SDHA4SLine
Registered User
In a similar fashion to another thread I made earlier but for a different subject matter...
Seems that a lot of members have questions about wheel sizes and offsets so thought I'd post a thread to collate all other threads covering these subjects that I can find.
I'll keep adding to it as I find them
Please correct me if I’m wrong with my understanding below as I don’t mislead someone but this is how I understand things...
Offset basics
The offset is described by the term ET, which is from the German word 'Einpresstiefe' translated as 'insertion depth'
The smaller the offset number is the further outboard the wheel will be. For example: an 18-8.5J ET45 wheel would sit further into the wheel arch than an 18-8.5J ET35 wheel would. In effect your wheel base would be 20mm wider (10mm a side) with the ET35’s when compared with the ET45 of the same wheel diameter & width
Just to complicate things a little, the offsets in the above examples refer to positive offsets; thought I understood the negative offsets but have since deleted my explanation as I'm not sure. Can anyone explain the negative offsets please?
Wheel size basics
For example you have a wheel size of 18-8.5J;
The 18 is the diameter of the wheel in inches from edge to edge, measured inside the flange.
The 8.5 is the width of the rim, again measured in inches between the flanges.
Note that the measurements are inside the flanges so are not representative of the absolute external measurements of the wheel.
The letter, in this case J refers to the shape of the rim. Rim contours are standardized by the Tire and Rim Association, so that tires will fit. I’ve not seen a wheel that isn’t quoted a ‘J’ yet!
Hope this helps someone
Regards
Steve
Links to threads below
WHEEL OFFSET THREADS
http://www.audi-sport.net/xf/threads/9jx20-offset-wheel-question.248048/
http://www.audi-sport.net/xf/threads/much-difference-in-offset-45-42.236412/
http://www.audi-sport.net/xf/threads/wheel-offset-question.224541/
http://www.audi-sport.net/xf/threads/offset-question.211031/
http://www.audi-sport.net/xf/threads/nice-clear-wheel-offset-help-site-for-those-confused-amongst-us.238023/
http://www.audi-sport.net/xf/threads/offset.178628/
http://www.audi-sport.net/xf/threads/wheel-offset-help.188326/
http://www.audi-sport.net/xf/threads/wheels-width-and-offset-question.169812/
http://www.audi-sport.net/xf/threads/wheels-width-and-offset-question.169812/
http://www.audi-sport.net/xf/threads/best-combo-of-tyres-offset-and-width.160631/
http://www.audi-sport.net/xf/threads/my-lack-of-offset-et-knowledge.160912/
http://www.audi-sport.net/xf/threads/would-an-offset-et29-fit.150591/
http://www.audi-sport.net/xf/threads/wheel-offset.108162/
http://www.audi-sport.net/xf/threads/b7-avant-wheel-offset.149840/
http://www.audi-sport.net/xf/threads/b7-a4-alloy-pcd-and-offset-and-centre-bore-size.138260/
http://www.audi-sport.net/xf/threads/wheel-offset-help.103220/
http://www.audi-sport.net/xf/threads/offset-for-2-0t-after-market-alloys.106726/
http://www.audi-sport.net/xf/threads/b7-a4-avant-19-wheel-offset-advice.109477/
http://www.audi-sport.net/xf/threads/18-s-line-alloys-correct-offset.107485/
http://www.audi-sport.net/xf/threads/maximum-offset-without-catching-scrubbing.93435/
http://www.audi-sport.net/xf/threads/what-sort-of-offset-can-you-get-away-with-on-a-s-line-avant.101095/
http://www.audi-sport.net/xf/threads/wheel-offset-question.79317/
http://www.audi-sport.net/xf/threads/what-offset-can-i-get-away-with-on-a-8j-18-wheel-on-my-2-0-tdi.104401/
http://www.audi-sport.net/xf/threads/pic-req-a4-cab-with-18-rs4-6-alloys-35-offset-show-diff-from-43-offset.89073/
http://www.audi-sport.net/xf/threads/help-offset.65914/
http://www.audi-sport.net/xf/threads/offset-question.64008/
http://www.audi-sport.net/xf/threads/alloys-offset-query.68912/
http://www.audi-sport.net/xf/threads/changing-wheel-offset-from-43-to-30-on-a4-cab-any-issues-wanting-to-fill-arches-out.88118/
http://www.audi-sport.net/xf/threads/rs4-rep-wheels-sizes-offset-query.62404/
http://www.audi-sport.net/xf/threads/what-offset-for-18-alloys.53774/
http://www.audi-sport.net/xf/threads/correct-offset.34684/
http://www.audi-sport.net/xf/threads/new-a4-cab-offset-pcd.39604/
WHEEL SIZE THREADS
http://www.audi-sport.net/xf/threads/wheel-sizes.243515/
http://www.audi-sport.net/xf/threads/rs4-minimum-wheel-size.238863/
http://www.audi-sport.net/xf/threads/steel-wheel-size-advise-please-ie-winter-wheels.202728/
http://www.audi-sport.net/xf/threads/wheel-sizes-will-i-get-issues.183165/
http://www.audi-sport.net/xf/threads/front-s4-discs-and-carriers-on-an-a4-wheel-size-question.189187/
http://www.audi-sport.net/xf/threads/18-wheels-what-size-tyres.156070/
http://www.audi-sport.net/xf/thread...ro-se-s-line-lowering-and-wheel-sizes.164309/
http://www.audi-sport.net/xf/threads/smallest-wheel-size-on-an-07-avant.136212/
http://www.audi-sport.net/xf/threads/tyre-size-for-staggered-merc-wheels.128845/
http://www.audi-sport.net/xf/threads/alloys-wheel-size-can-20-8-5-fit-straight-on.134667/
http://www.audi-sport.net/xf/threads/rs4-rep-wheels-sizes-offset-query.62404/
USEFUL EXTERNAL SITE LINKS BELOW
http://www.willtheyfit.com/ - The Wheel Fitment, Tyre Stretch, Rolling Radius & Speedometer Error Calculator
http://www.rimstyle.com/pages/alloy_wheels_explained.html - Alloy Wheel Specifications Explained, How an Alloy Wheel Fitment Is Determined
http://www.driverstechnology.co.uk/wheel-offset.htm - Wheel offset information
http://www.superforma.co.uk/hubcentric-explained - Hubcentric wheel spacers explained
http://www.1010tires.com/Tools/Wheel-Offset-Calculator - Wheel Offset Calculator
http://www.wheel-size.com/calc/?wheel1=205-55-16X6.5ET45&wheel2=225-45-17X7.5ET40&fcl=50mm&wcl=30mm&scl=50mm - Rim & Tire Size Calculator. Custom Offsets
Seems that a lot of members have questions about wheel sizes and offsets so thought I'd post a thread to collate all other threads covering these subjects that I can find.
I'll keep adding to it as I find them
Please correct me if I’m wrong with my understanding below as I don’t mislead someone but this is how I understand things...
Offset basics
The offset is described by the term ET, which is from the German word 'Einpresstiefe' translated as 'insertion depth'
The smaller the offset number is the further outboard the wheel will be. For example: an 18-8.5J ET45 wheel would sit further into the wheel arch than an 18-8.5J ET35 wheel would. In effect your wheel base would be 20mm wider (10mm a side) with the ET35’s when compared with the ET45 of the same wheel diameter & width
Just to complicate things a little, the offsets in the above examples refer to positive offsets; thought I understood the negative offsets but have since deleted my explanation as I'm not sure. Can anyone explain the negative offsets please?
Wheel size basics
For example you have a wheel size of 18-8.5J;
The 18 is the diameter of the wheel in inches from edge to edge, measured inside the flange.
The 8.5 is the width of the rim, again measured in inches between the flanges.
Note that the measurements are inside the flanges so are not representative of the absolute external measurements of the wheel.
The letter, in this case J refers to the shape of the rim. Rim contours are standardized by the Tire and Rim Association, so that tires will fit. I’ve not seen a wheel that isn’t quoted a ‘J’ yet!
Hope this helps someone
Regards
Steve
Links to threads below
WHEEL OFFSET THREADS
http://www.audi-sport.net/xf/threads/9jx20-offset-wheel-question.248048/
http://www.audi-sport.net/xf/threads/much-difference-in-offset-45-42.236412/
http://www.audi-sport.net/xf/threads/wheel-offset-question.224541/
http://www.audi-sport.net/xf/threads/offset-question.211031/
http://www.audi-sport.net/xf/threads/nice-clear-wheel-offset-help-site-for-those-confused-amongst-us.238023/
http://www.audi-sport.net/xf/threads/offset.178628/
http://www.audi-sport.net/xf/threads/wheel-offset-help.188326/
http://www.audi-sport.net/xf/threads/wheels-width-and-offset-question.169812/
http://www.audi-sport.net/xf/threads/wheels-width-and-offset-question.169812/
http://www.audi-sport.net/xf/threads/best-combo-of-tyres-offset-and-width.160631/
http://www.audi-sport.net/xf/threads/my-lack-of-offset-et-knowledge.160912/
http://www.audi-sport.net/xf/threads/would-an-offset-et29-fit.150591/
http://www.audi-sport.net/xf/threads/wheel-offset.108162/
http://www.audi-sport.net/xf/threads/b7-avant-wheel-offset.149840/
http://www.audi-sport.net/xf/threads/b7-a4-alloy-pcd-and-offset-and-centre-bore-size.138260/
http://www.audi-sport.net/xf/threads/wheel-offset-help.103220/
http://www.audi-sport.net/xf/threads/offset-for-2-0t-after-market-alloys.106726/
http://www.audi-sport.net/xf/threads/b7-a4-avant-19-wheel-offset-advice.109477/
http://www.audi-sport.net/xf/threads/18-s-line-alloys-correct-offset.107485/
http://www.audi-sport.net/xf/threads/maximum-offset-without-catching-scrubbing.93435/
http://www.audi-sport.net/xf/threads/what-sort-of-offset-can-you-get-away-with-on-a-s-line-avant.101095/
http://www.audi-sport.net/xf/threads/wheel-offset-question.79317/
http://www.audi-sport.net/xf/threads/what-offset-can-i-get-away-with-on-a-8j-18-wheel-on-my-2-0-tdi.104401/
http://www.audi-sport.net/xf/threads/pic-req-a4-cab-with-18-rs4-6-alloys-35-offset-show-diff-from-43-offset.89073/
http://www.audi-sport.net/xf/threads/help-offset.65914/
http://www.audi-sport.net/xf/threads/offset-question.64008/
http://www.audi-sport.net/xf/threads/alloys-offset-query.68912/
http://www.audi-sport.net/xf/threads/changing-wheel-offset-from-43-to-30-on-a4-cab-any-issues-wanting-to-fill-arches-out.88118/
http://www.audi-sport.net/xf/threads/rs4-rep-wheels-sizes-offset-query.62404/
http://www.audi-sport.net/xf/threads/what-offset-for-18-alloys.53774/
http://www.audi-sport.net/xf/threads/correct-offset.34684/
http://www.audi-sport.net/xf/threads/new-a4-cab-offset-pcd.39604/
WHEEL SIZE THREADS
http://www.audi-sport.net/xf/threads/wheel-sizes.243515/
http://www.audi-sport.net/xf/threads/rs4-minimum-wheel-size.238863/
http://www.audi-sport.net/xf/threads/steel-wheel-size-advise-please-ie-winter-wheels.202728/
http://www.audi-sport.net/xf/threads/wheel-sizes-will-i-get-issues.183165/
http://www.audi-sport.net/xf/threads/front-s4-discs-and-carriers-on-an-a4-wheel-size-question.189187/
http://www.audi-sport.net/xf/threads/18-wheels-what-size-tyres.156070/
http://www.audi-sport.net/xf/thread...ro-se-s-line-lowering-and-wheel-sizes.164309/
http://www.audi-sport.net/xf/threads/smallest-wheel-size-on-an-07-avant.136212/
http://www.audi-sport.net/xf/threads/tyre-size-for-staggered-merc-wheels.128845/
http://www.audi-sport.net/xf/threads/alloys-wheel-size-can-20-8-5-fit-straight-on.134667/
http://www.audi-sport.net/xf/threads/rs4-rep-wheels-sizes-offset-query.62404/
USEFUL EXTERNAL SITE LINKS BELOW
http://www.willtheyfit.com/ - The Wheel Fitment, Tyre Stretch, Rolling Radius & Speedometer Error Calculator
http://www.rimstyle.com/pages/alloy_wheels_explained.html - Alloy Wheel Specifications Explained, How an Alloy Wheel Fitment Is Determined
http://www.driverstechnology.co.uk/wheel-offset.htm - Wheel offset information
http://www.superforma.co.uk/hubcentric-explained - Hubcentric wheel spacers explained
http://www.1010tires.com/Tools/Wheel-Offset-Calculator - Wheel Offset Calculator
http://www.wheel-size.com/calc/?wheel1=205-55-16X6.5ET45&wheel2=225-45-17X7.5ET40&fcl=50mm&wcl=30mm&scl=50mm - Rim & Tire Size Calculator. Custom Offsets
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