Thread: Differences on gearing between 235/85 and 255/85

Pilfered from BFG MT KM2 website...

LT235/85R16 120/116Q diam 32" 650 revolutions @ 70km/h

LT255/85R16 123/120Q diam 33.3" 625 revolutions @ 70km/h


So in that particular tyre there will be a 4% variation in gearing between 235 and 255.


Steve

Thanks for that.

So low range decents will become even slower, and highway driving will require higher engine rpm?

depends which way you are going.
235s will require more revs for a given speed over ground (not what the speedo says it will change) than the 255s and similarly, in low range 235s will give you 4% deeper gearing. 4% aint much though.

255s are a great tyre size, good height for clearing a sals rear diff, not too wide.
Only problem is the limited number of tyres made in 255/85R16.

Steve

excelent, thanks for your help!

The difference between worn out 235's and new 255's is closer to 7% just going off my speedo readings.

Yes, the bigger tyres bugger up the turning circle, particularly on a 130 but you get used to it quickly. It's only when you jump into a GU Patrol and you do a U turn easily in the space a 5 point turn needs to be made with the 130 that you curse

AFAIK, only BFG MT's, Maxxis Big Horn 762's and Cooper ST's are available in 255/85/16 in Australia.

We have just put 33/10.5/15" bfg mt's and to be honest the only thing we have niticed is the speedo being a tiny bit out
Gearing is still fine
We are running slightly wider off-set rims so don't lose any turning cicle

TIM.

Im try to find out if Toyo do a 255/85. The Au site doesn't list one, but they're talked about on US sites. They look pretty good, a bit more open than a Bighorn.

Originally Posted by Aaron

Im try to find out if Toyo do a 255/85. The Au site doesn't list one, but they're talked about on US sites. They look pretty good, a bit more open than a Bighorn.

Dunlop do their aggressive MT in 255/85 for Europe, but not here, but the more people buy this size, the more likely it is that importers will bring them in.
IMO it's a great compromise.
oh, and the Maxxis is a bit bigger in the bag/wider than the BFG too, you can notice it when they are fitted, possibly 8mm or so.