Hey guys,
I'm buying 20 inch wheels and tires. Tirerack recommends 235/30 front and 305/25 rear. Front tires are almost identical in overall diameter. However I found that 305/25 is slightly smaller and 315/25 will be perfect match to oem 305/30/19.
http://tire-size-conversion.com/tire-size-calculator/
Click on middle tab(Tire size comparison)

Toyo T1R has 315/25/20 available. Should I run 235/315 or 235/305?
Any thoughts?

P.S. Don't tell me "Forget about them and go for 245/325 or even 345". I don't want to run bigger than OEM size.

 

Good question.....subscribed. I'd love to get some 20" HRE P101's for non-race events.

 

what width rim? I previously had PS2 235/30/20 & 305/25/20 and the rears looked too stretched on my 12" rear rims.

 

Im currently running 20" rims (9f,12r) with pss 245/30/20 and 325/25/20 imo its the best combo to go with to avoid any damage to the front differential

 

^^ This, for sure.

The 245/30 and 325/25 combo is what we've been running on our 20" wheels for years, without any issues. I would stick with the tried-n-true.

 

Thanks guys for your input.

By using the calculator, I found that 235/30, 305/25 set up has 1.1% total differencial(front and rear) from the OEM set up while 245/30, 325/25 set up has only 0.4% total differencial. So yes 235/305 sep up seems to be little excessive. However I think I can run 235/315 set up as this has only 0.4% differencial just like 245/325 set up. The only reason I want to run this size is that my front wheel has aggressive offset and my car is lowered.

Thanks again guys.

 

Thanks Guy for your feed back. I will keep an eye on it.

 

I run the 305/235 combo, Nitto Invos on 9" and 11" with zero issues.


Invos are -


235/30 25.71


305/25 25.94

 

Hello All,

My 997TT came with 20" wheels shod in :-

235/30/20 FRONT and
305/25/20 REAR Invo Nittos.

Not sure of exact width of wheels, but guessing rear is 10.5. I also have stock wheels with OEM tyre sizes on them.

Even visually looking at the front on the 20's, the tires look too narrow for the wheel, and rear looks fine. Just doesn't look right to me. Pics Below both front




So I did a search, came across this thread and saw the recommendations above for 245/30/20 and 325/25/20. I can't seem to find Michelin 325/25/20 even listed as an option in Australia, but can find 245/30/20 for the front easy enough. Closest for rear is :-

-315/35R20 Pilot Super Sport

Question 1 - Will the above be good for my wheel size?

Question 2. Based on the experience here, do you think I am best to:-

Option 1
Put the stock 19' wheels back on and leave everything OEM

Option 2
Keep my 20' wheels with 245/30/20 and 315/35R20 rear

Option 3
Keep my 20' Wheels 245/30/20 front and somehow source 325/25/20 rears from somewhere

Option 4
Keep my 20' wheels on current 235/30/20 FRONT and 305/25/20 REAR

Option 5
Any other suggestions?

Would like to try and keep 20, but if the absence of a 325/25/20 rear will prohibit this, I will likely change back to 19' stock wheels with OEM tyre sizes

Any advice much appreciated

Thank you
JKay

 

Just source 245/30/20 nitro invos to go with you 305/25/20 rears. They are a perfect match for rolling diameter. Your fronts are probably 9" and your rears are more then likely 11".

 

I can assure you that 305 rears WILL overheat the diff with 245 fronts.

 

Not with Invos. The 245/30 and 305/25 are both 25.71. They are an exact match.

 

They are a match.. that is the issue. Assuming we are talking about 997 Turbos you need the rear diameter to be larger. its obviously a %, but it works out (if memory serves me) about 3 tenths of an inch larger in the rear.

 

will post some pics when my new wheels and tires arrive:

Up front:

20" x 9"

245/30/20 Michelin Super Sport

Rear:

20 x 12"

325/25/20 Michelin Super Sport

 

Yes, 997 turbo. Just looked them up again.

Nitto Invo
245/30 25.8
305/25 25.9

Been using this combo on my 9" and 11" all summer with zero issues.