FRONT WHEEL DAMAGED WHEEL ARCH

[tonycharente]

Going quite slowly with wheels turned to the right, going up onto a double hump (up, down and up again) at a 45 degree angle, there was a loud bang - the front right hand wheel had struck the the front wing wheel arch, enough to badly break the fibreglass over a few inches (on the rim of the arch from the centre of the arch and running forward).

The car is a 1969 S4 SE ELAN FHC, on standard 4 1/2" steel rims with Dunlop SP10 155/80 13's. The body, wings/wheel arches and ride height look to be entirely normal and unmodified, and the springs and shocks seem normal.

The PO had rebuilt the car on an early (c. 1990, therefore "Lotus replica") Spyder chassis, which is still in excellent condition, with Spyder front wishbones. When I bought the car it was on 6" Minilites with Dunlop SP Sport D8 175/60 13's. These are both significantly wider and significantly lower diameter than the 155/80 13's. I reverted to the original wheels and tyre size as I didn't like the under-gearing and in particular (ironically) because the edge of the right hand rear tyre would scrape against the inside of the rear wing wheel arch when cornering hard. Reverting to the original wheels and tyre size cured both issues, and since then there has been no scraping anywhere when cornering hard.

Obviously I've now got to get my wing repaired, but before I do so I am anxious to discover how this could have happened. I had thought that with the original wheels and tyre size there was no way the tyre could hit the wheel arch, even if the suspension reached full compression, even with the wheels turned at the same time.
What can I do to avoid the same thing happening again?
All thoughts, suggestions, comments welcome, please.
Many thanks,
Gloomily,
Tony

[steve71]

Hi Tony,

WhenI first got my Sprint it had badly sagged front springs. I have standard size rims/tyres and had the problem of tyres fouling the inside of the wheel arches. I have replaced the front springs and this has raised the car enough to allow plenty of clearance between wheels and body. I think it is just fact that if the body is to low due to sagged or lowered springs it will hit the tyres.

Steve.

[archigator]

I had the exact same thing happen in my Sprint. I was corning hard right in a parking garage, while turning uphill and BANG! Popped out a big 3-inch chunk of my wheel arch. The tires were larger than stock (previous owner), so I reverted back to the stock 155/80 13's, and did not have the problem again, but I also haven't had it in a parking garage since. I have also since upgraded the front coil-overs.

Gary
'71 Elan Sprint

[rgh0]

Unfortunately the standard Elan front wheel clearances allow the wheel turned outwards to hit the body before reaching its travel limit. Normally when you have the wheel turned outwards that is the inside wheel and thus under little load. However in certain circumstances such as large bumps or ramps or when you get a big handfull of opposite lock on a race track you can end up at full bump with the wheel turned out and crunch on the body. I have cracks in both my Elan front arches from full opposite lock incidents to prove it

Smaller diameter than standard tyres ( eg 175 / 60 x 13) reduce the risk of major damage. Stiffer springs at standard ride height reduce the risk as it needs a bigger bump to get sufficient wheel travel to be a problem. Longer bump stops can be used to eliminate it but to be effective you loose to much wheel travel IMHO.

Rohan

[brassringfarm]

I recall a number of posts about 2 years ago discussing this problem and the general consensus was that there is a slight assymetry to the car body over the chassis, which mades the right front wheel a bit closer to the arch than the left one. My car is like that also, when I measured from tire to arch horizontally. I had the same problem as you with rubbing when sing standard tires, but switched to the Bridgestone RE92 tires that now give me plenty of clearance. My car is 4000 miles away right now, but I recall they were 165-70's, although I could be mistaken. They are commonly available and cheap at $50.00 each. If I encounter your problem on rolling surfaces, I'll do the spring change also.
Good luck
Paul Zimmerman
26/4600