could i put a set off 11 strings in a American special strat HSS with C shape neck with the properly set up or this its going to create a problem ....
Thanks for the help ..

Shouldn't be a problem, but you may have to make slight adjustments to the saddle height, and possibly the truss rod.

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Shouldn't be a problem with a proper set up.
Some nutwork may be required considering the strat is factory
set up with 9s.

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"Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the present."

oogway, kungfu panda 2008

If the bridge is floated or flush but not blocked, the bridge *will* pull up with heavier gauge strings and you'll have to adjust the spring tension as well.

Here's a link to the Strat setup guide:

http://www.fender.com/support/articles/ ... etup-guide

Read through the entire guide before you start the work!

Good luck!

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"The individual is handicapped by coming face to face with a Conspiracy so monstrous he cannot believe it exists. The American mind simply has not come to a realization of the evil which has been introduced into our midst." J. Edgar Hoover

+1 @ RCB-CA-USA

When I changed from 9s to 10s the pull from the strings raised the floating bridge more than double from its original factory setup. I was able to lower it back to spec with few turns on the spring tension screws. I've never used 11s but would imagine that the pull would be even greater so you "may" require more springs.

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This is the Blues. Are you listening?

You'll need to make some adjustments to the floating bridge and trem springs but otherwise you'll have no problem, if anything, you're adding meat to your tone. I had both my American Special and American Standard strung with 11s and they were great.

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2012 Fender American Standard Stratocaster
2013 Fender Pure Vintage 65 Stratocaster
2003 Gibson ES-355
2015 Gibson Les Paul Traditional
2002 Gretsch Duo Jet
1980 Rickenbacker 360/12 Fireglo
2014 Martin 000X1AE
2014 Fender Blues Junior III