Ltaboso

the lexus ccs-r is using
18×8.5J, off-set 30 front
18×9.5J, off-set 40 rear
245/40 R18 front
255/40 R18 rear
will the isf feel faster with this set up?

i use to have an altezza and mr2 sw20...what i noticed with RWD cars,when you change to smaller wheels the car will feel faster because the final drive ratio will change (engine being stock,no other mods).....anyone using 18s for daily?

vbb

iTrader: (3)

If the 18s are lighter than the 19s, which would definitely be the case when comparing the same wheel, then with less rotational mass/unsprung weight, the car would be marginally quicker. There would also be the fact that running 18s, in general, will mean cheaper tires. But realistically for the amateur that is interested in tracking the car, having more contact area with the tires is going to be more important than the slight weight savings you'd get by running 18s over 19s. For the street, I happen to think 18s look a bit too small for the size of the car. I can see someone who is drag racing this car wanting smaller wheels for that setup.

I know some members run 18s as a winter setup, but that is not for the purpose of being faster like you're talking about.

juanmedina

Some weight reduction depending on the wheels you buy. Another benefit is more wheel and tire options at a better price than 19" wheels and tires.

It seems that the 18's look a little small on the IS-F at stock ride height but when you lowered it looks just right IMO.

Joe Z

iTrader: (10)

Don't forget you need the right style /
design of 18" wheel to clear the OEM Brembo Calipers & Rotors..

Joe Z

I8ABMR

There may be a difference , but it will be the kind of difference you may feel if you are drag racing. On the street there may be a slight difference that you may feel but you will not feel it after maybe a couple of days. Kind of splitting hairs.

BLKLBL

18 inch wheels look lame on the ISF.. I'm rolling on some aftermarket 18s as a winter setup, and they don't do the rest of the car justice

Sean

iTrader: (3)

I don't know of anyone using 18s daily, but I've seen a couple of examples of track setups that actually look nice enough to daily IMO

From the drag racing wheels thread: https://www.clublexus.com/forums/is-...s-show-em.html

Fsport2UR

There are several factors why 18" wheels are more widely used in racing applications. Inexpensive to replace if they get damaged, more options as far as offsets and availability, more tire selections for street and track, better wheel well clearance, and more importantly lighter weight.
18s are also more structurally sound, they can handle a better beating than 19s. Typically you have to move to a smaller side wall with 19s if you want to drop your ride, but an 18 you can use meaty tires and still dump your car. This also gives a smoother better ride. 19s to me look better, but 18s are a better all around wheel in comparison. The BMW M3 crowd were once caught up in staying with 19s; but now many of them have moved down to 18s. Just wanted to reference the M3 owners because we're more in the same boat with them, and I see more M3s tracking than ISFs.

juanmedina

I would love to run 18" square setup. I wonder if the RPF1's 18x9.5 +35 will fit on the front with the big brakes...

darbs242

iTrader: (5)

They will not. 18x9.5 +45 barley clears.

Reaper21

iTrader: (1)

darbs is right that the RPF1 will not fit, but the justification doesn't really make sense. If a +45 offset barely cleared, then a +35 would clear. AFAIK, 18" RPF1s need around a +20 to clear the brakes.

Gymkata

There are a variety of reasons people go with 18 inch wheels vice 19s. One of the biggest reasons why I have considered it is having 1/2 inch more side wall for the bad roads around me. Also, 18 inch wheels are lighter overall than equivalent 19 inch wheels, and the rim weight is 1/2 inch closer to the hub. Furthermore, 18 inch wheels and tires are typically less expensive.

I think most people want a large wheel with low profile tires though and don't care about the performance tradeoffs. I am not one of them. Remember, until recently many AMG models used 18 inch wheels instead of going larger, and I personally thought it looked perfect on them.

EDIT: I just reread your post. The specs you listed for the CCS-R rear tires don't change the final drive ratio at all. Only shorter tires (not wheels) will affect your RPM at a given speed in a particular gear. 255/35R19 and 255/40R18 are virtually identical in height.

juanmedina

I been doing more research about the RPF1's.

It seems that some members have tested the RPF1's 18x9.5 +45 and they clear the front brakes by a tiny bit.

Wouldn't the RPF1's 18x9.5 +38 fit perfectly since they puck out 7mm more? Am I missing something?

ForzaF

iTrader: (3)

Main reason is like ppl said tire choice as well as cost per tire.

I'm planning to run 17" setup that clears my front just barely and rear is fine
Nitto nt01 in 17" setup will run me $800 all around from discountireco.

The reason the rpf don't clear in the certain offset is because it's a drop centre wheel
If you look that up you will understand why vs a non drop centre like my buddy club p1

Look into volks ce28n or le37 or te37 those might clear they don't dip in towards the caliper as drastic as the rpf1. I think work emotion stuff and weds need a look at. These are wheels designed for track purpose
The weds sa15 r look like the Isf ccsr wheels
Tc105n are one of the lightest track setups in the 18" that should clear our car

juanmedina

So have you tried to fit a 18x9.5 +38 set or a 18x9 +35 set?

It just doesn't makes sense that the drop center wheel is the issue. The issue with the 18x9.5 +45 was the really small clearance between the face of the caliper to the inner side of the wheel spokes.

The 18x9 +35 will stick out 3.7mm more than the 18x9.5 +45