360S Ground Clearance Under Sump

[ScottR400D]

#20 That's interesting. I understood that the standard 15" front tyre was a 195/50 (97.5mm sidewall) so going to a 185/60 (111mm sidewall) should have dropped the ride height by only about 12mm or so. 

 

[Mark420r]

#25 cheers, I'll do that

[DerekH]

I think it might be a 185/55. Standard Avon ZZS size.

I was measuring from the edge of the front number plate to the floor, so 30mm drop was easy to measure.

I also lost 1" in track width at the front going from 6.5J to 6J.  The car is just better on 13" rims. I have a lot more confidence in the car now.

DerekH

[aerobod - near CYYC]

Due to the major amount of wedge going from 195/50-15 tyres all around to 185/55-13 front and 215/55-13 rear, the front of the nosecone would drop about 30mm, but the front axle will drop about 21mm and the rear 5mm, with the lowest sump point being just behind the front axle, so dropping about 20mm. It is strange that Avon opted for 185/55-13 tyre size instead of 185/60-13, to better match the rear 215/55-13 diameter.

[ScottR400D]

#28 OK but even that should have only made a 20mm difference, approximately, in ride height. 

Of course if the rear rolling diameter stayed the same and you dropped 20mm at the front axle which is where ride height should be measured, you would get more of a drop measuring at the number plate, but that's not a 30mm drop in ride height. 

Edited: Beaten to it by James! Must type faster! 

 

[ScottR400D]

Though I wouldn't say that it's down to Avon to specify their tyre profiles to suit Caterham, the 215/55 and 185/55 13 seem to work well and give the right ride heights and geometry.

The issue is maybe more with the tyres being fitted to 14 and 15" rims? 

Come to that why do CC offer the bigger rims anyway, I've not seen many say they have any advantage over 13"? 
 

 

[aerobod - near CYYC]

Hi Peter, I would think that in 13" wheels these days for sticky tyres, Caterham would be a fairly large proportion of the sales for staggered front/rear fit. Overall 185/60-13 seems to be a more commonly used size than 185/55-13, but who knows where Avon thinks the market niche is, as they typically seem to have quite a few odd sizes that other tyre manufacturers don't produce.