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Pre-load on restrictor valving, Racetech G2-R?

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I'm setting up my '13 KTM 450 SX-F with Racetech G2-R Gold Valves in the forks and am a little confused as to what to do with the restrictor valve pre-load.  I've tried calling RT but they won't return my calls or e-mails.

I've set up a handful of my bikes with these valves and have always been pretty happy but have never played with the pre-load setting.  RT claims it makes the stack "digressive" or "progressive" but I don't know what that means.  The only info they really provide is that the "best preloads are usually between 0 an 0.10mm, but their potions are 0, 0.1 and 0.2.  ANybody have any experience with this?

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Progressive means that the stroke starts soft and progressively get stiffer.

Degressive means that initialy the stroke starts stiff but becomes softer as it continues thru the stroke.

 

I too have exchanged e-mails with Race Tech about restrictor valving and various other subjects,

in general I've found they are very informative but in the end actual testing in your riding conditions/skill ability

will determine what works and what doesn't in your specific application.

 

I'll continue updating this thread with the infos I've gathered.

Edited by mlatour

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Here's a thread I had started on the subject: http://www.thumpertalk.com/topic/1150827-gold-valve-restrictor-stack-preload/

 

My latest test has 0.05 preload on the restrictor stack, unfortunately my riding season is over so no more testing until springtime.

 

One thing I've learned with Gold Valves, if you are just going to slap stuff together don't assume that the 'on paper' preload and float values will be correct,

you must measure absolutely EVERTHING !

 

Because of production tolerances each part can be off by a few thousands (Race Tech's as well as you fork's OEM parts)

when attempting to adjust gaps in the .05 to .10 range it only takes a few thousands off on a few parts

to accumulate into a notable change in actual preload or float measurements.

 

-measure each individual shim's thickness making sure stacks in both forks have identical heights

 

-measure the spacers, cups, valve machined surfaces and especialy recess depths

 Sand with 800 grit sandpaper if required, making sure all parts and recesses are identical as possible in both forks.

 

-calculate preload with the actual parts measurements, recess depth versus shim stack height.

 Don't rely on the DVS suggested stack to have the correct preload if the recess height if off.

 

-physically measure the 'float' (mid-valve), re-adjust with shims to get the proper gap even if it means not following the DVS suggested packing stack.

 Again what is important is actual measurements, not the suggested shims that 'on paper' should give you the expected float.

 

Needless to say be very attentive to details and cleanliness,

after a few trials and errors, once you get the hang of it you won't hestate twice in taking the forks apart to fine-tune the settings.

Edited by mlatour

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Thank you for the quick reply, a bit of a "duh" moment for me.  I understand the concept of progressive suspension in general but was over-thinking it and thinking just about the individual valve stack in particular and not the overall suspension action.

I have set up a handful of my bikes with RT stuff and do know what you mean about measuring all the individual shims and the individual stacks.  The other times I did valve my bikes I was lucky in that I was very satisfied with the initial results and never had to go back in and fine-tune but the more I learn about the functions of each individual stack the better equipped I'll be to make fine-tuning adjustments.

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I think the amount preload on the Restrictor Valving only affects the action in the initial compression movement of the fork,

but once the stack lifts off the valve it no further affects anything thru the rest of the stroke.

Edited by mlatour

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I think the amount preload of the Restrictor Valve only affects the action on the very initial movement of the fork,

but once the stack lifts off the valve it no further affects anything thru the rest of the stroke.

That makes sense, like a cracking pressure on a check valve.

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I'm setting up my '13 KTM 450 SX-F with Racetech G2-R Gold Valves in the forks and am a little confused as to what to do with the restrictor valve pre-load.  I've tried calling RT but they won't return my calls or e-mails.

I've set up a handful of my bikes with these valves and have always been pretty happy but have never played with the pre-load setting.  RT claims it makes the stack "digressive" or "progressive" but I don't know what that means.  The only info they really provide is that the "best preloads are usually between 0 an 0.10mm, but their potions are 0, 0.1 and 0.2.  ANybody have any experience with this?

Johnny,

 

Can you send an email over to chris@racetech.com?   I will get any questions you have taken care of.  I'd also like to know who you've been trying to reach to ensure this isn't an ongoing issue as we take our customer support very seriously.

 

Thank you for choosing Race Tech!

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Johnny,

 

Can you send an email over to chris@racetech.com?   I will get any questions you have taken care of.  I'd also like to know who you've been trying to reach to ensure this isn't an ongoing issue as we take our customer support very seriously.

 

Thank you for choosing Race Tech!

 

Johnny, 

Why not just post the details here for others to benefit?

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Johnny, 

Why not just post the details here for others to benefit?

I am going to send an e-mail right now and I can post the reply here.  I've always done my own suspension but it's been a few years since I last did a setup and have never done WP stuff before so I'm feeling like I'm needing a "refresher" on some stuff.

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 With more preload on the G2 R it made it more linear less progressive , that wasn't the direction I wanted to go with the WP 4cs  , but would have been ok on the WP cc forks I had . I had to run more oil height with the preload and it ended up making more of the stroke harsh .

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I spoke with our R&D department and will follow up with an email for your settings question as well.

 

We recommend zero preload for offroad applications.  We typically only recommend running preload on the stack for supermoto settings.

 

The amount of preload determines the amount of force needed to initially open the stack.  Once it has preload, it will take more force to open the stacks initially and creates a harsher feel.

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Thank you again for the replies guys and I will wait for your e-mail Chris.  Thank you again, can't wait to get this done this weekend :)

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So what will shims smaller fiameter than the valve ports do? I am guessing it would make it progressive simce it acts lole a bleed port but more of a spike huh? Im just guessing also im going to start amd try to mess with mine

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RT_Chris I kind of struggle with where RT are going with their online marketing with forum postings, i understand your role is more marketing than technical but it sort of comes across as.......not sure if unprofessional is the word, but it just doesn't seem right that their forum posting guy doesn't have the technical knowledge of their products or even the general technical knowledge.  

I think it would be fantastic if someone more technical minded for RT or even the other companies factory connection, pro circuit etc would contribute more to forums like this and others. Terry Hay does a great job of explaining the benefits of RT products and what the end user can expect as an example.

 

sorry if it comes across as a personal attack but honestly i'm not trying to do that, 10 points for you for having a go. RT have some great products.

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