Rear tyres size increase?

[TheSebringOne]

With OEM REAR tyres being virtually like gold dust, I've been thinking about options when the rears do get to the TWI. Thinking of going down the Bridgestones REO50 route, but may think about GY Eagle F1 GSD3s (but some say tyre wall is'nt as stiff/ is more squidgy?). Is it possible to put 255s onto the 94+ OEM rear rim rather than 245s, so upgrading the rear to 255x40x17s !?

[mutley]

Im not sure about sizes with the later model NSX but all I can say is that the eagle F! has to be a contender for one of the best tyres on the market.

If I get round to going 17" all round that will be my tyre of choice.

Jim

[Silver Surfer]

James, are you planning to take the car on the track and give it some punishment? If not, you can't beat GYE F1 GSD3.

SS

[TheSebringOne]

Not planning to do tracking, just need to replace IDC! Some of you are using GY Eagle F1 GSD3s 245 & 255 combos (Senninha, TQO, Mutley & Si in the past, but Si did'nt really like em?). I know they're great in the rain, quieter, smoother ride & last 2-3 times longer than oems Bridgestones,Yokos, Dunlops (when road driving)!

The only thing is they seem to be more squidgy & sidewalls are not as stiff? I have experienced GY Eagles F1s on my old Prelude but that was FWD & they were great.

You can get 245x40x17 (91Y), but I know you can get 255x40x17 (94Y), the 91Y are direct fit/replacement for oem because of the 91Y, but I don't think they 94Y fits the 94+ oem rims & 02+? Or do the 255 only fits the 02+ rims? :dunno:

[TheQuietOne]

The only thing is they seem to be more squidgy & sidewalls are not as stiff? I have experienced GY Eagles F1s on my old Prelude but that was FWD & they were great.

Not at all sure where you got that impression from James? There isn't enough tyre wall anyway on the correct tyre sizes for our wheels for it to be soft! I'm 100% happy with my second set of F1's FWIW.

Happy decision making!

[Papalazarou]

I'm running the later Bridgestones and they're very good. The difference between the 245's and 255's is pretty minimal width-wise.

Cheers,


James.

[NSXGB]

I'm running the later Bridgestones and they're very good. The difference between the 245's and 255's is pretty minimal width-wise.

Cheers,


James.


Yeah, what's 10mm between friends?

[NSX 2000]

Yeah, what's 10mm between friends?

A sore arse! :laugh: :laugh: :laugh:

Sorry I just couldn't resist.

[gsuds]

With OEM REAR tyres being virtually like gold dust, I've been thinking about options when the rears do get to the TWI. Thinking of going down the Bridgestones REO50 route, but may think about GY Eagle F1 GSD3s (but some say tyre wall is'nt as stiff/ is more squidgy?). Is it possible to put 255s onto the 94+ OEM rear rim rather than 245s, so upgrading the rear to 255x40x17s !?

You can use F1s in std size - I have these just now - & last twice as long as Toyo Proxes (had these at 255 last time - no prob with changing widths at all), just about to change the F1s after 8K miles - 4K out of the Toyos....

HTH
G

[TheSebringOne]

Matt, I got that impression from Si, as well as one/two others thats all. Maybe you prefer them as its a daily driver & you do a fair bit of miles? I use my as a 2nd/3rd car, but like to have a real blast so prefer the best and get something with the same manufacturer that made the OEMs!
Mind you the modern Ford GT uses them & thats coping with 550BHP! Decisions, decisions!

Papa, have you got your gold split rims from your old Red Targa on? If so, are these with 245s or 255s Bridgestones?

[TheSebringOne]

Gsuds, are you now putting on GY F1s 255x40x17s 94Y on the 94+ rims? What was the exact size of the Toyo Proxys as I'm a little confused as to the 94Y as oppose to 91Y on the standard 245x40x17? The 94Y may not fit?

[markc]

Hi Guys,

The 91Y, 94Y part is the Load Index rating of the tyre and has nothing to do with either fitment as such, or year, of manufacture or anything else.

I'm currently running Bridgestone Potenza S03-Pole Position's in the 225x45x16 (89Y) and 255x40x17 (94Y) combo ie 1 size (width) up both front and rear on my car.
They've been fine and I've not noticed any significant differance in handling feel or balance to the previous Potenza RE711's (215 Fr & 245 Rr) that were fitted.

For some reason I find tyre tech fascinating, probably because it's confusing so please excuse the "know enough to be dangerous" information that follows and use or dismiss as you see fit... :)

Load Index (LI) is a standard tyre industry measurement and is quoted, and marked on the sidewall, for all new passenger car tyres. However, it (LI) does not indicate the sidewall stiffness even though it is probably related in some way to it for a particular tyre design (brand & model) at least. Seems logical to me?

Sidewall stiffness is not, as far as I can tell, measured in any industry standard way by the tyre manufacturers so can't be compared between tyres from the same manufacturer let alone differant ones!

Sidewall stiffness is a function of the design and construction of the particular model of tyre.

A Load Index of 91Y translates to a 615Kg max load for the tyre, 94Y translates to 670Kgs. I don't know what the "Y" sufix represents but it definately isn't the speed rating in this case.

Assuming for the moment that the NSX weighs 1400Kg, the oft quoted 42 Front/58 Rear (percent) weight distribution gives the rear tyres a static load of 406Kg each and the fronts 294kg each.

Even assuming the car is fully loaded with 2 large passengers and a boot full of luggage you'd be hard pressed to get anywhere near the typical 89-94Y Load Index found on "NSX spec" tyres.

So what does it all that mean? I've no idea except that the following observations are probably all true...

1) The original fitment designs for the 15/16 and 16/17 wheels from Bridgestone (RE010) Yokohama (AH022) and Dunlop (SP8050), and indeed the Bridgstone RE040 spec'd for the 2002 cars are all no longer readily available and some no longer produced at all.
2) Tyre technology has moved on in leaps and bounds since the NSX came out and these tyres were designed.
3) Many modern tyre designs (of the correct size and speed rating) are likely to work well on the NSX.
4) Some will be quantifiably better than others ie max lateral grip (in G's), wet/dry braking performance, noise etc.
5) Some will be subjectively better than others ie feel and feedback.
6) Some people will prefer one design over another.

Phew, I enjoyed that :)

Cheers

Mark

[Silver Surfer]

Pic for James to ponder on tyre spec.

SS ;)

[gsuds]

Gsuds, are you now putting on GY F1s 255x40x17s 94Y on the 94+ rims? What was the exact size of the Toyo Proxys as I'm a little confused as to the 94Y as oppose to 91Y on the standard 245x40x17? The 94Y may not fit?

I now have GY F1 245/40/17 on rear. Was Toyo Proxes T1R 255/40/17.
G

[markc]

Hi gsuds, all the details please :) what Load Index are your F1's?

Mark

[michaelw]

I have just ordered some CE-28's from Dali - superb service BTW but I am now having problems getting tyres.

I have managed to get the fronts (215/40/17) in the GS/D3 but can't get the rears (255/35/18 or 265/35/18). I have just been told that the GS-D3 have been replaced by the Asymmetric in certain sizes has anyone tried these?

I have spoken to Goodyear and they say that ideally you shouldn't mix the 2 but it will be OK. They don't do the new tyre in the size I need for the front or the old tyre in the rear size so I have no choice but to mix - oh great!

On a different tack are the Bridgestone SO-2's as good as the old SO-3's?

Apparently the new tyre has a harder compund and stiffer sidewall on the outside and a softer compound on the inside.


Michael.

P.S. Sorry if this is a bit of a threadhijack but may be worth considering what is available and checking stock before deciding which tyre to go for.

[gsuds]

Hi gsuds, all the details please :) what Load Index are your F1's?

Mark

Haven't a clue :laugh:

[Senninha]

James,

Plenty for you to digest. One small point I have been told by many that isn't clear from your original post is balance F to R. If you go up at the rear, go up at the front as well. If you dont then you run the risk of inducing higher levels of understeer the first time you go for a spirited drive. If you've driven a stock Elise then you'll know the feeling.

HTH, Paul

[AR]

215 f 255 r is about as usable as it gets for a street NSX on 17/17. 225 is nice but with no PAS is a pain parking drivers not built like Popeye.

[gsuds]

Agree Ary - had 225f with the 255r, one reason I've downsized again is slightly better steering precision with 215, and less weight with non-PAS.

[markc]

Michael, those Asymmetric's look very differant to the GSD3's. I'd keep searching for matching GSD's if I were you.

Re the Bridgestone's, when I was Porsche mounted and the SO-3's first came out there was a huge debate followed by a general concensus that SO-3's were inferior performers to the older SO-2's. All agreed that they were significantly quieter tho'.

In the Porsche world you have the Porsche specific "N" ratings to deal with as well as all the other variables.

This debate has settled down now and most people are happy with the SO-3's if they have a preference for Bridgstone over Pirelli, Michelin and Continental who also produce "N" rated tyres.

You can still get "N" rated SO-2's in some sizes and of course specific SO-2's (ES02JZ) for the Honda S2000.

Cheers

Mark

[TheSebringOne]

Mark, I'm impressed with your rubber knowledge and glad someone knows more than me, strangely I really got into rubber when had a rear tyre deflation in the fast lane of M6 at 80 mph! So Mark do you have Type S alloys, are they same size as 94+ 16/17 combos? I would seriously consider upgrading to 255x40x17 as the load issue has been explained by yours truly, thanks Mark for that! :)

Kare, wander what kind of motor can get those slicks hot/turning on a drag strip! Don't think Nitro would be enough! Wander if they have a TWI! :D This looks like the NSX Dragster in the other thread I posted!?

[TheSebringOne]

Gsuds, what were the Toyos Proxies like?

Ary, you say a 215 & 255 combo is perfect, but with 17s both f & r, what about oem 16/17s?

Paul, you stated I should think about upgrading the fronts to 225, aswell as upgrading to 255 rears to counter understeer, can 225 be fitted to oem 16 fronts?

One last Q, it seems those with non-pas have kept/reverted back to 215 fronts after 225 since help with quicker turn in & ease of parking, but this should not be an issue with pas cars?

Much appreciated & I welcome your thoughts & experiences :)

[michaelw]

Gsuds, what were the Toyos Proxies like?

I have them on my current wheels and to be honest I don't like them but I know a lot of people on here and NSXPRIME do. Mind you I do have a problem with wheel offset and have slight play in my rack both of which are about to be sorted hence the wheels.

When I first put the Toyo's on it seemed like a marked difference between them and the SO-3's I had before. The car doesn't seem as stable and I haven't got anything like the confidence I had with the Bridgestones. I also had a couple of "moments" whoch I don't think would have happened with the Bridgestones. Saying that I have only just seen on NSXPRIME that if you put the tyre pressures up that helps, which I haven't done. All IMHO of course and I am sure a lot of people will disagree.


Michael.

[markc]

..Sebring.. as I said, I know (or think I know) enough to be dangerous, don't mistake me for an expert and feel free to check or correct what I might say :)

Yes, I do have the Type S BBS's and yes they are the same size/offset etc as the MY94-01 16'/17' Blades. I've also added spacers (5mm front and 25mm rear) for purely asethetic reasons, IMHO they fill the arches much better, and I can't say they made the car feel any differant. The attached pics are the best ones I have that might show the larger tyres on the spacers...

My car has EPS so the wider fronts (and spacers) haven't made the steering feel noticeably heavier. Swapping the airbagged/cruise (367mm) wheel for a Momo Tuner (350mm) certainly did though! Made a surprising differant to the feel, weight and directness... highly recommended. :)

Mark

[gsuds]

Gsuds, what were the Toyos Proxies like?


Much appreciated & I welcome your thoughts & experiences :)

James, they were OK enough, but very fast-wearing. As I said before I wanted to go back to 215-section so went for GSD2s on front, wrong aspect ratio at 40 though...

G