tyre size
Submitted: Sunday, Jun 27, 2004 at 13:51
ThreadID:
14180
Views:
2687
Replies:
5
FollowUps:
5
This Thread has been Archived
Richard
Im currently running 265/75/16 BFG ATs on my patrol, want to also get a set of MTs but am considering upping size to 285s...what problems could i have if any or is there anything i need to know.
Reply By: lralfi - Sunday, Jun 27, 2004 at 18:17
Sunday, Jun 27, 2004 at 18:17
what is the reason for all these tyre-types. I use only 100 % height MT's like 8.25/16, 9.00R16, 255 x100. These tyres are a little less wide than a 285 or 265 but they are higher. That is an advantage in Mud and esp. in soft Sand.
In the moment I prefer Michelin XZL, XS and Pirelli Dakar.
If you increase the Tyre size, the following can happen. The speedo will show you a wrong speed (slower) the Tyres can hit the body or the frame of the car. The gears become longer, you loose torque and you crawling speed increases. Another problem can be that your axles brake earlier, esp. if you use Difflocks. This is known for older LR and Jeeps, also for Toyota LC but not typical. The brakes loose power.
Ralf
AnswerID:
65393
Reply By: Nigel (WA) - Thursday, Jul 01, 2004 at 18:57
Thursday, Jul 01, 2004 at 18:57
Hi all,
Well i read alot about what you guys are saying, but i got a point to argue here a set of 265/75/16 BFG ATs and 285/75/16 BFG ATs should not affect the speedo, why you ask,
well all that is different is the width of the tyre not the height of the tyre, your wheel shouldn't be covering greater distance and effecting you speedo.
Sorry can some tell me, how the width of a tyre can effect a speedo
Nigel
AnswerID:
66004
Follow Up By: Muddy 'doe (SA) - Thursday, Jul 01, 2004 at 20:33
Thursday, Jul 01, 2004 at 20:33
The 75 refers to the height as a percentage of the width. 75% of 285 is more than 75% of 265!
Steven
FollowupID:
326866
Follow Up By: Member - Rohan K - Friday, Jul 02, 2004 at 21:16
Friday, Jul 02, 2004 at 21:16
Ergo, as you increase width, you increase overall diameter (2x2 radius) so the tyre is taller/higher, whatever you want to call it.
To calculate overall diameter use:
(width mm x profile % x 2) + rim mm
(265 x .75 x 2) + 406.4 = 803.9 mm diameter
(285 x .75 x 2) + 406.4 = 833.9 mm diameter
Percentage change is:
(833.9 - 803.9) / 803.9 x 100 = % change
33/803.9 x 100 = 4.1% larger diameter.
FollowupID:
327037