True Tyre Size Comparisson

[Highway-Star]

I think this is a good thread, and hope my additions are of some value to someone.

Note:
- All measurements are unloaded (photos with tyres on vehicle, have the vehicle jacked up).
- All pressure readings taken with same gauge, and are to the nearest 5Kpa / 1Psi.
- All measurements (except tread depth) are to the nearest 5mm for no more accuracy can really be obtained IMO.

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Tyre: Bridgestone SF405 Steel (I believe this to be the exact tyre that WT Sierras came factory with)
Size: 205/70R15
Rim: 15x5.5JJ Sierra steel rim
Pressure: 110KPa (16Psi)
Diameter: 650mm (25.6")
Carcass W: 195mm (7.7")
Tread W: 165mm (6.5")
Tread: 5mm (Half worn)


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Tyre: Kuhmo Road Venture AT
Size: 205/70R15
Rim: 15x5.5JJ Sierra steel rim
Pressure: 190KPa (28Psi)
Diameter: 645mm (25.4")
Carcass W: 200mm (7.9")
Tread W: 155mm (6.1")
Tread: 6mm (Half worn)


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Tyre: Firestone ASR
Size: 205/75R15
Rim: 15x5.5JJ Sierra steel rim
Pressure: 170KPa (25Psi)
Diameter: 680mm (26.8")
Carcass W: 200mm (7.9")
Tread W: 155mm (6.1")
Tread: 9mm (Pretty good)


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Tyre: Firestone Destination H/T
Size: 235/75R15
Rim: 15x8 Jeep XJ Cherokee rims (sorry about this )
Pressure: 180KPa (27Psi)
Diameter: 705mm (27.6")
Carcass W: 230mm (9.1")
Tread W: 185mm (7.3")
Tread: 3mm (Essentialy bald)


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Tyre: Falken-RV Landair/AT Traction
Size: 31x10.5R15
Rim: 15x7 Kings steel (suit Sierra)
Pressure: 145KPa (22Psi)
Diameter: 760mm (29.9")
Carcass W: 250mm (9.8")
Tread W: 225mm (8.9")
Tread: 15mm (Pretty close to 100%)


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Tyre: BFGoodrich Mud-Terrain T/A
Size: 31x10.5R15
Rim: 15x7 Speedy steel (suit Sierra)
Pressure: 140KPa (20Psi)
Diameter: 750mm (29.5")
Carcass W: 250mm (9.8")
Tread W: 220mm (8.7")
Tread: 8mm (Pretty worn)


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Tyre: Sime Tyres Centipede MT
Size: 31x10.5R15
Rim: 15x7 Alloys (suit Sierra, unknown make)
Pressure: 140KPa (20Psi)
Diameter: 750mm (29.5")
Carcass W: 245mm (9.6")
Tread W: 210mm (8.3")
Tread: 15mm (Pretty close to new)


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Tyre: Silverstone MT-117 Extreme
Size: 31x10.5B15
Rim: 15x7 Speedy steel (suit Sierra)
Pressure: 110KPa (16Psi)
Diameter: 770mm (30.3")
Carcass W: 240mm (9.5")
Tread W: 250mm (9.8") (outer lug to outer lug)
Tread: 17mm (Pretty close to new)


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[hyzook]

Does any one run Silverstone mt117 extremes in 35x11.5x15 and if so what is the actual true diameter ? and I would also like to know what Q78 swampers are in 15" (measured 3 o'clock to 9 o'clock)

My BFG's 33x10.5x15 are 32 1/4" (3 to 9) 75% tread and i have been told swamper TSL 34X9.5x15 are 33 3/4" near new (also 3 to 9)

[hobzees4wdshop]

Heard unofficially that a Q78-15 is about 35.5" in diameter.

The Silverstone MT-117 Extreme in 35x11.5-15 and 35x10.5-16 are listed as 34.7" in diameter.

I also measured up a Maxxis 35x12.5-15 Creepy Crawler Before and it only measures 33.6"

if anyone is after these tyres drop us a line.

[TRobbo]

Hobzee if the diameter is so far out on the creepy, what is the actual width?

[hobzees4wdshop]

Hi TRobbo,

Actual width of unmounted Creepy Crawler 35x12.5-15 is: 33.6"x12.5", measured on one here in the warehouse.

EDIT: Ok It got the better of me, I just spoke to the Maxxis Distributor about this issue and he stated that Bias tyre umounted will not hold shape as well as a radial in storage.

"This tyre mounted on a 10inch wide rim inflated to operating road pressure ~35psi will actually measure 34.9". On narrower rims some crowning will occur to the centre lugs and will measure just over 35".

That solves the issue and hence the reasoning for getting dimensions of mounted tyres vs unmounted tyres.

[mike_nofx]

Silverstone Mt-117 Xtreme. 33x10.5" on 15x7" Rim.

I measured the tyres, using straight edges on opposite sides of the tyre (While fitted to the car, at the 3 + 9 o'clock points)

It measured exactly 809mm or 31.85".

[hyzook]

Heard unofficially that a Q78-15 is about 35.5" in diameter.

The Silverstone MT-117 Extreme in 35x11.5-15 and 35x10.5-16 are listed as 34.7" in diameter.

I also measured up a Maxxis 35x12.5-15 Creepy Crawler Before and it only measures 33.6"

if anyone is after these tyres drop us a line.

Thanks, I may be after a set of either dependind on engineering, is the listed size for the silverstone actual?

[jazuki]

Can anyone tell me the actual true diameter of a 32-9.5-15 super swamper tsl ?

Cheers
Jamie