MikeCapon
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| posted on 19/12/11 at 01:00 PM |
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Big wheels, wide tyres. Are we being had over?
I just fitted a set of snow tyres on our old (04, 200,000km) A6.
As the 'standard' 235/45 X 17 are horrific prices I got a second hand set of 195/65 X 15 steel rims and Michelin snow tyres for 200€ or
about £180 in real money.
I drove the car for the first time yesterday with the snow tyres fitted and it is a revelation. Lighter steering but you can still feel perfectly
what's going on. A delicate and precise turn-in without the clumsy feel of the bigger wheel/tyre combo. Miles more comfortable. So much nicer to
drive it is hard to believe.
And half the price....
I reckon the only things the bigger rim/tyre is good at is looking nice and just perhaps more grip on the limit. Given that I do not race the car (far
from it, it gets driven to get the most kms/litre and not wear out pads and tyres) I'm inclined to stick a set of 15" summer tyres on at
the end of the winter.
So why do we all want big rims and wide tyres? Or am I the only one?
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scootz
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| posted on 19/12/11 at 01:10 PM |
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I reckon most folk don't realise there's a direct correlation between wheel / tyre size and handling / efficiency Mike.
They're happy so long as it looks 'cool'!
It's Evolution Baby!
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mcerd1
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| posted on 19/12/11 at 01:19 PM |
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^^ what scott said
I don't want big wide rims.... at least not on the boring everyday tin-top 
mine's only got 195/60R15's and they seem fine with both winter and summer tyres
(although I can't help thinking a slightly lower profile would make the steering feel a bit sharper - but then I remember its only a crappy
little hatchback  )
my boss got himself an RS5, its got 'huge' big alloys with a few mm ofrubber stuck on round the outside - not cheap 
and I bet it'll be interesting in the snow (he doesn't beleve in winter tyres either!)
for the dax I went for big wide back wheels 'cause they look cool' 
but later I think I'll get a set of narrower track day tyres aswell
[Edited on 19/12/2011 by mcerd1]
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v8kid
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| posted on 19/12/11 at 01:32 PM |
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Yup I've had similar experiences.
I reckon its all marketing hype and we fall for it when we go in the showroom and see that shiny...Hmmmmmmm Oh YES!!!
What were you saying?
Cheers!
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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whitestu
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| posted on 19/12/11 at 01:45 PM |
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I put some new 165/70s on our old Toyota the other day - it steers, grips and rides perfectly well, so no need for anything bigger.
My old Citoren GSA had 145/15s and had plenty of grip. In fact it was up there with my old Alfasud [165/70/13s] as one of the best handling cars
I've ever driven,
Stu
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r1_pete
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| posted on 19/12/11 at 02:10 PM |
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I remember building a sebring rep MGB in th elate 70s, had 8 x 15 wheels on the back, were considered massive at the side of the 4.5 x 13 / 14 which
was the norm.
Mrs' Lexus has 7.5 x 17 now, with 225 45 tyres, and look small at the side of some even later cars.
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zilspeed
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| posted on 19/12/11 at 02:27 PM |
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We're being had over.
Mostly.
I'm cynical enough to always have believed this.
That's why our Passat has very modestly sized 16" wheels with 215/55 tyres.
They can easily be had for £55 for Kumhos.
Wife's Ibiza has (quite deliberately) 175/70 x 13s.
Tyres are two bob a corner.
Bloke at work has an Insignia with 255/40 x 18s on it.
£190 a corner for the Contis he insists on fitting.
I said to him, fit Kumho / Falken, you'll save a packet and probably won't die.
Was having none of it.
Yes, we are being had over, but by and large we're lapping it up.
With the exception of those of us (see above) who are having none of it.
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Neville Jones
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| posted on 19/12/11 at 05:33 PM |
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There's no car on the road as an every day driver, that needs tyres with less than a 65% profile.
The only reason mfrs install big bling wheels is as a selling point. Looks.
Just look at how much clearance most cars with big wheels have around the brakes. Most could drop 2" of rim diameter, then take it up with
higher sidewall profiles, to the drivers and publics benefit.
Cheers,
Nev.
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coyoteboy
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| posted on 19/12/11 at 06:43 PM |
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My first car was a pug 205, it came with IIRC, 145 70 13. I switched out to the usual 1.6GTI wheels with IIRC 185 50 15's and the level of grip
improvement and improved turn-in and steering response was quite remarkable. As with everything, I guess there's diminishing returns, the car
tramlined more and was worse in snow. No way in hell I'd go back to narrower high profile tyres to be honest, but there's a happy
medium.
[Edited on 19/12/11 by coyoteboy]
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coyoteboy
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| posted on 20/12/11 at 01:35 AM |
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Also interesting that the Caparo T1 runs 18/19" rims on super low profile tyres (bucking the common trend of 13's on here for a light
weight high power car.
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Pezza
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| posted on 20/12/11 at 06:53 AM |
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And of course the T1 isn't built at all with asthetics in mind.
You don't see formula 1 cars running stupid low profile tyres do you?
You couldn't pwn your way out of a wet paper bag, with "PWN ME!!" written on it, from the "pwned take-away" which originally contained one
portion of chicken tikka pwnsala and the obligatory free pwnpadom.
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Ninehigh
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| posted on 20/12/11 at 07:04 AM |
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quote:
Originally posted by Pezza
And of course the T1 isn't built at all with asthetics in mind.
You don't see formula 1 cars running stupid low profile tyres do you?
Exactly, there's your argument. If they don't do it in F1...
Then again I've found little difference, however I'd rather be driving the 106 (155/70/13) in snow than the mondeo (215/65/16)
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mcerd1
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| posted on 20/12/11 at 08:21 AM |
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quote:
Originally posted by Ninehigh
Then again I've found little difference, however I'd rather be driving the 106 (155/70/13) in snow than the mondeo (215/65/16)
my 106 was geat fun in the snow (145/70R13)....
.....but I think alot of that was due to the fact it weighed next to nothing (760kg) aswell as the supper skinny tyres
[Edited on 20/12/2011 by mcerd1]
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coyoteboy
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| posted on 20/12/11 at 08:25 AM |
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quote:
And of course the T1 isn't built at all with asthetics in mind. You don't see formula 1 cars running stupid low profile tyres do you?
Of course it was built with them in mind, but considering they're a team of ex-mclaren engineers who built it with extreme performance in mind
you'd think they'd at least have compromised only a little (15s, maybe 16s) considering their fairly high budget and ability to test. I
highly doubt they took the decision at the start of the design process to scupper the performance of their car by insisting on big rims to bling up
their car. And considering F1 folk are restricted to 13s by the rules...
I'm not saying it's ideal for a sunday shopper, mind.
[Edited on 20/12/11 by coyoteboy]
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alistairolsen
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| posted on 15/3/12 at 08:04 PM |
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All down to styling and selling cars on an image. Theres an Audi TT on 16 inch steels by my work because hes fitted winter tyres. perfectly sensible
move, but it looks horrible.
I agree though, I changed the wheels on my bora from 195/65 15 to 205/55 16 but decided against going to whole hog to 215/45 17 which is the next oe
size on the basis of tyre cost and the odds on knackering one in a pothole. The reasons for upsizing were availability of decent branded tyres and
looks, thats all.
My Build Thread
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coyoteboy
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| posted on 15/3/12 at 08:30 PM |
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I still don't quite agree it's that simple to be honest. The more I read on the subject the more I can see that, like anything in a car,
it's a compromise. It's certainly not "smallest wheel is best, for everything".
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MikeRJ
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| posted on 15/3/12 at 09:56 PM |
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quote:
Originally posted by coyoteboy
I still don't quite agree it's that simple to be honest. The more I read on the subject the more I can see that, like anything in a car,
it's a compromise. It's certainly not "smallest wheel is best, for everything".
Styling and brake size are the only reasons I can think of for using monster wheels on roads cars.
When it comes to unsprung weight and moment of inertia I can't imagine when more would be better. Lower profile tyres always reduce ride
comfort, make the car more susceptible to road imperfections and increase the chance of tyre and rim damage.
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vanepico
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| posted on 15/3/12 at 11:22 PM |
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I can't comment on car handling, only car I've driven to it's handling limits is a 1.7 diesel mercedes A class! From what I read in
the Chris Gibbs book, they are the laughing stock of everyone else!
Managed to go round a 240 degree corner at ~50mph
It was great fun doing handbrake turns in the snow, purely to gauge how the car reacted in icy conditions of course, to further improve my ice driving
capabilities
I am looking forward to trying rear wheel drive cars as I've heard they handle better.
To be honest I think wide thin wheels are stupid, there is a reason they evolved to have large sidewalls! Especially with all the pot holes in the UK!
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phelpsa
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| posted on 15/3/12 at 11:23 PM |
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The main reason for not using soft sidewalled, high profile tyres is that they are an undamped spring with a low natural frequency. That isn't a
brilliant scenario in terms of contact patch load fluctuations.
You will find with track tyres they are high profile but also generally very stiff. If you compare it to a coil spring, it means there is much less
chance of it going coil bound which would cause a very sudden load fluctuation and therefore sudden loss of grip.
The combination of sidewall height and stiffness should be defined by how good the suspension is at filtering high frequencies. In general, road car
suspension is pretty crap due to the amount of friction in the system and high COG, hence your average car will ride better on tyres that filter the
high frequencies better (generally soft sidewalls, which require extra height to stop them bottoming). However with a car with suspension that can
filter out all frequencies you couldn't tell the difference!
[Edited on 15-3-12 by phelpsa]
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coyoteboy
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| posted on 15/3/12 at 11:57 PM |
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Of course pushing the size to stupid levels will degrade the performance, but suggesting lower profile wider wheels are always bad is pushing it a bit
far. It's not impossible, for example, to get lightweight alloys that make a 17" tyre/rim combo have similar rotational inertia to a
15" or 16" with a cheapo/normal rim. Stiffer carcass means more responsive to steering input and more sensitive to suspension misalignment
but springy deep carcass means flex, tread roll and deformed contact patch under extreme loads? I need to read some more to be fair, im still not
entirely self convinced but there are plenty of low profile tyres used on road rally vechicles:
Clearly not open-wheel type sports cars but WRC cars are generally fairly light weight, high power and will do whatever it takes to get max grip on
any particular stage. On road/tarmac stages they generally run fairly wide, low pro tyres (similar to the road spec versions). When they need more
sidewall compliance and a narrower contact patch to dig into softer conditions they happily drop rim sizes by 2 or 3 inches and use appropriate tyres,
so it's nothing whatsoever to do with styling. Formula vehicles all tend to run a specified tyre size, so they're not really comparable.
And you can't really compare to vehicles with total rolling diameter variability as that brings in significant contact patch shape changes
too.
Complex subject, as I say I'm just not convinced the whole world has it wrong and "we've" got it right, quite frankly.
I'm not saying it's always right to run max width, low profile tyres on all vehicles, but I don't think the other extreme makes
sense either unless you're driving an under-powered vehicle with poor suspension design on dirt tracks.
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mcerd1
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| posted on 16/3/12 at 09:29 AM |
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^^ there is never going to be a 'perfect' tyre whatever you want to achive with it
as phelpsa says the low profile ones do have some good points
if you go to the levels of the WRC they don't worry about driver comfort much for a start, but they also have massive budgets to reduce the
compromises...
I've got a tarmac stage wheel from a mk1 WRC focus in the garage (5 spoke oz racing one) its 9"x18" but magnesium so weighs less
than my tintop's wheels which is a bog standard mk1 focus (6"x15" alloys)
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