Powerflex's road series replacement bushes are already a highly popular performance upgrade and replacement item for road and track cars. The existing compounds are already stiffer than stock rubber but in response to popular demand for a stiffer range Powerflex have followed up their Yellow and Purple Shore 70A/80A range with their new Black Series range.Whereas the purple series bushes are a mix of compounds designed for comfortable compromise between firmness and vibration control this new range from Powerflex are optimised for the most extreme track use and use their toughest Shore 95A compound.These bushes are on average a further 25% stiffer than their purple compound and up to around 80% stiffer than stock rubber bushes.In applications where additional vibration is not a problem this makes for the very best response and control.Using this grade of polyurethane bush ensures that the bushes are never the weak link in your suspension set-up and that every other component is doing exactly what you want it to, when you want it to without any compromise in performance due to worn bushes.Please note that these are the stiffest bushes Powerflex make. For more compliant bushes please see their yellow and purple range.