Is there any reason that I shouldn't have the back of the car wider then the front?
I want to fit 225s on 8 rims on the back, but just 205's on 7 inch rims on the front, and I want the rears as wide as possible to give me a
decent footprint.
Thoughts appreciated....
That practically my setup (except I've got 245/35 on the rear) and it handles beautifully
I think people get a bit carried on this site when it comes to handling, lets face it these cars are really low with great suspension systems compared to you average car. They are always going to handle well, unless someone does something really extreme like bike tyres on the front and balloons on the back. Slight differences in tyre size ain't going to make the slightest difference. More important is the quality of the tyres when it comes to grip. IMOP
One of my worries is overtyre-ing, don't want to be sliding around in the wet too much...
In my previous seven (a VM) I used to have 235/16/35 on the back and 205/16/40 on the front. This was what the factory was running on their
demonstrator (german company).
Looked good and drove good on good dry roads. It was tramlining like hell on bad roads and it really scared me in wet conditions.
Now I have 185/15/60 on the front and 205/15/55 on the back. I find this gives traction enough (Yokohama A048) for my 200bhp seven.
For a seven I would always go with the smallest diameter wheel you can have (my previous 13"did't give me enough clearance unless I went for
a bad setup), relatively high tyrewalls and when in doubt; go smaller!
Offcourse from the looks perspective it is a matter of taste. I actually like a seven with 13" wheels and highwall tyres. The current owner of my
old seven went and installed some 18" rims on 25 section tyres.......
Ahh yes, but mine iisn't a Seven 
yip for yours roller skate wheels should do fine
quote:
Originally posted by Jasper
One of my worries is overtyre-ing, don't want to be sliding around in the wet too much...
I have 235/40 x17 on the back, and 205/40 x 17 on the front.
I dont bother with a spare, (Spare is a can of puncture seal).
In Hindsight I should have gone 245 or even 265 on the rear...
I just cant get all the power onto the tarmac, in the dry.
Sod the Wet... it stays in the garage for that weather.
Been out when its a bit greasy on the road, ie not really wet, and its a bloody handful if you are silly with the right foot.
Stilll thats half the fun of a rear wheel drive V8 weighing in at approx 700Kgs.
I have 235/45/17's on the tin top and in the wet it's drift city. Hmm fun. As mentioned find me a set of tyres that can cope with 300bhp
RWD set up AND rain and I'd buy a set!
Mike
265/30/18 rear, handles like its on rails...
Handling and (roadholding) grip are two different things, handling is what you find out about when the grip runs out You want something that you
can catch when the grip runs out or you'll be claiming off the insurance.
With those wide rear tyres; what kind of pressure are you running?
My 205's at the rear run only at 14psi (when cold). Any higher and I can't get the heat evenly distributed.
With 40 series tyres the sidewalls must be very stiff or am I wrong in this? How can you make the middle of the tyre carry any weight?
This gave me problems with my last seven (toyo proxes; 235/35 16). I needed at least 22 psi to avoid the tire getting 'wobly' during
cornering. Then again I was only running 150bhp).
How do you guys do that?
ooohhhh this is so amusing!!!!!!!!!
I know of cars in autograss weighing 500or so kg, running 195mm wide tyres, putting down 500hp onto MUD, without issue.
I think this statement says a lot:
"265/30/18 rear, handles like its on rails...
"
30 profile tyres on a 7 will give launch (and bumpy road) grip akin to soap on lino.
There are a few on here that seem to understand how tyres work, and an awful lot that don't.
May I suggest looking at your suspension BEFORE looking at tyres, and using the HIGHEST profile, lightest tyre that you can find in a 185, 195 or 205
width. You don;t need any wider than that on a 500-600kg car, physics prevents use of more rubber than that, have a think first and you may see!
quote:
Originally posted by miegru
With those wide rear tyres; what kind of pressure are you running?
My 205's at the rear run only at 14psi (when cold). Any higher and I can't get the heat evenly distributed.
With 40 series tyres the sidewalls must be very stiff or am I wrong in this? How can you make the middle of the tyre carry any weight?
This gave me problems with my last seven (toyo proxes; 235/35 16). I needed at least 22 psi to avoid the tire getting 'wobly' during cornering. Then again I was only running 150bhp).
How do you guys do that?
Thought I might have stirred one up here......
So answer me this one then, I followed a CSi Caterham around damp alpine roads for a week and it ran 245 rears (Avon CR500) and never missed a beat,
it looked absolutely planted. The only time it got loose was a last minute complete lock-up headed into a hairpin (luckily there was an open gate and
a filed )
I was originally gonna fit the same tyres on mine (similar power/weight) but I thought I'd go a size down....
been looking at this car for some time, thinking to myself - damn that could do with some wide tyres!!!
Rescued attachment sidewaysA.jpg
quote:
Originally posted by Peteff
Handling and (roadholding) grip are two different things, handling is what you find out about when the grip runs out
quote:
Originally posted by miegru
With those wide rear tyres; what kind of pressure are you running?
My 205's at the rear run only at 14psi (when cold). Any higher and I can't get the heat evenly distributed.
With 40 series tyres the sidewalls must be very stiff or am I wrong in this? How can you make the middle of the tyre carry any weight?
This gave me problems with my last seven (toyo proxes; 235/35 16). I needed at least 22 psi to avoid the tire getting 'wobly' during cornering. Then again I was only running 150bhp).
How do you guys do that?
quote:
Originally posted by Peteff
Handling and (roadholding) grip are two different things, handling is what you find out about when the grip runs out
When I chose my tyres I took advice from Polley Motorsport where I bought the wheels and tyres. The discussion:
Me: What is the best tyre for a seven of 500kg and 200bhp?
- A good driver will be faster on any tyre than a shitty driver on perfect tyres. What are you?
Me: a novice. Some brains, less balls and no talent and a lot of ambition.
- Go with a tyre that gives you good feedback and is smooth around the edge of its grip: not too wide and as high a side as possible.
The I saw that price difference and it was an easy choice. I am happy with it.
I am very much with NS Dev & Peteff on this I have driven more than a few cars spoilt by tyres that were too wide and too low a profile.
quote:
Originally posted by miegru
snip
- A good driver will be faster on any tyre than a shitty driver on perfect tyres.
snip
quote:
Originally posted by NS Dev
sorry for this and who it may insult, but you have hit the nail on the head!!
You are actually driving your car, not pansying around in it, that's the difference!!!
You are exactly right, a 7 type car with low profile tyres will not handle, for exactly the reasons you say.
I'd hazard a guess that a tyre temp gun has not been near the tyres of those talking about 30 and 40 profile tyres!!!
Wish I could get close to 15k miles on my ZT
I have (alledgedly) posey 17" wheels on my car and as far as I'm concerned, they're fine. My car isn't the lightest by any stretch
of the imagination so maybe that counts for something. And they were only a 100 quid
Given the conjested nature of our roads and the fact that actually doing more than 40 mph for more than about a minute is fairly unlikely, I think you
need to bear that in mind. If you live in a fairly remote part of the country, or live for trackdays then it's probably a different matter.
ATB
Simon
quote:
Originally posted by Jasper
Thought I might have stirred one up here......
So answer me this one then, I followed a CSi Caterham around damp alpine roads for a week and it ran 245 rears (Avon CR500) and never missed a beat, it looked absolutely planted. The only time it got loose was a last minute complete lock-up headed into a hairpin (luckily there was an open gate and a filed
I was originally gonna fit the same tyres on mine (similar power/weight) but I thought I'd go a size down....
Chris,
While I don't don't the math, surely with a lower profile a lower pressure could be used, so how would that affect footprint?
ATB
Simon
Bling
For a hundred quid, I'd have used 10" minilights
I got 17" though
I reckon my car is heavier than quite a lot of others.
ATB
Simon
Im not sure I get where the idea that a tire can be too wide in the dry comes from.
If we are talking racing compounds, the wider tire runs cooler, allows you to run a softer compound, and increases contact patch (when I measured
this a 3" wider tire gained 6.2 square inches). Also if you lower the pressure (which you can and usually should) it will increase the contact
patch further.
If you run the same compound and go to a wider tire then yes, your stiction would be reduced, but why would you do that?
If you have the correct rims to match the wider tires you will not get any poor wear once you are dialed in. Far as I am concerned until it gets too
heavy, there is no such thing as too wide of a tire in the dry. If you aren't getting the heat into it, GREAT! Then run a softer compound, but
don't run skinnier tires.
The lousy thing about tire theory, is even if you know all the logic (I don't), you still do not have anything to go on unless you can convinve
the tire company to release their specs to you. Good luck with that .
Cheers.
i totaly agree C10CoryM
i have run both 235 and 265 on my car and the 265 were a massive improvement, but i only use my car in summer.. and we aint talkin cheap tyres in
either size.. all i can say .. is dont knock it till u tried it...