CnnmnSchnpps

iTrader: (1)

Hi guys,

I was wondering how much is too much when putting on tires of slightly different size between front and back? I'm talking in terms of circumferance. At what point do the wheel speeds become so different as to start messing with the ABS system, etc?

For example, would 225/45 and 235/40 go OK together? The difference is something like 2.2% (1.8 inches). If there is no hard number, could a couple people with staggered setups at least post the sizes that work for them?

From my estimates tire wear within the "legal" range can change the wheel diameter by up to 1.5% so that has to be ok still... But how much can you push it (safely)?

Thanks
-Dmitri

--edit--

Well I went out and had them installed and so far so good.

225/45R18 front
235/40R18 rear

I put the thicker tires on the rear since it's winter soon and I would rather have understeer than over in the snow (i can always kick it out if I want to have some fun ).

1000 miles later and no issues with this tire size combo. Even had an event when I had to brake hard enough to engage the ABS, which felt just fine. Overall, works perfectly!

ac3mastuh

iTrader: (1)

i have 275/30/19 rear with a 245/35/19 front and I get the occasional abs blip but it goes away once i restart the car

I have seen guys do 225/45/18 front with 245/40/18 rear and not have any issues.

http://www.rims-n-tires.com/rt_specs.jsp

that's a good tool to play with when you're looking into tire sizes.

CnnmnSchnpps

iTrader: (1)

Nice page, but I've got an excel sheet that does the same thing quicker ;-)

Umm... you get ABS blip with those sizes? Now I'm getting more concerned about using my combo.. Your sizes are only 1% off.. And not that far off stock either..

Can you elaborate a little - in what kind of conditions does this "blip" happen?

Thanks!
-D

CnnmnSchnpps

iTrader: (1)

No comment eh? Well I went out and had them installed and so far so good.

225/45R18 front
235/40R18 rear

I put the thicker tires on the rear since it's winter soon and I would rather have understeer than over in the snow (i can always kick it out if I want to have some fun ).

No ABS nonsense yet, and I pushed them a little bit so I'm hoping it will be fine. Doing over 1000 miles in the coming week, so I should have a definitive answer by the end of that time...

Brettus

iTrader: (2)

why didn't you go 235/40 all round ?

CnnmnSchnpps

iTrader: (1)

I had 235/40 all around last winter... The rear tires went from new to nada (it's surprising how abrasive a snow-covered parking lot can be ) so I was rolling on bald rears for a little while.... Then this little road trip came up and I didn't want to risk going all that way with 0-tread tires, and 225/45 was all that I could find under short notice.

Seems to work well so far, will report back once the snows come... Gonna have to take it easy so I have enough tread for the ice racing season

CnnmnSchnpps

iTrader: (1)

Not sure if anyone cares, but I will report back nonetheless (I hate the threads that end on "will report back later"). 1000 miles later and no issues with this tire size combo. Even had an event when I had to brake hard enough to engage the ABS, which felt just fine. Overall, works perfectly!

w0rm

thanks for the follow up. You might consider editing your first post with that info as well just incase someone goes searching for it :D

CnnmnSchnpps

iTrader: (1)

Good point. Done.