18" Tyre and Wheel Advice Needed.

[TVRProwler]

I have recently bought a Cebera with non standard 18" alloys however I have been informed that the tyres are the incorrect size.

They should be 235/35/18 front and 255/35/18 rear.

Can anyone confirm this, also tell me any tyres that can be recommended in these sizes.

Cheers,

[cirvy]

I'm presently on 225x40 front & 255x35 rear, all with 18" Spiders. Mine are SO3 Bridgestone, which i believe is what TVR recommended at the time, ( could be anything by now!)

Hope that helps

[TVRProwler]

Do you have any problems with the front wheels fouling the steering arms on full lock ?

[grahamn]

I currently have non TVR 18" wheels on mine, 235 on front and 255 on back and have no fouling problems at all.

Graham

[gazzab]

Suggest you check the offsets of wheels, bump stop fitment and tyre size.
Those wheels and tyres look a little bit 'wrong'.
I remember that car being for sale.

[J_S_G]

If the car drives fine, the tyres don't catch, they wear evenly, and the speedo is accurate, I wouldn't say they were the "wrong tyre".

On 18 rims, you're generally looking at a 35 profile tyre to give the correct circumference (i.e. to get an accurate speedo reading). Although I prefered 40s on the rear of mine (and 35s front). 235 & 255 seems fine, too. But that depends on the width of the rims (think that'd be for 8" rims - Tuscan Spider fronts).

Need a bit more info to give any real advice.

[david smith]

they look pretty good to me !! as they say if no fouling and she rides OK leave well alone ... DAS

[TVRProwler]

I think I may have confused you all. The current tyres fitted are 225/45/18 front and 265/45/18 rear on 8" rims with the same offset front and rear.

I have been advised I change to 235/35/18 and 255/35/18 I wanted to know if this is true and can anyone recomend any tyres in these sizes.

Cheers,

[J_S_G]

TVRProwler said:

I think I may have confused you all. The current tyres fitted are 225/45/18 front and 265/45/18 rear on 8" rims with the same offset front and rear. I have been advised I change to 235/35/18 and 255/35/18 I wanted to know if this is true and can anyone recomend any tyres in these sizes.

45s will probably give you a reading of about 7% low on the speedo. I.e. you're doing 32mph at a reading of 30mph or so. (Very approximately, on all counts)

I'd say that 45s are a bit big, and I'm surprised they don't rub a bit, unless it's had the arches shaved & lots of stops & spacers put on it. Having said that, if it drives right, and you're happy with it (and it's not catching on anything), I'd still wear the tyres out before replacing them. I'd be more worried re. what such a poor choice of tyre sizes said about the previous owner/garage (and what else they did) than the actual effect of the tyres themselves (assuming it's not negatively affecting the car).

235|255/35 ZR18s are generally the way to go. Goodyear Eagle F1s are a decent tyre for the money. As are Toyo Proxes.

[richb]

TVRProwler said:

265/45/18 rear on 8" rims

I would also say that a 265 on an 8" rim sounds rather wide. I have 255 on 8" rims only because Bridgestone didn't make a 245 when I bought the tyres and I will go for a 245 next time.

[TVRProwler]

They do rub front and back which is why I am thinking of changing.

I am struggling to find a matched set of tyres in 235/35/18 and 255/35/18.

[PHØENIX]

Prowler, larger profile is a very good idea, great traction and a much smoother breakaway, but you need to get the camber/toe spot on.... I'd recommend driving in to Joospeed and getting him to work on the alignment.... theres nothing wrong with 265/45 on 8" rims, the profile is large enough to dish out the tyre evenly, just get the wheel alignment sorted and you'll be able to keep your 'functional' fat tyres for pennies.

Every piece of traction you can muster out of these babies - is a BIG PLUS! I would recommend pick the fattest size you can pick for your rear wheels

My recommendations:

Front Tyres:
35-40 profile, softer compound, harder (extra loading) sidewalls, directional tread will help.

Rear Tyres:
As fat as you can go, medium-soft compound, soft sidewalls, directional tread.


Some ideas in sizing:

18" x 8J:
245 x 35 x 18 ZR
255 x 40 x 18 ZR
265 x 45 x 18 ZR

18" x 8.5J:
255 x 35 x 18 ZR
265 x 40 x 18 ZR
275 x 45 x 18 ZR

18" x 9J
255 x 35 x 18 ZR
265 x 35 x 18 ZR
275 x 35 x 18 ZR
285 x 40 x 18 ZR

Example:

For the front, you can go with the new Toyo Proxies, for the rear you can go with Yokohama's.... dont worry, they warm up very quick, but will be sticky as hell...

or

Go with Goodyears on the front, and bridgestones on the rear.

or

If you're in the money, go with Michellin PS2's all round. Rip-off prices though.

[J_S_G]

richb said:

TVRProwler said: 265/45/18 rear on 8" rims I would also say that a 265 on an 8" rim sounds rather wide. I have 255 on 8" rims only because Bridgestone didn't make a 245 when I bought the tyres and I will go for a 245 next time.

255 should be OK on 8" rims. I think (could be wrong on this one) that's what the Tuscan S does... 255s both front and rear, but 8.5 rims rear, and 8 front. (They may put 8.5s on the front, but I've never heard that mentioned)

I'd probably go a bit narrower on the front, to be honest - the 235s, probably, as the wider tyres aren't so great in the winter, especially on the pointy end...

[J_S_G]

[quote=PHØENIX]...[/quote]
But don't forget your speedo won't be particularly accurate. And don't whatever you do put Bridgestone S03s on the front of the car.

[PHØENIX]

J_S_G said:

PHOENIX said: ... But don't forget your speedo won't be particularly accurate. And don't whatever you do put Bridgestone S03s on the front of the car.

Valid point, keep the rolling radius within +/-3% tops if you dont want the speedo adjusted.

But for me its just a calibration issue, which can easily be adjusted for via a simple circuit wired in - I believe you can get them even on ebay, you basically dial up the percentage from baseline to either negative or positive. Theres a wheel/tyre calculator at www.tvrsupercars.com that will help out greatly. But whats the 'freedom' gap with the bib these days - 5mph?? in which case 3%+ could be the difference between a flash or no flash... hmmmm....

[TVRProwler]

What do you all think about 225/40/18 on the front ?

I have been quoted £500 all in for Toyo Proxes T1-R 225/40/front and 255/35/18 rear.

Quite a few tyre dealers have suggested a 225/40/18 as a replacement for a 235/35 !

Your comments are truley valuable.

[Plotloss]

I thought mixing tyre brands was a no no or is that just on particular brands/types of car?

[PHØENIX]

Most will say bigger is not better - there are merits in this point of view, but unless you're a hard hitting track demon, theres no point.

Through my own experience and a few others on here, we've realised that certain tyre combos can prove helpful and certain damper/wheel setups can prove very useful...

My 2 pence worth:

a) Soft tyre + stiff sidewall for the front.
b) Medium soft tyre + round/soft sidewall for the rear.
c) At least a 95 load rating for the front.
d) At least a 92 load rating for the rear.
e) Have a difference of 25 between the front and rear width of tyre contact patch, keep the rolling radius the same front and rear, unless you're building an all out street dragster.
f) If you are looking into aftermarket wheels, try and source 9J wheels, which will allow wider tyres and keep the overall sideview stealthy and low-profiled. Also with 9J's you will notice next to 0 tramlining and with 1 degree of negativecamber on the rear with the right toe-in - the rolling form is 'cone shaped' - the push and traction is phenomenally increased, corners are easily mastered and the back will kick back in under extreme load into a chicane/roundabout
g) Many on here on these forums can help suggest various setups but whats good for you is down to your own experimentation, but generally speaking people like JSG, Duncan and others have gone through a few combos and have their own views on what works - and generally speaking, you should notice a difference too. Joospeed can plug it all up with a set of superb dampers and stiffer springs to finish off the setup. A worthy investment - oh feck it, throw in an Emerald ECU upgrade too and enjoy the extra torque 'safely' with the new found traction/handling this summer... just stay away from the A1 - thats my GT's proving ground!

[PHØENIX]

Plotloss said:

I thought mixing tyre brands was a no no or is that just on particular brands/types of car?

The frictional losses that take place on different tyre setups can also play a part in some 'unwelcome' handling characteristics, but in general - for road use in particular, the characteristics are dwarfed in comparison to the 'welcomed' grip and train-like locking when running on the edge.

The same brand/make/spec across an axle is a must, for 4WD the same across all axles is imperative unless the loading distribution has been configured in a specific way such as fairyland cars eg. Lambo Murc...
With 2WD, its a little easier and more forgiving to play around, but if you are going with directional tyres, it is best to go with a similar flow on both axles.

[PHØENIX]

TVRProwler said:

What do you all think about 225/40/18 on the front ? I have been quoted £500 all in for Toyo Proxes T1-R 225/40/front and 255/35/18 rear. Quite a few tyre dealers have suggested a 225/40/18 as a replacement for a 235/35 ! Your comments are truley valuable.

I would suggest - if you want to bring it back in line with a little 'aftermarket' tweaks:

Safer - setup:

Front:
245/40/18
Toyo PROXES T1-R 245/40 ZR18 97Y RF Rim-protection £125 each
Goodyear EAGLE F1 GS-D3 EMT 245/40 R18 93Y M0 Extended (runflats - very useful) £158 each

Rear:
255/40/18
Bridgestone Potenza RE 050 A 255/40 R18 95Y A
£160 each

Thats my suggestion - and it will work beautifully!

>> Edited by PHØENIX on Wednesday 30th March 13:51