Suspension Travel

[SUSIT]

Can anyone tell me what amount of suspension travel front and rear the works Grp 4 cars had in tarmac and gravel settings? Inches or mm

[Martin K]

Don't know the answer, but I'll hazard an educated guess.

Rebound travel for tarmac rallying would commonly be around 2 - 2.5 inches, so full travel from full bump to full droop would be in the region of 6 - 7.5 inches.

On rough, the loose stages, rebound would be a minimum of 3 inches and could be as much as 5 inches, so ideally there would be 9 - 15 inches full travel.

The more upright front coilovers on the Group 4 cars were longer than those with a top mount sharing the same axis as the upper wishbone inner mounting points and would would therefore allow more travel, as well as eliminating the detrimental falling rate that the latter arrangement inherently has.

However, if the bump travel is simply not available in your struts or coilovers, the use of progressive bump stops and/or carefully matched (front and rear) progressive rate springs would help achieve the desired wheel rates at normal travel with increasing stiffness to avoid 'bottoming out' the damper on full bump travel. I don't know if the Stratos used progressive springs, but I know later Lancias (037, S4) did.

Martin

[Martin K]

I have just read that in 1977 the G4 Stratos had between 150 mm and 200 mm of suspension travel, I guess depending on 1) ride height setting and 2) 'tarmac' or 'loose' suspension settings

[SUSIT]

Thanks Martin,
Tryphon you must have these figures somewhere?