My wife's Accord V6 coupe needs new tires, and rather than buying her a new set, I thought I might just swap the OEM rims/tires from my '09 Civic Si sedan over.

It's a slightly different tire size: the Civic uses 215/45, and the Accord uses 215/50.

My Civic wheels are 7" wide...will that (or any part of this plan) pose a problem?

 

The only thing I don't like about this plan is that your (wife's) Accord will show it logging more miles than it actually is with 215/45.

When it comes time to sell in the future, you want as less miles on the clock, not more.

 

Would that even matter since speedo/odo signal come from countershaft not wheel speed sensor?

 

I've got to know the answer, since that will basically make or break this plan.

Don't want her odometer to be off by more than a few hundred miles, and if these tires (basically brand-new) last 30K, the difference could be significant.

 

I'm sure what you said is true. I don't have enough knowledge to know exactly where the signal would come from. However, no matter how we cut it, the tires still have to touch the ground and rotate to show an indication of MPH (and distance). Everything is connected like a "gear link" (I know it's electronic).

The only way speed and distance can be disconnected from this connection link would be something like a GPS system that can calculate speed and distance.

 

http://www.miata.net/garage/tirecalc.html

I believe the offset is also different so you may very likely run into clearance issues with the si wheels.

You will very likely need to use a 3-5mm spacer to keep the front wheel from hitting the brake caliper.
I've personally never been a fan of spacers. You can run into more issues with vibrations and such from the spacer being slightly off center.

The offset from what I've read is:
civic +45mm
accord +55mm
You may run into odd steering response issues as well.

info about this I found here:
http://www.driveaccord.net/forums/sh...ad.php?t=42055

Why not just buy some new tires for the correct wheels?

the actual miles that the car would report would be more then then the car has actually gone.
For instance if both tires are 17" comparing the 215/50 to the 215/45...
Speedometer reading with non-stock tire is 3.3% too fast. When your speedo reads 60mph, you are actually traveling at 58mph. that means that the car only travels 58 miles for the 60 miles that the odometer reports.

 

I have some super mint 09 accord coupe wheels i will trade for them 09 si's.. lmk

 

Speedometer accuracy threshold is + or - 3mph, so 2mph difference is almost negligible. A 240k car would really be a 232k car. 60k versus 58k no difference really. The offset difference maybe too great for caliper clearance. Easy to figure out though.

 

Alright, thanks for the replies guys. I think I will not do this.