Topic: Guide to Wheel Offset (Read 2883 times)

silky07 · « **Reply #20 on:** August 18, 2008, 10:54:57 AM »

il check out angels. thanks for all your help karma on the way

J@zV6 · « **Reply #21 on:** August 18, 2008, 13:48:54 PM »

Quote from: silky07 on August 18, 2008, 08:44:51 AM

ok im sorry but im totally lost with all of this lol .....

ok i want to put 17" on my calibra 8v is this off set to do with the rims or the tyres

thanks .

The offset is what relates the centre line of the wheel to the mating face on the hub. It has nothing directly to do with the diameter of the rim, the width of the rim, or the size and profile of the tyre - except that, if you use much wider rims and tyres than standard (e.g. >225) the offset does affect the clearance slightly, particularly when the wheel is on full lock.

For example, the standard rim is only 7" wide, but that can comfortable take a tyre of up to 205mm (8"). A typical aftermarket rim may be 8", 8.5", or 9".

My Kosei RT Penta 17"s are 9" wide and comfortably take a 215mm (8.45") tyre. I could probably fit a 225mm (nearly 9") tyre to the rim, but I'm not sure whether the tyre would get clearance on full lock, particularly because I have the wrong offset on my rims. I'm not sure whether ET35 would make the clearance more or less on the inside of the wheelarch...

Blaster · « **Reply #22 on:** April 16, 2009, 08:56:55 AM »

Im planning to use 215/45-17. But afraid it will scrub the arches if the offset is to low.
I have tested it with rims of 7x17 ET37. And they scrub in the front almost continuously.
Its realy hard to find some nice rims with high offset.
The car is lowered approx 30mm with Eibach springs. So, how low offset can I go to let this tires fit?

Anyone experienced?

J@zV6 · « **Reply #23 on:** April 16, 2009, 10:52:04 AM »

Quote from: Blaster on April 16, 2009, 08:56:55 AM

Im planning to use 215/45-17. But afraid it will scrub the arches if the offset is to low.
I have tested it with rims of 7x17 ET37. And they scrub in the front almost continuously.
Its realy hard to find some nice rims with high offset.
The car is lowered approx 30mm with Eibach springs. So, how low offset can I go to let this tires fit?

I think that the problem you've got might be the profile, rather than the offset. I think that you ought to be running a 40% profile, rather than a 45%. The rolling radius of the tyre you are running is around 9mm bigger than standard tyres. A 40% profile should be about 1mm smaller.

IIRC the offset on my wheels is ET35 (which is not recommended!). I don't get any rubbing, but I'm using 215/40R17.

Blaster · « **Reply #24 on:** April 18, 2009, 13:17:03 PM »

Yeah that may be the issue. But is you cally lowered? How much?

J@zV6 · « **Reply #25 on:** April 18, 2009, 20:50:39 PM »

Quote from: Blaster on April 18, 2009, 13:17:03 PM

Yeah that may be the issue. But is you cally lowered? How much?

Unless the car has been really slammed, clearance shouldn't be a problem if the rolling radius is roughly the same size as the standard tyre. It certainly ought to be possible to drop it at least -40mm without having to roll the arches, or anything like that.

thegeth · « **Reply #26 on:** April 18, 2009, 20:53:05 PM »

I had et38, lowered 40mm and got rubbing on large bumps and bumpy backroads.

J@zV6 · « **Reply #27 on:** April 18, 2009, 21:03:38 PM »

Quote from: thegeth on April 18, 2009, 20:53:05 PM

I had et38, lowered 40mm and got rubbing on large bumps and bumpy backroads.

With what wheels and tyres? And was it rubbing on cornering, or when driving in a straight line?

thegeth · « **Reply #28 on:** April 18, 2009, 22:19:13 PM »

Quote from: J@zV6 on April 18, 2009, 21:03:38 PM

With what wheels and tyres? And was it rubbing on cornering, or when driving in a straight line?

17" with 215/40's, mainly rubbing when going in a straight line. Was just catching the arch lining.

Blaster · « **Reply #29 on:** April 18, 2009, 23:36:49 PM »

I would guess that anything with lower offset than approx 40 will rub if the cally bump to much. I can see the edge of the wheel has a strait line to hit the arch with 37 offset. It may help using 215/40-17 with low offset, but as I see now, a final solution would be using 40+ offset (but how low...?). I talked to a guy recently, he has 215/45-17 with 45 offset, lowered 40mm. And has no issues with scrubbing at all. Im looking at some nice rims with offset 42. But I think its like gambling to buy them. Would be nice if anyone have tried offset 42 with 215/45-27, lowered 30mm+ with succe.

J@zV6 · « **Reply #30 on:** April 19, 2009, 11:42:34 AM »

Quote from: Blaster on April 18, 2009, 23:36:49 PM

It may help using 215/40-17 with low offset, but as I see now, a final solution would be using 40+ offset (but how low...?). I talked to a guy recently, he has 215/45-17 with 45 offset, lowered 40mm. And has no issues with scrubbing at all. Im looking at some nice rims with offset 42. But I think its like gambling to buy them. Would be nice if anyone have tried offset 42 with 215/45-27, lowered 30mm+ with succe.

With the exception of SRi & GSi models, Vx tends to overgear their cars, primarily for fuel economy. Why would you want to raise the gearing even further by using a 45% profile, when 40% is much closer to the original tyre size?

Blaster · « **Reply #31 on:** April 19, 2009, 12:11:43 PM »

45% is noticeably much more comfortable than 40%. I can tell for sure, tried both on several cars. And, 45% is still within the tolerance.
And as I can notice, whatever you run 40 or 45%, the arches may scrub with to low offset (but how low can we go

). I think its just the 40% have a bit more clearance before it does.

215/40-R17 215/45-R17 Tolerance 80 km/t
189.69 cm 196.44 cm 6.75 cm (3.56 %) 82.75
Diameter 60.38 cm 62.53 cm 2.15 cm

Ave · « **Reply #32 on:** June 15, 2009, 12:06:30 PM »

Hi all, i have a 2.5V6 Calibra 95 plate. it currently has 5 stud fox alloys on that are shot to hell.

i was looking on some sites for new ones and have noticed some listing alloys for Calibra's are only 4 stud. anyone know what the correct measurements are for my motor before i waste all my money on some alloys that wont fit.

JB · « **Reply #33 on:** June 15, 2009, 12:08:26 PM »

ET 49
PCD 5x110

J@zV6 · « **Reply #34 on:** June 15, 2009, 12:47:44 PM »

Quote from: Blaster on April 19, 2009, 12:11:43 PM

45% is noticeably much more comfortable than 40%. I can tell for sure, tried both on several cars. And, 45% is still within the tolerance.
And as I can notice, whatever you run 40 or 45%, the arches may scrub with to low offset (but how low can we go ). I think its just the 40% have a bit more clearance before it does.

   215/40-R17    215/45-R17 Tolerance 80 km/t
189.69 cm    196.44 cm 6.75 cm (3.56 %) 82.75
Diameter 60.38 cm    62.53 cm 2.15 cm

True, but you should be comparing it with the standard tyre, rather than another aftermarket replacement. The 215/45R17 will cause the speedo to under-read by 3.1% compared to a standard 205/55R15 tyre i.e. at a reading of 80mph, the actual speed will be about 82.4mph. It will be doing 16 revs less per kilometre. This may not be a problem, but the increase in rolling radius of 9.4mm may be a problem if the offset is too low, or the car has been lowered significantly.

Bovva · « **Reply #35 on:** September 06, 2009, 13:07:53 PM »

you guys have heard of spacers right? if you have ET38 wheels, buy a 2mm spacer!

win win!

supercalibra · « **Reply #36 on:** September 06, 2009, 13:42:06 PM »

Quote from: Bovva on September 06, 2009, 13:07:53 PM

you guys have heard of spacers right? if you have ET38 wheels, buy a 2mm spacer!

That would make them ET36

Bovva · « **Reply #37 on:** September 06, 2009, 13:57:18 PM »

Quote from: supercalibra on September 06, 2009, 13:42:06 PM

That would make them ET36

if you are having trouble with the wheels rubbing on the inner arches, using a spacer will push the wheel further out of the arch minimising scrubbing.

thegeth · « **Reply #38 on:** September 06, 2009, 18:14:15 PM »

Quote from: Bovva on September 06, 2009, 13:57:18 PM

if you are having trouble with the wheels rubbing on the inner arches, using a spacer will push the wheel further out of the arch minimising scrubbing.

Umm no it would just make the rubbing further inside the tyre.

Bovva · « **Reply #39 on:** September 06, 2009, 18:59:06 PM »

Quote from: thegeth on September 06, 2009, 18:14:15 PM

Umm no it would just make the rubbing further inside the tyre.

You may be right, surely this depends on how car the full lock allows the wheel to travel into the arch?

Author Topic: Guide to Wheel Offset (Read 2883 times)

Bovva

supercalibra

Bovva

Bovva