how big of tires can i fit on cobra R 17x9 rims? can i fit 10" in the back?
275/40/17 on a 9" wheel
and yes a 10" will fit with the right offset
what do you mean by offset?
The "ideal" section-width tire would be a 245 on a 9" wheel. When you go wider, the sidewall and bead area is pulled in to fit the wheel. You begin to lose the designed-in sidewall stiffness and cornering ability. It can also cause the tread to "crown" and wear in the center more at the required inflation pressure.
"Offset" is the difference from the center of the wheel to the mounting . It can be pos or neg.
Example:
A 10" wheel with 0 offset would have the exactly in the center, 5" from the back rim.
The same 10" wheel with 1" positive offset would have the mounting surface 4" from the back rim, with the wheel center shifter to the outside, making the -car's- "track" wider by 2", maybe requiring the fender lip to be rolled.
This same wheel would also be described as having 4" backspacing.
close.
offset is a calculation of the wheel centerline to the mounting pad, and is measured in millimeters.
backspace measures the inside wheel lip to the mounting pad and is measured in inches.
small difference in measuring systems that makes things kinda confusing when you try to go between systems. more info here. (http://"https://www.rsracing.com/tech-wheel.html")
Gumby is correct, except some companies DO list offset in inches(or used to).
That's what I get for posting in the middle of the night.....
if you're just wanting to fit the biggest possible... 315/35/17.
Would a 245 on a 9" wheel be ideal for traction on a drag radial in the 1/4 mile?
Tia
Mike
I worked for Goodyear in the mid '80s, before Zakspeed. Long ago.
I would check with a drag-tire expert to make sure. We worked the roadraces, but I asked about drag slicks just because I was curious. I think a drag tire will fit a slightly narrower wheel because of the taller, softer sidewall. Unless you are only interested in cosmetics, I would stick with their suggestions as to the ideal tire width. I had this proven to me once. I was given a pair of 255-50 roadrace tires for the rear when I had 8" wheels. The back end always wiggled and I was glad to be rid of them. I had to put a ton of air in them to keep from feeling like I was going to spin-out at everycorner, even on the street, and then wore them threadbare in the middle.
I have 255.40.17's in the back and 245.40.17's up front.You'll have to go 5 lug to use 10 inch Cobra R rims,as there aren't any 4 lug Cobras (believe me,I looked everyywhere).The 255's in the rear JUST clear my quad shocks.
I too think 315's will fit in the back. That is/was my plan.
because i still have the stock tbird rear end do you think i could fit 265's on the back?
im asking these questions now so i dont look stupid at a tire place..
honestly, i don't think a 315 will fit under the ass of a tbird. i've got them on my ranger. i thought he was just asking what size tire could be fit on the rim.
but will 265's or 275's?
what modification was necessary? did you have to roll the fenders?
Yep.
Thanks Sleeper.
does anybody know how big of tires i can fit WHITHOUT modifications?
i would guess a 255 or 275 would be fine.
Mustang-width axles/drums from a Bronco II, rolled lips, slight clearancing on the inner wheelhouse. The biggest bitch was keeping the e-brake cables from contacting the wheels/tires.
But, they fit.
(http://i13.photobucket.com/albums/a274/46Tbird/picture082.jpg)
People need to keep a very important fact in mind in regards to tires:
Not all tires are created equal. Rim width also plays a huge role here.
Claiming a 315 can fit is fine but the people heeding such advice need to keep in mind that tire brand becomes very important because I'll tell you right now......anybody who takes the 315 claim as the gospel is gonna be awfully pissed when they find the tire doesn't fit because one brands 315 can and will often be very different than another brands 315. A prime example....line up a Nitto 315/35-17 next to something like a Goodyear Eagle F1 and you'll quickly see they are quite different in terms of width.......the Good Year being noticeably and measurably wider. Lots of Mustang guys on Corral throw out the "I got 315's to fit no problem on my Fox 'stang" and most of the time it's a set of Nitto's which are barely wider than a 275.
Wheels also play a big role. A "true" 315 shouldn't be on anything narrower than 10.5" and a wider wheel will affect the overall section width of the tire which will also reduce the amount of room you have to play with.
Just something to keep in mind.
very true. i've never played with tire size on the bird. i'm just going off what i've done to the ranger. i'll bet if i had a wider rim, i could cram a 335 under that thing.
Greetings,
I am researching tire rim combos myself.
For the statement about 4 lug and no 10" available. If you can find 17x9 rims and the construction is correct (forged I believe) a quality rim shop can "split" the rims and weld in an extra inch. This is common with the 03/04 Mercury Marauder crowd. I had that done to a set of ROH Drift R's for the back of my MM.
What offset are folks running for the Cobra Rs? I can find them in
+18 and +24. I have seen several folks say 255s and some say 275s.
For the 275s what rim, what offset, any clearance issues?
I have 255's in the rear with a 17x9 Cobra R rim.I have a tiny amount of room between the tires and the quads.I'm using Continental tires with a z rating.