Tire Diameter, Front Tire Choise Options

[mzapisek]

I'm running 245/50/16 on the back and 225/55/16 fronts with GT steel flares. Tires look good and perform well. I do get rubbing on the inner fender well at full lock. I am using a 1/2" spacer in the front.

I have a spare set of 16" front wheels. If I go with 205/55/16 to reduce the section width the tire diameter reduces by almost one inch to 24.9". My current set up has almost identical tire diameters at 25.7".

Is there a problem with running smaller diameter tires in the front? Handling? Alignment? Would this create to much rake?

Appreciate some input. I searched but couldn't find a definitive answer.

Thanks.

[roblav1]

Personally, I'd go with narrower fronts, as George said. Lowering of the front by 0.8" will slightly increase rake, decrease caster, and generally contribute to more oversteer. You don't say what your current spring rates are or front and rear ride heights (or ARBs). If you're happy with the way the car currently handles, lower the rear slightly (if adjustable spring perches) or raise the front at the torsion bars.

IMHO, 205 front and 225 rear aspect ratio is right for flared 914. And 15" wheels are better than 16" wheels because of the lower rotating mass. Wider tires don't necessarily equate to better grip. Other factors play in the mix, particularly tire compound. The 914 is so lightweight anyway... they don't need the bigger tire sizes.

If you eventually swap out tires / rims, here's a general methodology for car setup:

- Set tire pressures
- Set ride height / rake
- Set corner weights
- Set caster and camber (I prefer more front caster in 914 / early 911)
- Re-check corner weights
- Set toe
- Re-attach adjustable ARB links