Ok, I know this has been discussed, but the threads I am finding are not specific enough.

1. What exactly is the offset?
2. What is the proper offest for CL? 42 or 45?
I have a CT drop and am looking for 18s.
3. What is the difference in tire sizes? 215, 235, etc?
4. What is proper tire size for 18 with CT drop? (does this vary depending on offset?)

Thanks,
David

 

1. Offset is the distance from its hub mounting surface to the centerline of the wheel.



2. 45 or more is good for a CL. I think 42 will work with a comptech drop, but there may be some minimal rubbing.

3. 215/50R17 means 215mm treadwidth, the sidewall is 50% of the treadwidth, so in this case 107.5mm. And of course the 17 is wheel diameter.

4. That depends on the width of the wheel. Some people have sqeezed 235s on to our stock wheels which are 7" wide. The widest I would go would be 235.

 

good calculator,, will keep your speedo correct,,, and shows the difference in tire sizes

http://www.miata.net/garage/tirecalc.html

 

OK, I am looking at 18x7.5 wheels. If I understand, I need at least a 42 if not 45 offset. I am unsure about what tire to go with, but if the wheel is a 42 offset then it sounds like I will need a 215 or 225 tire? Maybe 235 on a 45 offset???

Anyone else out there have some thoughts.

Thanks,
David

 

If you have a wheel with +45 offset, I know you'll be fine with 235s. But I'm unsure of anything below that. I've still got stock wheels so everything i know is from reading others experiences, and I can't be positive about anything below 45.

 

I just emailed the company regarding offset. Once I have that then I can find the proper tire size. I know there are multiple sizes that will fit, but I am just not into squeezing a tire on which is going to rub.

 

Well, for what it's worth.. I am lowered on H&R Sports and i'm running 18x7.5" rims with 225/45/18 tires. The offset is +45 and I've never rubbed and it doesn't stick out at all....

 

if you use less than +45 on 235s it would stick out.

 

so I can run +45 with 235s or +42 with 225 without rubbing or sticking out? Is this correct?

 

OK, I heard back from the wheel place which told me the wheel is a +42 and that I can run 215/40/18 w/o rubbing. Is this correct????

 

I just want to verify-- I was told by a member (who will remain anonymous) that I can successfully mount 235/45-17s on the stock TypeS rims.. I called Tirerack, and they said, no, that is not the case..

Can I get some justifications please? Much appreciated.

 

yes that's correct..although not guaranteed, as each vehicle varies individually

 

i doubt that will work

 

it worked for me with no problems

 

I had 18X7.5's with +42 offset & 235-40-18's, & a comptech drop. I had rubbing on the fenders when I hit some potholes, & speed bumps, or had any weight in the car. You will need at least a 45 offset with 235's, comptech drop 7.5" wide rims.

elliot
You can put 235-45-17's on stock rims. Lots of people run that. I do & never had problems. Tire rack only says that stuf for legal issue's so you don't hold them liable. Just like they won't sell you tires that don't spec exactly right as stock for load rating(even if it's it's higher then stock) Tire Rack sucks, I boycoted them a while ago.

 

OK, but if I go with a 42 offset then I can run 225 or only 215???

David

 

225..215 is not a wise option

 

well, fuzzy, i called Mr Tire who is a pretty large local chain and they too said they wouldnt go.. i dont know what to do!

 

it depends on what you're trying to do..are you looking to purchase tires from tirerack? they're not supposed to say no right away..they'll say they won't fit and then ask if you have that size on your vehicle at the moment..just say yes...

 

im trying/planning on purchasing from tirerack (or someone online) and have a local shop mount/balance them.. im having a lot of trouble deciding.. mostly b/c im not that well tire-savvy, as y9ou can see..

 

i have 18x8 235/40/18 45+ on comptech springs and experienced no rubbing.

 

I have 235/45/17 on the stock wheel- no problems at all.

 

The following email was received from Clay @ TireRack when I sent him a query concerning the 235/45/17 on 7" rims issue:

"Thanks for your inquiry.

Running the 235/45/17 size on the 7 inch wide wheel could possibly lead to uneven tread wear on the tire. I can't guarantee fitment of this size, but if enough people say that it works it must have some validity. The price for 4 of the Sumitomo's with shipping is $446.90.

If you have any other questions or need to place an order, please feel free to contact me. If you are placing an order online, please be sure to reference my name, so that I can watch over the order as it processes.

Best regards,

Clay

888-541-1777 ext. 206

574-287-2345"

I recently took the 235/45/17's off the wheels I had on my former Maxima and mounted them on my stock 7's. I have had no problems to date - period. Take this for what it's worth ... as I am in my 50's, I am extremely unlikely to do something that will expedite my eventual demise. This issue is a non-issue. If you need visual confirmation, look for my car at work ... you know where that is.