Help on wheels and tires

[hugosa]

Hello,

I am new in this forum and I would like to present myself to the community.

I live in Portugal and I have a Fulvia S3 1.3s from 1973. I am very satisfied with this fabulous car.

Recently I changed my wheels to a set of Cromodora CD28. I changed the tires to 185/70 R14, but now the tires (in some bumps or holes) hit the bodywork. I need to put the whee arches extensions. Can somebody help me on this?

Is this easy to install? Are they made from fiberglass? Do they have any kind of rubber between them and the original bodywork?

And what is the best tire measurements?

Thank you very much for your help.

Best regards,
Hugo

[lancialulu]

Hugo

Better stay with standard profile as the car handles a lot better and you wont have to "flare" the steel wheel arches to get the wheels to stop rubbing in the arch. HF1600s had flared arches to accommodate 175 section tyres.....

Tim

[Huib]

I agree with Tim. Use the standard 4,5J14 rims (either steel or alloy, I prefer the steel wheels any time) with 165R14 tires. The Vredestein Classic Sprint 165R14 is an excellent tire at about €100 each.. If you really want to get the best performance you are lucky. Original Michelin XAS tires are reproduced in the correct 165R14 size. They cost about €200 each.

If you go for the Cromodora's or any other wheel that is wider than the original 4,5 inch, it does not really matter what size tire you put on. You will never get it right anyway.

If you still want the wider wheels and tires, you should also check what happens if a rear spring breaks. It does happen.

Note that the amount of rubber on the road does not depend on the width of the tire. Remember the good old formula Force = Pressure x Surface area from high school? Written differently S = F / P. In this case F is the weight resting on the wheel. P is the pressure put into the tire. The size of the contact area S is determined by weight and tire pressure. The width of the tire does not enter in the equation.

[Ed Levin]

I'd completely agree with Tim and Huib about sticking with the original wheel/tire size.

But, with all due respect, Huib's analysis doesn't fully account for the shape/orientation of the tire contact patch, and its relationship to slip angles and lateral forces. For the same size/weight car, a wider tire may have the same contact area as a narrower tire, but the wider tire will have a shorter, wider contact patch, and the extra width of the patch will indeed have greater lateral resistance--in other words, on a skidpad, it'll pull more lateral g's than the narrower tire, even though the contact areas are identical. The real problem is that--for the very same reason--the wider tire will create greater steering resistance, dulling the Fulvia's pin-sharp handling. As I say, it's not worth the trade-off on the street. But there is a significant difference. If there were no difference in cornering, there'd be no difference in steering.

[Jean de Barsy]

Wheel arches will only cure the problem if you cut away the steel on the existing fenders. Are your rims the "standard" Fulvia alloys? Maybe your car sits too low due to sagged suspension? The later Fulvia's should be "higher" than the first series and then there"s also the offset of the rim. Maybe you don't have the correct rims as it seems they're too much on the outside.

[Ed Levin]

Oh, please. If you need more clearance, don't cut away the lip of the wheel arches--just roll the edges.The lip is there for a reason; you can crimp it to a hem, but don't lose the edge stiffness by cutting it off.