 | Home > Wheels & Tyres > Confused on tyres and sizes |
 
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| MC84 Member Since: 22 May 2016 Location: Near Bristol Posts: 360   
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Hi. I’m a bit bewildered with all the wheel and tyre information. I’m wondering if someone could guide me please? I have a Defender 90 2001 that I use 100% on road. Snow isn’t usually an issue where I live. I currently have Michelin XPC 7.50 R16’s on but they are getting a bit thin. Is there a good equivalent to these as I was told I might have trouble getting hold of the now and that I should go for Coopers. I might also look at replacing the steel wheels for something a bit more appealing. But the main question would be can I look for the size convention I’m more used to, namely 235 70 R16 for example as I’m not used to 7.50 format or am I indeed looking for 7.50’s? Mike
Hard Top 90 TD5 2001 Ford 100e 1959 www.youtube.com/mikemakesit |
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4th Dec 2018 9:09am |
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| MC84 Member Since: 22 May 2016 Location: Near Bristol Posts: 360
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So the 7.50 is the imperial equivalent to say 235 metric sizing? The penny is dropping! Mike
Hard Top 90 TD5 2001 Ford 100e 1959 www.youtube.com/mikemakesit |
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4th Dec 2018 10:00am |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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The 7.50 is approximately the same diameter as a 235/85 but is a lot narrower. Moving to a 235/85 will give you a lot more choice but you will also need new wheels as standard steel wheels are too narrow for them. The wider Wolf wheels are ok, or you could pick up a set of Boost alloys for not very much money. Darren
110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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4th Dec 2018 10:30am |
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| srod Member Since: 20 Mar 2015 Location: Argyll Posts: 190 |
Just a related question as black circles have a 10% off sale today and I need 4 new tyres myself.
Black circles don't have 7.5r16 listed but they do have 750 80 R16, do you think this is the same thing? The resulting tyre selections look like whats usually available (latitude cross, xzl, rangemaster etc.). I doubt I'll get a straight answer from their customer services number.... I want to stick to 7.5r16 for my 5.5j rims as I have seen 235 85 r16 fitted to this size of rim and it looks wrong. |
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4th Dec 2018 10:30am |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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750 80 r16 should be the same as 7.50 x 16. The '80' is the aspect ratio(width x sidewall height expressed as a percentage) but as it's essentially the same for all Imperial sized tyres, it's often left out of the description. Darren
110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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4th Dec 2018 10:35am |
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| WindyJ Member Since: 18 Oct 2018 Location: France Posts: 190 |
What width are the standard steel wheels? Mine are steels with 235/85 on, but maybe not standard wheel size then as seem seated perfectly. |
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4th Dec 2018 12:14pm |
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| WindyJ Member Since: 18 Oct 2018 Location: France Posts: 190 |
If converting to euro metric then 7.50 would be 205 I think but if going P-metric, like in USA then it would be higher, perhaps 235. |
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4th Dec 2018 12:17pm |
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| srod Member Since: 20 Mar 2015 Location: Argyll Posts: 190 |
Yes I think you are right. As expected contacting Black Circles got me nowhere. So I googled "750 80 r16" which resulted in an eBay listing for a Latitude Cross tyre in this size, seller was Black Circles 😀! On the eBay listing in the description was "MPN: 3528700240832" so I googled this number which led me to another tyre supplier site that had it listed as 7.5r16!! |
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4th Dec 2018 12:28pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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I'm sorry but this has no relevance. The difference between 'euro metric' and P metric tyres is in the load rating and not the physical dimensions. A 7.50 tyre is only considered to be the Imperial equivalent of a 235/85 (the second number is important in this context) because they're approximately the same diameter. They can therefore be interchanged without adversely affecting the speedo reading or the gearing. A 235mm tyre has a tread width approximately 45mm wider than a 7.50, though. Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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4th Dec 2018 1:11pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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Standard steel wheels for a Defender are 5.5 inches wide. The recommended minimum for a 235 tyre is typically 6.0 inches. Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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4th Dec 2018 1:24pm |
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| WindyJ Member Since: 18 Oct 2018 Location: France Posts: 190 |
Right, so a 7.50 could be eiher a 235 or 190 depending on which way you look at it (literally)...all depends on the profile..i.e you can only compare ones with the same profile? |
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4th Dec 2018 1:32pm |
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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 8155  
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the 7.50 relates to the width in inches
if not stated i thought it was a 90 or 100% aspect ratio,? the aspect ratio is the height of the rubber between rim and out tyre tread (the sidewall), so for total tyre height there are two of them to add in. the % figure is a % of the width. 16 is the rim size inches a 235 is the width in mm 85 is the aspect ratio ie 85% of 235mm for 1 of the two side walls. 16 - rim width in inches a 7.50 x 16 would be a 7.5 inch tyre width (190.5mm) with an 100% aspect ratio to give you a total tyre height of (7.5*1*2)+16 = 31" 235.85R16 = (235*0.85*2)+(16*25.4) = 805.9mm = 31.7" 255.85R16 = (255*0.85*2) + 16 = 840mm or 33.1" the height of the tyre on the rim also depends on the rim width. a 5J rim is narrower than an 8J. With the same width tyre on each the narrower rim will have a taller tyre as the centres are pinched in . Something else to consider is the narrower the rim for the tyre width the great the chance of damage to the sidewalls from off road damage. But go too wide and you loose the height and end up scuffing the rim everywhere! Cheers James 110 2012 XS Utility 130 2011 M57 bespoke Camper 90 2010 Hardtop 90 M57 1988 Hardtop |
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4th Dec 2018 2:23pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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As the profile is essentially a ratio, they don't have to be the same but they do have to be equivalent.
For example, 7.50r16, 235/85r16 and 265/75r16 are all sizes that have been standard on Defenders at various times. They're all equivalent diameters (within half an inch or so) and so are interchangeable without needing any mechanical alterations. They're all different widths, though. Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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4th Dec 2018 2:28pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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Actually, that's correct. Dunno what I was thinking earlier. That does make srod's Google result a bit odd but he still appears to have gotten to the correct result. Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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4th Dec 2018 2:33pm |
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