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Rim / Tire size by model/configuration look-up table
I am in the process of building 993 RSR clone on a NB and invariably had questions about rim/tires combos. Looking at searches I realized I am not the only one. The forum is full of posts asking about tires, rims, max diameter, offsets, etc. With this in mind, I think it would be useful to get all this info in a look-up table and pin it as a sticky for everyone to see. What I have in mind is a table, where members could post their car detail, as well as people like Bill, Steve, Juha, BoomBoomThump, ...you know who you are .., could opine on ideal set up in terms of vehicle dynamics. If this gets traction, I would be more than happy to maintain the table based on members feedback to this thread. It could look something like this:
this could take the guess work out of many rim/tire decision.
It seems not all sizes are equal from a fitment across different tire brands/models (edge profiles), so identify of which tire could be a critical data point maybe deserving of a column beyond the notes.
Also noting if fenders were rolled to make them fit.
Thanks for taking the initiative to collect the data!
Latest table updated - modified as per Kein_Ersatz suggestion - good one. If you see yourselves in the user column, please review/complete info as needed
Latest table updated - modified as per Kein_Ersatz suggestion - good one. If you see yourselves in the user column, please review/complete info as needed
thanx
Very connfusing and misleading
yes. I make the calim that for a 993 n/b max front width is 245 and max rear is 285, anyone can go and measure that
the wheel width and ET are critical, the closer to the max the more critical,
In front 8.5 ET54 w/ 245/35 has zero extra room on either side, the installed tire with on that wheel is 246mm, w/ 69.2mm f/s and 177.2mm b/s
I've also used 9 ET50 here but the widest tire that could be used would be a 225 due to the lower numerically ET, the tire center line at max fitment has to be precisely located
similarly 285on 10 ET65 has an installed width of 290mm and f/s of 79.8mm and b/s of 209.8mm. again there is no extra room on either side, every 993 n/b that I have worked on has a slight asymmetry in back, there is less room on the left rear lip w/ more room inside and less room on the right rear inner w/ more room at the lip
If I had unlimited funds I'd like to try a 10.5 wheel ET65+/- You would need to experiment a bit here) w/ 285 tire, the extra stretch that the extra .5" provides might be doable, I know of 2 such installations 10.5 ET61 and ET59 295 tire and both reported serious work necessary on the lips
Travelling, but will make updates at some point Monday. I will also remove " qualitative calls" in the notes section as I may be causing confusion. Point taken.
Again, my aim in starting this thread is to centralize what tire/rim combinations work on our cars so as to provide guidance to those seeking information.
Can confirm... 18x11 et60 w/ 285/30 fits in rear, BUT, being as low as I was, it required a very agressive alignment (something like neg 2.5 camber and slight toe in)... but that was with a Pirelli Pzero Rosso tire which is MUCH beefier than say a Sumitomo HTR Z III in the same "size" 285/30. I dont believe there was much fender lip modification with the Pirellis... possibly some mild manipulation towards the front of the arch... but def none needed with the skinnier Sumitomos. I'll post pics...
When I did a wheel/tire change, I went from the Techart 11" et60 and the Pirelli 285/30, to a Fifteen52/Outlaw 18x11 et63 with the aformentioned Sumitomo 285/30 tire, and there was MUCH more TIRE clearance, inside and out, but that wheel was CLOSE to the suspension. But hey... close only counts in horseshoes & hand grenades Deflection and tire roll will absolutely play a part in rubbing contact but I never rubbed inside or out with the narrower tires. Outside, possibly over very large bumps before going to a narrower tire, but it wasnt notable.
Stretching narrower tires on wide wheels isnt for everyone but it's effective and its worth noting for those who are seeking the info. Bill V is THE authority on what is known to fit so he's not gonna tell you what he doesnt know. He knows his **** inside and out. I'm only reporting my experience with my setups. I dont mind some mildly stretched tires if it's all for aesthetics. A proper offset 10" with a 275/35 or 285/30 would be ideal for most. and ride/handle much better.
The pic below is comparing a 11" w/ a Sumitomo HTR Z III 285/30 (left) to an 11" w/ a 285/30 Pirelli PZero Rosso (right). HUGE different and one that makes all the difference in the world for tire clearance. Personally I prefer the chunky Pirelli but I didint know how skinny the 285 Sumitomos were when I bought them LOL. I like the wheel protector bead to be flush with the wheel lip... not past it, not behind it. These Sumitomo's on an 11 were way behind the lip... but hey a little poke never hurt anyone, lol. (Flame Shield Up) #stanceboy #tirestretch LOL
05-11-2022, 06:39 AM
Rim / Tire size by model/configuration look-up table
, could opine on ideal set up in terms of vehicle dynamics. If this gets traction, I would be more than happy to maintain the table based on members feedback to this thread. It could look something like this:
Deflection and tire roll will absolutely play a part in rubbing contact but I never rubbed inside or out with the narrower tires. Outside, possibly over very large bumps before going to a narrower tire, but it wasnt notable. 
