any - Thinking of 'upgrading' to a bigger wheel/tyre com - unthrottled

www.caranddriver.com/features/effects-of-upsized-w...d

Interesting reading. Especially for the disciples of the "bigger tyre=bigger contact area=bigger grip" school.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - gordonbennet

Yes it is interesting, notice that the best tyres for grip were slightly larger than standard but not the ridulously large that mean a spray on tyre with almost no sidewall.

I have non standard tyres on my MB, the standard car comes with 15" and suffered severe body roll on cornering, it was almost impossible to find suitable (preferred) 16" wheels so 17's were bought.

The result is a much improved handling and almost no roll, had them on for about the last 8 years and another set of 17" for winter set...suitable tyres carefully researched as always.

The downside is the magic carpet ride isn't any more...and i wouldn't do the same again, i would have found the rare slightly wider wheels as fitted to Sportline versions of my old car, and stuck with a slightly wider slightly lower profile version of the usual 15" wheel and compromised...lesson learned but no regrets.

Another thing which people forget when upsizing is tyre cost...premium 15" tyres are roughly half the cost of premium 17/18's, so people can't afford good tyres when upgrading and end up with el cheapo ditchfinders...which defeats the whole point..unless image and looks is the sole purpose, which i suspect is the case for many....look at online ads for large tyre and wheel packages and some of the tyres i've never heard of.

Edited by gordonbennet on 04/10/2012 at 09:56

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Ed V

I was interested that the noise difference was relatively small - 70 v 71 Dcbs - although the reporter noted a more 'pleasant' noise from the smaller wheels.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - drogers

Rather than spend good money repacing sound original car wheels and tyres with 'bigger' ones that inflate your ego (but no one elses) why not spend the money on bringing your mortgage down ?

And if you havent got a house your buying then surely your priorities are a tad wrong ?????????????

any - Thinking of 'upgrading' to a bigger wheel/tyre com - oldroverboy.

Rather than spend good money repacing sound original car wheels and tyres with 'bigger' ones that inflate your ego (but no one elses) why not spend the money on bringing your mortgage down ?

And if you havent got a house your buying then surely your priorities are a tad wrong ?

Beg to differ. some smaller wheels and tyres DO look out of place on certain cars.

I would actually like some smaller wheels (15") on the cruze as some current model astras have them fitted and it would make the ride a bit better than the 205/60/16s fitted. All those people spending money on their cars are paying 20%vat to hmrc so don't knock it.

And for those prudent enough to have paid down/off their mortgages, well, you have worked for your money, so it is yours to spend. One of my old friends has a 4.0 supercharged s type just for fun, a bmw 3 series petrol auto (work) (does not like diesels) and an audi tt for his other half. he pays to maintain them all, and pays the ved and insurances for them all, and i am certainly not going to knock his pleasures, especially after the amount in income tax he is paying in the first place.

DON'T forget if we all drive zero rated ved cars they'll only find another way to get us. Just be thankful for all those chinese shoppers in london over christmas. And certainly don't forget that someone paying £60,000 for a jag xj or somesuch is contributing £10,000 to the treasury.

Edited by oldroverboy. on 01/01/2013 at 20:00

any - Thinking of 'upgrading' to a bigger wheel/tyre com - gordonbennet

Well said ORB, we by sheer hard work paid the house off way before time and don't owe anyone a bean, therefore that entitles us to spend our hard earned on whatever we want, preferably avoiding the excess greed of the wasteful overbearing nanny state as much as possible in the process such as the £470 VED catchment.

By the way as a general observation being debt free is an incredibly liberating experience, when no one including the govt has any power or hold you can say and do what you like so long as its not illegal, highly recommended.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - RT

Well said ORB, we by sheer hard work paid the house off way before time and don't owe anyone a bean, therefore that entitles us to spend our hard earned on whatever we want, preferably avoiding the excess greed of the wasteful overbearing nanny state as much as possible in the process such as the £470 VED catchment.

By the way as a general observation being debt free is an incredibly liberating experience, when no one including the govt has any power or hold you can say and do what you like so long as its not illegal, highly recommended.

The wonderful feeling of freedom as you pay the mortgage off early is incredible - it's hard work but I recommend it to everyone.

The experience does come second best though when you also aquire enough capital/savings to retire early - if you organise it right then you don't even have to pay any tax - legitimately.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Engineer Andy

1dB increase in noise is equivalent of about 25% greater noise, so quite an increase (3dB increase is just under 2x the noise level) - its a logarithmic scale (see Wikipedia).

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Avant

Many thanks for that, Unthrottled; very interesting and backs up what I'm coming to believe from my own experience.

The standard tyres on my Octavia vRS are Continental 225/40/18: as that article shows, they are fitted mainly for cosmetic reasons. Lower-spec Octavias handle perfectly adequately on 16" wheels.

These tyres are the reason why the vRS is the first FWD car I've had which was no good in snow and thus needs winter tyres. These are 205/55/16 Kleber Quadraxer all-weather tyres on steel wheels and either make no difference or perform better.

I can detect no difference in acceleration or roadholding (the latter might be less precise if I drove the car to its limits). Economy is 2-3 mpg better (I have checked the odometer over a known journey and this is unaffected as the overall diameter of wheels + tyres is much the same). Ride is more comfortable and road noise reduced. And the cost of each tyre (£72) and each steel wheel (£52) combined was less than the cost of a 225/40/18 tyre on its own (£143, as I discovered the hard way after a puncture which Slowfit refused to repair).

I'm not too worried about the look of the thing: the steel wheels are black which looks fine with a white car, and little worse than alloy wheels which soon look grubby and are a pain to wash.

The temptation to leave the Klebers on all year is growing, given that they're all-weather tyres.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - veryoldbear

I suspect they would wear a bit faster.

Edited by veryoldbear on 02/01/2013 at 09:32

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Collos25

Seems like a waste of money to me.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Engineer Andy

I just wish more of the "upmarket" cars were available with (and allowed by insurers and possible at reduced premiums) options for more standard profile tyres, given that most good quality tyre manufacturers produce perfectly good 50-70 profile tyres with not that much compromise on handling unless you take the car to the ragged edge in poor weather conditions.

I must admit I'm a bit perplexed as to why some, such as Honda, Toyota and Lexus (especially) now insist as our German friends do to only having bling-bling 18in rims as a minimum on their "executive" saloons and GT cars (the Toyota GT86 being the exception) - I thought the whole point of such cars was to have a decent amount of poke when getting away at the lights/overtaking but to have a decent (long-term) ride quality, unlike most upper-market cars which have bone-jarring ride quality these days (barely better than the Flintstones' "car"!).

Friends of mine who own Audis, BMWs etc have said they're ok for about the first 6 months to a year, then the ride starts really firming up (even if they replace the tyres (at huge expense). The amount of back problems that modern firm-riding cars (with ultra-low profile tyres as standard/minimum) must be costing the country (except osteopaths, etc) a fortune in days lost when people are off sick.

I've driven the model down from my Mazda 3 TS2 (on std 205/55/R16's) and there's no discernable difference on its 15in rims/tyres to grip, and possibly slightly better comfort due to there being more of an air cushion between you and the road.

I bet this is all down to (in my view - I have no proof) the car and tyre manufacturers conspiring to fleece us of more money to change the shorter-lasting low-profile tyres more often at greater expense to offset reductions in sales of cars generally and the "consumer backlash" price reductions in the early 2000s (when UK prices came down hugely when prople started buying the same models cheaper from the continent).

any - Thinking of 'upgrading' to a bigger wheel/tyre com - unthrottled

I must admit I'm a bit perplexed as to why some, such as Honda, Toyota and Lexus (especially) now insist as our German friends do to only having bling-bling 18in rims as a minimum on their "executive" saloons and GT car

People like the look. If you don't pander to what your customers think they want, you don't sell cars. Honda and Toyota have seen their market share in the UK fall fairly dramatically. They've learned their lesson.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - veryoldbear

Nowt so daft as folk.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Engineer Andy

I must admit I'm a bit perplexed as to why some, such as Honda, Toyota and Lexus (especially) now insist as our German friends do to only having bling-bling 18in rims as a minimum on their "executive" saloons and GT car

People like the look. If you don't pander to what your customers think they want, you don't sell cars. Honda and Toyota have seen their market share in the UK fall fairly dramatically. They've learned their lesson.

People like the "look" for about 6 months, then hate the "feel". To be honest I think its as much about media hype about the "need" for low profile tyres as people "demanding" them (mostly young men [who can't afford expensive beemeres anyway] and men between 45-60 who'd rather get a pimped up German car than sports bike to pretend they have a large willy). From talking to colleagues and family members over 60, they'd rather have something with a bit of poke but is comfortable, long-lasting and not cost the earth too run, but with being too showy.

Honda and Toyota used to be able to attract the "more mature" audience (Corolla, Avensis and standard Civic & Accord) - the same for Lexus, with Honda and Toyota also attracting the "boy racer" with the Civic Type R 1st Gen (not the rubbish 2nd Gen) and the Celica/MR2 - now the GT86 is back but it costs £25k (the Civic Type R 1st Gen only cost £16k in 2005). Somehow I doubt if you actually asked the majority of Honda, Toyota and Lexus owners they would say that they wanted low profile (hard riding) tyres - only the boy racers who now only account for a tiny fraction of their sales.

I would like an more "upmarket" car with the cruise control, sat nav, etc, but always I find they have 17in rim at least, when I would prefer 16's or 15's, so I could get a better ride (as well as not having to shell out £450 every few years for a set of tyres and lots of money on back treatment) - most of the time nowadays you can only get luxury WITH sports packages, when in the past you could mix 'n' match.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - countryroads

I went from 16s to 18s on my A4 and I love it, I also have aftermarket lowered and uprated suspension on it too. Rides the same if not better than factory 'Sport' suspension due to progressive springing and better damper rates and of course looks great. I am all for it frankly, if its what people want from their car then dont knock it, better than undermaintained sheds rocking around! There is a reason why I drive a tastefully improved bright green Audi rather than a doom blue or mineshaft grey diesel Focus et al....but as I will always maintain, each to their own, do not judge lest ye etc etc.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - unthrottled

due to progressive springing and better damper rates

Springs are pretty much beaten by compressed air when it comes to progressiveness. No problems with spring harmonics, stress corrosion cracking or, coil binding, or fatigue. 4.5" of tyre sidewall thickness has more shock absorbtion than 3.5". Moreover, the jolts are absorbed by the tyre rather than being transmitted to the suspension. Add in reduced rotational inertia and unsprung weight and the case for high aspect ratiotyres is compelling. Greater resistence to aquaplaning (assuming narrower width), and improved ability in snow are further benefits.

I'm glad you're pleased with the set-up but the stack is very much piled in favour of pram wheels!

any - Thinking of 'upgrading' to a bigger wheel/tyre com - countryroads

Of course thats all true, but get into different brands of tyre within the same size and they will react differently too due to sidewall construction, weight of the case in relation to unsprung weight etc. I want the suspension to do the majority of work springing the car, not the tyres, thats why old Jags etc are actually pretty pants on rough roads, the suspension isnt absorbing and damping the jolts, its so soft because the baloon tyres at 26psi are, and their movement is somewhat unregulated.

I run 225 40 18 instead of 205 55 16, the sidewall difference is only 2.2cm with brand new tyres.

I know they are 'experts' but if the car feels better, grips better, stops and rides better..not on track or a totally smooth skidpan but on the road, then surely it is?

My 1989 Camry has 185 70 14s, now thats a sidewall....its rubbish compared to the Audi in ride and handling, both FWD medium saloons...is it the tyres or the car?

any - Thinking of 'upgrading' to a bigger wheel/tyre com - Avant

"I run 225 40 18 instead of 205 55 16...."

That's the exact opposite to the fitting of the all-weather tyres on mine - clearly these things will vary from car to car.

I would imagine that the Camry was designed as a softly-suspended cruiser; I'm surprised you say that ride, as well as handling, is rubbish.

any - Thinking of 'upgrading' to a bigger wheel/tyre com - countryroads

Its rubbish in the same way my dads xj6 is rubbish, rolling smoothness is good, as is low frequency ride, speedbumps etc, however high frequency/rapid impacts to the wheels not great, the damping isnt up to it, soft springs, soft dampers and soft, tall tyres that exaggerate it cant react quickly enough and it creates a pitching and rolling, wobbly sensation that doesnt inspire confidence. Im not saying they are worn out, you have to imagine the sensation rather than a comical movement of the car!

Motorway expansion joints are a good one, the Audi glides because the suspension and wheel set up is tuned to the weight of the car and all movement is well regulated, proven because you can hear but not feel them at all. The soft cars with big tyres I find less impressive, creating actually more body movement and less body control. However I prefer a fimer more controlled ride, other people like to float, its personal choice and im never going to argue with anyone who fits taller tyres to their car. Suspension tuning and matching of components can however yield good/better results, elimating undamped movement, ie tyre jounce is a part of that.