Re: !!! LET Motorsports Pulley Failure !!!
Originally Posted by 70GT6
Checked NSK site and they do not even list a 6303z..
Bearings listed are 6303,6303DDU, 6303NR, 6303VV, abd 6303ZZ.
The ZZ looks to be the correct bearing, as both sides have a sheild.
If this is the correct part, the bearing is listed as "Speed Limit" (grease) 15000 rpm
Interesting - I'm looking at my stock idler pulley and the bearing is marked with a "6303 C3" and the green seals are stamped with "6303 RDD" but with a different type of seal then the bearings used on the LET or ASP (they look impervious to debris)
Now - if "speed limit" is 15,000 RPM - then we have a problem Houston!!
The stock idler pulley is approx 90mm
(178 / 90) = 1.978 * 6,000 engine RPM = 11,667 idler bearing RPM
(181 / 90) = 2.011 * 6,000 engine RPM = 12,067 idler bearing RPM
(185 / 90) = 2.056 * 6,000 engine RPM = 12,336 idler bearing RPM - No problem here.
The LET idler pulley is approx 60mm (and if the ASP idler is the same size):
(178) / 60) = 2.967 * 6,000 Engine RPM = 17,800 idler bearing rpm
(181) / 60) = 3.017 * 6,000 Engine RPM = 18,100 idler bearing rpm
(185) / 60) = 3.083 * 6,000 Engine RPM = 18,498 idler bearing rpm
Can someone verify the ASP idler pulley size and bearing used?
Looks like someone didn't do any math and just copied the OEM bearing part number...
Last edited by BrianBrave; 11-10-2008 at 10:21 PM.