Mick, Unsprung mass has been one of my favourite areas of work for a while. Sumitomo 2 spots with 250mm vented discs and 60mm ID springs, get the strut/brake assembly mass down to 20KG.
I have weighed datsun struts with a popular cruiser 4 spot/honda disc conversions that weighed 35kg for the same thing. Of this figure probably 32 kg would be unsprung mass. (half piston and half spring masses). Tyre and wheel combinations are another area where lots of unsprung mass can be saved. I have slicks on 3 piece rims that weigh 10.5 kg's. I also have 15 x 7" rims that weigh 12 kgs for rim only!!!! With tyre they weigh in at 22 kgs, If these 22 kg rims are used on a 35 kg strut assembly (as mentioned above) there is a total of 54 kg's unsprung plus half control arm mass and stabiliser bits etc. The stock 510 unsprung mass is 32.5 kg (19kg strut/caliper/brakes and 13.5 kg wheel/tyre). The sprung to unsprung ratio for the stock 510 is (240kg corner weight, divided by the 32.5kg unsprung mass)= 7.38:1. With a 54kg unsprung mass, this ratio becomes 4.44 . The end result is that the wheel is less able to follow any surface iregularities at speed and tyre grip is lost easily. For the rear axle the same thing applies. A lot of people overbrake the rear end, even when it does 20% of the work in severe braking situations. Cheers Feral Errol www.datrats.com.au -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.9.18 - Release Date: 19/04/2005 --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [email protected] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ --------------------------------------------------------------------- -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.9.18 - Release Date: 19/04/2005
