Sweptline.ORG

I've been researching tire sizes. I've got to get the 31/10.50s off the truck. Its a bugger to get rolling and turning is kinda rough. I'm just going to buy tires locally. The FSM and it shows a 6.70 or a 7.10 for a D100. I looked at several tire conversion charts and this seems to be the converted size to a modern tire. I have a 64 Utiline with a /6 and 3.91 gears. I calculated rpm at 60 mph. I read that the recommended tire size is 235/75/15 here by members. My wheels are 15X7.

6.70-15 is a P205/75R15 and 7.10-15 is a P215/75R15

205/75R15 = 27.1X8.07R15 2909rpm
215/75R15 = 27.7X8.07R15 2846rpm
225/75R15 = 28.3X8.07R15 2785rpm
235/75R15 = 28.9X8.07R15 2728rpm

Two questions:
Which size would look the best and be easy on the starting and turning?
Anyone else with the /6 and 3.91? What size do you have and if you changed what size would you get?

Thanks, Craig

I have 235/75/15's on my '61shorty. /6,3:91. handles just fine.

Txas2step wrote:I have 235/75/15's on my '61shorty. /6,3:91. handles just fine.

Thanks, I'm bumping this for more suggestions.

I like the 235/75's on my truck. They're Cooper Trendsetters. Easy to turn and they handle pretty well.

i have a 318 with 3.5 rear and i can't think of any complaints with the size.. but I guess i don't have much to compare it to either.

i used 235/75-15 but mostly because that's what was already on there and also because that is the stock size for a Jeep Wrangler,
which meant I was able to find 5 lightly used tires and rims on craigslist for $120..
unmount/remount and balance was $100,
sold four of the bare wrangler steelies for $80,
kept the last wheel + tire for a spare (mine was missing)
not a bad deal i think

Also, you might want to consider the type of tire you choose, P-series tires are more passenger car related vs a LT type tire. A P-series will give you a better ride and they will have a lower psi rating usually a P-series tire will be rated at 35-45 psi. A LT type will be rated at 50-80 psi and will give you more of a truck ride.

The narrower the tire, the easier it is to turn the steering wheel, regardless of the vehicle.

I've got P235-75R15 radials on stock 15" x 7" Mopar steel wheels on the unmodded '68 D100, and the truck rides and drives great.

Thanks guys! I went with the p235/75/15 on my Kelsey Hays steel 15x7 wheels. The truck is so........easy to steer now. The tire size looks correct. Thanks for the advice and comments.