7.50x20 tire source

my KB-6 has 8.25 20s on it,

I lucked out at a liquidator store, got 4 brand new and 2 recaps for $50 each.

the only tires in the whole store and they were my size,

Since metal valve stems were on it when I separated the old tires and tubes from the wheels, I think that's what I'll replace them with. Hopefully I'll have a full set of mounted tires by next week. Wagons ho.....

Cornbinder, which type of rim requires which type of tube? Can you expand on your prior email.

My second questions is if K7 could be spec with 7.5, 8.25, 9.0, or 10, is there a rule of thumb that guides how wide the rim needs to be? For instance, how wide does a 7.5 vs a 10 need to be?? I assume you can go up or down a size from a given rim size ( not sure ) but can you go up two sizes and squeeze them on?

i know that both the Goodyear and the BF Goodrich websites have information on what width rims accommodate various width tires. or visa versa anyway. or at least they did a couple years ago when i was trying to figure that out for another vehicle i have.

Cornbinder, which type of rim requires which type of tube? Can you expand on your prior email.

My second questions is if K7 could be spec with 7.5, 8.25, 9.0, or 10, is there a rule of thumb that guides how wide the rim needs to be? For instance, how wide does a 7.5 vs a 10 need to be?? I assume you can go up or down a size from a given rim size ( not sure ) but can you go up two sizes and squeeze them on?

As the prevous poster noted, there are charts as to what rim is used with which sized tire. On spoke wheels there is also dual spaceing bands, which must be correct for the spoke design width.
For example 10.00x20 is designed for a 7.5" width rim (design rim width) but is premissable on 7" or 8" rim widths. If too narrow a rim is used for a tire, the sidewall is pinched inward and the tire cannot support the load as designed. Also if the rim is too narrow the dual spaceing will be too close and the tires can "kiss" at the bottom wich will rapidly distroy the sidewall.
As the rim width increases the offset mfg into them also increases to maintain proper dual spaceing.
Most modern 20" spokes will accept up to 8" rim width (for 20"rims, the same spoke will take upto a 9" 22.5 rim). The spokes on the K 6-7's series are narrower and I think a 7.5 may even be too wide. I would have to measure mine to see what the differance is.
The narrowest tires in the 20" rim size fit a 5.5" or 6" rim, while the largest (13 or 14x 20) need a 10" or wider rim.

Well, one tire was mounted before quitting time today and the metal valves on the tubes I got from Coker seem to work fine altho they appear to be a little short thereby making the task of airing them up a tad difficult. The tire guys seem to think valve stem extensions will solve that problem. I was surprized at how fast they installed the liner, tube and lock ring. I'll add a little black touch-up paint to the wheels and I'll be one step closer to a rolling chassis by Friday afternoon. As Phil says, "I'll be happy, happy, happy!"