backspace on a 17 x 9.5 wheel?

[390BB 10]

Hi guys

 

Just joined the forum after purchasing a 1969 Mach 1 390 4spd and now having a long wait for it to leave your shores and reach me in Australia.

 

Have been reading a few other threads in relation to wheels and tires. The general consensus is that 17 x 9.5 wheels will fit comfortably on the back of the mustang with a 5.5 - 6" backspace.

 

Have located a dealer that does the Torq Thrust 11 wheel as standard (and in stock)

17x9 1/25x4 1/2 6.375

 

Is this backspace okay or will i need to get a custom rim made with a smaller bs ?

 

Thanks for your assistance.

 

Gary

[Pakrat 1,043]

I think that is seriously going to rub the leaf springs unless it has a generous offset too like .75 to 1 or you add an equivilent sized spacer which aren't cheap and may make the total cost the same or more as a custom setup. When you go narrower you want less BS. For my new 17" wheels I am going with a 17X9.5 out back with 5.75bs and a 17x8 up front with 4.5bs, just as an example.

[390BB 10]

Thanks Pakrat, i didn't think they would fit. Spacers are not road legal here in Australia so that is not an option. Was hoping they would fit as there is a 6-10 week wait on getting the custom wheels. My car will be shipped iout to Australia in a few weeks and i was hoping to bring a set of wheels out with the car. Looks like i will have to wait for the wheels. The customs wheels are only an extra $40 each so no real drama.

 

Cheers

[Jayru 17]

I just put 17x9.5's on my rear with a 5.5 backspace. They fit real nice. There's about a 1/2" from the wheel to the inner wheel house. The max i would say you can go is 5.75 backspace (on a 9.5 wheel). 6 BS would be cutting it close.

[390BB 10]

Thanks Jayru. What size tyres are you running on the rear?

[Jayru 17]

Thanks Jayru. What size tyres are you running on the rear?

 

275 40's

[Thunder Kiss 13]

Hi 390BB, I think I've seen you over on one of the Aussie sites, anyway, when the car arrives grab a pair of 17x8 AU-BA-FG Falcon wheels and try them on the back. AU+ Falcon alloys have 6" backspace, so if they fit without scrubbing you wont have a problem.

[buening 63]

Yep, 6" is the max you will want to go for backspacing on the rear based on my recent measurements. You will likely have to use a BFH to the front bottom area of the inner wheelhouse. I haven't made a thread yet, but I've measured up my 70 mach and in the spring I'll be squeezing 17x10.5 rims with 315/35 rubber (12.5" section width Sumitomo HTR Z tires). These have a backspace of 6.8" but will need spacers to get it at 6.0". The only clearance issues is that section of the wheelhouse and the fact the quarter lips will need rolled. Measurements were taken using the Percy's Wheelrite: http://www.jegs.com/i/Percy%26%23039%3Bs/760/01201/10002/-1

 

Grabber70mach has this exact same wheel/tire setup.

[ForceFed70 14]

Like mentioned, it's the wheel well that will interfere not the leaf spring.

 

A lot of this depends on the tire being used. I would think that with that wheel/tire you would need to use a 1/2" or 5/8" spacer which is no biggie. The spacer is cheap, hardest part is putting in the new studs. If you go with studs 1/2" longer than stock, you should be able to insert them without removing the axle from the diff. Any longer tho and you will need to remove the axle to get the studs in.

 

The expensive spacers are the ones that are 1" thick or thicker as you really should get the bolt on style spacer if going that thick.

[SM69Mach 68]

I am running the 18X10 Bullit wheels that have a 6.3" back spacing. They are VERY close to the leaf spring and I had to massage the front inner fender for it to fit properly, but other than that and rolling the fender lip, no other mods. Running a 305/35/18 Nitto.