t900 thanks.

 

Yeah, what he said.

 

Does the front tire width matter if you have stock manual steering? I currently have 205/75R15 up front and 235/75R15 in the rear on my 51 F1. They are the tires that came with the truck and are pretty worn. The steering in smooth but hard to turn. I remember when I drove a 47 with original tires and tubes that the steering was very easy, quick, responsive and smooth. Nearly one finger steering. I want to get new tires and want to be sure that just changing to the same size is the best thing to do. Thanks, Steve

 

This decision is quite a bit more complicated than it seems at first. You have not only the ride height and wheel clearances to consider, but also the "filling the wheel well", the "rake", and the rear tire gear ratio issues that Julie raised.

The wheel clearance is affected by the height and width of the tire, as well as the wheel offsets. If you want to throw in a few more variables like modern vs. vintage treads, tread wear ratings, and blackwall vs. whitewall vs. raised white letters, then it becomes a real mind-bender.

I've been stuck in "analysis paralysis" for several weeks on this subject, and I decided that I needed to nail a few things down in order to attempt to break the Gordian Knot. To make things a little simpler, I decided to nail down the wheels as 15x8 with 4" offsets. This is what the truck has on it now (even though I'm switching from Cragars to Smoothies), and it gives me a point of reference to work from. My truck has P235/60R15's on it now. I don't like the way they look(too squatty) but it it allows me to measure clearances to see how much wider/taller I can go without getting into clearance problems.

Assuming 15x8's with a 4" offset, I measured that I can tolerate another 3/4" inch of height on the front with scrubbing (my truck has less clearance up front because of the Monte Carlo frame splice). I put together this spreadsheet to help me decide what size tires will fit:


I figure that I can stand up to a P225/70 up front. I don't think I'd be able to get 75's under it without getting into wheel spacers (I've already purchased my new wheels with 4" offsets). I can go as large as I want in the back, but I do need to take the "rake" into consideration. I'm thinking of going with P255/70's in the back. I think they'll fill the wheel wells up nicely, and give it a slight rake from back to front. As far as brand, I'm leaning toward BF Goodrich TA radials. Not a vintage tread, but I like the way they look, and I'll probably turn the blackwall out.

Unless you guys talk me out of it, I'll probably buy the tires in the next week or two, and post photos.

-DV

 

I only changed my mind about eight times before pulling the trigger, but here is where I wound up: P235/70R15's on front and P275/60R15's on the rear (They're almost identical in profile height between front and rear). The wheels are Wheel Vintiques 12 Series bare smoothies 15x8 with 4" backspace. I did have to use 1" spacers on the front to get enough clearance because of the Monte Carlo front clip on this truck.

Yes, that is a lot of rubber, but it takes a lot of tire to fill up these wheel wells. The truck had P235/60R15's on it when I got it, and they looked like bicycle tires on this truck.

I'm happy with the overall ride height/tire/wheel set-up, but I'm not happy with the way it rides right now. I'll elaborate more on that in another thread shortly.