Re: Problems with Larger Tires?

[tsm1@domain.elided (Tom Mandera)]

>I am considering putting larger tires (larger than stock) on my 1980 Scout
>II and would like to get any "warnings" and "experiences" before I do so.
>
>1) What problems could develop with steering?

Larger tires can make an existing steering issue worse.. worn tie rods, drag
link, whatever.  Larger tires just amplify this.

>2) What front end problems could this cause?

With *wider* tires, you may have a problem with the camber up front.. the
"centerline" of the tire turning axis is general moved outwards (unless you
get some off-set rims.. which would be a good idea), making your Scout hug
the road crown just a little less.

>3) Does a front end alignment need to be done with the larger tires?

IMHO, no.  Wouldn't hurt, but you shouldn't need it.

Having a 1980 w/ 2degrees of caster in the front axle, you're already way
ahead of most Scouters in the handling department. 

>4) Would acceleration be adversely effected?

Yes, but how much depends on how big.  Are you running 3.07 gears w/ a 196
and a 3spd w/ 29" tires now?  If you are, performance probably SUCKS, and
adding larger tires will just necessitate 4-lo for commuting..

OTOH, on my '72 w/ a 3spd, 304V8, 3.73, and 29" tires, I installed
31x10.50s, and saw no discernible difference in performance (maybe the tires
didn't break loose from the asphalt as often.. a function of taller tires,
or a better grip.. who knows).

On my '77 w/ 196, 3spd, 4.09 gears I went from my stock 29" tires on stock
wheels to the same 15x8" Chrome wheels w/ 31x10.5 BFGs that were on the '72,
and it felt like I'd put lead bricks on instead of round tires.. the added
weight *and* size really bogged down that 196 noticeably.. BUT, I was going
on a road trip and wanted the extra 5mph the 31s gave me.. 

>5) Has anyone broken an axle due to the larger mass of large tires?

According to Jim Weed, 33s are about the biggest thing you want to run on a
stock axle setup... with 35s, doing anything but commuting and/or trailer
queen duty (GASP!  A trailer queen 'Binder??!!), you run a high risk of
snapping axle shafts.. Jim said a custom 35-spline Dana 60 w/ 1.5" axle
shafts would solve that problem.. :)

Consequently, I'm opting to run 33s with lots of articulation, and no busted
axles vs. the 35s I should be able to fit on my '72 when I'm done.

Note the DECELERATION (braking) *will* be adversely affected.. PERIOD.  You
now have larger and *heavier* tires those brakes need to stop.. going from
235/75R15 (29") to 31x10.50s you probably won't notice.. but wanna run 33s
or 35s.. 

Also, 31s will clear on a stock Scout II.. wanna go higher, you need a lift
of some sort, or a sawz-all. :-)

See the IHFAQ @ www.binderbulletin.com for a chart of tire size and lift
requirements.

-Tom Mandera, Helena MT
http://www.tmcom.com/~tsm1/scout
'72 and '77 Scout II