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• Suspension & Tire Archives
"I want to upgrade my stock 1991 Jeep Wrangler with a suspension lift and larger/wider tires. I don't want a lot of hassle, so is there a complete suspension kit out there that will allow for an upgrade to 32" or 33"x11.50 or 12.50 tires?"

There are several manufacturers offering complete kits for your Jeep that are easy to install. You'll need one that provides a full 4" lift to run 33's. Visit your local 4x4 shop for all the available kits and prices.


"I have a 97 Jeep TJ with the 15x8 rims and 30 inch tires. I was wondering if 31x10.50 tires would rub if I did not use a lift? If I do need a lift, which one is better, body or suspension?"

TJ's will take up to a 31x10.50R15 without a lift kit.

Whether a body or suspension lift is better depends on why you want to lift your Jeep. If you just want larger tires, a body lift will do the job. If you want the opportunity for improved articulation and travel, as well as greater frame to ground clearance, a suspension lift is the way to go.


"I own a 1991 Jeep Wrangler with the stock 4.0 I-6 w/5-speed. How large of a tire can I upgrade to before I should swap my stock 4.10 gears?

If your gears are the originals, they're not 4.10's. You could only get 4.10 gears with a 4 cylinder/5 speed combination. The only gears available for a 5 speed I6 were 3.07's. To verify this, jack up both rear wheels, place a chalk mark on both the tire and the driveshaft, then count how many revolutions the tire makes for one revolution of the driveshaft. If you have 3.07's, the tires will turn just a tad over 3 times.

In my opinion, 3.07's shouldn't be in any 4x4 that's actually used off road. A 4.10 gear swap is a good idea regardless whether you install larger tires. The 4.10's will work fine up to a 31" tire, beyond that, go with 4.56 gears.


"Grant, I just recently purchased a '91 Jeep Wrangler w/the Islander Package. I want to upgrade my tires a little (higher and wider) to give it a more rugged look. What is the largest tire I can go on the 15 x 8 alloy wheels and stock suspension? Also, do you recommend a suspension lift?"

You can run 30x9.50R15 tires on your stock rims and suspension. You may encounter some slight rub on the leaf springs during very sharp turns. 235/75R15's are about a half inch shorter and are nearly identical in width with the 30" tires, but you won't have any rubbing problems.

I'd recommend a suspension lift if the type of off road driving you do requires it. If your Jeep takes you everywhere you want to go in stock form then a lift is basically pointless.


"I have a 94 YJ with a 3.5 lift . I recently purchased a set of 35's . I haven't gone off road in those tires yet because I know it will rub...my question to you is, what would be the best way to modify my YJ to fit 35in. tires. It seems I have more room up front than in the rear. My main concern is the rear tires rubbing. Should I get a body lift , taller shackles, fender trimming, or a combination of some sort? I haven't done anything to my driveshafts. Any help would be appreciated."

You could probably do some minor trimming on the back edge of the rear fenders to clear the 35's. This is the cheapest route and it won't necessitate any more suspension mods. That option is entirely up to you though. Once that sheetmetal is cut, you can't put it back. The best option would be a 1" body lift, contact JB Conversions for a kit. The 1" body lift with your 3.5" suspension lift should clear the 35's ithout rubbing.

There's not much lift to be gained with longer shackles, and there are plenty of drawbacks. If you buy shackles one inch longer than stock, you'll only gain 1/2" of lift. For that half inch of lift, you've reduced approach and departure angles, changed the driveshaft angles (rotated the pinion upward on both axles), changed the caster on the front end, and added more stress to the frame due to the added leverage of the longer shackle. Use lift shackles as a last resort and not more than 1/2-3/4" longer than stock.


"I have a '97 Cherokee Sport. I was wondering if I could run 30x950x15's on 7 inch rims with the stock suspension?"

If you have the factory "Up Country" suspension then 30" tires will fit. If not, 235/75R15's are as tall as you can go.


"I have a 1998 TJ Wrangler Sport with 15x8 rims. I was wondering if I could run 32-11.50 All Terrains on the stock suspension."

Sorry, 31x10.50 is as large as you can go without a lift.


"I drive a 1997 Wrangler TJ Sport with 15x7 inch rims. I live in Denver and need a tire that is good for snow/ice, even more so than off road. What 30x9.50/15 tire is good for this?"

I've said before I'm pretty partial to the BFGoodrich All Terrains. I think they deliver much better traction off road than the average AT tire, but you still get exceptional tread wear and low noise levels on pavement. The fact that the BFG's construction is superior to nearly all other radials is added piece of mind whether you're on or off road. Also, a little tip for better traction and even treadwear, don't run your tires at the max inflation pressure listed on the sidewall. Probably 25-30 psi front and 15-20 psi rear will be about right on your TJ. To check this, use a grease pencil to make a mark across the width of the tire. Drive around the block. If the pencil mark is still on the outer edges of the tread, lower your air pressure. The difference in traction will be immediately noticeable.


"I own a 78 CJ-5, and I am looking to make it a serious off-road machine. It has a 258 straight 6, and most everything is stock. I was wondering if you recomended any suspension systems for my Jeep. I also want to get a carburetor that is higher performance and better suited for off road use. If you can give any suggestions on these or other topics on my Jeep it would be greatly appreciated."

Generally 2-2.5 inch suspension lifts offer a better ride and greater flexibility than 4 inch kits. Regardless of the height you choose, be sure to get "Softride" or "Superride" (or whatever other catchy name the manufacturer came up with) springs. The point is, avoid the "heavy duty" springs, they are way too stiff.

A replacement carburetor? I'd rather dump the money into an aftermarket EFI kit. The performance, driveability, and efficiency of the EFI should far exceed the capabilities of even the best tuned carb. Holley's Pro-Jection kit is a simple throttle body setup and is a relatively affordable way to get rid of your carburetor troubles for good. The price is around $700. Of course, you could go the high dollar route with the Mopar EFI kit, this basically turns your engine into a newer 4.0L. The asking price reflects the complexity of the kit, around $1800 dollars.


"I have a 79 CJ-5 with springs that have quite a bit of arch in them. They also have about 6 leafs in each. The thing sits way to high and I belive the unstable ride is due to this. With 31 inch tires, I have approx. 6-10 inches of clearance between tire and fender! It was obvioulsly set up for HUGE tires. My question is what do you think it will cost me in parts and how much labor am I looking at to replace the springs on it now with used stock springs? Thanks!"

I can't give you a cost estimate on used stock springs, you'll have to call some salvage yards and/or post an ad in our "Want Ads" section. I did find new stock height replacement springs for about $350, but with a little shopping I'd imagine you could get a set for a whole lot less, maybe half that much. Your current shocks will be too long after you install the stock spring packs, they'll have to be replaced. If your CJ has a "dropped" steering arm, it will need to be replaced with the stock unit as well. The good news is you can probably sell all of the lift pieces to offset the cost of the new stock parts.

As far as labor, it's a very simple job. With hand tools and the usual battle with a few stubborn bolts, it will eat up the majority of your saturday. If you've got a friend with huge arms, you might want to invite him to the leaf spring swapping party. There's nothing like like removing and then installing eight U-bolts to make you appreciate air tools.


"I want to fit 33's on my 77 CJ-5, but I don't want to compromise the driveshaft angles. I know someone who used a 2 1/2" lift, but others say I need 4". 3" sounds good to me, but the only kits I can find are for 2 or 4 inches. What about a 2" spring lift combined with a 1" shackle lift? Will the shackles mess up the pinion angles which are set by the wedges on the springs? The main reason I don't want to go 4" is so I don't need a dropped pitman arm or need to lower the t-case. The tires I want to fit are the tall skinny ones 33x9.5 BFG's or Buckshots or Swampers in a similar size. Any help is appreciated."

A 2" spring lift will clear 33's, barely. If you go with the narrow tire on a stock offset wheel, you shouldn't make any fender contact. Going with the smaller lift will generally result in a better ride too.

The shackle lift will change the pinion angle. If you have some vibration problems with the shackles then you'll either have to remove the spring wedges or replace them with ones that aren't as steep. How much affect the shackles have on the pinion angle depends on how much longer they are than stock. I'd consider shackles an inch longer than stock (resulting in half an inch of lift) the absolute max.


"I have a 97 TJ with the P225 15" tires. I would like to upgrade to a larger tire, but am not planning to change the suspension or wheels just yet. How large and wide a tire can I go up to without adversely affecting the stock suspension. Also, if I do upgrade the wheels, how big can I go without lifting or modifying the suspension."

Your tire choice is somewhat dependent on your rim width. The TJ's were available with 6",7", and 8" (only with 30" tire package) rim widths. Since your Jeep has 225's, we can rule out the 8" rim. For optimum tread wear on a 6" rim, you'll need to run a fairly narrow tire, such as a 235/75/R15. You could use a 30x9.50R15 on a 6" rim but you'll need to run low air pressure to get even tread wear. On a 7" rim, 30x9.50R15s will work great, 31x10.50R15's on the same rim would again require low air pressure. The largest tire you can use on a stock TJ is a 31x10.50R15.


"I'd like to lift my '72 Blazer something like 2". I can't find any companies selling a kit like this. Is there something out there close to 2"?"

Superlift makes 6 and 8 inch lifts for your Blazer, Rancho only makes a 4 inch. Skyjacker is the only company I found that makes a 2-2.5 inch lift (what's in a name?). Rocky Mountain Suspension Products (800-521-4908) carries Skyjacker products, they're selling the kit for $275


"I have a '97 TJ Sport with the standard suspension package (225R15 tires though). In comparing it to my '95 Wrangler, the TJ does seem to dive and squat a bit upon stopping or starting. Is it my imagination or are the shocks and/or springs on the standard suspension a bit soft?

I was curious if you had noticed this or if you might some recommendations."

Compared to a YJ, the TJ's suspension is very soft. The softer coil springs translate into a better on road ride and better articulation off pavement. If you find the movement of the jeep excessive during acceleration or braking, it could be greatly diminished with a quality set of aftermarket shocks with only minimal loss in ride quality.


"I have a question for you regarding shackle lifts and suspension lifts. I recently read that if you have replacement shackles (longer than factory stock) and you put say a 2.5" suspension lift on, the shackles will eventually straighten our the leafs and ruin the suspension lift. Is this the case? Will this be reduced if you put on a moderate lift (like a 2.5") or is it the case with larger lifts?

I bought a set of Con-Ferr shackles and would hate to have to replace them when I put my lift kit on."

The use of longer shackles does create some adverse affects, but they absolutely do not straighten and ruin the springs. Keep your shackles.


"I'm building a new frame for my Jeep CJ-7 and I want to incorporate independent suspension. I've seen pictures of a Ford 9 inch set up with the disc brakes mounted at the diff. There is a street rod chassis shop here in town (Oklahoma City) that does this set up all the time but is not very willing to give out info. I don't have the money required for someone else to do the fabrication and machine work for me but I do have access to a machine shop at school and I'm capable of doing the machine work myself. I'm 46 hours away from etting my Electrical Engineering degree at OU. I guess what I'm trying to say I'm a poor ollege student that is capable of doing the work myself, all I need is a design (blue print)to replicate from. If you can help or know of any mag articles please let me know."

I haven't seen this conversion done on a CJ yet, most people prefer the greater travel potential of the solid axle design. On road handling and ride comfort should be significantly better after the swap though. You might try contacting TSM (303) 688-6882, they build 9" IFS setups as well and may be more willing to help.


"I got a 95' Cherokee with factory off road suspension package. Just wondering what the largest tires I can put on without the rub, lifting it, or changing rims."

Either a 235/75R15 or a 30x9.50R15. They are almost exactly the same width, but the 30" is about half an inch taller.


"I have a 1983 CJ-7. It is in great condition so I plan on keeping it forever. The complaint I have is the quality of the ride. I realize CJ's are not suppose to ride like luxury cars but I feel surely I could make it a little smoother. I have 32" 11.50s on aluminum wheels with heavy duty gas shocks. Would replacing the old springs help ease the jarring over bumps?"

Yes, replacing the stock springs can help, provided you don't replace them with even stiffer springs. Choose your new springs carefully. Your "heavy duty gas shocks" could also be partly to blame, if they are too stiff, they may not allow the springs to flex enough to absorb bumps. You might consider an adjustable shock instead.


"I own a '74 Jeep CJ5 and have just installed '78 disk-brakes from the spindles out. It was a straight swap with no complications and the Jeep stops great now. The problem I now have is that the Jeep handles horribly. It has very sensitive steering and almost wants to speed wobble. Could it be that the '78 spindles have a different camber than the original '74 ones?

The only other work I did between "test drives" was new polyurethane bodymounts.

Could the body be rocking on the frame and causing the steering to be affected?"

Sounds like some loose front wheel bearings, you might want to recheck them.


"I own a 91 Wrangler and am considering installing a 2" add-a-leaf kit. With this lift, will I need to do any other modifications, such as transfer case lowering, changing the pinion angle, etc... or can I just install it and go? Will it affect the steering? Any help would be appreciated."

To ensure that absolutely no driveshaft vibration exists, you'll have to lower the transfer case about an inch and rotate the axle pinion upward a few degrees. If you didn't want to lower the transfer case, then you could install a CV style rear driveshaft intead. The affect on steering will be noticeable, you will have some bumpsteer, but it's liveable and you quickly get used to it. Since there are no panhard rod drop brackets included with an add a leaf kit, the rods will pull the axles to the side after the lift is installed, offsetting them slightly. After installing another leaf in the spring pack, you'll have to buy new U bolts and spring center bolts as the old ones won't be long enough. You'll of course need longer shocks too. Most of these things can be fixed, but the real problem is your Jeep is going to ride like a tank, add-a-leaf lifts do not make for smooth riding vehicles. I think you may find it's a lot easier to buy and install a complete 2.5" spring lift then it would be to piece together an add-a-leaf setup.


"Grant, I just bought a 83 Chevy Blazer that runs on diesel. I am wanting to put a lift kit on it myself. Could you tell me the cheapest and easiest lift kit to use."

Body lifts are by far the cheapest, but the difficulty of installation outweighs the cost of a suspension lift. Frankly, since your suspension design is so simple, all the aftermarket suspension lifts are very similar and all very easy to install. Most will consist of new front springs and a lift block for the rear. You'll have to buy longer shocks with the lift, and you should buy a "dropped" steering arm to correct the steering geometry if you intend to lift your Blazer 4" or more. You could easily do all this for less than $500.


"My wife just got a 94 wrangler with 31" tires.She likes the way they look, but they rub every now and then.iI really don't want to spend the money on a suspension lift. What are the pros and cons of a shackle lift or body lift?Which would you recommend?"

I'd go with a small shackle lift just because it's easier to install (and later remove if you want) than a body lift. The only problem with shackles is that you are only moving one end of the spring, which will rotate the pinion up slightly and might cause some driveshaft vibration at higher speeds. If you use a modest lift shackle like 3/8" or 1/2", I doubt there will be a problem.


"Grant, I recently bought a 1991 Wrangler, and it is pretty much stock. It has a 2.6L fuel injection 4-cylinder with 30X9.50 inch tires. I am looking at putting a 2.5-inch body lift on and possibly upgrading the tires. Will the body lift do anything or is it a waste of time? Also, I was considering a tire change to a 31x9.50 inch. What affects will this have on engine performance and will the body lift take care of the clearence problem?"

The only thing the body lift will do is give you enough clearance to add the 31's. There is no other benefit. I realize there's a significant difference in price, but a good 2.5" suspension lift would be a better investment for off road performance.

If the performance of your 4 cyl. with 30" tires is satisfactory for you now, then 31's won't make much difference. If you go any taller than a 31" tire, I'd recommend swapping your stock 4.10 gears for a set of 4.56's to offset the increased tire size.


"Dear Grant, I've bought a CJ2A and want to put a 350 Chevy in with a 3-speed turbo box and lift the suspension about 2 inches. Can you tell me any big problems I might encounter and give me some tips as there ain't to many specialists around here.

My main concern is the suspension as I will be increasing it's top speed and want fairly good road holding."

Forget putting an automatic in a CJ2A, the short wheelbase would result in an incredibly short rear driveshaft. Go with a 4 speed manual instead. The suspension won't be the major problem in high speed handling, however, the stock steering would be not only dangerous but just plain scary. Swap out the entire stock setup for a later model power steering unit. Advance Adapters sells a complete kit for the swap.


"I have a '74 CJ5 304, T-18 tranny, model 20 transfer case, with stock Dana 30 front diff and power drum brakes. I would like to upgrade the Dana 30 to a Dana 44 with disc brakes for increased strength and stopping. What would be my best/"easiest" choice for a front Dana 44 donor vehicle providing the strongest axles? What modifications will be needed to make it work?

If I wanted to add room for 36's, could I get away with a spring-over conversion or should I go with a suspension lift, etc? Your knowledge and insights are appreciated!"

I'd recommend contacting Dynatrac (www.dynatrac.com) for your Dana 44. The prices are really fairly reasonable for the incredible amount of labor involved in building a custom axle assembly. I'm unaware of any front Dana 44 assembly that would require only minimal modification to bolt in.

Thirty six inch tires are a bit much on a CJ5, but if that's what you want than go with a 4" suspension lift combined with a body lift; the fabrication, tools, and knowledge involved in properly executing a spring-over are tremendous.


"I have a question about a suspension lift for my 1995 Wrangler. I would like to put on a 4-inch Pro Comp lift. How much do they cost? And, what are the biggest tires I can put on without hitting the fenders? I have 31X10.50's on right now, and they hit when I do anything offroad. I also have Currie shackles. Can I still use them when I lift it? winches, what kind of pull do I need in pounds? Are light bars any good? I have 4 Hellas on my front bumper."

Four Wheel PaAnd rts Wholesalers is advertising the lift you want for 400 with shocks, a dropped steering arm should be added as it is not included with the kit. You can run up to 33" tires with this lift and keep your Currie shackles. An 8000 lb. winch should get you out of any trouble you encounter without any problem. Light bars are fine if you like them, watch out for those low tree branches though.


"Hello Grant. Was wondering if you would know specifics regarding fitting 1978 Scout Dana 44's into new style CJ5? Concerned with spring perches and steering arm. Have a good set available and was hoping this would be more practical than big $$ beefing of the AMC 20 diff. in the CJ presently. Any info would be greatly appreciated."

If you have installed aftermarket one piece axles in your model 20 than you already have a stronger rearend than a Dana 44. The ring and pinion gears in the model 20 are actually larger than that of a Dana 44. The model 20 has developed a bad reputation due to a terrible two piece axle design, once the axles are replaced it's plenty strong for CJ use.

Replacing your front Dana 30 with a 44 would be a nice upgrade. I'd recommend calling one of the numerous custom axle manufacturers, tell them you have a front 44 from a 78 scout, and ask how much they would charge to do the appropriate modifications to fit your CJ5, this stuff should be left to the pros. It may be more attractive to purchase a brand new Dana 44 custom built for your CJ5 than to modify the scout unit.


"Currently I run 35 inch Swampers on my 85 CJ7. The suspension lift was on there when I bought it. I believe it is 3 to 4 inches. I added a 3 inch body lift. What I was planning on doing was the shackle reversal kit with the spring over axle. I was told that it would give me a much better ride on the road. Should I take out the 3-inch body since it would kind of be over kill for 35's?

How much am I looking at for the shackle reversal kit? What are your thoughts on this situation? Oh, I forgot to mention that I have CURRIE greasable shackles on it too. I can still use them with the reversal kit can't I?"

I really don't believe what little benefit is gained in a shackle reversal is worth the cost of the kits on road and especially off road. There may be some handling improvement at highway speeds but nothing drastic. Besides the cost, the other problem with a shackle reversal is that now as your suspension compresses the tire will be moving toward the rear of the vehicle as it moves up, bringing it closer to the fenders rather than pushing towards the front with the stock shackle arrangement.

If you want to soften the ride in your CJ, have a set of custom springs made with the same (or less) lift than your current springs. The expense far outweighs the difficulty in properly executing a spring-over swap.


"I have a 1981 Ford F-150 and I just put 31.10R15 on with 15x8 inch rims and the front end doesn't seem to be high enough, even though the Ford book says that it should be able to handle it. The coil springs are, (look like) passenger car springs, very wimpy. If I put cargo springs on the front will that cure the problem of the tires hitting the wheel wells. Or am I going to need to put a body lift on the front, or both. It is an automatic transmission so if I do need to put a lift on will I need to do any rigging, (welding). Would a spring spacer work to put under the cargo springs or will they cure all of the problems, the problems of the front tires hitting the wheel well, the rear tires have tons of clearance."

Your problem is a lot easier to fix than you think. Skyjacker (318) 388-0816 sells replacement coils for your truck that will raise the front end 1.5-2 inches, this should leave you plenty of room for 31's. The coils sell for $115 and are easy to install. You will need to realign your truck afterwards.


"I was just wondering if I would be able to install 31" tires on my stock 90 Wrangler without putting a lift kit on? I understand it would rub a little at certain points but would I still be able to do it?

Go with 30" tires instead. The 31's with no lift will rub so much as to do more harm than good off road.


"What can you tell me about the pros and cons of lifting a CJ7 with a spring-over conversion? And do you know of any problem with the rear universal joints in a wranglers."

The biggest problem in doing a spring-over is the amount of labor and specialized skills involved. You have to be a competent welder and be able to determine exactly where the new spring pads are located so as not to adversely affect caster and driveshaft angles. You are also more likely to experience "axle wrap" with a spring-over as it is placing more leverage on the springs.

The advantage to doing a spring-over is that you don't have to replace your stock springs with usually stiffer aftermarket ones and there is very little materials cost. You will still have to buy longer shocks and a dropped pitman arm as you would with a normal spring lift.


"I have a '93 Jeep Grand Cherokee with 3 inches of lift, ARB, etc... I'm looking for a mud tire that is fairly road worthy. How do the BFG Mud Terrain and the Goodyear Wrangler MT compare on road, snow, rain, and of course, mud. I'm looking at a 31x10.50 15 on a 15x7 (not stock) How much road noise will I encounter compared to my current Dunlop Radial Rover RV 30x9.50?"

A true mud tire is loud, period. I would guess the Wrangler MT would be a little quieter on dry pavement and resist hydroplaning better than the BFG. Off road I believe the BFG would be superior in all conditions except sand. Which tire you choose depends on your priorities.


"On my 90 Cherokee Laredo I added 29x10.50 Superswamper Thornbirds. When I make a sharp turn the really large lugs on the tires hit the rear add-a-leaf. When I measure the distance between the largest lug and my rear add-a-leaf there is about 1.5-2 centimeters of space. I have the stock 15x7 Laredo rims and I don't want to replace them. Is there anything I can modify or buy to spread out the wheels a few inches? I really don't want to buy new wheels. However I was wondering if it would make any difference if I bought a 15x8 wheel with about the same offset as a stock setup. I could buy a 15x8 wheel with a few inches more of offset but I am afraid of fender rub on turns in the back. So my main question is will a 15x8 stop the bulging out of the tire? I think this buldging is causing the lugs to be too close to the leaf springs..."

"Thanks for your help"

Purchasing new rims is the best way to solve your problem and keep your tires. Buying 15x8 rims with the same offset as the stock rims will help slightly but probably not enough to stop the rubbing. You will need 15x8 rims with greater offset than stock to run these tires. I'd suggest keeping your stock rims and buying a narrower tire.


"I have a 1986 Jeep Cherokee Laredo. We mainly use it in the city, but it's nice to have some all-terrain tires for camping/skiing/fishing so we don't get stuck, what do you recommend for on- and off-road performance?"

I feel that BF Goodrich makes the only true all-terrain tire. Most other brands do not have an aggressive enough tread pattern for any true off-road performance. I know from personal experience that these tires perform beautifully in all areas with the exception of extremely deep mud. That's what the BFG mud terrain is for.

A big selling point for me was the construction of the BFG All Terrain and Mud Terrain. Most radial tires on the market have 4 plys in the tread and 2 ply sidewalls. The BFG Mud and All Terrain have 5 plys in the tread and 3 ply sidewalls. I like the idea of some extra protection when I rub a sidewall against a sharp rock.

The all terrain also behaves well on pavement. It is not loud, and I have managed to get 40K+ miles on a set. These tires are extremely popular and for good reason.



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