Hey all, I have a question about tire and rim. When I bought my car used, it already came with 20 inch wheels and 245/35/20 tires. I just bought some new tires from tirerack and tried to get it put on today. The guy who was putting it on for me said the tire was too big for my rim 20x7.5 and could not put it on. He tired but did not work. I bought the same size tire Sumitomo HTZ III 245/35/20. Current tire i have on is Goldway, can't really find much info on it, only thing i really found is it is made in China. Do the Chinese measure tire size different? Or did it bring it to the wrong people? Can 245 fit on 7.5 rims safely

After a little searching on the web, I found the same tire package that the pervious owner bought and yes, they do offer rim size 20x7.5 with 245/35/20 tires on it. If 245 does not fit on it, what is the biggest size i can fit on a 7.5 rim? Thank you

 

245/35/20 is too big for a 20x7.5. you need 225/35/20 that would fit nicely in the rim. I would also suggest that you get rid of the 7.5" width and get a bigger width rim that will fit in the tire.

 

how do you know YOUR rims are 7.5? may be the tire has to be REVERSED mounted on to rim. or maybe the tire guy never mounted a 20inch before. sometimes you need 2 people if the side walls are really stiff.

 

I'm pretty sure it is 20x7.5 since that is what's printed in the back of the rim. I just don't understand why the tires I have on now fits and the new tires I bought does not fit. I triple checked the size on the tires and old and new set is 245/35/20.

 

I have 245/35/20s on 8" rims and they fit no problem, I wouldn't recommend that size on 7.5s but they should be able to mount them~I doubt a half inch narrower would be a major problem, just might cause the center of the tread to wear a bit faster.

 

ive put a 265 on a 7.5 yea it bubbles out a lot. but its doable. a 245 is definatly doable

 

So that means I just need to find someone that can put it on for me right? is it that much more difficult to put on a bigger tire on smaller rim? If they do manage to put it on, are there any safety concerns that I need to be aware of? Thank you all for your help.

 

lots of people are going to say there are safety concerns im sure. but i really would not trip about it. ive run tires that have massive bubbled side walls and never had a problem

 

So I been doing a little more searching on wheel and tire sites. There seem to be a lot of sites that are selling packages with 20x7.5 wheels that comes standard with 245/35/20 tires on it. So I do not understand what the difference is with the tires that I bought on tirerack. I will take the tires to another shop and see if they can help me put it on.

 

Different manufacturers have different guidelines for how wide of a rim their tire can be mounted on.

 

it's also a matter of sidewall


245/35ZR20
Load Index 95 = 1521lbs (690kg) per tire
Speed Rating “Y” = 186mph (300kph) 95Y XL Treadwear: 300
Traction: AA
Temperature: A300 AA A 1521 lbs.
50 psi
10/32"
27lbs.
8-9.5" - RECOMMENDED RIM WIDTH
8.5"
9.7"
8.8"
26.7"
774
Country of Origin "JP" = JAPANJP

http://www.tirerack.com/tires/tires....odel=HTR+Z+III - click specs tab

 

245/35R20 tires are made for rims with a width of 8-9.5".

Popcorn +1...

 

Basic rule for tire size: Tire width shouldn't be more than 2" wider than the wheel width. Tire is 245mm wide, 7.5" wheel is about 190mm wide, so the tire is about 55mm wider, or just over 2" (2.15"). Technically, it's too wide for the 7.5" wheel, which is why you see the 8"-9.5" recommended width. But in practice, it should work fine. If the place you took it to can't install it, I'd go somewhere else because I don't think they know what they're doing.

And who would make a 20x7.5? What a stupid size.

 

Well, today I brought it to another tire shop and they were able to put it on for me. Don't know what was going on with the other guy but this shop only took 10 mins on each wheel. I can tell it is a little wider than the one I had on despite the fact that they were the same size. It pushes the sidewall out a little but not a lot, maybe 1/4 of an inch. I guess each company is a little different with their tires seeing that this one does not fit as well as the ones I had on. Thanks for all your help. Hopefully the tires wont blow up on me now! I will keep an close eye on it too. Once again...thank you all.

 

I got 245/45R18s on my OEM Sports Rims wich are 7.5inch wide. Widest tire you can get on 7.5inch rim.