea:


Steel is at 30 modulus (Modulus - stiffness)

Titanium at 16ish

Aluminum at 10ish

[CoppellStereo]

well by flexy i mean the stiffness of it, i was saying i thought aluminum was stiffer

[Total Uni]

Aluminum is 1/3 as stiff as steel. Steel is the way to go for a booster. Though it is harder to machine, you could draw a good outline, and rough cut it on a bandsaw or something of that sort then sand the edges round, Then with a drill press or mill drill your holes.

[CoppellStereo]

hehe, i think you are reading sheldon brown

[Total Uni]

Truthfully, i just checked there to double check the stiffness of titanium.


But i did know the stiffness of aluminum and steel i sware! lol.

[Don Coyote]

Steel is also about 3x more dense than aluminum, so your steel booster will weight 3x as much. An aluminum booster will have less flex by weight, which is what is important.
XTR V boosters are pretty good if you can get one. It's also carbon, but more of an I-beam shape than the salsa, so likely stiffer, and that was also the XC consensus back in the day. Having more material where the highest stresses are is most important about a booster, and the XTR beats the Salsa there. Sorry, can't say if it's stiffer than any of the trials v boosters, I don't use em.

[heatsink]

Here are some figures. The grades aren't precisely what you'd use for a booster, but remember that stiffness doesn't change across grades of a set metal.

There's an interesting thing you'll find if you find your own figures aswell: There are a variety of metals that have matching strength/density (weight) ratios. This is the key thing, which seems to so easily be over looked when marketing steps in! So if you produce the booster to the best shape (material on outside and inside of booster where the compressive and tensile stresses respectively are at their maximum) boosters weighing the same in steel and alu can be made to have matching stiffness.

Alu has the advantage of being softer so making it more attractive to both CNC (bulk production) or hand cut (one off in the shed)

I've never heard of any booster snapping due to fatigue, even the thin ones. So the benefit which Steel and Ti have of an Endurance limit (a stress level below which no fatigue will ever occur) doesn't seem to be required.

You can extend the comparision and look at Titanium too. I believe the price of Ti has gone up more relatively to Alu and steel recently though.

Steve

[Total Uni]

Steel is also about 3x more dense than aluminum, so your steel booster will weight 3x as much. An aluminum booster will have less flex by weight, which is what is important.
XTR V boosters are pretty good if you can get one. It's also carbon, but more of an I-beam shape than the salsa, so likely stiffer, and that was also the XC consensus back in the day. Having more material where the highest stresses are is most important about a booster, and the XTR beats the Salsa there. Sorry, can't say if it's stiffer than any of the trials v boosters, I don't use em.

I see...Weight...yes....You trials guys do like light stuff dont you. Well i am making a steel booster, il post results.

[eturt9]

For v's, make sure you have your booster lifted up about a half inch or so with spacers. Then the booster can have more leverage on the bolt holes..

and that heatsink booster can have my babies. I only wish it came in v style.