Widest rear rim/tire that will fit on the Datsun Roadster (well sort of)
Posted: Thu Feb 29, 2024 7:03 pm
Widest rear rim/tire that will fit on the Datsun Roadster (well sort of).
The specs on the wheel/tire combination pictured below may help you if you are trying to get max rubber down with your engine swap (without modifying the frame or mini tubbing the car)
Note the very small clearances and other detail here before running out and buying wheels and tires with these specifications. I will be using a Ford Mustang 8.8 rear differential that will be shortened such that the wheel mounting face location will be 1/4" inboard from the stock roadster. I will be moving the stock leaf springs (which are approx 3/4" outboard of the frame to essentially in alignment with the frame. When you see the clearances below you will understand why these modifications will be made.
Rims: UK Revolution, Rally ET 30, 7.0 x 15, offset +30mm (Fronts are 5.5 x 15, offset +15mm)
Tires: Kenda Kaiser (kr20a) - 225/45zr15 (check online for specs)
The pictures below are using my stock donor car. To test mount the setup I had to bend away the outboard tab of the forward leaf spring retainer. In theory the retainer could be repositioned slightly.
The clearances are: 3/16" upward at the narrowest point between the section width of the tire and the inner wheel well flange sheet metal. 1/8" between the section width of the tire and the rear outward edge of the leaf spring. 1/16" between the section width of the tire and the forward outward edge of the leaf spring. Enough clearance to fully mount the rim with tire and spin the tire at ride height. Not enough clearance for driving but enough for proof of concept and possibly for your reference. Project car will likely be lowered 3/4-1" with a single lowering block on OE leaf springs.
The keys are obviously rim width, rim offset and tire selection. In this case the numbers essentially use up the entire available rear wheel well space in the stock roadster. I spent a lot of measuring before selecting these rims and tires and maybe this info will save you a bit of time.
The specs on the wheel/tire combination pictured below may help you if you are trying to get max rubber down with your engine swap (without modifying the frame or mini tubbing the car)
Note the very small clearances and other detail here before running out and buying wheels and tires with these specifications. I will be using a Ford Mustang 8.8 rear differential that will be shortened such that the wheel mounting face location will be 1/4" inboard from the stock roadster. I will be moving the stock leaf springs (which are approx 3/4" outboard of the frame to essentially in alignment with the frame. When you see the clearances below you will understand why these modifications will be made.
Rims: UK Revolution, Rally ET 30, 7.0 x 15, offset +30mm (Fronts are 5.5 x 15, offset +15mm)
Tires: Kenda Kaiser (kr20a) - 225/45zr15 (check online for specs)
The pictures below are using my stock donor car. To test mount the setup I had to bend away the outboard tab of the forward leaf spring retainer. In theory the retainer could be repositioned slightly.
The clearances are: 3/16" upward at the narrowest point between the section width of the tire and the inner wheel well flange sheet metal. 1/8" between the section width of the tire and the rear outward edge of the leaf spring. 1/16" between the section width of the tire and the forward outward edge of the leaf spring. Enough clearance to fully mount the rim with tire and spin the tire at ride height. Not enough clearance for driving but enough for proof of concept and possibly for your reference. Project car will likely be lowered 3/4-1" with a single lowering block on OE leaf springs.
The keys are obviously rim width, rim offset and tire selection. In this case the numbers essentially use up the entire available rear wheel well space in the stock roadster. I spent a lot of measuring before selecting these rims and tires and maybe this info will save you a bit of time.
