Hey WOW... another tyre size question !
Discussion
Yup apologies... have tried a few searches & local dealer... just not sure I've got the definitive answer yet.
Q: 225/50/15 or 205/55/15 (front) on a 96 PAS 500 ?
Currently its got completely the wrong tyre fitted (havent changed them since I bought the car - that's how hard they are), and since I've got no work to do I like to cheer myself by spending dosh on the 500.
Ed
Q: 225/50/15 or 205/55/15 (front) on a 96 PAS 500 ?
Currently its got completely the wrong tyre fitted (havent changed them since I bought the car - that's how hard they are), and since I've got no work to do I like to cheer myself by spending dosh on the 500.
Ed
EdT said:
Both will fit, 225 would have been standard, IMO 205 is a more appropriate size and will perform better.
Peter.. can you explain further if you wouldnt mind ?
Ed
It's all to do with the shape of the sidewalls. If the tread is wider than the rim, the sidewalls taper in to the rim. Looking at it in cross section, you can see that as the contact patch is pushed sideways relative to the rim, the tyre twists and tends to pick up the inside edge of the contact patch. This distorts the contact patch and loses grip.
Although you can stretch wide tyres onto much narrower rims, really you never want the rim narrower than the contact patch. It is normal to quote roadgoing tyre widths as the width at the widest point on the recommended rims. This is typically about an inch wider than the contact patch. So the rule of thumb for typical tyre sizes and profiles is, the nominal tyre width should be no more than about 1" wider than the rim.
Sometimes, putting relatively narrow tyres on much wider rims works very well indeed. This time the twist works in your favour as it picks up the outside of the contact patch. Body roll will normally cause the wheel to lean outward and put more weight on the outside of the contact patch, so the twist helps counteract this effect.
Hope this makes sense!
Cheers,
Peter Humphries (and a green V8S)
Hi Ed
Original fit 225/50 ZR15 SO2's on the front of mine (98S 500 with power.)
Now have SO3's on the back, can't tell any difference from SO2's... An earlier thread saying problems with SO3's, I believe turned out to be with non-standard 17inch wheels compared to the rear 16 inch wheels. Something to do with side wall stiffness,etc.
B
>> Edited by bjwoods on Tuesday 26th August 20:48
Original fit 225/50 ZR15 SO2's on the front of mine (98S 500 with power.)
Now have SO3's on the back, can't tell any difference from SO2's... An earlier thread saying problems with SO3's, I believe turned out to be with non-standard 17inch wheels compared to the rear 16 inch wheels. Something to do with side wall stiffness,etc.
B
>> Edited by bjwoods on Tuesday 26th August 20:48
225s on the front should give you better straight line braking in the dry, cornering improvement with standard rims is dubious. Although 225s on the front will give little if any aggregate gain you must wonder about creating oversteer in the wet if you fit 205s at the front and 245s at the rear.
It's the ratio. If 225 and 245 is balanced then a 205 with a 245 will give more grip at the front in the wet and give rise to oversteer tendancies. I don't know how much of a problem this is, as I said before I was just wondering. GreenV8S sometimes suggests 205/225 I think which would seem to be more logical for the standard rims.
19560 said:Oh I see, well I doubt Blackpool were particularly worried about balance either way the tail swings out at the least provocation
It's the ratio. If 225 and 245 is balanced then a 205 with a 245 will give more grip at the front in the wet and give rise to oversteer tendancies.
Rich... RichB said:
It's the ratio. If 225 and 245 is balanced then a 205 with a 245 will give more grip at the front in the wet and give rise to oversteer tendancies.
Oh I see, well I doubt Blackpool were particularly worried about balance either way the tail swings out at the least provocation
Tried most combinations on the Griff over the years and the best does seem to be the 225/245 combination. 205/215 Front don't have the grip or turn in and are several miles an hour slower on a track when pushed irrespective of the conditions. The rears are probably less fussy because the car is well overpowered anyway but the 245 does have an edge.
Biggest factor is the initial driver-accelerator linkage system. Has a terrible habit of becoming a digital...
My car was originaly non pas,& was converted as part of the purchase price. It therefore had 205/55/15 fronts when I first got it & at the first replacement set of fronts (S03's, couldn't get 225's at the time), the last new set of boots I put on were 225/50/15 S03's.
The 225/50's have a lot more grip on track & do give a more balance feel to the car, but on the road the 205's were much nicer with a lot less tramlining & much better steering feel. When you compare the way the 2 sizes look on the wheels, the 225's seem to 'balloon' the sidewalls out a bit - my theory is that the extra flex here causes the increased tramlining & reduces the steering feel.
The 225/50's have a lot more grip on track & do give a more balance feel to the car, but on the road the 205's were much nicer with a lot less tramlining & much better steering feel. When you compare the way the 2 sizes look on the wheels, the 225's seem to 'balloon' the sidewalls out a bit - my theory is that the extra flex here causes the increased tramlining & reduces the steering feel.
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