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-   -   245/45/17 on FD...?? (https://www.rx7club.com/suspension-wheels-tires-brakes-20/245-45-17-fd-713093/)

apexFD 12-14-07 08:58 PM

245/45/17 on FD...??
 
Hey guys,



Recently aquired some 17x10's/17x9.5 and i am wanting to put some new tires on them.


Currently they have 255/40/17 rears and 235/40/17 front. I am wanting to put 245's all the way around..




I figured out that 245/40/17 is the best fit VS OEM. But my local tire shop can only offer 245/45/17's...

-----------------------
245 40/17, diameter diff: -0.57% , speedometer will read faster than actual.
Original tire
Sidewall: 4.43 in
Radius: 12.43 in
Diameter: 24.86 in
Circumf: 78.09 in
Revs/mile: 811.32
New Tire
Sidewall: 3.86 in
Radius: 12.36 in
Diameter: 24.72 in
Circumf: 77.65 in
Revs/mile: 815.98


Speedometer reading with new tire is 0.57% too fast.
When your speedometer is reading 60mph you are actually traveling 59.66mph.
-------------------


VS



---------------------

245 45/17, diameter diff: +3.31% , speedometer will read slower than actual.
Original tire
Sidewall: 4.43 in
Radius: 12.43 in
Diameter: 24.86 in
Circumf: 78.09 in
Revs/mile: 811.32
New Tire
Sidewall: 4.34 in
Radius: 12.84 in
Diameter: 25.68 in
Circumf: 80.68 in
Revs/mile: 785.33


Speedometer reading with new tire is 3.31% too slow.
When your speedometer is reading 60mph you are actually traveling 61.92mph.

-----------------------




Is this 3.31% too much differance?


I am concerned with the ABS and how it will be affected, anything else i whould be worried about? Im positive the tires will fit.



Thanks in advance.



=Ben

cewrx7r1 12-15-07 12:40 AM

You are over thinking this.
For AVS ES100 Yokohamas:
Stock rims 225/50-16 : 829 RPMile
I have run 245/45-16 on stock rims. 843 RPMile
I have run 255/40-17 on my Enkie RP01 9X17. 828 RPMile
Now have 245/40-17 on front and 275/40-17 on rear. 809 RPMile
I never got a ticket going the speed limit with any tire combo, and the ABS cares less.

ABS does not seemed affected by this as far I can notice.

cabaynes 12-15-07 10:18 AM

what are your offsets

aznpoopy 12-15-07 10:47 AM

just buy online

i find discounttiredirect to be usually cheaper than the local store anyway

Mahjik 12-15-07 11:51 AM


Originally Posted by aznpoopy (Post 7627696)
just buy online

i find discounttiredirect to be usually cheaper than the local store anyway

I agree. However, I doubt you'll notice that much of a difference running that tire. It's not ideal, but that's never stopped people from doing similar things.

maxcooper 12-15-07 10:13 PM

The main risk is rubbing in front. 245/45-17 is definitely pushing it, and may be too large.

-Max

apexFD 12-16-07 01:36 AM

well i am running stock suspension, and i wouldnt want to lower the car more than .5" front and 1' rear anyways.



=Ben

1st to 3rd 12-16-07 05:59 PM

ABS will not be affected. The tire size is not ideal, but it should work with the stock suspension.
Unless you are going for the stretched look, your wheels are outside the recommended width range for 245/45's.
The height and width of 255/40’s is a better match, if you can fit them. What is the offset front and rear?

apexFD 12-17-07 12:46 PM

I am not sure on offset. How can i measure this?




When i was installing the wheels i measured the width with a tape measure, from tire bead to tire bead the front was 9.5" and the rear seemed to be 10".


The tires that are on the car right now are 235/40/17 front and 255/40/17 rear. They do not seemed stretched.... although i am not an expert.


I will take pictures later today for you guys.



=Ben

ptrhahn 12-17-07 01:01 PM

With those widths, I'd run a minimum of 245/40 front, and 265/40 rear.


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