What size tyres for Jap 16" wheels?

Hi,

I got my Supra this July and with the Welsh winter (and de-cat!) approaching, I want to get shot of the Avons that came with the car and get some Goodyear F1's.

What size are the rear tyres 'sposed to be on J-spec 16" wheels?

My rears are currently 245/45-16, from searching it seems that others are using 245/50-16. My fronts are 225/50-16.

Cheers

Tom.

Welcome aboard.

Standard 16" tyre sizes are 225x50x16 front and 245x50x16 rear.

Check it out.

Cool, thanks.

So my Supra has the wrong size tyres on it!

This may be a very stupid question, but will this make much of a difference? I know Avons aren't the best anyway (!)

Not much. You'll have a tad less tyre roll around corners because of the smaller sidewall. Your speedo will be under reading by about 4%, and if you are hyper-sensitive to these things you may notice a tiny, tiny bit less acceleration when you change to 50's.

Originally posted by Darren Blake

Your speedo will be under reading by about 4%

Over reading. Sorry. Your speedo will be over reading because your rolling radius is smaller.

Sorry to butt in Tom......

ANYONE KNOW IF SLIGHTLY WIDER TYRES (if available) WILL

GO ON THE STANDARD 16" WHEELS ? ?

ie. ~235/50-16 or 245/45-16 fronts

~255/50-16 or 265/45-16 rears

IF I put new tyres on the 16"-ers instead of

getting 17's, I'd like the tyres to push slightly further 'out'

on the rims if possible (those buggers are just TOO easy to kerb)

Fat S.

According to some tyre info I have kicking around:

The "J" wheel rim standard means that you can fit up to 0.5" less to 1.5" more than the standard bead width. I think the bead widths for the 16" wheel are 8" front and 9" rear (17"s are 8" front and 9.5" rear - from the "Features" page).

The bead width is typically 10mm less than the tread width so the fattest tyre you could put on a 16" rear would be:

Max bead width = 9" + 1.5" = 10.5" (267mm)

Max tread width (approx) = 267mm + 10mm = 277mm

Nearest tyre size = 275mm

Plus you will need to adjust the sidewall height to maintain the rolling radius.

Standard tyre sidewall = 245mm x 50% = 122.5mm

New profile = 122.5mm / 275mm = 0.45 = 45%

So in this case you should be able to fit 275x45x16 to a rear rim.

*Disclaimer* I know diddly squat jack sh*t about tyres. All this is just maths than I happen to have on a data sheet. I have no idea what putting these fatter tyres on your car will do to its handling.

F1 come with a rim protector bead, so you don't need to go extra wide just to protect the rims. I just put some F1's on the front on 17's to early 50 miles to say what they are like yet.

CHEERS Darren,

NO, I don't want to go fattest possible , just would like

slightly wider than standard as they allow the rims to touch TOO

early (for kerb-huggers like me - don't trust Romford/Dagenham

drivers !)

So 'IN THEORY' I could go, say, 235/245 fronts and 255/265 rears

(IF they're available, IF I don't decide on 17's anyway)

The reason I'm shying away from 17's/18's is my suspension is

already ROCK hard ! and being that I bought the Soop to be

A) Extremely capable 'SPEED' wise

but also,

B) Auto/Air-Con/P-Steer etc ie fairly comfortable, I don't want to

lose what little suspension is already there ! !

I would like someone else to just tell me if my ride is

abnormally hard or just Soop/Jap spec(?) at some time.

mmmmmm..... starting to thinking FATTER now (not that I don't

think that normally anyhow !)

THANKS, S.

Originally posted by Steve W

So 'IN THEORY' I could go, say, 235/245 fronts and 255/265 rears

In theory, yes. But remember to adjust the profile to keep the same sidewall hieght and rolling radius.

In case its important, I have J-spec suspension and 17" wheels. When it came across the water, my three-spokes were encased in very very poor quality Japanese domestic rubber, and the ride was very crash-bang. After a few months when the tyres started cracking up I changed the fronts for Goodyear F1s and the ride and handling was considerably better. When I had my wheels refurbed and I changed the rears for Yoko AVS it was like a different car. I'm not saying that Yokos are better than Goodyears - I'm saying that good quality rubber made up for a lot of the poor ride I had on low-spec tyres.

YES, understand about Radius...

(Although I HAVE got Pete's adjustment available now for the

necessary speedo accuracy - I realise any increase/decrease

will affect gearing/acc'/topspeed etc - I AM a bit of a long/tall

gearing lover.... I MIGHT increase rear radius slightly and

sacrifice acc' for a tidge higher gearing !?)

I would DEFINITELY keep front radii (?) the same as standard

for predictable steering AND P/Steering etc

AND always best to keep fronts-to-rears width ratio right-ish

( 225 - 245.......245 - 265..... ? ?

mmmmmmm.......yeah I see what your saying about the tyres

I think 2 of mine - can't remember b/f - are Bridgestone Turanza's

? Jap ? or older Brit' ? I'll check makes tomorrow.

SORRY AGAIN FOR BUTTING IN OUTATIME ...

HOPE 'ANY' OF THIS IS OF USE TO YOU TOO, MAYBE ? ?

Fat S.

Yeah, I'm still watching!

Does anyone have Toyotas guidelines for what tyres can/should go on the stock 16" rims.

I have been told it is best to get thinner tyres within the limits set by the wheels to stop tyre roll. This is 245 for the rears right?

I just got this quote from Michel Delver. These prices are for 2 tyres and include delivery.

----------------------

245/45ZR16 Goodyear Eagle F1 GSD2 = £218.84

245/50ZR16 Goodyear Eagle = £294.04 (Not F1 Pattern - F1 Pattern not made in this size)

225/50ZR16 Goodyear Eagle F1 GSD3 = £181.24

Please note 245/45R16 is only made in old F1 pattern at this time and 225/50R16 is only made in new F1 pattern

----------------------

I guess I'll stick with the 245/45's on the rears then...

Tom.

I would think , Toyota only quote/suggest the standard

tyre sizes. ? ?

They don't want you using anything else and compromising their

original handling.

It certainly only quotes the normal in handbook/manual/etc

unless anyone else has seen a TOYOTA guide elsewhere

(TOYOTA that is ! !)

They probably spent thousands of pounds testing to get just the

right combination of wear/handling/economy etc

and what's the first thing most owners do . . ? ?

put EXTREMELY low profile, FAT tyres on ! ! ? ?

(....now....what's the biggest hoops I can sling on me' ride baby)