Good bit of analysis Errol. Puts the suspension options into a better perspective. ----- Original Message ----- From: "Errol Smith" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, April 21, 2005 9:01 AM Subject: RE: Biggest rear tyres ever on 510?
> 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 > > > > -- > 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 > -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.10.2 - Release Date: 21/04/2005 --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: 266.10.2 - Release Date: 21/04/2005
