Tyres And Wheels Sizes

[thewelsho]

Ritchie very kindly gave me a set of tyres for my track wheels (cheers mate!) and I just wanted to check that they will fit on my wheels.

I have STi8 wheels fitted with 225/45/17 tyres. Ritchies tyres are 215/45/17, just wanted to check that they will fit ok before I take the lot down to the tyre fitter.

Thanks!

JW

[Guest]

They will fit fine mate.

[thewelsho]

They will fit fine mate.

Cheers mate!

[RS Grant]

Bit narrow... but they'll fit... and dont think they'll cause you any sort of problems.

Cheers,

Grant

[james666]

Ritchie very kindly gave me a set of tyres for my track wheels (cheers mate!) and I just wanted to check that they will fit on my wheels.

I have STi8 wheels fitted with 225/45/17 tyres. Ritchies tyres are 215/45/17, just wanted to check that they will fit ok before I take the lot down to the tyre fitter.

Thanks!

JW

eh last i knew if the size says 17 at the end then they will fit any 17inch wheel!!!!!!!!!!!!!!!!!!! as for the 215 bit that is width and the 45 is height of tyre from the wheel to top of rubber bit thats on the road!!!!!!!!!!

[thewelsho]

eh last i knew if the size says 17 at the end then they will fit any 17inch wheel!!!!!!!!!!!!!!!!!!! as for the 215 bit that is width and the 45 is height of tyre from the wheel to top of rubber bit thats on the road!!!!!!!!!!

Yeah, I know what all the numbers mean, and yes any 17" tyre will fit any 17" wheel in diameter, however, as you pointed out, the diameter is not the only factor. If the tyre is narrower than the width of the wheel, then this could cause issues with the bead not completing an air-tight seal at the wheel's rim.

[james666]

Yeah, I know what all the numbers mean, and yes any 17" tyre will fit any 17" wheel in diameter, however, as you pointed out, the diameter is not the only factor. If the tyre is narrower than the width of the wheel, then this could cause issues with the bead not completing an air-tight seal at the wheel's rim.

so if you know wot all the numbers mean then why ask and no it wont coz it not to bead correctly as it is still 17" and its only 10mm narrower i run 31/1050/15 on my jeep and they seal fine. the reason your tyres are 225 is coz it a newage as most newages run the wider tyre

[fai17]

nice reply john.

[craigdmcd]

so if you know wot all the numbers mean then why ask and no it wont coz it not to bead correctly as it is still 17" and its only 10mm narrower i run 31/1050/15 on my jeep and they seal fine. the reason your tyres are 225 is coz it a newage as most newages run the wider tyre

James, what size are your tyres on you jeep, because those aren't normal numbers, unless the first number is a 31" tyre (seen this and much bigger in Iceland) and the last is a 15" wheel, but what is the part in the middle?

BTW, the 45 isn't a direct number but the percentage of the width of the tyre (therefore a 235/60R15 is a taller tyre than a 205/60R16). The number is called the aspect ratio.

All newages don't automatically have 225 tyres. All newage WRX's come with 215/45R17, wheras STi's come with 225/45R17 on wider wheels to accomodate the Brembo brakes, and I'm guessing that is what John is wondering about, whether the slight extra size of the wheel (I think they are a 8J on a STI wheel compared to 7.5J on a WRX) is going to make a difference. If so John, they aren't perfect, but will do the job, and should give no adverse effects.

[Spaceman]

wrx wheels are 7 inch and sti wheels up to 2005 are 7.5inch then 2005 on sti are 8 inch

and as correctly asked by kohn its important regards the width as it you strech the tyre to much then esp under the load of a track day the tyre can pop

happens alot with the vag guys that try to strech skinny tyrs on to wide wheels,

215 on your 7.5 inch wide wheels will be fine tho john.

[james666]

James, what size are your tyres on you jeep, because those aren't normal numbers, unless the first number is a 31" tyre (seen this and much bigger in Iceland) and the last is a 15" wheel, but what is the part in the middle?

BTW, the 45 isn't a direct number but the percentage of the width of the tyre (therefore a 235/60R15 is a taller tyre than a 205/60R16). The number is called the aspect ratio.

All newages don't automatically have 225 tyres. All newage WRX's come with 215/45R17, wheras STi's come with 225/45R17 on wider wheels to accomodate the Brembo brakes, and I'm guessing that is what John is wondering about, whether the slight extra size of the wheel (I think they are a 8J on a STI wheel compared to 7.5J on a WRX) is going to make a difference. If so John, they aren't perfect, but will do the job, and should give no adverse effects.

the tyre size on my jeep in 31/10.50/15 and they are called imperial sizes and yes you can get bigger but i dont want to have to cut bits off jeep to fit them!!!! for those that dont know!!!! but i'm not gonna start going into depth on tyres and wot they are coz at the end of the day they are black rubery things that fit on wheels and go round!!!!!!! and they dont have bigger tyres to fit over the brembo brakes on the sti, coz i had the brembos on my classic and i ran 215/45/17 you will find that the new sti has different offset of wheel compared to the other bangers. end of rant.

BUT AT THE END OF THE DAY THESE ARE TRACK TYRES SO YES JOHN YOU CAN RUN THESE SAFELY.

[fai17]

All newage WRX's come with 215/45R17, wheras STi's come with 225/45R17 on wider wheels to accomodate the Brembo brakes, and I'm guessing that is what John is wondering about, whether the slight extra size of the wheel is going to make a difference. If so John, they aren't perfect, but will do the job, and should give no adverse effects.

That is correct.

So in all fair honesty John,your car will be fine with 215/45/17 on your 7.5inch wide STI wheels.

It just might be a very little strech on your tyres but it will be grand.

Jst be carefull with the new tyres tho...you will need to get use to them first.

P.S....JDM STI came with 235/45/17 on the SAME wheels....how comfusing!

Edited March 21, 2009 by fai 17

[craigdmcd]

the tyre size on my jeep in 31/10.50/15 and they are called imperial sizes and yes you can get bigger but i dont want to have to cut bits off jeep to fit them!!!! for those that dont know!!!! but i'm not gonna start going into depth on tyres and wot they are coz at the end of the day they are black rubery things that fit on wheels and go round!!!!!!! and they dont have bigger tyres to fit over the brembo brakes on the sti, coz i had the brembos on my classic and i ran 215/45/17 you will find that the new sti has different offset of wheel compared to the other bangers. end of rant.

BUT AT THE END OF THE DAY THESE ARE TRACK TYRES SO YES JOHN YOU CAN RUN THESE SAFELY.

I see about the Jeep tyres now, in your first post you put 1050, and then 10.50 in your second so obviously the tyres are 10.50 inches wide. Every day is a learning day.

I hate to correct you at the end of your rant, but the STi did have bigger wheels to go over the STi Brembos, and I stand corrected that they are actually 7.5" wide. If you try to fit standard WRX wheels with the correctly fitted 215/45R17's on an STi, they will not fit and fowl the calipers - FACT.

Hence the STi has wider wheels with wider tyres to accomodate this, and as Peter has stated, JDM cars even came with 235's on them.

So back to the original point - Yes John, 215's will fit the wheels, they are stretched ever so slightly, and will not be ultimately as good as the equivalent 225's, but since it is on a budget (if you weren't you'd have just splashed the cash on the correct 888's), they will work with no detriment that you will notice.

[TPS_SCOOBY_2]

He's another quandary for the experts, would running a different thickness of tyre to the front and rear make any great difference.

For example I have a set of Innovits 7.5x18 I was wanting to run 225 x 35 x18 to the front and 245 x 35 x 18 to the rear I cant see a problem anyone else foresee one?

[arch]

the tyre size on my jeep in 31/10.50/15 and they are called imperial sizes and yes you can get bigger but i dont want to have to cut bits off jeep to fit them!!!! for those that dont know!!!! but i'm not gonna start going into depth on tyres and wot they are coz at the end of the day they are black rubery things that fit on wheels and go round!!!!!!! and they dont have bigger tyres to fit over the brembo brakes on the sti, coz i had the brembos on my classic and i ran 215/45/17 you will find that the new sti has different offset of wheel compared to the other bangers. end of rant.

BUT AT THE END OF THE DAY THESE ARE TRACK TYRES SO YES JOHN YOU CAN RUN THESE SAFELY.

[arch]

Think he needs to undestand about cornering forces on track and the effects these have on tyres. Maybe fit some 145x45x17's to the RA they should be lighter and save a bit of weight

[buffalo]

it will be fine, as stated previously it seems to be the in thing with the VAG guys.

if your going to try to belittle people or shout them down james666, its best you get ur point across correctly ie not 10mm but a percentage of aspect ratio etc. really find it hard to justify ur aggressive undertones in ur posts. though then again you are a grown man with 666 in his user name.

tp scooby, i was always under the impression an awd vehicle should run the same tyres, though porsche etc may have a different view on this.

[craigdmcd]

I think the biggest thing with running different size tyres front to rear is that the rolling circumference is the same, so the diffs are not working against each other, so something along the lines of 225/40R18 fronts and 245/35R18 rears may work although I haven't checked the exact rolling circumference on them - that is roughly what you are looking for.

[TPS_SCOOBY_2]

I think the biggest thing with running different size tyres front to rear is that the rolling circumference is the same, so the diffs are not working against each other, so something along the lines of 225/40R18 fronts and 245/35R18 rears may work although I haven't checked the exact rolling circumference on them - that is roughly what you are looking for.

Cheers craig, was that a typo with the profile sizes as surely having different profiles will upset the rolling circumference with the larger profile constantly increasing the load on the diffs as it tries to keep up with the slightly smaller 35 profile? Obviously only relevant on 4x4's.

Back in my vauxhall days I used to regularly run 15" rims to the rear and 14"s on the front to slightly tip the weight onto the constantly understeering front end. It gave no problems at all.

[craigdmcd]

Cheers craig, was that a typo with the profile sizes as surely having different profiles will upset the rolling circumference with the larger profile constantly increasing the load on the diffs as it tries to keep up with the slightly smaller 35 profile? Obviously only relevant on 4x4's.

Back in my vauxhall days I used to regularly run 15" rims to the rear and 14"s on the front to slightly tip the weight onto the constantly understeering front end. It gave no problems at all.

No, that is correct. The 35 and 40 profile parts of a tyre size are the "aspect ratio". This is the percentage of the width of the tyre that is the sidewall height - so 225 x 40% = 90mm sidewall(not exact, but for point of this) , 245 x 35% = 86mm (so like I said - it was a guess at the right size).

If you used what you suggested, a 225 x 35% = 79mm, the difference between front and rears is greater than what I suggested (by almost double). Now take what I have given as examples, then using what you learned at school to do with working out the circumference of a circle with the help of Pythagora's thereom (spelling?) which if I remember correctly is the radius of a circle multilpied by 3.147 (IIRC), and you can work out how much further/less a wheel on the front of a car would travel compared to the one on the rear.

At what point it starts to upset the centre diff I don't actually know, but do know that old Vauxhall Cavaliers and Calibra's used to blow the centre diff if badly uneven tyres were on different axles of the car and that is 7mm of a difference.

[J.C.]

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