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Bases not flat - time for a grind?

post #1 of 14
Thread Starter 

I took a straight edge to my 3 year old Blizzard Titan Cronus bases. Lots of light from concave bases (ie: edges higher than base center). Is this the time to get a grind to flatten them out?

What are the on-snow symptoms of a ski with a concave base?

Thanks.

David

post #2 of 14

ARE YA CRAZY???

You know the answear before you posted here on this one!!

If you use a true bar and see copious amounts of light under the bar ya have no choice dave.

Besides 3 years ..no big deal to run them over the grinder.

Or just ski somthing else!!

post #3 of 14
Thread Starter 
Quote:
Originally Posted by Old Boot View Post

ARE YA CRAZY???

You know the answear before you posted here on this one!!

If you use a true bar and see copious amounts of light under the bar ya have no choice dave.

Besides 3 years ..no big deal to run them over the grinder.

Or just ski somthing else!!


Dang Brother Boot, did you get up on the wrong side of the floor this morning?biggrin.gif

"Ski something else." Going to tell Ms D1 that you said I need new skis - a pair of Kastle MX 88's I think it was.

Regards to the Lady......
 

post #4 of 14
Quote:
Originally Posted by deliberate1 View Post




 

"Ski something else." Going to tell Ms D1 that you said I need new skis - a pair of Kastle MX 88's I think it was.

 


Now that's creative! Get out your oldest skis, gouge some p-tex out of the middle, post, on Epic that your skis are concave and now crap, show to post to wife and then go buy new Kastle MX88's.

 

d1, if you get away with that one, you're a far better fast-talker than the average Bear!

 

but, I like your thinking.

,

post #5 of 14
Thread Starter 
Quote:
Originally Posted by Living Proof View Post




Now that's creative! Get out your oldest skis, gouge some p-tex out of the middle, post, on Epic that your skis are concave and now crap, show to post to wife and then go buy new Kastle MX88's.

 

d1, if you get away with that one, you're a far better fast-talker than the average Bear!

 

but, I like your thinking.

,



LP, way too complicated.

Occurs to me that the Blizzards and Kastle's are remarkably similar in appearance. If I take a little white spray paint to the Kastle tip and and a little festering green to the tail - voila - a pair of three year old Blizzards.

Also seems to me that Kastle could dramatically increase sales among those with watchful spouses if the colored discs that distinguish their various models were interchangeable. One disc for several different skis.....brilliant.

 

 

 Go to fullsize image

 

  

Go to fullsize image

post #6 of 14
Quote:
Originally Posted by deliberate1 View Post

I took a straight edge to my 3 year old Blizzard Titan Cronus bases. Lots of light from concave bases (ie: edges higher than base center). Is this the time to get a grind to flatten them out?

What are the on-snow symptoms of a ski with a concave base?

Thanks.

David

They're toast.  Sent them to me to properly dispose of themdevil.gif
 

post #7 of 14
Thread Starter 
Quote:
Originally Posted by crgildart View Post



They're toast.  Sent them to me to properly dispose of themdevil.gif
 


I would, but you are far too nice a guy for me to burden you in that way.
beercheer.gif

post #8 of 14

Seriously though, I've heard that some race skis and carvers have intentionally somewhat concave bases near the shovel and tail of the ski.  Is it concave under the boot or just on the ends?

post #9 of 14
Thread Starter 
Quote:
Originally Posted by crgildart View Post

Seriously though, I've heard that some race skis and carvers have intentionally somewhat concave bases near the shovel and tail of the ski.  Is it concave under the boot or just on the ends?



I ran the straight edge which showed concavity along the entire base. And these are not race/carvers - 88mm in the waist and no metal internals. I know it is perhaps a nube question, but I have never given the flatness bases much thought even though I should. So can you tell me how a concave base affects performance. I read that you should have flat bases. I just want to know why. Tx

post #10 of 14

A concave base makes the ski run straighter than it normally would, because the guiding tunnel effect of the concavity fights against the turning effect of small-angle edge engagement.

 

If you only use small-angle edge engagement that makes the ski very problematic.    Sounds like you use bigger angles, so flattening the base wouldn't solve a problem for you so much as make the ski more responsive to the small angles you have as you are moving towards the bigger ones you use.

 

Base concavity can also mess up the edge bevels if you use hand tools. 

post #11 of 14
Thread Starter 
Quote:
Originally Posted by comprex View Post

A concave base makes the ski run straighter than it normally would, because the guiding tunnel effect of the concavity fights against the turning effect of small-angle edge engagement.

 

If you only use small-angle edge engagement that makes the ski very problematic.    Sounds like you use bigger angles, so flattening the base wouldn't solve a problem for you so much as make the ski more responsive to the small angles you have as you are moving towards the bigger ones you use.

 

Base concavity can also mess up the edge bevels if you use hand tools. 


Thanks for that. Makes sense.

So if a ski feels a bit squirrely running flat, is a concave base one possible explanation?
 Edit: Sorry, went back and reread your post. You are suggestng that a concave base actually maeks a ski runs more true when flat. No?

post #12 of 14

How concave are they?  If it is just the thickness of say a piece of paper I'd flatten them out.  If it is much more than that then you're going to be taking down a lot of your edge and thinning the p-tex next to the edge to make them truly flat.  If they are say over a 1/16th" railed then I'm guessing they are supposed to be that way.

post #13 of 14
Quote:

So if a ski feels a bit squirrely running flat, is a concave base one possible explanation?
 Edit: Sorry, went back and reread your post. You are suggestng that a concave base actually maeks a ski runs more true when flat. No?



Not likely; there would have to be weird things going on at the edges themselves.  Like burrs or off angles or ...weird things.

 

Convex base -> "squirrelly"   is more likely than Concave base -> "squirrelly".

 

In regards to your edit, yes, that is what I am saying.

post #14 of 14
Thread Starter 
Quote:
Originally Posted by crgildart View Post

How concave are they?  If it is just the thickness of say a piece of paper I'd flatten them out.  If it is much more than that then you're going to be taking down a lot of your edge and thinning the p-tex next to the edge to make them truly flat.  If they are say over a 1/16th" railed then I'm guessing they are supposed to be that way.



I will run the true over again. My sense is that it is < 1/16th ".  Will stick a piece of paper under the the bar to measure. Thanks for that tip.icon14.gif

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