Perhaps a little too big...

rob_w · tinkerer Joined: 19 Feb 2002 Posts: 395

Hey guys, i just wanna know if running 185/75/13's on bathurst globe mags- either 13 or 14 inch-is just too big. i had them on my car before i changed the engine, and just want to know if i should bother putting them back on, or go for a smaller profile tyre.
ps, they don't scrub on the front guards either.
appreciate it, thanx for the patience,
rob.

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

yeah you will be fine but expect a little lack of steering responce, but gems came out with 165/75/13's, i run 205/60/13 on bathurst globes on the pv, no prob

ps anything else you need on sunday?

cheers
Eggy

FrAsErTaG · tinkerer Joined: 04 Oct 2001 Posts: 166

I also have 205/60/r13 on my Centreline Globes
Work a treat.

rob_w · tinkerer Joined: 19 Feb 2002 Posts: 395

yeah dude, your panel-van!!!!! i wish i had da money...but i do have 2 cents.......[sorry, bad joke]
anyways, see ya tomorrow.
rob.

Badger · tinkerer Joined: 13 Feb 2002 Posts: 155

185/75 tyres have an outside diameter of 608 mm
205/60 are 576 mm
165/75 are 578mm
(depending on tyre manufacturer, these are for Nankang except for 185/75 which is calculated)

this means that the 185's are 5.5% bigger than the std, 205's are 0.3% bigger
this gives you less (5.5 or 0.3%) torque at the rear wheels, and also means your speedo is out by that amount too

185/75 is a really usual size! are you sure they are not 185/70 or 185/65 (both 596 mm OD, 3.5% bigger, the 185/65 is actually 189mm wide)

besides less acceleration, the bigger tyres will be squirmier, as there is more sidewall to flex, however, this may be compensated by the wider tyre having more grip.

in the dry, 205's will be the best, but are a bit wide for a light car like a gem in the wet, I have 185/65 r13 on my rally car, work very well