Candleman

Do having these wheels in this picture cause the odometer to read lower than actual mileage? Is the speedo effected? Any difference here between the analog display and the 89+ digital? I know the wheels are larger than stock but is the overall radius with the tire also larger? I would assume there are lower profile tires one can get to keep the actual radius the same as stock when using larger wheels, correct?

Candleman

Duh

Bill Ball

Yes, it's the rear tire diameter [EDIT: FRONT tires beginning in 91] that effects the speedometer and odometer reading, regardless of analog or digital. Stock tires are ABOUT 25". You can get all kinds of tire diameters depending on the profile you choose and the manufacturer, regardless of wheel size.

IcemanG17

My rear tires are 6.7% taller than stock and 54lbs heavier than my 16" too..... My mileage is slightly down compared to the smaller less grippy 16" tires...maybe 1 mpg average......

Tom. M

I think the speedo pickup moved to the front in 91...or so it seems when those cars run on the dyno and the dash is freaking out //
Later,
Tom
89Gt
82 Track car

Bill Ball

That's news to me, but you are right!

FlyingDog

Stock 928 tires vary from 24.7-25" in diamter (by standard calculations, actual tires vary even more). I think it was DR that told me not to go over 26". Most of us run tires that are 24.7-25.6".

Candleman

Just checked, 25 in. all around so I guess I don't need to worry about incorrect readings. Thanks for the quick answers.

Iceman, 57 lbs heavier for all four so each wheel is 14+ lbs heavier than stock? What wheels do you have, and is that weight just the wheel or wheel with the tire on? It seems like a lot of weight but then again I am not all that knowledgeable about the subject.

Vilhuer

In '92 or '93 MY that ABS speed pulse was changed to rear wheel.

Bill Ball

Jeez!

FlyingDog

The forged dish wheels weigh about 17-18lb each. Most 17 or 18inch wheels for 928s (not includeing high dollar HRE/Kinesis/Fikse/Forgeline) are 25-28lb each. Larger tires also often weigh more.

IcemanG17

oops I was off on the weight #'s.......I meant 24lbs.....1lb for each front wheel-tire and 11lbs for each rear wheel-tire..... The stock forged wheels are VERY light...well under 20lbs....

mark kibort

but then 1mpg is 5% less, and that matches how much further you traveled, so its a wash.

mk

mark kibort

25 to 28 Lbs is for the copy C2 wheels, and that is very heavy. you right

my kinesis 18s, 9.5" wheels are a very light 19lbs and the rear 11" rims are 20lbs (very light for such a big rim. the tires can range from 25lbs to 30lbs depending on now much steel are in them.)

mk

mark kibort

actually, im now at 26.2" rear tire diameter. interesting, ive been clocked by radar at exactly 60mph when the indicator reads 60mph. for some reason, maybe safety margin, the stock wheel will indicate faster than you really are.

mk