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Is anyone on here running Cayman S wheels? I've been thinking about getting a set for my Box. I did a photoshop of them in a dark satin bronze to see how it would look, and I quite like it. White-letter tires might not be to everyone's taste.
I've read that they will fit a 986 pretty well. I'd like to run a 45 or 50 profile rear tire for a nice meaty look, but still have enough room to slightly lower the car.
It's funny I think they look better on the 986 than they do on the 987! Looks great. What sidwall profile are you running Cosmo? Looks like a 40 or 45 from the pics. (Funny, my username on many forums is Eunos_Cosmo )
It's funny I think they look better on the 986 than they do on the 987! Looks great. What sidwall profile are you running Cosmo? Looks like a 40 or 45 from the pics. (Funny, my username on many forums is Eunos_Cosmo )
235/40R18 front and 265/35R18 rear. From the factory the 986 with 18's used 225/40 and 265/35's so I am one size wider on the front. No rubbing on the inside at all.
The handling of the car from the factory is gorgeous so I don't want to upset that with an improper tire spec.
If I were to run a 265/40 on the rear, would it make sense to go with a 225/45 on the front? I guess sidewall profile makes less of a difference than width, but there must be a reason Porsche chose a thinner sidewall for the rear.
The handling of the car from the factory is gorgeous so I don't want to upset that with an improper tire spec.
If I were to run a 265/40 on the rear, would it make sense to go with a 225/45 on the front? I guess sidewall profile makes less of a difference than width, but there must be a reason Porsche chose a thinner sidewall for the rear.
If you were to run with a 265/40 and 225/45 the height will be taller than stock spec and the speedometer will be out about 5%
My speedometer is 5% under right now so that sounds great.
Final drive gearing will be 5% taller too so slightly less zippy off the line.
As for the sidewall numbers, the series is a percentage of section of width. So 265/35 means the sidewall is 35% of 265 mm. 265/40 is 40% so it's a taller sidewall.
Porsche have staggered wheels with wider section on the rear then the front, so in order for the front and rear tires to have the same diameter, the aspect ratio on the rear is less.
Final drive gearing will be 5% taller too so slightly less zippy off the line.
As for the sidewall numbers, the series is a percentage of section of width. So 265/35 means the sidewall is 35% of 265 mm. 265/40 is 40% so it's a taller sidewall.
Porsche have staggered wheels with wider section on the rear then the front, so in order for the front and rear tires to have the same diameter, the aspect ratio on the rear is less.
I knew that...somewhere in my brain. Thanks for clarifying!
On the subject of final drive ratios, is that something that can be changed? I feel the car is geared way too long for the torque it has. It's kind of between a rock in a hard place on the 2.5 because it has a relatively low redline and relatively little torque...so I'm not guessing you'll gain much by reducing the final drive ratio, but it could make low speed tractability a bit better.
Porsche have staggered wheels with wider section on the rear then the front, so in order for the front and rear tires to have the same diameter, the aspect ratio on the rear is less.
There is no reason for the front and rear tires to have the same diameter, often they do not.
If it was AWD or 4WD they would have to be the same diameter (unless corrected by axle ratios).
There is no reason for the front and rear tires to have the same diameter, often they do not.
If it was AWD or 4WD they would have to be the same diameter (unless corrected by axle ratios).
Not always. The 996 Turbo has different diamenter front and rear tires. The rear tires are slighly smaller in diameter so the rears make more rotations per distance traveled.
This is so the plates inside the viscous coupling and driven by the transmission turn faster inside the viscous coupling which heats up the viscous fluid to the point it gets well more viscous and imparts some torque to the plates that are connected to the front wheels/tires.
Both the rear and front diffs have the same final drive ratio.
Additionally even if one was willing to render the AWD inoperable the PSM would complain as it is designed to take into account the different speeds of the rear and front wheels/tires.
I knew that...somewhere in my brain. Thanks for clarifying!
On the subject of final drive ratios, is that something that can be changed? I feel the car is geared way too long for the torque it has. It's kind of between a rock in a hard place on the 2.5 because it has a relatively low redline and relatively little torque...so I'm not guessing you'll gain much by reducing the final drive ratio, but it could make low speed tractability a bit better.
No easy/inexpensive way to change final drive ratio I know of.
The 5-speed that came with the 2.5L car already has shorter ratios of some gears to help with the engines lower torque output.
Also, it is not clear to me you are going to run 18" wheels but the early Boxsters were not sanctioned by the factory to run 18" (or bigger) wheels. The later models were but they received some strengthening of some parts of the chassis to better withstand the forces 18" wheels can impart to the suspension attachment points.
I have 19" wheels on my '99. it came that way from the original owner, I am the second owner.
I have never driven a stock boxster nor a boxster s so I have nothing to compare against. I do know that my car handles very well and other 911 owners have driven it and love the way it handles.
it will get off the line quite well and run out of rpm in 1st at 40mph. it's just enough to put a Honda s 2000 down in the first 3 gears...
Yeah I really don't see how slightly taller wheels would be detrimental to the car aside from a slightly longer effective final drive ratio and potentially some rubbing issues. They might be marginally heavier, but I sincerely doubt that Porsche engineered the Boxster to such a narrow safety margin that putting on wheels an inch taller would decrease the longevity of the suspension or chassis components. If I was putting 22" wheels on the car I could see some risk, but I'm not really into donk...
05-24-2016, 11:56 AM
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