# Help with Fitting Tires to Rims???



## Bigmarcus (Aug 25, 2009)

Hello all, I'm new to the site and just started getting back into slots. It has been quite a few years and things sure have changed. I have a couple of 1/32 Flex cars that I plan on trying out at the local track. It's only been over 40 years since I have run on a commercial track. I am also into HO scale and still have a bunch of my old 60s stuff which blows me away at what some of it is worth now.
Anyway, my question concerns fitting tires to rims. In a perfect world one would measure their rims and then pick up the right size tires. Well, it doesn't appear like that is always fesable. My question is what are some of the tricks for cutting down tires to fit rims accurately? I have been able to get the right ID tires, but their width needs trimming down. I know one does not just take a razor blade and chop. Also, what about changing the outside diameter once mounted? Especially with silicones which seem a little fragile. Thanks in advance.. (Note: This is a repost from the General Discussion area, I may have put it in the wrong area to get answers)


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## rc_jeff (Jun 18, 2009)

I have put tires on the rims, on a spare axle rim setup and run them at a slow speed in a dremel and trim the edges with an xacto knive, you can then also sand them down to size and round-over the edges.


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## Bill Hall (Jan 6, 2007)

Jeff's right.

You have to spin them up on some kind of mandrel at slow speed. Some compounds cut easier than others. It's handy to keep a set of calipers ready or at least a go-no-go tire guage so that yer work is even side to side.

I use PVT tires exclusively on my HO projects. They grind nicely with 180 or 220 grit sand paper. For narrowing or cutting I use sharp scissors and then grind the rough edges off after they have been cut to approxiamate size. Harder compounds might require a blade or another counter rotating grinder to be used to accomplish the removal of material.

As stated previously it's always important to roll both the inside AND outside edges of the tire. For sloppy fits I scuff the rim with 220 and use a little black RTV silicone as a mounting adhesive.

For routine scuffing/maintenence, I just run the tires on a chunk of green scotchbrite.

Really a simple thing to do. It just takes time and patience ...but makes all the difference in the world.


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