FOX Podium RC1 shocks - Help

FunJimmy

FunJimmy

Been Around the Block
Does anyone have experience with setting up FOX Podium RC1 shocks?

I recently purchased a pair but can't seem to get the correct sag setting using Fox's softest spring. Typical rule of thumb is 25% suspension sag with rider. According to Devin, these shocks have 3.47" of stroke so a good starting point would be about 7/8" (22mm) sag. Even with the softest springs the maximum amount of sag I get with 190# rider is 7mm. Only 1/3 of the ideal amount of sag. These shocks are WAY to stiff for our bikes.

How can Fox get it so wrong with over 40 years of technical expertise in the performance suspension business?

Does anyone have experience or a spring rate recommendation to suggest? I don't want to be shipping a whole lot of springs back and forth to get this right. I shouldn't have to!

 
Did FOX design the shock for "our bikes" or did Devin and FOX come up with a plan to move some product in a seemingly stoopid market.
 
What is your bike and rider combined weight? And how long is the spring free length versus its length when set to minimum preload on the bike? 85lbs/inch springs are very soft. I run 90lbs/inch springs on my 270lbs Rd350 and I weigh 140lbs. My guess is that either your bike is too light or there is too much preload even at the minimum setting.
 
Sav0r said:
What is your bike and rider combined weight? And how long is the spring free length versus its length when set to minimum preload on the bike? 85lbs/inch springs are very soft. I run 90lbs/inch springs on my 270lbs Rd350 and I weigh 140lbs. My guess is that either your bike is too light or there is too much preload even at the minimum setting.
Click to expand...


Good point. I haven't weighed the bike (CB550F) but I tip the scale at a lofty 193#. According to Fox's spring code the free length is 9" and the length at minimum preload is 8 1/4". That's a lot of preload!



 
(.75)(85)(2)=127.5lbs of spring force as they sit. That's not what I would call a lot, but it is certainly significant. If you could get rid of that preload you would be a lot closer, but I'm not sure that's your issue. I googled the CB550f, it says 420lbs (stocK). Your bike and rider combo weight should be fine, if not a bit heavy for those 85lbs/inch springs. Are you sure your swingarm is moving freely? Make sure you aren't binding up the shocks at their mounting points, specifically the top one.

The spring rate estimator on my site says that you should get around .5" of sag even with the .75" of preload. Links below for the basic and advanced estimators. You can play around with them and get an idea of where you should be.

http://chrislivengood.net/wp/spring-rate-estimator/
http://chrislivengood.net/wp/advanced-spring-rate-estimator-new/

Edit: and just to be sure, and honestly I am not trying to insult your intelligence here but rather trying to be thorough, make sure your chain tension is loose enough to allow for the swingarm to move.
 
Sav0r said:
(.75)(85)(2)=127.5lbs of spring force as they sit. That's not what I would call a lot, but it is certainly significant. If you could get rid of that preload you would be a lot closer, but I'm not sure that's your issue. I googled the CB550f, it says 420lbs (stocK). Your bike and rider combo weight should be fine, if not a bit heavy for those 85lbs/inch springs. Are you sure your swingarm is moving freely? Make sure you aren't binding up the shocks at their mounting points, specifically the top one.

The spring rate estimator on my site says that you should get around .5" of sag even with the .75" of preload. Links below for the basic and advanced estimators. You can play around with them and get an idea of where you should be.

http://chrislivengood.net/wp/spring-rate-estimator/
http://chrislivengood.net/wp/advanced-spring-rate-estimator-new/

Edit: and just to be sure, and honestly I am not trying to insult your intelligence here but rather trying to be thorough, make sure your chain tension is loose enough to allow for the swingarm to move.
Click to expand...

No offence taken. I agree. Leave nothing to chance. The swingarm is a Dresda and moves freely on sealed bearings. Chain is confirmed to be adjusted correctly without any binding at all.



The Works Performance shocks that I'm replacing have lighter springs. Not sure what the spec is but they allow full travel (albeit a bit too soft) without and issues.

Could the Fox springs be stiffer than claimed?

The Works springs are; 8" free length, 2.250" OD, 0.250" wire diameter, 10 total coils.

Fox springs; 9" free length, 2.40" OD, 0.275" wire diameter, 10 total coils.
According to the spring calculator below the Fox springs should be 107 in/lbs

http://www.thespringstore.com/spring-calculator/spring-rate-calculator.html



Thanks for the help.
 
I did the calculation and came to almost exactly 85lbs/inch for the fox spring. And when I used the calculator you provided I got 87lbs/incb.
 
Sav0r said:
I did the calculation and came to almost exactly 85lbs/inch for the fox spring. And when I used the calculator you provided I got 87lbs/incb.
Click to expand...

Sav0r

Thanks for the confirmation.
Could you confirm what the Works springs are?

Thanks a bunch
 
I get 70lbs/inch for the Works spring.

What is the ID of those springs on the Fox units? I think I have a new set of 75 lb/inch springs with a 1 7/8" ID and 8" free length on my shelf. Though I can get them as soft as 50lb/inch and 60lb/inch in those same dimension. Send me a PM, I can give you pricing.

The damping of the shock shouldn't effect your sag, but there is something odd going on here. You should be getting more sag than you are, even with that much preload. I wonder how much canister pressure the fox uses?
 
Sav0r said:
I get 70lbs/inch for the Works spring.

What is the ID of those springs on the Fox units? I think I have a new set of 75 lb/inch springs with a 1 7/8" ID and 8" free length on my shelf. Though I can get them as soft as 50lb/inch and 60lb/inch in those same dimension. Send me a PM, I can give you pricing.

The damping of the shock shouldn't effect your sag, but there is something odd going on here. You should be getting more sag than you are, even with that much preload. I wonder how much canister pressure the fox uses?
Click to expand...

I think the centre number of the Fox spring code is ID. If that's correct 1880 is 1.880" ID. I haven't removed the springs but I'll try to get a measurement when I get home.
 
I pulled one of the Fox springs and confirmed 21.5mm of preload due to the excessively long springs. That combined with 7mm of sag would net out to approx 28mm with correct length springs. That's about the right amount.


 
I'd like to shout out to Chris (Sav0r) and CL MotoTech for all the help sorting my spring issues. Chris located Eibach 8" springs in 72.8lbs/in (1.3 kg) as well as a 89.6lbs/in (1.6 kg) with the correct ID from RaceTech.

I've still to hear back from FOX but suspect that they will also confirm availability of an 8" spring. Will wait and see before pulling the trigger on the RaceTech springs.

Thanks again
 
Heard back from Fox and they've indeed located an 8" spring option.
Unfortunately it's stiffer than the current spring (albeit, shorter) and red.

Suggestion?
Recommendation?

[size=8pt]Jim

I spoke to our engineers and also researched what FOX has available and what could be ordered. What we have is an 8” spring that is 100lb. Looking at the set up and amount of preload with the engineers, they felt that the 8”, 100lb should work. The catch is that the springs a red. This is the only thing FOX has in stock. With the research I did, finding a different color and or weight in the exact spring specs from our current vendors isn’t going to happen. This might be why FOX does not have anything different in stock.

Let me know if you want the springs and I’ll send them out on Monday. I won’t be back in the office until and I don’t check email over the weekend. That said, any feed back you have I’ll get back to you on Monday.

Enjoy the weekend.

Stacey Sell
FOX Global Distributor Sales
 
Sav0r said:
Buy the Racetechs. The science points to them being what you are looking for.
Click to expand...

I agree. Going to order them on Monday.
Thanks for the help. Will post a follow up when the springs arrive.
 
Sav0r said:
I get 70lbs/inch for the Works spring.

What is the ID of those springs on the Fox units? I think I have a new set of 75 lb/inch springs with a 1 7/8" ID and 8" free length on my shelf. Though I can get them as soft as 50lb/inch and 60lb/inch in those same dimension. Send me a PM, I can give you pricing.

The damping of the shock shouldn't effect your sag, but there is something odd going on here. You should be getting more sag than you are, even with that much preload. I wonder how much canister pressure the fox uses?
Click to expand...

That question has remained in my head for a while now. I can't tell you at what pressure the canister is charged but I can tell you the general effect it has. As suggested, Fox Podium RC1 shocks are gas charged and the internal gas pressure contributes to spring rate. Curious of the contribution I compressed one of the shocks (sans spring) approx 1" travel onto a presision scale. Not scientific but the pressure measured 41.4 pounds. Multiply that by two shocks and there's an additional 82+ pounds of spring rate.

 
Wow! That's quite a bit! They must have some serious pressure in that canister. My guess is upper 200's. Plenty of space to bring them down. No need for anything over 80-90psi on road going stuff.
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom