New Wheels & tyres iQ

[Rob1769]

Hi all, having a bit of a dilema.. car has standard 15'' alloys with 175/65/15 tyres and  I am wanting to change the look somewhat, have been looking @ vatrious wheel & tyre setups  18'' & 17''  but wanted to fill the arches a little more  but have got a tad confused !!

 

I was pointed here which is a good help site  http://www.willtheyfit.com/index.php?width=175&aspect=65&diameter=15&wheelwidth=5&offset=45&width2=205&aspect2=45&wheel_size=17&wheel_width=8&offset2=45

but when I go with recommended tyres  they are literally about the same overall diameter  so  I think they will not do what I am wanting !  Or will there be an illusion as the alloys are 3'' bigger if I go with the 18''  they will look bigger ???

Any help greatly appreciated !!  also  any preferences on the wheels shown below ????

[FROSTYBALLS]

You have to be aware of the effect on the speedometer reading. It is illegal for a speedometer to under read (show less than the actual speed) and there are also limitations on how much a speedometer can over read (show more than the actual speed). Best to work with less than a 10% over read.

Both profile and tyre width can affect speedometer readings. The website you linked to provides an indication of the speedo effect.

Also you need to notify your insurer beforehand in case they view the change as a modification, and charge an increased premium.

[Rob1769]

Hi FrostyBalls  the only thing that will affect speedo readings is the overall diameter of the rolling rim which as you say is influenced by profile & tyre size

[2015iQ]

One sure way to 'fill' the arches  (and imo) is to go down the lowering route Rob. 

 

Customising is all about personal choice, and as they say 'beauty is in the eye of the beholder. Fill the arch with oversize tyres and imo you stand the chance of looking like a tractor or a roller skate because you will be lifting your car up off the ground, although if that's the style you like, then that is your choice. There could be (more than likely/sure bet) clearance issues too.

 

The larger you go in rim size, basically the less sidewall height is 'recommended'. 

Road holding will improve (especially as after market rims are generally wider than manufacturer's) but the flip side is generally the skinnier the side wall height, the bumpier the ride....all depends want sort of ride you want.

 

There is another site I tried to find for tyre comparison that actually shows the wheel size compared to standard (in picture form) but it's no substitute for the real thing of course.

 

Even with a good comparison site and all the good will in the world of trying to work out various formats, it's not a dead certainty that the computer (or my workings) will come up with result that won't raise problems as I've found out to my cost.

Another thing that will affect clearance issues is the offset, and whilst offset causes some people headaches, imo what is important is the clearance/measurement of the inner edge clearing suspension and other parts. 

 

Just one final word (honest)....as I 'mailed you, now is a good opportunity to inform other readers/owners who may not be aware that fitting after market rims may affect your insurance. Check with your insurance company/broker before fitting/buying. Failure to do so could and probably will invalidate your insurance and even lead to you being uninsured and having you pride and joy seized.

[FROSTYBALLS]

9 minutes ago, Rob1769 said:

Hi FrostyBalls  the only thing that will affect speedo readings is the overall diameter of the rolling rim which as you say is influenced by profile & tyre size

No.

Different tyre widths also affect the speedo readings. Eg. the standard example on the site you linked shows the speedo reading at 30 of 205/45/17's is 29.62mph. Change to 215/45/17's and reading at 30mph is 29.19mph. For 225/45/17's the 30mph reading is 28.78mph, etc, etc.

The increased grip of the wider tyres must affect the speedometer readings.

[Rob1769]

Thanks to all !!! The world has gone MAD !!!!!    -anyhow  which are the prettiest ????

[Rob1769]

On a positive note just rung insurance company & NO CHARGE !!! Bonus 

[drb5]

Ive spent some time going over the same dilemma. 

Ive looked at 17, 18 and even 19 inch, but decided I wanted more of a sidewall so plumped for 17". 

19's looked too much IMO, but 18 inch looked spot on. 

As mentioned above, different width wheels and tyre sizes make a big difference, so I used the following site for help...

https://www.wheel-size.com/calc/?wheel1=195-45-17X7ET45&wheel2=225-45-17X7.5ET40&fcl=50mm&wcl=30mm&scl=50mm&sr=0mm

Sparco Trofeo 17x7" ET37 in Gloss Bronze with Falken ZE914 215/40R17 tyres FYI. 

Good luck in your decision. 

[Rob1769]

drb5....  any photos?

 

[drb5]

Waiting on the wheels turning up and still to fit the lowering springs. 

Will fire pics up in the next couple of weeks. 

[Rob1769]

superb...........

[Heidfirst]

On 11/09/2017 at 8:49 PM, FROSTYBALLS said:

The increased grip of the wider tyres must affect the speedometer readings.

you have shattered my vision of the omniscient Frosty!  

Tyre profile is an aspect ratio. If you increase tyre width you must therefore change tyre section height to keep the aspect ratio the same.  The change in section height> increase in diameter >change in rolling circumference & it's the change in circumference that affects the speedo reading.

[Rob1769]

Well...  Wheels & Tyres arrived.. all fitted now they have sent the correct nuts & locking nuts !!  I am quite dissapointed really with the outcome      17'' with 205/45/17 tyres  and  they seem a little sad / lost...  not even sure if I go down the lowering route that it will improve the appearance -  Yout Thoughts ??????????????

 

 

 

[2015iQ]

At the risk of repeating myself, the only way wheel arches can be filled without putting the share value of Paracetamol up on the stock market is to lower the iQ. To fill arches with rim and rubber would have created clearance problems, unless you want to go down the heavily modified route and handy with a decent saw and welding gear or glass fibre. You may want to consider a 50mm & not a 30 to get rid of even more airspace between the tyres and bodywork, but of course the ride will be a lot firmer. 'bit like a see-saw really....when it's level, everything's alright, but press down on one end and the other end is directly affected.   

Personally, I like the rims you've chosen Rob but I know only too well that if the look you want to achieve just hasn't happened or just out of financial reach, then you wouldn't be the first to say enough's enough and walk away.

[xengibez]

Can't be bothered with lowering, I am 50 and I kinda like the 4x4 look the car has  

Each to their own I guess..

 

 

[Soeley]

The wheels look good. The size you have chosen are the same overall diameter as the 16" rims only wider. I would also guess they are the same diameter as the 15" rims (not sure what you have removed?) The iQ does sit quite high on it's springs I lowered mine 25mm front and 30mm at the rear to give it a level stance. going much lower I would be concerned with speed humps.

Have a look HERE to see the difference in my lowered look.

[Rob1769]

2015iQ - Keep Calm !!!  no need for the paracetamols... I odrered these last night...   http://www.ebay.co.uk/itm/S038063-SPAX-LOWERING-COIL-SPRINGS-fit-Toyota-iQ-1-0-04-09/291683916557?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Weekend job then hopefully I will be a tad happier... 

[Rob1769]

Lowered the rear by 30mm -- now have issues with the sidewalls rubbing on the arches  when cornering fast (ish)  I know  hard to do in a 1.0 ltr !!!  any ideas  as to resolve ???

[craggle]

Drive slower round the corners.... 

What offset wheels are they? I have 205/45 17 tyres too on OZ racing wheels with an ET 42 offset and they seem fine. 

Are they rubbing the plastic wheelarch liners rather than the metal bodywork?

Craig.

 

[Rob1769]

Hi Craig,  35 offset  struggling to see where they are rubbing.. I need a couple of big heavy lasses to sit in the back while I have a look !!!

4x	17" Axe EX5 - Gloss Black with Polished Face (17 x 7.5" 4x100/N ET35)
4x	Falken ZIEX ZE914 205/45R17 88W XL (EB71)