Larger Wheels

[ThaiPauly]

A while ago I was looking to put some 17' wheels and tyers on my car.

I am not an afficiodado on anything mechanical or mathematical, but the woman seeling them said I could use the spare 16" wheel if I got an un-repairable puncture.

I am now re-visiting the option but I am sceptical about her information and feel she may well be saying it just to get the sale, anyone know for sure?

Thanks

[MoonRiverOasis]

So long as rolling diameter is maintained, you can use an odd spare so long as you remain mindful that one corner has different traction, handling and spring rate than the rest, and drive accordingly until the primary wheel is repaired.

If the rolling diameter is different by more than a couple of percent, the handling will be adversely effected and you'll also be overworking mechanical components like the diff, so top speed should be well and truly limited as should number of KM's travelled with the spare on.

Here's a good tire size calculator that will help you work out the difrerence: http://www.1010tires.com/tiresizecalculator.asp

[katabeachbum]

on the Fiesta you can use any size spare. Prefered to use od size as rear wheel. as MRO said, be aware of different handling

make sure you have nuts/bolts for your spare, as the 17inchers may not fit

[transam]

If your ride has fancy VSC or LSD then perhaps a prob if the circumference of the wheel/tyre combo are not similar. You can do an easy check on the Net. If similar then the spare will get you home. But remember to keep a set of lug nuts in the trunk as they might be different.

[MoonRiverOasis]

make sure you have nuts/bolts for your spare, as the 17inchers may not fit

But remember to keep a set of lug nuts in the trunk as they might be different.

Good point on the lug nuts guys - 3 brains are better than one

ThaiPauly: the bottom line is that the salesrep wasn't lying - it's highly unlinkely they're recommending a fitment that dramatically changes the OD (as that would likely interfere with the body/suspension during normal driving) - so in that case, so long as adequate precautions are taken using the spare as a temporary "get me home" fix will be fine.

[wandrinstar]

Call a Tyre firm,you wont get the Nuts off.A Torque Wrench is a Spider here.Or do what my Family do. drive on till they find a Depot.

[ThaiPauly]

Thanks for the useful info everyone

[ThaiPauly]

Well, so I thought OK I'll do it then after your helpful responses.

went to another wheel place to get a comparison price, saw some nice wheels, and asked about low-profile tyres, they don't stock them, but, but, the manager said that low prifiles are no good for the Fiesta as they make the drive too hard.

So is he winding me up or is he right?

I had LP's on my previous BMW , which was obviously heavier and never had a problem, so why shold it be a problem on a smaller car?

Thoughts from the guys in the know would be appreciated

Cheers

TP

[transam]

Well, so I thought OK I'll do it then after your helpful responses.

went to another wheel place to get a comparison price, saw some nice wheels, and asked about low-profile tyres, they don't stock them, but, but, the manager said that low prifiles are no good for the Fiesta as they make the drive too hard.

So is he winding me up or is he right?

I had LP's on my previous BMW , which was obviously heavier and never had a problem, so why shold it be a problem on a smaller car?

Thoughts from the guys in the know would be appreciated

Cheers

TP

He is right, sort of. Rides with low profile tyres from factory will have suspension design to compensate or perhaps 'not' for a sporty ride, which usually is a harder feel.

[bino]

The rule of thumb for tire sizing is to add a centimeter of width for every 10 percent of profile reduced.

Tires measurements are weird, like this: 175/70-13. 175 is the tread width, in millimeters, 70 is the tire profile height measured as a percentage of the tread width, and 13 is the rim size in inches.

Therefore, a 175/70-13, a 185/60-14 and a 195/50-15 should all be "pretty darned close" in the "rolling diameter" mentioned by MoonRiver.

And yes- the ride will be harder because the sidewall / height of a tire absorbs a lot of the initial impacts / smaller bumps. Conversely, the cornering performance will increase because there will be less "flex" in the sidewall caused by G forces when cornering at speed.

[katabeachbum]

The rule of thumb for tire sizing is to add a centimeter of width for every 10 percent of profile reduced.

Tires measurements are weird, like this: 175/70-13. 175 is the tread width, in millimeters, 70 is the tire profile height measured as a percentage of the tread width, and 13 is the rim size in inches.

Therefore, a 175/70-13, a 185/60-14 and a 195/50-15 should all be "pretty darned close" in the "rolling diameter" mentioned by MoonRiver.

And yes- the ride will be harder because the sidewall / height of a tire absorbs a lot of the initial impacts / smaller bumps. Conversely, the cornering performance will increase because there will be less "flex" in the sidewall caused by G forces when cornering at speed.

comfort of the ride depends on new rims width and make/model of tyre and its load index

In general a wider rim reduces comfort as tyre flexes less. In addition a lower profile tyre, needed to abtain rolling diameter, flexes less.

However a better quality tyre can be more comfy even on wider rim and lower profile tyre. And lower load index will usually be more comfy

all this is theory

moving up one inch in rim and thus slightly lower profile on tyre does not make much difference to comfort. Make sure you do not get tyres with higher load index than needed tho, and use quality tyres only

[ThaiPauly]

Wow, you learn something new every day, thanx guys :jap:

[transam]

Wow, you learn something new every day, thanx guys :jap:

Yep, there are always trade offs.

[arthurwait]

Low profile, wide tyres on Thai roads. Rather you than me.

[ThaiPauly]

Low profile, wide tyres on Thai roads. Rather you than me.

You are being pretty general with this remark.

I had them on my last car, wasn't a problem, would not be considering having them on my new car now would I if the experience had been bad?

[Spoonman]

Low profile, wide tyres on Thai roads. Rather you than me.

Yep, It certainly bites when you damage the sidewall on an 8000b tyre a week after fitment.

[katabeachbum]

Low profile, wide tyres on Thai roads. Rather you than me.

Yep, It certainly bites when you damage the sidewall on an 8000b tyre a week after fitment.

and it certanly is a huge improvement to handling and braking

[Spoonman]

Low profile, wide tyres on Thai roads. Rather you than me.

Yep, It certainly bites when you damage the sidewall on an 8000b tyre a week after fitment.

and it certanly is a huge improvement to handling and braking

Actually my braking got worse (well appears to have), belts the ABS way to easily.

[transam]

Low profile, wide tyres on Thai roads. Rather you than me.

Yep, It certainly bites when you damage the sidewall on an 8000b tyre a week after fitment.

and it certanly is a huge improvement to handling and braking

You can have a set up that is race car perfect BUT Ma & Pa behind you will certainly end up UP your ass.

[Tanaka]

Actually my braking got worse (well appears to have), belts the ABS way to easily.

That may be your tyres. My original 16' Bridgestones did just as you describe. Now with 18' Nittos, there is no tendency for the ABS to engage, unless under very heavy braking and surface with less grip.

[Tanaka]

Call a Tyre firm,you wont get the Nuts off.A Torque Wrench is a Spider here.Or do what my Family do. drive on till they find a Depot.

Or get a lug/wheel wrench and an 1 meter steel pipe with an inside dia to fit over the wrench lugs. Now you have an extension of your arm muscles that no wheel nuts can resist.

[katabeachbum]

Low profile, wide tyres on Thai roads. Rather you than me.

Yep, It certainly bites when you damage the sidewall on an 8000b tyre a week after fitment.

and it certanly is a huge improvement to handling and braking

Actually my braking got worse (well appears to have), belts the ABS way to easily.

Chevy? 3 sensor, only one rear sensor in diff

two ways to go

adjust EBD or rear load sensor to believe load is lighter rear, then you will barely have rear brakes when not loaded, but braking distance gets shorter

or disconnect ABS by removing fuse

Due to Colorado/DMax only 3 sensor and slow frequens ABS, most ambulancedrivers in Scandinavia disconnect ABS on DMax even on snow and ice

[katabeachbum]

Low profile, wide tyres on Thai roads. Rather you than me.

Yep, It certainly bites when you damage the sidewall on an 8000b tyre a week after fitment.

and it certanly is a huge improvement to handling and braking

You can have a set up that is race car perfect BUT Ma & Pa behind you will certainly end up UP your ass.

thats what my mirrors are for

[Spoonman]

That may be your tyres. My original 16' Bridgestones did just as you describe. Now with 18' Nittos, there is no tendency for the ABS to engage, unless under very heavy braking and surface with less grip.

Iam quiet fond of my 275/45/20 Falken Ziex's, vast improvement over the old maxxis crap that was on it.

Chevy? 3 sensor, only one rear sensor in diff

two ways to go

adjust EBD or rear load sensor to believe load is lighter rear, then you will barely have rear brakes when not loaded, but braking distance gets shorter

or disconnect ABS by removing fuse

Due to Colorado/DMax only 3 sensor and slow frequens ABS, most ambulancedrivers in Scandinavia disconnect ABS on DMax even on snow and ice

Yeah upgrade to 350mm front discs and 295mm rear being fitted this coming Saturday, if that does not help then I'll pull the ABS fuse.

[transam]

thats what my mirrors are for

Yep, to watch them rear end you whilst they munch on pok pok eh.