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1989 Isuzu TrooperTire Fit Modifications

Bump Stops and Fender Trim

(You can click on any picture for a better view) 

Installing BFG Mud Terrain KM 33 x 12.50 tires on my '89 Zu has provided added lift and ride comfort, but they don't quite fit a stock truck.  I was able to make them fit with two very easy modifications.  First I added taller bump stops above the rear axle to prevent tire rub.  Next, I trimmed the fender just a little to get added clearance.  Here are the details of what I did.

wheel_well_rub.jpg (14439 bytes)Notice the slight wheel well rub.  I needed to extend the bump stops 3" to prevent this. 
old_bump_stop.jpg (20074 bytes)The original bump stops are 1" steel lumps filled with dirt - completely and totally useless.  I measured the axle to bump stop gap while the axle was fully articulated and found out I needed a 4" bump stop. 
drilling_3-8_hole.jpg (26431 bytes)Since I couldn't find any aftermarket 4" bumps with 5" centers holes, I opted to make the single bolt urethane version from Energy work by drilling a single 3/8" hole in the bracket.  Be aware there is very little clearance between the bracket and axle!
installed_bump_stop.jpg (19327 bytes)About an hour worth of work for both sides with a good 90 degree drill.  Total cost, less than $50.
under_vehicle_view.jpg (18740 bytes)A look under the truck at full axle articulation after the mod shows the bump stop doing its job, keeping the wheel just off the wheel well.  While there is not enough side clearance for chains, full rear axle articulation is unlikely in show conditions unless I'm off the road in a ditch. 

The BFG Mud Terrain KM 33x12.50 tires create a severe lack of clearance between tire and fender.  Put tire chains on and hit a little bump and the fender is gone.  I needed to add an inch or two on each side.

before_fender_trim.jpg (22154 bytes)after_fender_trim.jpg (22396 bytes)Before






cut1.jpg (17816 bytes)First, I used a hack saw to make a cut just below the trim.  I made another cut at the bottom, where the fender wraps under.  This allows the metal to be easily pounded flat against the inside of the wheel well.
bend_flat.jpg (18230 bytes)Next I bent the metal into a semi-flat shape with a pair of pliers. 
pound_back.jpg (18923 bytes)Next, I used my trusty BFH to pound back the soft sheet metal.  The easily bendable fender wrapped nicely around the back of the wheel well. 
apply_undercoat.jpg (19868 bytes)After masking the area, I liberally applied a rust inhibiting spray undercoating.
max_compression.jpg (28743 bytes)max_extension.jpg (28572 bytes)After the fender trim I now have plenty of fender clearance, even with snow chains.  I am planning on removing the stock trim strip and installing Pacer aftermarket fender flairs.


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