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Spring rate question

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Old 07-06-2009 | 07:23 PM
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Spring rate question

I wanted to beef up my fork springs but not sure to what. I heard they could bottom out easily but thought guys were crazy but mine's doing it on large potholes and stuff. My riding style is fairly aggressive but no track days serious. Now bikebandit offers 0.8 kg/mm, 0.85 kg/mm, 0.9 kg/mm, 0.95 kg/mm, and 1.0 kg/mm from raceTech. Any suggestions? Stock is almost 6
Old 07-06-2009 | 07:26 PM
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Anything over about .85 and you're looking at a revalve. The stock valving won't be able to keep up with the springs.

What you fail to mention, and is a key bit of information, is your weight.
Old 07-06-2009 | 07:30 PM
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around 170
Old 07-06-2009 | 07:32 PM
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Racetech has a weight calculator which appears down at the moment. This page has the link. http://old.racetech.com/evalving/eng...ngname=english

If you tell us your weight, I'm sure someone can tell you off the top of their head. I'm about 165 riding and could use either a .85 or .9. I switched to CBR1k forks and the stock springs were .88, which is just about perfect.
Old 07-06-2009 | 07:34 PM
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those are probably inverted too which is cool
Old 07-06-2009 | 07:42 PM
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Yeah, both Greg's in this thread have 'em. The big guy did his first and I followed.
Old 07-06-2009 | 07:45 PM
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does everything bolt up or do you have to change anything else?
Old 07-06-2009 | 08:07 PM
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Who you callin' "big", mister?

You might want to weigh your bike to use this spring rate estimate:
Attached Thumbnails Spring rate question-spring-rate.gif  
Old 07-06-2009 | 08:13 PM
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Are the CBR forks any lighter? and does it help steering or just suspension stuff?
Old 07-06-2009 | 08:16 PM
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There are a bunch-o-threads about forks swaps using different source bikes. Here's the link to Hawkrider's conversion.
https://www.superhawkforum.com/forum...ther+fork+swap
In the Knowledge Base there is a thread about the different forks to use.
https://www.superhawkforum.com/forum...ad.php?t=13401

I don't think any of the conversions are really "plug and play", but I was able to do my first conversion from just reading what others had done on this forum. Though I do know a little bit about wrenchin'
Old 07-06-2009 | 08:19 PM
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Originally Posted by Hawkrider
Who you callin' "big", mister?
If I had said "fat ***" you'd know I meant it "the other way".
Old 07-06-2009 | 09:11 PM
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Hey I resemble that...I mean resent that.
Old 07-06-2009 | 09:20 PM
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Originally Posted by RuthlessButcher
Are the CBR forks any lighter? and does it help steering or just suspension stuff?
I don't know about lighter. The triples are Al vs stock steel, but are much beefier. Everything else is just bigger diameter, including the rotors. But the wheel itself is a couple pounds lighter, so it may all be about the same in the end. More weight on the front of the VTR is a good thing anyway. I think there's a 45/55 front/rear weight bias stock, which doesn't exacly lend to great drive out of corners if the front wheel is in the air. Yeah, it's fun, but I'd rather have it planted.

As for steering, that all depends how you set it up. If you read my thread (linked above) then you'll know that I actually went through calculations for rake and trail as well as doing some trial and error after the build. Very rarely will you get it right the first time.

I have the 06 1000RR forks on mine, and after riding a while on my 04 RR with Ohlins internals I'm starting to think the 06 front end is a little harsh on the high speed compression. I will wait for a while before doing anything though. I only have another year up here in the land of frost heaves and potholes we call Upstate NY. The forks will probably be better suited for more southern/western pavement.

BTW, the braking performance alone was worth the effort. Of all the brake combinations I tried with stock forks (a variety of pad compounds, different masters, SS lines, and even Galfer Waves), nothing I did before compares to stock 1000RR radial calipers, rotors, and pads.

Hope this answers all your questions.
Old 07-07-2009 | 05:08 PM
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Thanks a bunch. Got me interested now
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