Va Maddog Posted July 24, 2005 Report Share Posted July 24, 2005 In 2001 you could order an STS with an option package that included 17" chrome wheels from the factory, an upgrade from the standard 16" wheels. My question is when they went to the 17" wheels did the factory also adjust the axle ratio's? What I'm really wondering is would the net affect of the 17" rims be a slightly lower hwy RPM more similar to that of an SLS and thus a little better mpg on the hwy? Does anyone know the answer? Link to comment Share on other sites More sharing options...
TDK Posted July 24, 2005 Report Share Posted July 24, 2005 Va Maddog, I don't think the FWD transaxle is very adjustable, per se. The STS has a higher number ratio to go with the engine powerband, the SLS and others get a slightly lower number ratio for their engine. I don't think there were any other options or choices available. While I am not certain about this, Caddy may have changed the tire height from a 60-series to a 55 or 50-series when going from 16" to 17" rims. Thus ending up with the same outside tire diameter and no reason to adjust anything. Then again, they may have simply changed the computer slightly to account for a taller tire for the speedo and let 'er go at that. IMHO Add power to leave problems behind. Most braking is just - poor planning. Link to comment Share on other sites More sharing options...
bigjayzway Posted July 24, 2005 Report Share Posted July 24, 2005 Caddy may have changed the tire height from a 60-series to a 55 or 50-series when going from 16" to 17" rims This is exactly the case. Big Jay Life is too short to grow up! Link to comment Share on other sites More sharing options...
JasonA Posted July 24, 2005 Report Share Posted July 24, 2005 As stated, the overall TIRE diameter didn't change much, if at all. If it did change, it would have been slight, and probably negligible in terms of the engine rpm at a given speed. The speedometer would have been calibrated slightly differently if this were the case, but the axle ratios are static (at least until currently). 3.11:1 for an LD8 engine and 3.71:1 for an L37 engine. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Va Maddog Posted July 25, 2005 Author Report Share Posted July 25, 2005 Thanks guys. I was sort of hoping that the RPM's would have dropped a little thus leading to better mpg for the 17" STS - closer to what the SLS can get on the hwy - but it is what it is. I was looking at a 2001 STS on EBay with the 17" wheels but it sold via a buy-it-now option so I'll have to keep looking. I'm thinking about moving up from my 95 SLS to a 2001 SLS or STS if I can find the right car at the right price. Link to comment Share on other sites More sharing options...
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