I often see Spitfires with dodgy front springs or springs that are not a matching pair, as there are so many different front springs it is worth listing some of the variations.
| Spring Rate | Free Length | |
|---|---|---|
| Spitfire MKI Early | 140 lbs | 12 1/4" |
| Spitfire MKI Late | 150 lbs | 12 5/8" |
| Spitfire MKII | 150 lbs | 12 5/8" |
| Spitfire MKIII | 150 lbs | 13" |
| Spitfire MKIV | 150 lbs | 13" |
| Spitfire 1500 | 180 lbs | 13 1/4" |
The fitted length with all front spring is 7 1/2" to 8" with the early MKI - 7 1/2" and the 1500 - 8" and the other models somewhere in between. Originally these springs were colour coded, but that has long since gone. The 140 lbs springs have a wire thickness of 419 thou, 150 lbs springs are 426 thou and the 180 lbs springs are 440 thou. As for aftermarket springs, that's another story.
| Fitted Length | LBS | Free Length | |
|---|---|---|---|
| Rimmers Standard | 8" | 167 | 12 1/2" |
| Rimmers Up-rated | 8" | 200 | 10 3/4" |
| Moss Up-rated | 7" | 330 | 9 1/2" |
| Competition | 7" | 480 |
Well that's about it for front springs, next will be rear springs.