Recommendations for Adding ~1" to 2.5" Coil...
 

I have a RK 2.5 max travel kit with 35 trail grapplers but I'm looking for just about an inch or so of extra tire clearance. I don't want to trim the fenders and a body lift isn't an option. Would I be OK throwing some Synergy 3/4" spacers in front and back? If so could I use the same height spacers front and rear or need more in front to stay level? Running AEV bumpers front and rear, full size spare, 9500 winch.

Thanks for any help.

I have some 1" coil spacers on this forum for sale..... just sayin'. :wink:

Just so you don't waste too much time on this, adding a spacer will not help tire clearance. It will make your Jeep sit higher at ride height, increase driveline angles and therefore wear, and also make the handling characteristics worse.

If you are trying to prevent your tires from eating your fenders on uptravel, you need to increase your bump stops (they limit how far your axle can travel up). Just be aware that as you add bump, you lose suspension travel.

Sorry, I'm having a hard time following. If he adds spacers and increases his ride height, will his tires not have to travel an additional inch before hitting the fenders? I get what you're saying about bumpstop, and mostly agree with other comments you made, but I think adding spacers absolutely will help with clearance. I realize he needs to increase bumpstop to actually prevent the tires from hitting the fenders, but how does adding 1" spacers not help with tire clearance?

Clearance from what? He's not rubbing at ride height. The shocks will still compress and extend the exact same amount.

Let's try it this way. How does adding 1" spacers effect the tires rubbing the fenders?

Think about it in terms of geometry. Your shocks and coils represent the y-axis. There is a min and max (full compressed and fully extended). That is determined by your shock extended length and bump stop. You can set your ride height anywhere you want on the y-axis (where on that axis will change what we refer to as uptravel and down travel). Maybe you have 5" up and 5" down. Add a 1" spacer and now you have 6" up and 4" down.

This is the most misunderstood topic with lifts. People think more lift means more tire clearance. It means nothing (shocks and bump stops held constant). Now, the one argument for more lift is when a person has to limit uptravel significantly (like 37s and stock fenders) and they want to balance up and down travel.

How is that? I added spacers and did not notice any negative handling characteristics.

I get what you're saying, but seems to me you're talking about travel and not clearance. Maybe you're just defining "clearance" differently than I am, and then again maybe I'm just wrong. Consider the top of his tire as a fixed point and measure to the fender. Now add a 1" spacer. You've raised the fender 1" and have therefore increased clearance between the fender and the tire. I call that increasing the clearance. You've also increased the clearance at ride height underneath the vehicle pretty much everywhere except the axles.

I understand what you're saying. He won't be increasing his travel any because he's still limited by his bumpstops (or fender in this case) at full stuff, and by his shocks at full droop. However, I would say he is increasing his clearance, even if only at ride height.

And just to be clear, I agree 100% that he really needs to add more bumpstop if his goal is to keep his tires off his fenders. I can't tell from this guy's post what he's actually looking for. All he asked was if he could add some 3/4" spacers front and back to add a little more clearance. To that, I say yes. You could simply add 3/4" spacers front and back and you will get a 3/4" more clearance between the top of the tire and your fender. No need to add any additional height to the front since it sounds like the 2.5" lift he's already running probably removed the stock rake he's concerned about. If he adds equal-sized spacers to front and back, it will lift the front and back equally. If he has any rake or uneven ride height that he's trying to remove, he'll need to add different sized spacers accordingly to compensate.

The other things Invest2m4 mentioned above are considerations though. I wouldn't necessarily be concerned about a substantial decrease in handling characteristics, but you could experience driveshaft issues or at least increased wear due to the increased angle.

He lost height due to the bumpers and winch, bringing the tires closer to the fenders (or the fenders closer to the tires, I guess), and compressing the shocks a bit. Adding the spacers brings him right back up to where he started. The fact that the phrase 'tire clearance' was used, or that the shocks started at 5up/5dn and are now at 6up/4dn doesn't matter. He adds the spacers and returns to the same lift height/shock travel/tire clearance/whatever that he started with.

For what height you need front/back to get level, you are asking for guesses. You might be a bit better off just doing some looking and measuring.

It was a generality. If you increase ride height and make no other changes, you will decrease caster and therefore have some decrease in handling (whether you notice it or not, depends on some other factors).

No clue if you understand. You are talking about "visual/aesthetic" clearance, not functional clearance. Whether he adds the spacer or not, when he goes over train tracks, he will have the same issue he does today. He could put a 2" spacer and it would still happen. Regardless, gaining clearance at ride height obviously provides no actual benefit since clearance issues happen the more the suspension is compressed.

Now, going back to what the OP said. He specifically stated that "he does not want to trim his fenders or get a body lift." I paraphrased there a little. What he has implied is that right now his tires will rub his fenders as the suspension compresses. I've said what I have to say on this topic. It is one that for reasons I don't quite understand, creates a mental block for some people.

So, assuming the OPs issue is that his tires are hitting his fenders, I'll turn it over to you to tell him if adding the spacers will solve the issue.

I'm not arguing here but I probably have that mental handicap too. Pun intended... But I'm wondering if he would at least increase belly clearance? On the other note, I would really like to understand what your talking about. Could you point me in the right direction or video please. Im probably going to re read dirtman's thoughts on lifts again. Thanks

Invest2m4 is correct in adding spacers only changes static ride height, so in the driveway with the jeep in park you will see a height gain and clearance between the fender gain. When wheeling adding the spacer will not limit up-travel (which seems to be the ops actual issue) unless the coil is at full bind which is likely not the case. So the op can add spacers to regain lost ride height but will still need to extend bump stops to eliminate rubbing/contact issues. He will still rub during up-travel....

You are correct about belly clearance. To clarify, my comments were specific to tire clearance and holding all other factors constant (i.e. the OP changes nothing else except for adding the spacers).

What I am saying is that using more lift to clear larger tires is in most cases, total BS. Now, that does not hold true in 100% of scenarios. For example, someone going from no lift to a 2.5" lift could clear larger tires without sacrificing travel. Why? Assume that the person adds 2" of bump stop, but also adds longer shocks. In that case, travel was maintained (you are shifting the y-axis down 2").

In most cases, the taller lift has the same shocks. Look at any of the off-the-shelf kits. Compare the 2.5" to the 3.5". The shocks are the same. Therefore, unless you add more bump stop to the 3.5" lift, you don't gain tire clearance.

To paint a picture, imagine a Jeep on a lift with the axles fully drooped. The axles can't go any further down because the shocks are fully extended. Let's assume they are the shocks that came with the Boulder Krawler 2.5" lift. Looking from the side of the Jeep, draw a straight line up from the bump stop pad on the axle to the bump stop. That is your Y-axis. Now, upgrade to the Boulder Krawler 3.5" kit. What do you get? Coils that make your Jeep sit an 1" higher at ride height. Shocks are the same, bump stops are the same. What did you gain? As you pointed out, you do gain belly clearance from a static perspective.

So, in that case the only way to change the y-axis is to add or remove bump stop, install longer or shorter shocks... or, for a more custom build, move the mounting points.

It's all good, I'm over it. It's not a mental block. I know exacxtly what you're saying, and again it seems your using the term "clearance" one way and I'm using it another.

All the guy asked was if he could add 3/4" spacers to add more clearance, and he asked if he needed to run different size spacers to "keep it level". Since uses the term "keep it level", I think it's safe to say that the Jeep is already currently level, so there should be no reason to run different size spacers front and back.

By your own admission you're making an assumption that he's having rubbing issues. All he said was that he wanted additional clearance, and he said he didn't want to trim fenders or add body lift. He could very well just want the appearance of more space in the fender wells. I have the exact same lift and RK recommends 2" of bump stop with that lift for 35's. I guess I'm making an assumption as well in that he went with RK's recommendations and is already running the proper bumpstop to avoid fender rubbing, and that all he's really asking for is additional height for a more balanced look overall.

Again, I don't disagree with anything you're saying. I'm just saying I think you're jumping to conclusions about the OP's actual issue, and you're using the term "clearance" in a different way than I am. I'm just trying to answer his/her question.

Ah, I got it now. Thanks for the picture. Or the mind blowing event that just happened. LOL

http://i743.photobucket.com/albums/x...psbop96ktr.jpg
Chris has plenty of belly clearance with those 37's lol.