I am thinking of upgrading the wheels of my car from 15'' pressed steel to 16'' alloys (manufacturers genuine parts).
Can I expect any improvements in terms of ride and handling? I know they will lower the unsprung mass of the car and the wider tyres should offer more grip but will the differences be noticeable in normal conditions?
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Any change will be due to the change in the tyre.
>>I know they will lower the unsprung mass
That's extremely unlikely.
Enjoy the look of the alloys, but don't kid yourself that they're a performance improver!
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The ride will probably be poorer, the handling may feel slightly different, replacement tyres will normally be more expensive.
Undeniable though that they will usually look much nicer providing you wash them regularly especially in the winter, and don't allow the muck to get ingrained, if i miss a week or so i can tell.
Beware which tyres the dealer will supply though, one dealer i go to regularly does tyre and wheel combo's, the tyres are often cheap and tacky, they would not be an improvement in any way, the original tyres fitted to the car will usually be decent stuff.
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Probably worse. In my experience, smaller wheels are overall better at everything apart from looks.
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They are more expensive, the ride on bigger rims will be harsher, the tyres will cost more, the grip will be better but not necessarily the handling so no point unless you are going racing.
Plus: quite a lot of tyre fitters in my past experience use the same rough equipment on alloys that they use on steel wheels and damage them, scraping the edge of the rim and removing the protective lacquer. I have even known them to hammer crimp-on balancing weights onto the rims of alloys as if they were steel.
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The bigger the tyre, the lower the profile, and they tend to "tramline" more.
Alos, as pointed out, kerbing them becomes an expensive party.
Off on a tangent, some of the 'mags' I see round these days cannot possibly help the performance - I'm sure with all the bling and fake allen-key heads etc, plus the Bodaciea-type central spinners, they probably weigh twice as much as an equivalent size steel wheel!
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I have even known them to hammer crimp-on balancing weights onto the rims of alloys as if they were steel.
Depending on the shape of the edge of the rim, alloy wheels need either (a) special shaped weights to suit the profile of the edge of the rim, or (b) self adhesive weights when the edge of the rim isn't intended for knock-on weights.
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Don't confuse cheap & heavy production alloys with the magnesium alloy ones fitted to racing/rally cars.
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Alloy wheels will give rise to less vibration problems than steel because they have greater dimensional accuracy. The rims have better roundness, better concentricity i.e less radial runout, and less axial runout.
Alloy wheels also generally don't have wheel trims which have a habit of flying off.
No contest.
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And are more easily buckled,damaged they go pourous and leak.And given that they have greater dimensional accuracy why are they more difficult to ballance having said all that they can look nice.
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Aaah...
But we've overlooked the BIG thing in the OP's post... that he is going for the manufacturer's wheels.
No half-decent manufacturer, unless deliberately appealing to pimps and rap stars, is going to fit chromed 20" alloys.
Most of the time, factory-fitted are very tasteful, and a marked improvement on steels.
It is when the boy racers fit 17" shiny thin-spoke alloys to their 1.1-engined noddy cars, brilliantly displaying the rusty rear brake drum, that things start getting silly!
Oh, and by the way sonny, that 215 tyre looks silly, increases rolling resistance, and is a surefire recipe to roll the car if you start going sideways!
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As you are going up a size then the profile of the tyre will be lower and may be noticeable in terms of ride. The car is liable to be more steady on its feet and a touch heavier on the sterring when stationary. Your insurance may up your premium as the car is more attractive to nick or they will exclude the allows from any claim. Regards Peter
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And are more easily buckled damaged they go pourous and leak.And given that they have greater dimensional accuracy why are they more difficult to ballance ...
I've had alloy wheels exclusively on 8 cars for the past 22 years. I've never buckled one, although I do admit to having damaged the rim of one when I slid off the road and over the kerb on a snow-covered road. The impact would have damaged any wheel, alloy or steel. The wheel wasn't buckled but I had a new wheel and tyre just as a precaution. I've never had one go porous or leak, and I've never had any problems geting them balanced. I've always had self-adhesive balance on the inside of the wheel, and I've never had one fly off.
I certainly wouldn't go back to steel wheels.
Edited by L'escargot on 27/10/2008 at 10:05
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>and are more easily buckled,damaged they go pourous and leak<
Damaged, maybe; leak (round the bead), definitely, older ones anyway. But I shall continue to disbelieve the tale that alloys become porous, until someone can persuade me of some mechanism how that happens. My 19-y-o GTi has its original alloys - only one of them loses any pressure (about 1psi a week) and I am 99% sure that is bead leakage due to slight corrosion.
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But I shall continue to disbelieve the tale that alloys become porous until someone can persuade me of some mechanism how that happens.
It's not unknown for alloy components to be porous, when external machining cuts through internal blow-holes. However, it's also common for alloy components which need to be leak-proof to be resin impregnated after machining to minimise the risk of leakage. It's possible that alloy wheels are pressure tested as part of the quality control process before they leave the manufacturer, but I couldn't be categoric about that.
Edited by L'escargot on 27/10/2008 at 12:51
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>It's not unknown for alloy components to be porous, when external machining cuts through internal blow-holes. <
Yes, I accept that; what I was querying is the notion that alloys become porous, as distinct from starting out porous?
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.......what I was querying is the notion that alloys become porous as distinct from starting out porous?
I suppose it's possible in rare instances for the resin impregnation to fail.
Edited by L'escargot on 28/10/2008 at 07:54
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For many years I had an Audi 100 with silver plastic wheel trims - dead easy to clean and always looked good.
For years I have had an A6 with alloy wheels. They're a pain to keep clean and at 10yrs old look worse for wear than my old Audi's did at 13yrs old.
Give me easy-clean trims/steel wheels any day.
[this is a bit like the pressed steel v. spokes argument 50+ yrs ago]
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To keep the same diameter for the wheel, the 16" alloy will need lower profile tyres which will make the ride firmer. And I would not think handling will change (maybe changing other items would make a difference) but grip could improve with wider tyres.
I would also agree that insurance likely to increase with this modification - and you do need to tell them of this modification. I knew someone who changes the wheels on his Audi A6 for a different design of the same size - he fell foul when involved in an accident.
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I did the same thing - 15" steel wheels with 195/60 tyres were replaced with 16" OE alloys with 205/50 tyres. Sizes were as recommended in manufacturers handbook.
Its 4+ years ago now so my memory of the comparison is fading, but:
- Steering feel improved with a crisper turn-in, less "wooliness".
- Grip improved, better braking.
- AFAIR ride was not adversely affected to a noticeable degree.
They look better, I was able to dispense with the awful plastic wheel trims. Insurance premium didnt increase, "Its not an issue, we'll just make a note of it."
The old tyres were Pirelli P6000s, the new ones Michelin Pilot Primacy, so I dont know how much of the improvement was down to brand or size difference. Back to back the 205 Michelins felt far more surefooted and made the 195 P6000s feel like awful lurching things.
Dont know how they compare weight-wise with steels, I never bothered to weigh them. I would not expect them to be lighter, maybe about the same; as they are OE wheels Saab would not make them significantly heavier would they?
HJ's CBCB for my Saab 9-3 hatch recommends the use of Mich Pilots on 17" wheels. I went for 16s thinking I would save money on tyres, but in hindsight I may have been better with 17s. I can elaborate if you like?..
Edited by Rich 9-3 on 27/10/2008 at 11:10
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Give me easy-clean trims/steel wheels any day.
What about having alloy wheel trims on steel wheels? Then they'd look like the real thing.
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Apologies if this is hijacking the thread and going off on too much of a tangent.
I'm wondering about doing the opposite. I have allow wheels with low(ish) profile tyres, but I notice the Ford Eco range have narrow wheels with hard wearing tyres. Seeing as most of my driving is motorway, the low profiles are somewhat wasted, and I'm wondering if I can bump up my mpg by switching to 'eco style' wheels and tyres. Or is there very little in it?
Peanut.
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if I can bump up my mpg by switching to 'eco style' wheels and tyres.
For various mpg gains, work out how many miles it would take you just to cover the cost of the new wheels and tyres!
Edited by L'escargot on 28/10/2008 at 15:04
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Fair point. But steel wheels cost a tenner each at a breaker's, and new tyres for them will be cheaper than the grippy low profiles. So, in effect, how long to get back £40. If mpg can be increased by 10%, then it all look like a good idea.
Peanut
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Had this brought home to me the other week. My wife ( who constantly points out that she has the IAM qualification and I haven't ) banged the wheel of one of our cars on a kerb hard enough to Jacobs a wheel and tyre. ( Heh heh )
Fortunately it was the one car we have which has steel wheels and unfashionably skinny tyres. Total cost of putting a new wheel and tyre on it was quite a bit south of £70.
Almost worth it for gloat value.....
Edited by Humph Backbridge on 28/10/2008 at 19:04
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Almost worth it for gloat value.....
Don't Humph you are tempting a mischievous one, mrs gb put a nice 2" scrape on the nsf wheel of the old MB and i teased her for ages, even moving the car when parked at home to bring the scrape to the top for maximum visibility.....horrid chap i know.
Several months later we are out in the estate car, me the professional..yeah right...at the wheel and i manage to scrape the entire circumference of the front wheel...on my own side for goodness sake....she just laughed her silly head off.
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