TYRE/WHEEL SIZES

[captaintact]

Hello
I have a '94 Chimaera 4.0HC NON-PAS Model. I will be needing a new set of Tyres very soon. My current setup (which was on the car when bought) is 245/40/17 REAR and 215/40/17 FRONT all Toyo. I find the ride very hard and harsh especially on the front where the wheels tramline and wander very easily!

What were the ORIGINAL wheel/tyre sizes?

Are my CURRENT tyre sizes correct given on 17" wheels? If not what should they be?

If i were to use the ORIGINAL WIDTH sizes on the 17" wheels, what profile would i need?

As i am only a road user (no track) i am thinking that a larger profile tyre with original width MAY offer better comfort on the crap pot holed roads and easier turning for a NON-PAS model?

All thoughts appreciated.

cheers

G

[JR]

Originally 205/60/15 and 225/55/16. If you're going to address the ride problem you'll need new springs (and probably dampers) or smaller dia wheels, or all of the aforementioned. Sorry.

[captaintact]

JR said:

Originally 205/60/15 and 225/55/16. If you're going to address the ride problem you'll need new springs (and probably dampers) or smaller dia wheels, or all of the aforementioned. Sorry.

Thanks for that. If i keep the same original width (205 & 225) on 17" wheels then that should raise the profile from 40 which should help ride quality? Making sure that overall size remains correct of course.

[haircutmike]

Wider wheels with low profile tyres tramline more then standard.

Also the more a tyre is worn, the more it grips in the dry and tramlining is worse.

My current very worn, (2mm left) 225/40/17's on the front tramline like a bast*rd!

[Chilliman]

I would also add that in my experience (not with the Chim) wider tyres, particularly with little tread, greatly lowers the aquaplaning threshold (I mean it can happen with less standing water). And there you have it.... Aquaplaning... probably one of the finest brown trouser experiences money can buy... And on that bombshell...

[haircutmike]

Chilliman said:

I would also add that in my experience (not with the Chim) wider tyres, particularly with little tread, greatly lowers the aquaplaning threshold (I mean it can happen with less standing water). And there you have it.... Aquaplaning... probably one of the finest brown trouser experiences money can buy... And on that bombshell...

That's why, if the weather forcast is for rain on Tuesday, I have a new set in the garage ready to go on for a T/D at Snett

[SILICONE KID]

[quote=captaintact]Hello
I have a '94 Chimaera 4.0HC NON-PAS Model. I will be needing a new set of Tyres very soon. My current setup (which was on the car when bought) is 245/40/17 REAR and 215/40/17 FRONT all Toyo. I find the ride very hard and harsh especially on the front where the wheels tramline and wander very easily!

What were the ORIGINAL wheel/tyre sizes?

Are my CURRENT tyre sizes correct given on 17" wheels? If not what should they be?

If i were to use the ORIGINAL WIDTH sizes on the 17" wheels, what profile would i need?

As i am only a road user (no track) i am thinking that a larger profile tyre with original width MAY offer better comfort on the crap pot holed roads and easier turning for a NON-PAS model?

All thoughts appreciated.

Sell your front wheels and tyres and fit 16" wheels with 225/45/16 Tyres ...thats what i did the results are amazing !What wheels dp you have?

Edited by SILICONE KID on Friday 25th March 12:55

[captaintact]

SILICONE KID]aptaintact said:

Hello
I have a '94 Chimaera 4.0HC NON-PAS Model. I will be needing a new set of Tyres very soon. My current setup (which was on the car when bought) is 245/40/17 REAR and 215/40/17 FRONT all Toyo. I find the ride very hard and harsh especially on the front where the wheels tramline and wander very easily!

What were the ORIGINAL wheel/tyre sizes?

Are my CURRENT tyre sizes correct given on 17" wheels? If not what should they be?

If i were to use the ORIGINAL WIDTH sizes on the 17" wheels, what profile would i need?

As i am only a road user (no track) i am thinking that a larger profile tyre with original width MAY offer better comfort on the crap pot holed roads and easier turning for a NON-PAS model?

All thoughts appreciated.

Sell your front wheels and tyres and fit 16" wheels with 225/45/16 Tyres ...thats what i did the results are amazing !What wheels dp you have?

Edited by SILICONE KID on Friday 25th March 12:55

I had thought of putting original size wheels on (as i don't know what a Chim rides like in original form). But i do like the 17" ones that are one there.




Using the Tyre Calculator ( http://www.club80-90syncro.co.uk/Syncro_website/Te... ), i have worked out the following equivalent sizes for 17"

205/50/17 FRONT

225/50/17 REAR

Edited by captaintact on Friday 25th March 21:08

[SILICONE KID]

I have never been 100% happy with the steering even with the 15" wheels.Its always been a bit twitchy and seems like i need to correct it.I wondering if its normal for this car.
Its been poly bushed
upper lower ball joints
Drop links
reconditioned steering rack

4 wheel alignment
anti roll bar bushes
both Uj`s

if the car hits a small bump it seems to go to the left..It does not feel unsafe just uncomftable..

Edited by SILICONE KID on Friday 25th March 22:23

[captaintact]

I wonder if PAS helps the general stability? This is my 1st CHIM so i don't know how mine handles compared to others. However it is not a patch on my Alfa 164 or 156! There doesn't seem to be enough "play" in the suspension for normal roads and as such the front end just bounces all over the place.

Just a thought.....i am using the same tyre pressures as the ORIGINAL size tyres. Should they be different for my wider, lower profile ones? The rear feels good and stable.

As tyres are expensive, i want to make a good, informed choice both in size and type when i change them in the next few weeks. The TOYOs seem popular, however is this favouring racing/track days? Does anyone use Continentals/Pirellis/Bridgestones/Uniroyals etc. These are the sorts that are more favoured on "road" cars.

[captaintact]

Any thoughts guys?

[SILICONE KID]

I have Falken 452`s which seem to good for me .I would check your off sets and rim width before buying new tyres .your car would handle alot better with standard wheel sizes ..i have just gone 1" larger with 16" fronts and 17" rears but still get some bump steer.Tyre pressure is set at 25 front 27 rear but they have a 1" smaller wall height to the standard set up.Got to say you do have to hold on the steering wheel abit, don`t no if that is normal..Make sure you don`t have 7j rims as you will be limited on tyre sizes.I have a front pair of Pro Race 1.2 with as new falken tyre`s for 160 beer tokens if any one is interested.

Edited by SILICONE KID on Monday 28th March 13:35

[captaintact]

Cheers. I better check the rim size.

[Derek Smith]

captaintact said:

I wonder if PAS helps the general stability? This is my 1st CHIM so i don't know how mine handles compared to others. However it is not a patch on my Alfa 164 or 156! There doesn't seem to be enough "play" in the suspension for normal roads and as such the front end just bounces all over the place.

Just a thought.....i am using the same tyre pressures as the ORIGINAL size tyres. Should they be different for my wider, lower profile ones? The rear feels good and stable.

As tyres are expensive, i want to make a good, informed choice both in size and type when i change them in the next few weeks. The TOYOs seem popular, however is this favouring racing/track days? Does anyone use Continentals/Pirellis/Bridgestones/Uniroyals etc. These are the sorts that are more favoured on "road" cars.

Can I suggest going to a TVRCC meet and having a ride in a normally shod Chim?

I have manual steering with standard 205s on the front. I've driven a manual with 245s and I found it a bit of a pain at low speed but now real difference once under way. If pushing things a bit there is a little initial understeer on my car but not much. I find it a bit reassuring.

Chimaeras give a comfortable ride when normally shod. I've driven for over four hours on non national routes in France and both my wife and I got out of the car feeling quite comfortable. Two hours in my Ginetta at a similar speed would have required a spell in traction.

I've driven a few Chims with various makes of tyres and I'm damned if I can tell any difference at road speeds. Various people swear by various makes for wet grip. There is, unfortunately for you, little in the way of concensus.

[spend]

They were only 205 fronts, till 55 profiles became available. I wouldn't base any selection decision against 205/60/15 fronts rather use the later 215/55/15 or 225/45/16 IMHO.

You've probably got rubbish geometry Daz, wouldn't be the first thing it's taken you many tries to get right would it ~ and there are a lot more variables in the geo depending on ride height, tyres / wheels, chassis pivots for corners & steering.... that have been 'tweaked'. I certainly wouldn't expect any of the published geometry settings to work 'out of the box' due to any of the myriad of changes you have made?

[JR]

spend said:

They were only 205 fronts, till 55 profiles became available. I wouldn't base any selection decision against 205/60/15 fronts rather use the later 215/55/15 or 225/45/16 IMHO.

Except I think that the OP wants to keep his 17" wheels.

[JR]

captaintact said:

205/50/17 FRONT & 225/50/17 REAR

I'd be wary at the front. The bodies vary in: thickness, shape and location on the chassis. Some have found trouble with the larger tyre sizes on the front of the Chim, occasionally rubbing on the battery box. It also depends upon so many other things: ride ht., spring stiffness, dampers, driving style, roads so that there is no universal answer. FWIW with all things being equal I check out 205/45/17f & 235/45/17r; both are about 1%less rolling rad than original. Have you had a chance to check your rim widths?

[SILICONE KID]

I had it setup by a TVR specialist..what i have noticed is the front camber..they seem to go inwards alot at the top of the tyre..Are you saying these cars have zero bump steer when set up properly.(it did improve the steerng going from 17" to 16" front wheels) What i did cure after three years of the suspension banging at the back,turned out to be the rear N/S light pod had come loose and what a job that was...no more rattles..even the bulb holder rattles when clicked in..

Edited by SILICONE KID on Tuesday 29th March 17:01

[spend]

JR said:

Except I think that the OP wants to keep his 17" wheels.

Yes he was using 205/60 as a base datum for evaluating suitable 17".

I didn't feel it necessary to quote verbatim... to sensible readers

[JR]

captaintact said:

JR said:

Originally 205/60/15 and 225/55/16. If you're going to address the ride problem you'll need new springs (and probably dampers) or smaller dia wheels, or all of the aforementioned. Sorry.

Thanks for that. If i keep the same original width (205 & 225) on 17" wheels then that should raise the profile from 40 which should help ride quality? Making sure that overall size remains correct of course.

The change in tyre wall ht will be barely perceptable. In theory on a car what you say would generally be OK but there's not too much room under the wheel arch of the Chim. If your concern is ride quality I'd look at 16" all round. 16"f & 17"r may help with steering & handling but you sit close to the rear axle so it won't help much with ride quality. The only other way is softer springs which may mean new/rebuilt dampers.