How To MEASURE WHEEL OFFSET (in detail) - written by myself: (I have included real figures). Example based on tire/tyre 226 wide (nominal 225/45/16)
- Remove a wheel, and lay the outside face of the wheel flat on the ground. (So now your looking at the wheel mount face)
- Place a flat piece of material or other flat material wider than the tire/tyre on top of tire, and carefully measure from the ground the overall height (or width) of your tyre & rim package = eg. 226 mm high.
Then divide your answer by 2 = 113 (this gives you the centre line of the rim and tyre)
- Place a ruler though the middle of the rim and measure from 'ground to wheel mount face' = eg. 92.5
- Subtract 113-92.5 = 20.5 mm. This is your wheel offset.
Most rims are positive offset these days, the mount flange being way out near the outside of the wheel. - From rim centre line, positive offset is where the hub / mount flange is toward the outer edge of rim.

More advanced double check method - You have measured the overall width of rim or wheel, eg 226. To check your math, your after the two figures from your wheel that will combine & add up to 226.
Your previous << Place a ruler though the middle of the rim and measure from 'the ground to wheel mount face' = eg. 92.5 >> Now do from top of wheel down to the mount flange eg 133.5. CHECK 92.5 + 133.5 = 226 overall width.
If your figures don't add up to the overall width, then keep checking all 3 figures till they do. It can be agony but ultimately you will understand your wheel perfectly.
Offset check - Once your above figures add up, you will get the same offset answer using either dimension, Eg. 226/2=113 centre line of rim.
Now 113-92.5 = 20.5 mm being the same as 133.5-113= 20.5 mm offset.

Whatever your wide wheel width, try and keep at least 25 mm or 1" clearance on inner tire/tyre to inner guard.

Examples of spacer thicknesses to achieve a wider track:

RIM DIMENSION	TIRE / TYRE SIZE	OPTIMIZED SPACER THICKNESS	FINAL OFFSET
Standard 15" rim offset 20 mm		R-Sport 20 mm or ~ 25/32"	20 - 20 = 0 mm
16 X 7 with std rim offset 20 mm	225 / 50 /16	8 mm or 5/16"	20 - 8 = 12 mm

LONGER WHEEL STUDS - Notes: On a 240 with Volvo spec rims, if fitting spacers over 5 mm thick, longer wheel studs are definitely required - always check for full nut thread length.
The 240 Volvo & SAM extended wheel bolts (studs) are available individually - Part #8360085. Volvo and SAM can also supply a (expensive) factory 240 Spacer Kit #8360083 that includes 2 x 20 mm rear wheel spacers plus 10 extended wheel bolts and longer attachment screws (if required, the alloy spacers can be machined thinner).
For the 740, the SAM longer stud is #9508764 . Nearly all large Volvos use the 5 x 108 PCD stud pattern even on the newest models.

240 wheel stud thread is 1/2"x 20 TPI UNF. The only 17" Volvo wheel designed for the Volvo 200/700 series where the Polaris, PN 3529717. A most attractive 17x7" five spoke wheel with a 20mm offset. Wide wheels are best utilized in low offset configurations so wider tires don't rub the inner rear fender.

Wheel Lip Roller Tool - New and trendy solution - There available in the shops these days. Or call the Tire Rack, 1-888-981-3952, and rent their professional Wheel Lip Roller Tool - fast, cheap and high quality results (pics, thanks Alvo, USA)

Pic A

Different Types of wheel spacer: Standard Offset Rims: See Pic A - Reasons for wheel spacers: to move a wider rim away from the inside arch (thus to reduce rim offset); and / or to obtain a slightly wider wheel track for enhanced cornering stability. Most Volvo 240/740 alloy rims have a offset of 20 mm. - Method: Longer genuine Volvo wheel studs #8360085 combined with a spacer of thickness between 5 and 20 mm. The spacer Pic A is both hub and stud centric. Spacer attaches to hub with 1 screw as per Volvo rear standard. Important note: Ensure spacers have a big countersunk / chamfer / relief on each stud hole. This is to clear the base diameter of the wheel stud, as its a lot larger than the thread, and to ensure wheel nuts torque up properly. The spacer must fit dead flat against the hub - check this.

PIC B (Pic by Alvaro Gil)

Large Offset Rims: See Pic B (850 type onto a 240/740) Reasons for wheel spacers: 850 rim offset is 43 +mm, so at least a 30 mm spacer is req'd to suit a 240/740. On a 240 with T-5R rims,a reader says 15mm spacer on the front works. (real offset 43-15=28mm) Pic B shows a large offset adaptor. Stage 1 bolts up to the existing hub using wheel nuts. Stage 2 - uses the new wheel studs pressed in from the back to attach to new rims. Commercial units are available and are listed on this webpage. An alternative is to track down a precision machinist to make the spacer, as both lathe and milling machines are required. Custom made spacers offer the chance to change the Stage 2 PCD (pitch circle diameter) dimensions to suit a more popular rim. Using a milling machine with a dividing head attached to the bed, the centre bore must be clocked up exactly before the pitch circle diameters are slot drilled or twist drilled through. Both sets of PCD holes should be drilled (or at least pilot drilled) in the same setup, otherwise the rim will never run concentric with the axle/spacer, no matter how well the wheel is balanced. ADAPTOR Kits - front& rear ADAPTS 850 wheels onto 200/700/900 Sources: 'Gil Racing Products' in USA, or 'In Styling' in Finland

FURTHER READING and Selection: H&R Wheel Spacers in USA. (Australian agent is TCCA Motorsport)
H&R Spacers for a variety of Volvo models

---

Typical Volvo Offsets (not all model variants are listed)

100-series : 5 holes x 108mm bolt circle, 40mm offset. - Up to 1974
100-series : 5 holes x 108mm 25mm offset - 1975-
200-series : 5 holes x 108mm 20mm offset.
700-series : 5 holes x 108mm 25mm offset. - 700-series will fit 200-series and vice versa
900-series : 5 holes x 108mm 25mm offset
850-series : 5 holes x 108mm 43mm offset - 1994 on
S80 T6 - 5 holes x 108mm 17 x 7 with 35mm offset
S80 17" Canopus Rims : 5 holes x 108mm 49mm offset #9451347

---

Technical Article

Wheel Track, Brakes and Rims By Anthony Hyde 15 /1/2008 - For NSW Volvo Club newsletter

This months technical musings touches the subject of Wheel Track, Brakes and Rims.

Wheel Track is the width between the front wheels verses the width between rear wheels. Note this is different from 'wheelbase' being distance from front to rear wheel centres. Track dimension depends on the width of rim / tyre fitted. A reason for looking deeper into this is a 240 front brake upgrade and hence rim clearance.

The 240's have a rather odd Track width, the front being far wider than the rear, so when viewed from behind it's very noticeable, and if one didn't know any better you might conclude the chassis is out of whack. Keen car club members eyes are drawn to cars with dents and chassis issues.

240 Track width (with alloy rims) is typically Front 1420 mm and Rear 1350. That's 70 mm difference or a very noticeable 35 mm per side. No wonder R-Sport offered 20 mm per side wheel spacers !

By comparison :
142 Track width is both 1350 mm Front and Rear, so dead even.
740 Turbo Track width is both 1460 mm Front and Rear, so even. Other 740s are within 10 mm of this, so at worst a 5 mm difference either side.

A Victorian Volvo club fellow, Ash Davies, worked out Mazda RX7 Turbo brake callipers can be adapted without drama to the 240. I have the parts on the work bench for investigation. The RX7 calliper is of similar design to the Volvo being a 4 piston design, but is made from Al.Alloy being 1.8 kg lighter than the Volvos cast iron. The brake disc is from a 740 Volvo 1988-95 being 23.4 mm bigger in outside diameter so offering more leverage.

But, the RX7 Turbo brake callipers are a bit wider by about 6 mm, and placed further out on the 740 disc, so the typical Volvo 15x6 242GT / GLE Virgo rims don't fit.

Volvo 16" rims (Gemini 5 spoke) fit but need a 6.4 mm spacer, so freak me out, the front track would be even further out per side 35+6 = 41 mm. The wheel alignment guy would laugh.

This leads to considering custom rims, the 3 piece design by Simmons Wheels in Sydney. This way a rim can be made so they don't need spacers, will clear the brakes, and the rim will sit where a standard one does thus avoiding tyre scrub issues. To my surprise, the price of Simmons is much the same as 10 years ago, so a lot more affordable these days.

Wheel Track, Brakes and Rims, they all need to be considered as the 240 front to rear Track is rather odd compared to other Volvo models.

---

Back to Quick Technical Index OR Back to Volvo Turbo World OR Back to 240 Sports Handling Article

Updated 1/2008 AH.