Options for bigger than the chart tires

Smaltze

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E320 S210 2002

Currently have 245/40Z R18 tires. They're in need of replacing soon, and id love to be able to stick some thicker tires on for looks. 245/50 or 60. Obviously every chart on the internet is telling me this isnt possible and so are my fingers (only one fits between the tire and upper control arm on the fronts!

Is it possible to get bigger tires, my main thought would be getting spacers, since it should then clear the upper control arm, and i think thats the only thing in the way, am i wrong?
What about stretching a narrower set too so the walls are slanted, this would give me more clearance (but yes i know, less ground contact - less grip).

Any other options?

Thanks :)
 

Naraic

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What are you trying to achieve?
 

turbopete

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firstly stretched tyres (no matter how commonly you see them) are ILLEGAL under some regulations or other (construction and use springs to mind)

wheel spacers WILL add strain to the bearings. it may not be significant but it does add strain to them and they usually fail sooner than if not spaced also this alters the offset and will therefore change the position in the wheelarch of the wheel, potentially causing other fouling issues. this is also classed as a modification and your insurers may not take too kindly to it.

other than that, you could probably go up to 245/45's without too much issue. the standard sizes would probably be 225/45 front and 245/40 rear id guess on the staggered set-up

if adding sidewall is only for appearance purposes, then depending on the width of the wheels, you could possibly go to 225/45 or possibly even 225/50 without too much issue, as long as the wheel is wide enough (about 7.5j would be the max width for that)
other than that, id suggest changing to a 17 inch wheel instead of the 18 inch currently fitted.
 

hotrodder

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What about stretching a narrower set too so the walls are slanted, this would give me more clearance (but yes i know, less ground contact - less grip)

It doesn't work like that... wider tyres do NOT put more 'rubber on the ground', the size of the contact patch is set by weight acting on the tyre and the pressure they're inflated to. The shape of the contact patch changes with tyre width i.e. for a given pressure narrower tyres have a longer, narrower contact patch and swapping to wider tyres = a shorter but wider contact patch of virtually the same area.
Under some circumstances the wider tyre will have more grip while in the wet it will have less and be more prone to aqua planning etc [/gross generalisation]

A 245/50 or 60 isn't wider than a 245/40, just taller. That'll make the speedo under read, reduce the cars acceleration & the tyres are more likely to contact the wheel arches as the suspension and steering moves. The second number of the tyre size is the aspect ratio which referss to the height of the tyre sidewall as a % of it's width i.e. a 245/60 r18 is nearly 100mm larger in diameter than a 245/40 r18 and when your speedo says you're doing 70mph you'll actually be doing 80.5

As said wheel spacers put more strain on things like wheel bearings and they also mess with suspension geometry, specifically changing the https://en.wikipedia.org/wiki/Scrub_radius
 

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You standard tyres have a sidewall height of 98mm, 45 would take it to 110mm and 50 would make them122.5mm

So your diameter would go up by 220mm (that is almost an inch and 50 would be 245mm, way over the top.

I juggle my tyre sizes and I have increased the profile height by 9mm, but no further, as said the speedo will be out.
 

L John

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This tyre calculator should help.
The alternatives in the green section are the most likely to be a good fit, check they fit your rim width.
Click on the alternative tyre size for more info.

Your insurer might refuse to pay out on a claim if the tyres are different to the correct size originally fitted.
 
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Smaltze

Smaltze

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A 245/50 or 60 isn't wider than a 245/40, just taller. That'll make the speedo under read, reduce the cars acceleration & the tyres are more likely to contact the wheel arches as the suspension and steering moves. The second number of the tyre size is the aspect ratio which referss to the height of the tyre sidewall as a % of it's width i.e. a 245/60 r18 is nearly 100mm larger in diameter than a 245/40 r18 and when your speedo says you're doing 70mph you'll actually be doing 80.5

https://en.wikipedia.org/wiki/Scrub_radius

i know this, i meant i want thicker sidewalls, not wider tires. I was thinking that having a narrower tire with thicker side walls would mean i get the effect i want but also might mean the tires clear upper control arm due to the changed profile of the tire.
 
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Smaltze

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What are you trying to achieve?

just thicker side walls, i like the look. big chunky wheels. wider would be nice too. Im not in this for functionality, just having fun modding my car.

firstly stretched tyres (no matter how commonly you see them) are ILLEGAL under some regulations or other (construction and use springs to mind)

wheel spacers WILL add strain to the bearings. it may not be significant but it does add strain to them and they usually fail sooner than if not spaced also this alters the offset and will therefore change the position in the wheelarch of the wheel, potentially causing other fouling issues. this is also classed as a modification and your insurers may not take too kindly to it.

other than that, you could probably go up to 245/45's without too much issue. the standard sizes would probably be 225/45 front and 245/40 rear id guess on the staggered set-up

if adding sidewall is only for appearance purposes, then depending on the width of the wheels, you could possibly go to 225/45 or possibly even 225/50 without too much issue, as long as the wheel is wide enough (about 7.5j would be the max width for that)
other than that, id suggest changing to a 17 inch wheel instead of the 18 inch currently fitted.

Im not too concerned about the strain on the bearings, ive had spacers before. ill live with the side effects.

I guess i could go up to 245/45 but it wouldnt really make the difference im after. Id rather keep the wheels i have too, i like them more than how much i want thicker tires.

Is there anything i could do perhaps involving modding the upper control arm to get it out the way? Just talking in theory here.
Im doing these things just for fun and modification, so im just enquiring really.
 
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Smaltze

Smaltze

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You standard tyres have a sidewall height of 98mm, 45 would take it to 110mm and 50 would make them122.5mm

So your diameter would go up by 220mm (that is almost an inch and 50 would be 245mm, way over the top.

I juggle my tyre sizes and I have increased the profile height by 9mm, but no further, as said the speedo will be out.

Yeh definitely worth considering, im not sure if my tires are factory since i bought it used but the speedo seems accurate currently.

When you say 220, i assume your mean 22? 2.2cm's?
 
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Smaltze

Smaltze

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Perhaps ill not worry about the front tires, and go for bigger ones on the back, Mad Max style :). i assume this is going to alter the speedo though, can i manually recalibrate the speedo?
 

EmilysDad

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Perhaps ill not worry about the front tires, and go for bigger ones on the back, Mad Max style :). i assume this is going to alter the speedo though, can i manually recalibrate the speedo?

if the front & rear tYres are too different in size, then your ABS traction control will beconfudled
 
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Smaltze

Smaltze

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if the front & rear tYres are too different in size, then your ABS traction control will beconfudled

Bummer, my options are getting fewer and more difficult!
 

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My sizes I put up were in mm.

You should not have 245 wide tyres anyway for 18" rims, they should be in the order of 225 to 235 on a 210
 
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L John

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Well at least this guy is giving Calumco a break.
 
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kid-jensen

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Just go for the smallest spacer you need to clear the suspension... Do this after fitting whatever tyre you settle on to make sure there's no wheelarch fouling.

The downsides caused by a slim spacer will be managable.
 
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Smaltze

Smaltze

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Just go for the smallest spacer you need to clear the suspension... Do this after fitting whatever tyre you settle on to make sure there's no wheelarch fouling.

The downsides caused by a slim spacer will be managable.

im still left with this battle with the speedometer though.
 

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im still left with this battle with the speedometer though.

As I have said, you should be running on 225 or 235 x 40 tyres. 235 x 45 would give you a side wall height of 105.75mm and the speedo would still be near enough.
 

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