wheels question, again!
Discussion
ok, so i may sound like a complete dufus here, but how come i havent seen any chims with the team dynamics pro race 2's or 3's on? i know plenty of people have 1.2's, but i prefer the look of the five spoke wheels. from my web browsings they seem to come in the right fitments, so is there a reason why we couldnt have them?
thanks dudes!
thanks dudes!
prettyboyben said:
well, im actually after 17's all round, as i like that look, but on further investigation that wouldnt work as the wheels are only 7 wide, so not big enough to take the 225/235 tyres i'd need on the back! darn it. haha!
Ben, if it's any help to you I run 17" all round all on 7J fitting. I have 215/40/17's on the front and 225/45/17's on the rear. Handles beautifully once the Geo was set up correctly 
I ran my car all last summer on 205/40 17s on 7J wheels, after I had an issue with bigger tyres catching on the wheel arches on a track day (I think the offsets are wrong on the wheels i bought). The next day I popped into my local tyre place and they had a brand new (minus a short driving session when the first owner hated them) set of tyres available for bugger all money, so i bought them.
They were brilliant both on the road and the track. They were a little smaller circumference than standard, so the speedo would have been reading about 5% fast. Speedo runs off the rear wheel size, as the sensor sits on the diff. The tyres were Yokohama Parada Spec 2, dry grip was awesome, damp grip ok, only thing they didn't do well was standing water.
Only other downside was at 135mph on a track day - the bonnet popped open, as the more nose up attitude of the car allowed too much air to get under the nose and up under the bonnet, bowing it enough to pull the bonnet catch apart. It came up six inches and stopped. Handling wasn't affected, just the bonnet catch.
They were brilliant both on the road and the track. They were a little smaller circumference than standard, so the speedo would have been reading about 5% fast. Speedo runs off the rear wheel size, as the sensor sits on the diff. The tyres were Yokohama Parada Spec 2, dry grip was awesome, damp grip ok, only thing they didn't do well was standing water.
Only other downside was at 135mph on a track day - the bonnet popped open, as the more nose up attitude of the car allowed too much air to get under the nose and up under the bonnet, bowing it enough to pull the bonnet catch apart. It came up six inches and stopped. Handling wasn't affected, just the bonnet catch.
prettyboyben said:
Thanks guys! So, ghost, are the tyres not stretched at all on the back? I thought the minimum wheel width for 225's was 7.5j? And qBee, are you running 205's all round? Sorry I got a bit confused by that one. Haha!
Yes, I was/am. But more because I bought the wheels off another Chim owner without thinking, and then discovered the issues with the wheels, and the tyres that came with themThere are ideal/recommended tyre and wheel sizes for Chimaeras, sure, and for the speedo to be accurate your rolling circumference needs to match the factory advised one.
As Pi is a constant, and the circumference is Pi x the diameter, we can work in terms of wheel plus tyre diameter. So when seeing what overall combo of wheel and tyre to use, just do the maths.
Wheels are specced as the diameter in inches.
Tyre widths are in millimetres.
Tyre wall heights are expressed as a percentage of the width, so 225/40 is a tyre 225mm wide by 225 x 40% high, or 90 mm high.
So the overall diameter of a 17 inch wheel with a 225/40 tyre on it is
17inches x 25.4 = 431.8mm for the wheel rim, plus
2 x 90mm for the tyre = 180mm
Total 611.8 mm
The standard Chimaera rear on Imolas is I think 225/50 16
So 16 x 25.4 = 406.4mm for the rim
225 x 50 % x 2 = 225mm for the tyre
Total 631.4 mm
So the example above is about 20mm, 0.8 inches, under size.
So the speedo will read 3.2% fast. Big deal.
So long as your tyres are the right width for your wheels, which your tyre fitter can advise, then within reason you can do what you like. Too big, or too wide, and the tyres will catch on the wheel arches or chassis. Too small and they will look silly.
My 205/40 17 s were a bit small, specially on the rear. I wanted 40s to get the stiffness in the sidewalls for track use. But they drove fine and handled fine, thanks to being good tyres. I should have gone for 235/40 17s to get the rolling circumference right, but I had been having problems with my tyres catching on the wheel arches on hard cornering, thanks to my offsets being wrong, so opted for narrower tyres for safety. I went looking for 215s, the 205s were what was sitting on the floor of the tyre shop at a cheap price when I rocked up at 5.29 pm on a Friday.
My latest track tyres are 17 inch 215/45 fronts, 18 inch 235/40 rears, on Silverstone SP12 wheels. These were designed for the Chimaera - be wary of after market wheels - the offsets can be an issue.
Edited by QBee on Saturday 23 March 17:57
Not had a wheel cap off my 500 so unsure as to whether they are 4 or 5 stud, could anyone enlighten me (I'm not at home to have a look). Many thanks.
So, I'm looking at Pro Race 1.2. Website shows 7x17 shod with 215/45R17 front and 8x18 shod with 245/40R18 rears. Previous poster has 235/40R18 which I presume causes no issue with wheel arches. How close does it get with 245's.
I confess, I know nothing about wheels, offsets and all that. Need some advice before I commit to anything. Would you go wider on the front? Narrower on the rear? Same rims front/back? confused.com
So, I'm looking at Pro Race 1.2. Website shows 7x17 shod with 215/45R17 front and 8x18 shod with 245/40R18 rears. Previous poster has 235/40R18 which I presume causes no issue with wheel arches. How close does it get with 245's.
I confess, I know nothing about wheels, offsets and all that. Need some advice before I commit to anything. Would you go wider on the front? Narrower on the rear? Same rims front/back? confused.com
C
What wheels do you have on it at the moment?
On the other point, I have three sets of wheels and tyres ( I am not simply confused!). On one set I have 235/40 18 rears on SP12 wheels. The previous owner had problems with 245s, which are 10mm wider, catching on the insides, so changed them. Also, every car is slightly different, and the two sides of your car might no match precisely.
If you are fitting tyres very close to the size limit you need to be sure the wheels are correctly offset. The tyres not only don't want to foul the chassis on the inside, they have to miss the wheel arches on the outside. Don't forget that this has to be true when moving, both over bumps and on hard cornering with a passenger weighing the car down. The tyres on my 17 inch wheels were nothing particularly large, but the offsets were wrong, and on hard cornering they caught on the wheel arches and ground a fair bit of rubber off before the end ofte track evening.
macca said:
Not had a wheel cap off my 500 so unsure as to whether they are 4 or 5 stud, could anyone enlighten me (I'm not at home to have a look). Many thanks.
So, I'm looking at Pro Race 1.2. Website shows 7x17 shod with 215/45R17 front and 8x18 shod with 245/40R18 rears. Previous poster has 235/40R18 which I presume causes no issue with wheel arches. How close does it get with 245's.
I confess, I know nothing about wheels, offsets and all that. Need some advice before I commit to anything. Would you go wider on the front? Narrower on the rear? Same rims front/back? confused.com
Not had a wheel cap off? Pardon? On all TVRs I have seen you can see your nuts.So, I'm looking at Pro Race 1.2. Website shows 7x17 shod with 215/45R17 front and 8x18 shod with 245/40R18 rears. Previous poster has 235/40R18 which I presume causes no issue with wheel arches. How close does it get with 245's.
I confess, I know nothing about wheels, offsets and all that. Need some advice before I commit to anything. Would you go wider on the front? Narrower on the rear? Same rims front/back? confused.com
What wheels do you have on it at the moment?
On the other point, I have three sets of wheels and tyres ( I am not simply confused!). On one set I have 235/40 18 rears on SP12 wheels. The previous owner had problems with 245s, which are 10mm wider, catching on the insides, so changed them. Also, every car is slightly different, and the two sides of your car might no match precisely.
If you are fitting tyres very close to the size limit you need to be sure the wheels are correctly offset. The tyres not only don't want to foul the chassis on the inside, they have to miss the wheel arches on the outside. Don't forget that this has to be true when moving, both over bumps and on hard cornering with a passenger weighing the car down. The tyres on my 17 inch wheels were nothing particularly large, but the offsets were wrong, and on hard cornering they caught on the wheel arches and ground a fair bit of rubber off before the end ofte track evening.
macca said:
Not had a wheel cap off my 500 so unsure as to whether they are 4 or 5 stud, could anyone enlighten me (I'm not at home to have a look). Many thanks.
So, I'm looking at Pro Race 1.2. Website shows 7x17 shod with 215/45R17 front and 8x18 shod with 245/40R18 rears. Previous poster has 235/40R18 which I presume causes no issue with wheel arches. How close does it get with 245's.
I confess, I know nothing about wheels, offsets and all that. Need some advice before I commit to anything. Would you go wider on the front? Narrower on the rear? Same rims front/back? confused.com
Looking at the pic on your profile they are Estoril's which are 4 stud.So, I'm looking at Pro Race 1.2. Website shows 7x17 shod with 215/45R17 front and 8x18 shod with 245/40R18 rears. Previous poster has 235/40R18 which I presume causes no issue with wheel arches. How close does it get with 245's.
I confess, I know nothing about wheels, offsets and all that. Need some advice before I commit to anything. Would you go wider on the front? Narrower on the rear? Same rims front/back? confused.com
You need 4 x 108, 7 x 17 et 25 (215/40/17) front and 8 x 18 et 35 (245/35/18) rear
I have these sizes in SP12 wheels (very similar to Pro Race 1.2), they fit perfectly, no rubbing, no modifications required.
macca said:
As ever, this forum is the nuts!
On the subject of nuts, I'm embarrassed to say I can't recall ever seeing them (ooooo'errrrr
). So, looking at my profile picture I still can't see them for the cap - is there something obvious that I'm not noticing?
An Estoril with the cap removed On the subject of nuts, I'm embarrassed to say I can't recall ever seeing them (ooooo'errrrr
). So, looking at my profile picture I still can't see them for the cap - is there something obvious that I'm not noticing? 
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