Upgrades
Reviews
What Fits and What Hits*
Wrangler (YJ)*
(TJ's
May use up to 1" larger tire onstreet)Tire Size (Diameter) | Suspension Modifications | Body Lifts | Fender Trimming |
|---|
| 30" | No lift required - however small
lifts will increase articulation greatly | No lift required - however a
1" or 2" body lift could be used to increase
articulation | No trimming required and none
recommended |
| 31" | No lift required for street use but
there may be some slight plastic fender rubbing. 2" to
3" lifts are recommended for trail use to increase
articulation | No lift is required but a 1"
or 2" body lift can be used in place of a suspension lift
to gain clearance and eliminate rubbing | No trimming is required and none is
recommended |
| 32" | A 2" to 3" lift would be
recommended, a 4" lift would provide greatly increased
articulation without rubbing | A 2" body lift combined with
1" lift extended shackles could be used to clear this
size on an extreme budget. | With extended shackles or small
suspension lifts there may be some rubbing at the corners of
the plastic fenders under extreme conditions. |
| 33" | A 4" suspension lift or spring
over conversion is recommended. | A 1" or 2" body lift is
recommended to increase clearance | Some rubbing may occur Some
trimming of the bottom trailing edge of the rear fender may be
useful. |
| 35" | A 4" suspension lift or spring
over conversion is necessary. Axle & brake upgrades are
highly recommended as well. | A 2" body lift is recommended,
a 3" lift can increase clearance. | With a 2" body lift trimming
some fender edges as much as 1" or 2" may be needed. |
CJ*
Tire Size (Diameter) | Suspension Modifications | Body Lifts | Fender Trimming |
|---|
| 30" | No lift required - however small
lifts will increase articulation greatly | No lift required - however a
1" or 2" body lift could be used to increase
articulation | No trimming required and none
recommended |
| 31" | No lift required for street use as
this is close to stock size. 2" to 3" lifts are
recommended for trail use to increase articulation | No lift is required but a 1"
or 2" body lift can be used to gain clearance and
articulation | No trimming is required and none is
recommended |
| 32" | A 2" to 3" lift would be
recommended, a 4" lift would provide greatly increased
articulation without rubbing | A 2" body lift combined could
be used to clear this size. | No trimming is required unless
rubbing is actually observed in use. |
| 33" | A 3" to 4" suspension
lift or spring over conversion is recommended. | A 1" or 2" body lift may
be used to increase clearance | Some rubbing may occur Some
trimming of the bottom trailing edge of the rear fender may be
useful. |
| 35" | A 4" suspension lift or spring
over conversion is necessary. Axle & brake upgrades are
highly recommended as well. | A 2" body lift is recommended,
a 3" lift can increase clearance. | Some trimming of fender edges may
be needed to eliminate rubbing problems |
Cherokee (XJ & ZJ)*
Tire Size (Diameter) | Suspension Modifications | Body Lifts are not available. | Fender Trimming |
|---|
| 30" | No lift required - however small
lifts may increase clearances & articulation | N/A | Some minor fender trimming may be
required if rubbing is a problem with wider tires |
| 31" | 3" lifts are possible, 4"
lifts would be better for trail use. | N/A | Trimming may be required with wider
than stock tires |
| 32" - 33" | A 5" or larger lift is
required. | N/A | Some trimming is required |
| 33"-35" | A 6" or larger suspension lift
is required | N/A | Serious trimming may be required |
[
C101 Jeepster Guidelines - Click Here ]
* IMPORTANT NOTE:
The above tables are only guidelines reflecting popular trends or upgrade combinations. Other combinations
are possible, for example: I know of a YJ owner who uses a 3"
body lift and a set of 1.5" lift Con-Ferr extended shackles to
clear 33" tires. This is not what I would run or recommend - but
it works for him. Your mileage may vary and we do not claim that the
above is the definitive word of god on the subject of tire clearance.
Some other combinations may work fine or on some vehicles the
guidelines shown above may not apply.
Tradeoffs - Tire Size (diameter)
As with anything in life there are tradeoffs when it comes to
selecting tires for your vehicle. Increasing tires size can greatly
increase the off-road capabilities of your vehicle. Larger tires
provide increases in total ground clearance, an increased traction
footprint & flotation, make climbing obstacles easier, can be
easier on the environment and just plain look better on your Jeep.
However all of these benefits have a price.
Larger tires are more expensive in general and may require
expensive suspension upgrades for proper clearance, especially on the
trail.
Tires more than an inch or two larger than stock may require you to
change the ring & pinion gears in the differentials of both the
front and rear axle in order to keep your engine running in the
optimum power range - especially when off-road, going uphill or
driving on the freeway.
Increased tire diameter increases the torque loads on the axles,
u-joints & drive shafts. For significantly larger tires it is
usually necessary to upgrade these components, especially where
traction aiding devices such as lockers or limited slip is used, or
you may risk breaking one of these components on the trail.
Bigger tires are heavier tires. This increased rotating mass and
the increased leverage provided by the larger tire often call for
increases in braking power: changing brake pad materials, rear disc
brake conversions, beefing up the master cylinder or even switching to
larger disk and calipers are all options. Driving a tall, heavy,
modified short wheelbase Jeep with 35" tires and stock brakes in
poor condition at highway speeds can be a recipe for disaster!
Increases weight caused by the larger tire and any axle or brake
upgrades also increases unsprung weight. This does not matter much on
the trail, but can make the ride a higher speeds much more harsh. When
mounting the tire you will find that it is often much more difficult
to balance the tire correctly. This is due to the extra weight of the
tire, the increased rotating inertia of the tire and manufacturers
tolerances on larger tires. It can take quite a bit of weight to
balance a large tire and many shops that do not routinely handle tires
of this size may not do a good job.
So - bigger tires have a price, the bigger the size change the more
modifications are needed to properly set up your Jeep; still, on the
trail, there are times when putting more rubber on the ground, or more
space between the vehicle and the ground, is exactly what you need.
On my 1990 Jeep YJ I decided to switch from 31" tires to
35" tires while not wanting to risk breakage on the trial. The
total price of those 4 35" tires was probably close to $7,000
dollars!. This included a 4" suspension lift, a 2" body
lift, fender trimming, changing to heavy duty, custom modified, 1 ton
truck axles, changing to 4.10 gears in both differentials (+ lockers
and carrier changes), and adding rear disk brakes. In addition the
lift and axles necessitated transfer case modifications and custom
drive shafts in both ends. It was not a simple, cheap or fast project
- but on the trail it sure is sweet!
Trade-Offs Tire Size (width)
Tire diameter is not the only issue - tire width is important to.
Wider tires increase footprint which can be important for traction or
increased flotation. The tradeoff include that wider tires can also
require extended fender coverage in many states and may require
changes in wheel width & offset to work properly. On stock offset
wheels the tires may be mostly covered by the stock fender flares but
rub on suspension components when turning thus reducing effective
turning radius. The incredibly tight turning radius of a jeep is one
of it's important advantages on the trail. Wider wheels or wheels with
increased offset move the tires outboard and can greatly reduce the
rubbing when turning but make the vehicle wider. This increased width
may be an advantage for stability if you drive a lifted vehicle or a
disadvantage of you are squeezing down a trail better suited for a
Samurai or a quad. Lastly narrower tires can sometimes be an advantage
where the best traction is located just a few inches below the surface
(such a shallow snow or mud) and the decreased footprint and increased
pressure aids the tires in getting down to where it can get a bite.
Tread Patterns
The choice of tread pattern is important in your new tire decision
making process. Tread pattern should be chosen based on the intended
use of the Jeep. The most popular tread pattern for all around
off-road use is a mud terrain pattern.
The mud terrain or mud tire pattern is characterized by large lugs
on the tire with large voids between these lugs. The large lugs
provide plenty of bite in low traction conditions while the large
voids allow the tire to clean itself by throwing off mud or other
material when spinning thus providing a good bite on every rotation of
the tire. These tires are also very popular for rock crawling as the
large lugs can provide a way of gripping and pulling the tires up and
over irregular rocky edges where a smoother pattern would just spin.
The biggest disadvantage of these patterns is that they run rough and
loud on the highway. To reduce this problem choose a tire with
irregular or asymmetric spacing of the lugs and voids to reduce
harmonic vibration at highway speeds. There are also situations such
cold powder snow or sand where an all-terrain pattern would be better.
The general purpose all terrain tire generally has an interlocked
tread pattern with siping (small cuts) on the tread blocks. The voids
in these tires are also generally much smaller than those on tires
designed for use in the mud. The denser pattern of blocks and smaller
voids make these tires quieter on the street. It also increases the
surface area of the tread which gives the tire improved flotation on
surfaces such as light powdery snow or sand. The increased siping can
be important in snow were it is the number of edges, even quite small
edges, biting into the snow that provides the "bite". The
downside is that the smaller voids cannot clean themselves as easily
of packed mud or slush as the larger voids on mud tires do. If these
voids fill up with mud the tire loses much of it's "bite"
and traction is lost.
While the all terrain pattern's improved flotation and additional
siping may be an advantage in absolutely dry powder or packed snow,
the mud terrain may be the wiser choice if the snow or underlying
terrain is, or can turn, slushy or muddy. In these cases the all
terrain pattern can become packed with mud and stuck where a mud
terrain pattern would self clean and plow on through.
In sand the improved flotation provided by the dense tread pattern
of the all-terrain tires can be a distinct advantage.
A variety of manufacturers also offer a family of tires sometimes
called trail tires or something near that. These are most often tires
designed for use on light trucks or sport utility vehicles which see
most of their use on the street. They will generally be quieter, get
better gas mileage and last longer than either of the other off-road
patterns. The tread patterns are designed to provide significantly
improved comfort or performance on the street which can sometimes
compromise serious off-road capability. I personally would not
recommend them for anything other than light off-road use in dirt, on
unpaved roads or trails where you are unlikely to encounter mud,
significant rocks or other unpleasant conditions. Fortunately this is
the limit to which most of their intended market are likely to take
them.
Factory Options
Essentials
