I was trying to work out which is the bigger tyre for my series 3 88
235/85/16 31/10.5/16so im assuming thats 235mm Width which is 9 inches so the 31/10.5 is a wider tyre at 10.5 inches. Diameter wise its 31 inches but the diameter of the 235/85. hmm thats 85 percent of 16? or 85% of the width? So 16+the 85 perecent?? or is the 85 a radius in which case its 16+ 85%
+85%..?Im still slightly confused. Any pointers?
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235mm = 9.25 inches wide, so yes, the 10.5 inch tyre is wider. 235 x 85% = 199.75mm = 7.86 in sidewall. (2 x 7.86) + 16 = 31.75 in diameter.
So the 235/85 is 1.75 inches narrower, but 0.75inches bigger in diameter.
FWIW, I've just fitted 235/85s to my Ser IIa - brilliant! Less bouncy ride and a slight increase in gearing. Plus they fill the arches and look the biz. Remember wider tyres are generally less good in shallow mud, and if you haven't got power steering, 10.5in wide tyres could be hard work, at least at parking speeds. (Having said that, I haven't noticed much increase in steering effort going from 6.00x16 to 235/85.) Also, 10.5 wide might mean that the tyres project beyond the bodywork (235s just make it inside) which may mean a problem at MoT time, and will certainly cover your sides in mud at playtime.
HTH
On or around Mon, 30 Aug 2004 17:06:09 +0000 (UTC), "Richard Brookman" enlightened us thusly:
the 110 was almost unsteerable on a couple of occasions when I lost the PA bit of the PAS..
mind, a manual steering box is lower geared in the first place, I think.
as has been said, 235/85 are slightly bigger diameter than 31x10.5R15. 31 is nominally the same diameter as 7.50x16, but some of the 7.50R16 radials are taller than they should be.
Well, yes, but despite the lower gearing it is still harder to turn than a PAS-equipped vehicle. As I found out the other day. I've driven the series
2a to work for a fortnight now (despite the higher fuel cost) and I must be developing arms like Geoff Capes, cos when I got in the Rangie to pop into town I nearly mangled it on the bridge 200m from my drive. Turned *gently* to the left and - wham - the car scooted off at 90 deg towards the bridge wall. Took it a bit more carefully after that. :-)MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.