Splitting and rebuilding rims is not a difficult task by any means, but it can be hard to find clear and sound advice online. After reading and understanding these instructions, you should be able to successfully rebuild any two or three piece wheel with confidence.
Splitting Split Rims
Splitting your wheels will depend on their design, but the principle is generally the same… If you have a two piece wheel where the face of the wheel is bolted to the barrel, you can simply remove the bolts and withdraw the wheel face. All other designs are sealed with silicone to make them air tight (unless welded in the case of some Japanese wheels) and will require a little more persuasion to make them split. The steps below explain the process of splitting a modular wheel, using a sandwich mount three piece wheel as an example. Read more here about different wheel mounting configurations.
After tyres have been removed, take out the split rim bolts following a star pattern to evenly remove tension. Put a soft cloth (glasses cleaners are good for this) inside the socket you are using to prevent damage to each bolt head.
If your wheels have nuts on the rear of the face (i.e. three piece wheels), always loosen from this side while holding the bolt head still at the other. This technique will reduce the risk of marking/damaging the bolt head and the same techniques apply when rebuilding.
You will now see the silicone that runs around the circumference of the wheel. Its ONLY purpose is to prevent air escaping through the joins between each section when the tyre is inflated. If you are working with a sandwich mount wheel, begin by running a Stanley blade around its circumference, cutting as close as possible to the wheel lip.
To remove the lip, turn the wheel upside down and strike the back of the lip with a wooden/rubber mallet. Don’t be afraid to use some force as this is often necessary but ensure that you rotate the wheel instead of hitting it in the same place every time. If you can feel that the lip is not separating from the face of the wheel, try cutting the silicone again before repeating. Once part of the lip dislodges, it’s sometimes possible to remove it by pulling from the wheel face with a steady force. If you are unable to remove the lip of the wheel with this technique, use a heat gun to soften the sealant before trying again.
Once the lip has been separated from the wheel face, take your Stanley blade and cut along the silicone again, but this time where the wheel face meets the barrel. The centre can then be persuaded from the barrel by striking it with a wooden block from the rear side.
For two piece (as well as face mounted and reverse mounted wheels), use the same method for removing the wheel lip as described above. Note that it will only be possible to make one cut into the sealant at the point where the lip and barrel meet.
If sealant was used between the wheel surfaces when built (as opposed to being applied as a final step), you will not be able to cut into it and this will make the task of splitting wheels considerably harder. It is unnecessary to put sealant between the wheel surfaces when reassembling and we would not recommend doing so for the reason mentioned above.
Preparing Your Wheels for Rebuilding
With your wheels successfully split into two or three separate parts, the next stage is to prepare the surfaces for rebuilding. You can also take this opportunity to refinish your centres, polish your lips or replace your hardware.
Prior to reassembling your split rims it’s essential that all surfaces are as clean and flat as possible. A wire wheel can be used to quickly remove sealant however a gentler surface preparation drill attachment is the preferred option for minimising surface marks. A rotary tool with a suitable attachment can also useful for removing all traces of silicone sealant.
For the centre of the wheel remove as much silicone as possible with a Stanley blade. A surface preparation drill/rotary attachment can then be used to take off any remaining sealant. It does not matter is the powdercoat or paint is removed as long as the surface is flat, smooth and free of old silicone. When the previous sealant has been removed clean all wheel surfaces thoroughly, ideally with a panel wipe or isopropyl alcohol solution.
Rebuilding Split Rims
As previously mentioned, there is no reason to use sealant between the wheel surfaces. This means you can start reassembling the wheel dry with mounting hardware.
Do however put a drop or two of Loctite 243 or equivalent on each bolt to help prevent them from vibrating loose. When using hand tools the fastest way to rebuild a wheel is to insert all the bolts that hold the wheel together, before tightening them fully to the required torque. As with the wheel disassembly process, a cloth should be used inside the socket which comes into contact with the bolt head to prevent damage and all tightening should be done from the nut site if possible. When torquing the bolts, be sure to follow a star pattern to tighten the wheel together evenly. Finish by tightening each bolt to the specified torque again in series, one at a time, to make sure that none were missed. If your wheels do not need to be sealed, the rebuild is now complete. For all wheels with a separate lip it is always necessary to ensure that they are made air tight again…
Sealing Split Rims
Unless you are working with a two piece wheel with removable face, your wheel will now be securely held together but will not be airtight. This is where sealing comes in. This requires no expensive/specialist products – regular bathroom sealant is absolutely fine (preferably with a mould inhibitor).
Lay the wheel on a flat surface so you can rotate it as you run a bead of sealant as evenly as possibly along the seam(s). When you have completed one full rotation, put a little bit of diluted washing up liquid on the end of your finger (to stop the silicone from sticking) and gently run it around the silicone bead. This will allow you to smooth the bead out against the lip/barrel of the wheel as shown below.
For a really neat job you can mask the lip and the barrel with tape to get a perfectly straight line of sealant. This works particularly well for face mount or reverse mount wheels as the join isn’t as deep or wide as with a sandwich mount wheel. Just remember to remove the tape before the sealant starts to cure.
Now put your wheel to one side and allow the sealant to fully cure before refitting tyres. There is absolutely no need to over-complicate this process and one solid bead of sealant as shown in the example will guarantee a fully airtight seal.