Tire update, a couple thousand miles in.
Just wanted to give an update on the tire situation now that I have some miles under my belt. I'll need to do another because I don't recall what I put on for the steers. I think I wanted to keep the bigger tires up there for the weight rating, and I went with the Dayton 11r from GCR Tire in Seattle. They were great, I would recommend them.
A couple of things also happened in the tire switch: the first, and one reason the bus was riding low, was that there was a broken leaf spring in one of the rear packs. Somehow my previous mechanic never noticed this? Now fixed, and riding higher. Also, I needed new bushings--something that buffers the frame and suspension I think?--all around as the old were smashed and worn out. That added about an inch or less, too.
The tires have been great. I think the idea of a retread really only makes sense in a fleet vehicle where the tread is worn much faster than the sidewall. As has been mentioned before, you will most likely age out of the tire (7yrs, maybe a bit more if you are adventurous) before wearing the tread out. I went with Dayton as a second-tier tire of American make; it was described to me as coming out of the same factory as the top tier but with a lot less choice in sizes and makes. Fine by me.
Regarding size and performance, I knew that the smaller tire would push the engine RPMs up for maintaining any given speed compared to the older, larger tires. Indeed this has been the case. I'm probably up 100-200 RPM. And the top end (right, with a skoolie) has gone from maybe 65 with a tailwind to 63ish. I hardly ever see those numbers anyhow. Mostly I run around 55-60, and the tires have been surprising here. Why is that? you may ask. Well, let me tell you. The bus is "torquier" at higher speeds. Where it used to be difficult to accelerate nearing top speeds, say 50-65, now it runs more like a Maserati (well...). I can go from 50 to 65 in most situations (now, I may not like running it there for comfort, but it can be done) whereas I used to max out wherever the road would allow (smoother=higher speed) as the gearing just didn't have much torque at high speed.
The most noticeable thing about this added power is going uphill. I go to Burning Man, which means I am likely near my GVWR because I'm carrying **** for a circus apocalypse. It also means long grades on I5 from Seattle to Medford, and a half-dozen *nasty* state highway passes. I can now take those at 5mph higher than before. Where I used to be at 15, I'm now at 20. The worst of the worst still has me at 10 mph, but you just gotta be kind to the old Cummins Triple Nickel and it'll get you where you are going. A new radiator helped with the temperature issue, too (that was several years ago, a great investment).
One thing I did was to choose the metro steer tire, for metro buses. My new mechanic, who is also a skoolie guy, suggested a highway steer instead, as the former has a rounded edge from tread to sidewall and the latter a more squared. The metro thus turns a little better, and the highway tracks a little better. He thought there would be less constant steering necessary with the highway version. Meh. I need the exercise.
1981 Bluebird All American