Description of the Runflat Compression tool:

I have an Allied International model 82392. (Allied Signal)

It is 27' by 2", and rated as follows:

• Webbing strength 10,000 lbs
• Working Load Limit 3,300 lbs

The length of the lever arm (from the pivot of the ratchet to the end of the handle) is about 6-1/2". I have seen some with closer to 8" long handles, and HIGHLY RECOMMEND them. The longer the arm, the easier they are to use.

Description of the original tool:

Two pieces:
- ratchet with short (about 12") strap, with hook
- 26' long strap with hook

Description of modification:

The short strap has a loop in one end which is looped around a bolt in the ratchet assembly. Remove this bolt, and remove the short strap. (It will not be used with runflat operation.)

The long strap has a loop in one end that is looped around a hook. Remove the hook by any means that preserves the strap. Place the long strap where the short one was removed. (i.e. with the loop around the bolt in the ratchet assembly.)

The resulting assembly is a ratchet with a long strap attached, and no hooks anywhere. The long strap may be shorted if desired (or if salvaging a damage strap). Only about 7' will be used.

The ratchet strap is placed around the runflat just as described in the video, and is used similarly. I have had to use my foot to work the ratched handle in order to compress the runflat enough to insert it into the tire. Use of a pry-bar should be avoided as it can bend the handle of the ratchet.

The strap is positioned around the center of the runflat, with the ratchet near the edge, but on the flat part of the strap where it goes across the hole in the center of the runflat. When compressed (the two opposite sides of the runflat are about 2 inches apart), the runflat will become crescent-shaped. This allows the runflat to be removed from, or inserted into the tire. (But not without some effort and lubrication with soapy water!)

When tightening, be careful to prevent the loose end of the strap from becoming caught or tangled in the ratchet. If this happens, back off the tension (as described below) and try again.

When releasing the strap, it is important to release the tension gradually. Simply opening the ratchet handle compeletly will cause sudden, and possibly dangerous, release of tension. To release the pressure gradually, use the following procedure:

• using the handle release, move the handle most of the way to the "open" position (but not far enough to release the ratchet!).
• tighten the ratchet with the handle just enough to relieve pressure on the ratchet.
• push (and hold) the ratchet release bar.
• slowly allow the handle to un-wind until it is about to the closed position.
• release the "ratchet release" allowing the ratchet to hold the tension, and freeing the ratchet handle.
• repeat until most of the tension is released.
• after most of the tension is released, open the handle all the way to release the remaining tension, and remove the strap from the runflat.

This process is difficult to describe without pictures or examples. Recommend you try it with just a little pressure until you "get the hang of it".

The tire changing video is titled: Hummer Tire/Wheel Service and is Copyright 1993 Goodyear tire ...

I do not have the part number, but I will try to get it from the dealer the next time that I am there. If anyone else has it, please post it.

It talks about two-piece run-flat assemblies. Most if us have one-piece, but the procedure is basically the same. The most important thing covered in the video is the danger of disassembly of a tire/wheel that is not completely deflated. This can be very dangerous! So dangerous that tire shops have special cages used to prevent injury in the event of a rim explosion! This is the reason (right or wrong) that the AMG lawyers are requiring the use of the five-sided nuts, and making the socket difficult to get. Please be careful! (Commentary about the socket and the nuts covered at a later time.)

Dave Breggin
'95 Diesel Wagon