Wheel Sizing
05-29-2006, 08:42 PM
#1
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Wheel Sizing
What is the best way to stagger rims? 6x16 and 7x16 for street with 8x16 and 9x16 for track/autoX... or would it be better to use 6/8x16 street and 7/9x16 track?
I have recently found a set of 8x16 and 9x16 Fuchs for my 1987 911 cab with factory 6x16 and 7x16s running bridgestone so-3's in 205/55/16 and 225/50/16. I do a good balance of AutoX and DE and bought a used tire trailer to use to use shaved toyo ra-1's in 225/50/16 and 245/45/16s. The suspension is a complete TRG RSR coilover setup with rolled fenders and streetable camber settings.
Will the 8's fit well up front with a 225/50/16? I think I read a thread here that mentioned that tires of the same listed width are acutally wider when used on a wider rim... Anybody want to chime in? I want to buy tires this week that fit and the Pelican tire sizer spreadsheet approves of the tire size in total diameter but does not take into account the rim you will be using. Thanks!
I have recently found a set of 8x16 and 9x16 Fuchs for my 1987 911 cab with factory 6x16 and 7x16s running bridgestone so-3's in 205/55/16 and 225/50/16. I do a good balance of AutoX and DE and bought a used tire trailer to use to use shaved toyo ra-1's in 225/50/16 and 245/45/16s. The suspension is a complete TRG RSR coilover setup with rolled fenders and streetable camber settings.
Will the 8's fit well up front with a 225/50/16? I think I read a thread here that mentioned that tires of the same listed width are acutally wider when used on a wider rim... Anybody want to chime in? I want to buy tires this week that fit and the Pelican tire sizer spreadsheet approves of the tire size in total diameter but does not take into account the rim you will be using. Thanks!
05-30-2006, 01:30 PM
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A tough call. I had an '89 Carrera that I AXed (but ended up using 7/8x15s). The '89 was the only year of that series that had as standard 6/8x16s... so, I bought some 7/16s for the front end and tried 225s and actually had a little rubbing on the left fender well (also rolled). It was lowered and had -1.5 camber up front - you may have more.
If your installer will accommodate you - maybe they can mount what you think would be the biggest tires and dry test them on their rack while you cycle the steering wheel and they pull down on the front end - might give you a better feel for what will work - maybe $50 for the exercise?
As far as stagger front to rear - you can see that Porsche ended up with 6s and 8s on 16s for the Carrera series - but I think that 'may' have been a little safety consciense thinking because the bigger spread caused a little more understeer - for that car. I'm thinking the bigger spread will help more at the track and the lesser spread in AX... and to me, your 6/8 and 7/9 combo idea seems good... it would be nice if you could get 225s up front for both AX and track... have you tried the TireRack 'recommended sizing' charts when you search for a particular tire?
good luck,
If your installer will accommodate you - maybe they can mount what you think would be the biggest tires and dry test them on their rack while you cycle the steering wheel and they pull down on the front end - might give you a better feel for what will work - maybe $50 for the exercise?
As far as stagger front to rear - you can see that Porsche ended up with 6s and 8s on 16s for the Carrera series - but I think that 'may' have been a little safety consciense thinking because the bigger spread caused a little more understeer - for that car. I'm thinking the bigger spread will help more at the track and the lesser spread in AX... and to me, your 6/8 and 7/9 combo idea seems good... it would be nice if you could get 225s up front for both AX and track... have you tried the TireRack 'recommended sizing' charts when you search for a particular tire?
good luck,
05-30-2006, 04:44 PM
#3
The 8's will fit in front IF they are the 951 part number. 23.3mm offset. 911 "8's" don't fit in front without flares. Wrong (10.6?mm) offset.
So. assuming 951 8 and 911 "9s" put those on as track/autocross tires. If you run a 225 you will need to massage the front fender lips, whether you run the 7's or 8's.
If they are the 911 8's, then well, 7/9 track tires and 6/8 streets.
So. assuming 951 8 and 911 "9s" put those on as track/autocross tires. If you run a 225 you will need to massage the front fender lips, whether you run the 7's or 8's.
If they are the 911 8's, then well, 7/9 track tires and 6/8 streets.
06-07-2006, 06:32 PM
#4
For your intended use at A/X or DE 8 & 9 x16 has the edge. Keep in mind that each 911 body is slightly different and all tires measure different from their nominal sizing. The left front is generally the hardest corner to fit.
225/50 can usually be made to fit on the front of a 911 w/ the +23.3mm ET 944/951 8" wheels, +25-31mm ET fits more comfortably. But, w/ all, lip shaving is recommended. As is more than usual(for street use) - camber.
225/45 will provide additional clearance
In the back there is a ton of room for 245/45x16 on the +15mm 9s. If you try to go wider to say a 255, the tire height negatively affects low speed performance. lots of us do use taller 275/40 x17 but not for A/X(at least not w/o regearing the trans)
225/50 can usually be made to fit on the front of a 911 w/ the +23.3mm ET 944/951 8" wheels, +25-31mm ET fits more comfortably. But, w/ all, lip shaving is recommended. As is more than usual(for street use) - camber.
225/45 will provide additional clearance
In the back there is a ton of room for 245/45x16 on the +15mm 9s. If you try to go wider to say a 255, the tire height negatively affects low speed performance. lots of us do use taller 275/40 x17 but not for A/X(at least not w/o regearing the trans)