I just order new rims for my FD and i was orginally thinking that i need a +45 offset on a 19"X8.5 rim. The manufacture of the rim company thought the +45 would be to much,and recommened a +40 offset to clear the brakes. Will both offset work. Is one offset better then the other. What would be the best offset to use? Right now i have the +40 coming,but i could change it today if i find out what is correct.

 

This sounds like it has to do with the wheel's pad height. Some wheels require less offset for the wheel's spokes to clear the brake calipers. Wheels with large caliper clearances are not this restricted, and you can focus on offset/backspace. With wheels that have straighter spokes (don't bow outward), you do have to pay attention to pad height. The wheel supplier is probably correct, and the 40-mm offset is the one to go with...

 

5mm.

 

too easy...and predictable...

 

.2"

 

It depends on the wheel manufacturer. I suppose less expensive wheels may simply add on pad height to increase brake clearance , and end up with a numerically smaller offset number as they go.

If the wheel is a higher end model, there are typically different pad heights to clear different size brakes. I posted recently here:

https://www.rx7club.com/forum/showth...hreadid=210217

What brand/model wheels are you getting?