05RollaXRS

Thanks. So you are running MPSS in the rears?

05RollaXRS

I have been planning for my next year mods to the RCF, after much research and thinking, I am going to take the common sense approach and to go with Michelin Pilot Sport 4S (XL) in 295/30/19 rear and 255/35/19 in the front. They should be good for street driving and also hopefully address my gripe with the soft sidewalls of the OEM Super Sports.

Since I am going wider and shorter on the rear while keeping stock in the front, my questions are:

1 - Having a wider differential between front and back, how would it change the handling characteristics while taking a corner fast? Will it introduce any unpredictability?

2 - How will 295/30 sit on the stock 10 inch wheels? Is the 295 mm width comfortably seated on 10 inch wide wheel? I want to make sure the tire does not bulge out on the side introducing any "sponginess", which I would want to avoid at all costs.

3 - Since the rear will be shorter (26 inches diameter front and back while the stock rear is 0.5 inches taller), would the car have a "raked" look"? I always love the high tail and low nose look with the staggered wide rear. Gives it the classic sports car look.

4 - Any advantages of sticking with 275/35 rear over the 295/30 slightly wider rear? I believe the tire weight is almost the same. The shorter height also gives slightly shorter gearing, which is good as RCF gearing is tall already.

Just want to make sure I spend my $1800 with the right decision. Thanks.

flowrider

iTrader: (9)

^^^^Thought we went over this:

https://www.clublexus.com/forums/rc-...-today-40.html

Lou

05RollaXRS

True. Just was wanting to see if there are more people with any thoughts on this.

RaulTX

Did anyone notice that the 2020 "RC F-spec" MPS4S are now available? From the original press release: "Compared to the standard Pilot Sport 4 S tires, the RC F’s design is differentiated by a revised shoulder profile, extended bead and trapezoidal shape. The grooves in the tire also have a different shape, depth and location compared to the off-the-shelf Pilot Sport 4 S. Another departure for the RC F spec tire is an increased level of dry grip thanks to revised silica content levels at the outside edges of the tread." What they failed to mention is that they are back to the old OEM MPSS' load indices: 92Y (front) / 96Y (rear), compared to the off-the-shelf PS4S' 96Y (front) / 100Y (rear). Going from MPSS to off-the-shelf MPS4S made a favorable difference in my lap times at the track, so I was really excited to try the new "RC F-spec" MPS4S as soon as they came available... now I don't know what to think!

flowrider

iTrader: (9)

^^^^That is because the are SL tires, not the XL load rated tire with stiffer sidewall. This is certainly a





Lou

05RollaXRS

One month before I put the MPS4S tires on. I am trying to get the RCF-Spec versions of the MPS4S using the part number. I also noticed the RCF-Spec MPS4S are 1 lbs lighter each than the standard MPS4S tires. Hopefully, I can find those specific ones.

RaulTX

Yes, the off-the-shelf MPS4S is a pound heavier because of the extra carcass stiffening material needed to contain the higher pressures associated with the higher load index. I guess the only way to know which one is better is trying both tires on track and compare handling and durability (particularly shoulder durability)... new resolution for 2020!

05RollaXRS

Interesting. If you end up doing that, do write your impressions here.

05RollaXRS

So unfortunately, as it seems the RCF-Spec Michelin Pilot Sport 4S don't have the extra load rigidity unlike the off the shelf PS4S. It seems Lexus stuck with standard load tires on the RCF (including track edition) just like the original MPSS tires. I might end up going with the off-the-shelf XL version of the MPS4S even though, Lexus claims the RCF-spec one's are optimized for RCF. Tough choice here, urgh!

flowrider

iTrader: (9)

^^^^XL FTW

Lou

05RollaXRS

An update, today I finally placed the order for my Michelin Pilot Sport 4S with the extra load rating. I decided to not go with the RCF-spec Michelin Pilot Sport 4S despite them being designed for the RCF geometry simply because they are not extra load rated like the Super Sport our RCFs came with. I would like to have extra load rating as it will make the sidewalls stiffer.

Now, here is the issue. Michelin is saying their production is halted and the tires would not be in stock for another 4 - 6 weeks due to the pandemic. I had a tough choice either to buy them off a website vs ordering fresh new ones. I decided to wait longer and go with the fresh new ones as especially high performance tires, sitting on the shelf age and lose their compound. I can't be sure how long they have been sitting on the shelf so I decided to wait it out a bit and order fresh new ones.

If anyone is interested, here is the SKU number for the ones I ordered. 66901 (fronts) and 10078 (rears).

05RollaXRS

Update: Set of tires has been located by the tire shop. OEM size 275/35 and 255/35. They will be arriving in two weeks. Hopefully, I should have the XL MPS4S before the end of the month. I will write a detailed review of the OEM MPSS vs initial impressions of the MPS4S soon after.

rexio83

iTrader: (4)

A year ago I would be all over a performance tire like p cups, when I got my gt 350 2 years ago first mod I did was change to trofeo r, similar to cup 2s, an amazing tire at the track that made big improvements in the corners, I mean serious advantage where I shot past the cars in front of me cause I was able to go wot a second or two before they could, mid corner. On the street, traction was crap, unless lots of heat they don't stick. Now that I switched to the gsf, I thought the dws6 the previous owner put on from the get go were a bad decision, was I wrong, street grip is amazing. I don't plan to track the gsf, when it's time for a new tire I will probably go with ps4s, even though dws6 do a great job on the street, p cup2 belong on the track and will get outperformed by the ps4 on the street in every category

05RollaXRS

Thanks for sharing. Yeah, over time I decided to stick with Mchelin Pilot Sport 4S with extra load stiffer sidewalls rather than the RCF-spec MPS4S that are not extra load rated.

When I created this thread, I seriously was thinking about Cup 2 as this is my own occassional driving car and always driven in dry/sunny weather. However, over the course of this thread, I ended up getting PS4S XL tires, which are on order right now. For someone like me who will not go to the track, there is no point in getting Cup 2 for just spirited driving. From what I read, they should be leaps and bounds better than the OEM Super Sport pre-2020 RCF came with. I should have those tires on in 2 weeks and I will write an initial impressions review. Cheers!