Tyre Question

[heyes]

On a V70 T5 with 18" wheels can u put on 225 on the back and 215 on the front.

[RT MECHANICS]

Hi yes you can but its not advised why do you want to run smaller tyres on the front i run 225/45/18 with no problems just small mods.

Russ:)

[heyes]

Hi Iv'e got 215's on front fairley new but back needs changed. I want to go 225's but start with the back until the front need changed. What is the down side of doing this

[bubba_1986]

On a V70 T5 with 18" wheels can u put on 225 on the back and 215 on the front.


I used to run 225 at front and 245 at back, not advised as diff will knock speedo out, and also made ride worse

Bubba

[thunderace]

Hi yes you can but its not advised why do you want to run smaller tyres on the front i run 225/45/18 with no problems just small mods.

Russ:)

what mods would they be then Russ?

[Baj]

I have 215/35/18s on the front and 225/35/18s rear.

Surely it is just wheel width. Why should that make any difference to speedo readings?

[t5tart]

if you running a size up width wise and the same 23 profile the o/d of the tyre will be bigger

if you go up a size width wise general rule of thumb you shpudl be running a 30 /25 profile tyre

[fraz13]

A used to run 225/40's on the front but changed to 215/40's coz a culdnt handle the rubbing any longer

215's on the front and 225 on the rear wont be a problem

[t5 stealth]

if you run diffrent size tyres you will probly get abs light on wen u move the car cos the smaller wheels will be turning faster than the bigger wheels,
the abs will think a wheel is spinning etc etc,
the side profile of the tyre is a percentage of the width,
215 45 is 45 percent of 215 mm. etc etc so narrower tyres means a lesser percentage on side wall which gives you the total rolloing radius,
simple really,,if any one wants me to explain that then no i cant cos iv confused my self now,hope this helps

[arbee]

I have 215/35/18s on the front and 225/35/18s rear.

Surely it is just wheel width. Why should that make any difference to speedo readings?

the profile is expressed as a percentage of the width, eg 35% of 225 means a bigger rolling radius than 35% of 215 :)

[volvotuning]

Hi Iv'e got 215's on front fairley new but back needs changed. I want to go 225's but start with the back until the front need changed. What is the down side of doing this

Apart from the rubbing problems, another potential downside is worse traction in the wet as a wider tyre will have a tendency to aquaplane more than a narrower tyre. However, how much difference this actually makes between 215 and 225 width, I don't really know.

Adam.

[t5tart]

simple maths

if you have a tyre 100 mm wide and a 30 section
and a tyre 110mm wide and a 30 section

the trre wall on tyre a is 30mm on tyre b is 33mm

so if the wheel is 100mm in diameter add on 60mm to the total diameter for tyre a and 66mm for tyre b
160 and 166 respectivly

the circumference is Pi d

so 3.1415 x 160 = 502.64mm
3,1415 x166 = 521.48mm

so about 19mm per revolution more

hence the smaller wheel appears to be spinnng cause it is rotating faster to keep up with the bigger wheels
now enlarge that difference to an 18 inch rim with a 225 40 section tyre
you can see that the difference can be quite alot

[heyes]

Well guys I'm glad I didn't ask anything complicated. Some of the well meaning advice went straight over my head. Bottom line, is this combination going to cause real problems. Thanks for all your help.

[Engineer]

Well guys I'm glad I didn't ask anything complicated. Some of the well meaning advice went straight over my head. Bottom line, is this combination going to cause real problems. Thanks for all your help.

I guess the answer is yes sometimes but other times no, when in doubt don't do it lol. Unless you want to learn when and why which takes time. :rolleyes:

[Baj]

I still dont see the problem unless you are running a 4x4.
No ABS light on problems either.

I didnt know the 35 was a percentage tho :)

[fraz13]

As a said in ma first post theres no problem

[t5tart]

no problem but i would go for a lower profile on the wider tyre