Posted 27 June 2010 - 03:21 PM
SLOT CAR TIRE MOUNTING PROCEDURE
1. Get enough axles (old, new or bent, it doesn't matter) to mount all of the hubs you're going to glue. I put a hub on each end of the axle but if you've got enough axles one hub per axle is a little easier to handle. You'll also need adhesive (I now use 3M #80 Spray Adhesive), lacquer thinner, and a wide-mouth glass jar a few inches deep.
1a. (Optional) At this point take one of the rims and put it on your Hudy tire truer. Use a few spacers to get it centered on the truing drum. Now move the tire cutting pin so the point is right at the outer edge of the hub. This will be a big help when you start to trim the tires since this is hard to set precisely after the rubber is mounted.
1b. (Optional) Mark the position of the setscrew on the inner face of each hub (where the axle spacers would touch) with a scratch or drill "dot". You don't have to do this on SpeedShop rims since you can usually see the position of the set screw after the tire is mounted. However, a few times it has been helpful when I mounted a tire too far over the inside flange.
2. Tighten the hubs onto the axles (fairly tight) near the ends of the axle, make sure you position the hubs so the set screws line up if you put two hubs on an axle.
3. Put at least an inch or two of lacquer thinner in the jar and dip the hubs in for a few seconds. Remove, shake, and let dry a few minutes. This will degrease the hubs; don't touch them with your fingers after this.
4. I spray a small amount of 3M #80 into a shallow cup and then using a small stick or brush coat the inside of the tire donuts with a fairly thick coating of adhesive. Use too much rather than too little and make sure the entire inside diameter of the donut is coated, especially near the ends. Set them on their side to dry, it usually takes about 15 minutes but check the manufacturers instructions.
5. While the tires are drying coat the hubs with contact cement. Use the same procedure as with the donuts but try not to let the glue drip down into the set screw access hole and get in the screw. It's OK to get a thin "film" over the set screw access hole (this will usually go away as the glue dries) but it doesn't really matter since this hole will be cleaned out later anyway. Stand the hubs/axles on their end and let dry. Check the adhesive manufacturer's instructions but it's usually better for the glue to be a little bit too dry than too wet.
6. Now for the moment of truth! Take a donut and dip it in the lacquer thinner for four or five seconds. Remove and quickly slide it onto the hub with a twisting motion and align the inner end of the donut with the inner edge of the hub. It shouldn't be sticking out over the inner edge of the rim more than a 1/16" (it's OK if it does but it will take you longer to trim the tires). It should stick over the outer (open) end of the hub, depending on the donut an 1/8"or more.
***IMPORTANT NOTE*** This operation has to be done in about three to five seconds; after this the glue will grip and you won't be able to move anything. If you find that the donut wants to stick to the hub immediately you will have to leave the donut in the lacquer thinner a little longer and dip the hub, too. Another possible cause is that the glue wasn't dry enough.
7. Let the tires dry for at least three days before trimming or truing.
8. The next step is to make a hole in the donut so you can get at the set screw (this depends on the make of hub). I do this with a Dremel and a small (approx. 1/16" dia.) ball grinder but you can also use a drill bit. I hold the axle and while looking at the inside of the hub and try to drill straight down on top of the set screw. This takes a little practice but once you've done it a few times it's easier than you think. If you miss a little bit it's OK, just move a little and re-drill. I've mis-drilled tires a few times and it really doesn't seem to affect tire performance at all.
9. Now you can remove the tires from the axles and mount them on your tire truer. First cut the outside excess rubber off using the previously positioned (step 1a) cutter. Next I finish the inside edge with a quick touch of an emery board; if you mounted the rubber correctly you should have very little to remove here. You can now grind/true the outside diameter of the tire. I usually only take them down to around .850" since the tires will change size slightly over the next few weeks. This allows me to have fresh rubber on the surface when I true them to the needed size (just before a race).
10. When you have used the tire and the rubber is worn too low all you have to do is put the whole thing in the jar of lacquer thinner. In about 30+ minutes they will pop right off the hubs and be ready for another retread. You can retread them many, many times. Just check that the hubs aren't bent, the axle holes aren't worn, and the set screw can be tightened without stripping.
Final note: I know this sounds like a lot but it's not so bad after you've done it a time or two. I like to do twenty or more pairs at a time and get it all over with at one time.
Jay Guard
IRRA Board of Directors (2022-Present),
Gator Region Retro Racing Director (2021-Present)
SERRA Co-Director (2009-2013)
IRRA BoD advisor (2007-2010)
Team Slick 7 member (1998-2001)
Way too serious Retro racer