But its the same shock. Fox only has one number they use on both the XJ and the TJ. How do you tune one shock to work properly on a leaf spring XJ wagon and a TJ with its short wheel base and coils. I am under the impression that a shock tuned for a TJ will work better on a TJ than a shock tuned for an XJ will work on an TJ. Fox does not tune for a TJ, you get a generic XJ/TJ shock. BDS and JKS tune their Fox offerings for the TJ. That is why I said they will work better. I'm not looking for an argument about spring weights, these are two signifigantly different vehicles. I think they would each perform better if the shock was tuned for the vehicle. But maybe I'm wrong. Maybe Fox shocks hit the sweet spot that one size fits all. But I doubt it. I think a shock tuned for a TJ will work better than an generic TJ/XJ tune. But I'll wait and see what JMT has to say.
All in the name of science
- Thread starter hosejockey61
- Start date
The fox shocks that are recommended are not off the shelf shocks. They are custom tuned factory race series shocks.
Don't know, don't care all that much. What I do know is that I have ridden and driven a few different "TJ tunes" in Foxes from various sources and each one is noticably different. Meaning that I don't really know what a TJ tune is.
At which point you are at the mercy of the abilities of the shock tuner to tune the shock to the vehicle and to the driver.
I've not seen that differentiation apart from Savvy. My apologies if you were talking about custom tuned. That is a different ball game.
I usually see Savvy/Fox, which indeed are custom tuned and different. And I expect they would perform well. But often I also see Fox 2.0 being recommended because they are most similar in price to OME, Bilstein, 9000XL, etc. At that price point, I question if the generic Fox is that superior.
I have not looked into the Fox reservoir shocks or higher end shocks. Fox may very well do different tunes. Certainly they are available from people like Savvy and Accutune and others. I think Fox is the most widely tuned shock. For that reason they would be great if you get a special tune.
I was only referring to the generic off the shelf 2.0 fox for the XJ/TJ vs 'custom tunes' from JKS, BDS, and Savvy. I think the 'custom tuned' Fox will perform better than the generic Fox. I also think the tuning done by OME and Bilstein on their respective shocks is more in depth than what Fox does on their entry level shocks. But its all speculation. I have not run any where near all these shocks.
EDIT: I put 'custom tuned' in quotes. I don't know the extent of tuning done by JKS, BDS or Savvy. Other than reports of the Savvy being significantly differen than other Fox.
You're assuming Savvy, BDS, JKS, and any other that boasts a Fox shock have different tunes. What's the curb weight of an XJ. Vs. A LJ/TJ? And like you mentioned, a XJ has leafs so how do you tune for that? I'm willing to bet that the off the shelf non resi Fox shock has one generic tune, and that's what you get.
I'm not assuming they have different tunes. I am believing each company when they explicitly state their Fox shocks are custom tuned for them.
Thats all I'm saying. An off the shelf Fox has a generic tune for the XJ and a TJ. Rancho does the same thing with some of their shocks like the 9000XL. It seems to me a shock tuned for a specific vehicle will produce a better handling shock. That's why everyone loves a Fox with a custom tune.
A little digging revealed a stock XJ weighs 3,057 lbs - 3,386 lbs and a stock LJ weighs 3,730-3977. So a stock LJ can be 30% heavier. Which explains why Bilstein has more rebound dampening but less compression dampening for the TJ/LJ than they do for the XJ. The XJ has a more firm valving on compression but less rebound dampening. That makes sense because a heavier vehicle will require a heavier spring to carry the weight. Which in turn will require more dampening to control the larger mass of the heavier vehicle during rebound.
For those curious about the numbers I refer to. Here is the valving info I have on the shocks I am referring to. These are rear shocks. I was looking for something with a collapsed length of 14".
These numbers are an abbreviation representing 1/10 of the Newtons for that shock. The first number is the rebound force in 1/10 Newtons at .52 m/s and the second number is compression force in 1/10 Newtons at .52 m/s. https://www.my4by.com/bilstein-valve-ratings
Bilstein shock for Cherokee #24-185639 is 137/81 = Rebound 137 / compression 81
Bilstein shock for TJ/LJ #25-193145 is 154/61 = Rebound 154 / compression 61
So the Bilstein TJ shocks will ride softer but return slower than the XJ shock.
|
You could leave out the part about the heavier springs and just focus on the difference in vehicle weight.
How can you tune a shock to a specific application that varies in over 1000 lbs. of difference?
I agree. And that is why the Savvy, JKS, and BDS tuned Fox are more tempting than the generic. (If you believing them that they actually are tuned differently) Almost certainly they won't be the best tune for everyone, but you would think that they would have to be better than the generic Fox tune since they were tuned specifically for a TJ. Particularily in the case of Savvy who are not just selling a product, but who are enthusiast. But in the end, the best shock will always be the one tuned for your Jeep.
EDIT: The day I find someone locally who can tune Fox shocks, my interest in Fox will increase exponentially. Until then, I will consider Fox on an equal field as others like Bilstein and OME. Even though the technologies are very different and Fox cetainly has some advantages. Unless they can be tuned locally, they are still more or less a disposable shock.
2nd EDIT: I just spent $70 to send back OME shocks. Shipping shocks across the country for tuning is not cheap.
Last edited:
$70 is pretty insignificant when compared to the cost of good shocks.
That is my problem, I don't believe them.
Fox: Ok XYZ Offroad, here is our shock that fits your TJ/LJ/XJ app. At the popular 2"-4.5" lift travels. Market it at your discretion.
Fox: Ok XYZ Offroad, here is our shock that fits your TJ/LJ/XJ app. At the popular 2"-4.5" lift travels. Market it at your discretion.
You don't.
You can't even tune one vehicle for all conditions.
There will always be compromises.
In a recent video by fox they were commenting that they tune for rocks and the whoops suck. They tune for whoops and something else sucks. There's no perfect tune. Maybe the new computer controller valving will get it there.
Drain the nitro or zip tie them compressed. USPS large flat rate board game box for $21 will fit at least two 12" 2.0's
And this is why I spend $50 a shock for said shock that can't be tuned to my jeep, as opposed to spending $100-$170 per shock for a shock that can't be tuned to my jeep.