Larger tires and front end wear

[Jack K]

There's a fair amount of discussion on the relationships between axle ratios, engine displacement plus tire sizes - and getting an optimum combination between them. I haven't found any reference, though, to the effect that tires larger than 285s have on front end components in terms of extra wear and tear, so this seems to warrant a separate thread on the topic.

My question is this. I have a 2013 6.8l V10 4X4 with 4.10 gear and 33" tires (BFG KO2 LT285/70R17), standard SMB lift and front axle. I'm considering switching to 35" tires, primarily because they look proportional to the van. I've read that the larger tires can produce premature worn ball joints, worn wheel bearings and suspension and steering system wear. Those of you using these larger tire sizes, have you had any issues with premature front end wear over the long term, since the larger mass and wider footprint add greater rolling resistance and weight on the machine.

This, in addition to the issue whether the 4.10 gear ratio and 35" tire diameter are appropriately matched and can fit without modification.

This would be a significant change, and I don't want to switch and end up with repair and replacement bills down the road.

Thanks!

[Carl]

I run BFG KO2's in 325/65/18's which are about 35" and find them great with little change from prior smaller size. Certainly they look better and are great in sand/off road. SMB West did original build/lift (2010 E350) and I have no rubbing or issues with clearance/turning.

[Jack K]

Great news! How long / ~ how many miles have you had those tires on?

By the way, one nice bad-a@@ looking van you got!

[Carl]

Thanks. I've got about 15k on this set.

[saline]

4:10's and 35" tires are a good match on a V-10 or diesel.
Yes larger tires do ad to the unsprung weight and put a bit more stress on the running gear but i'd say minimal in comparison with 285's.
I'd say the biggest effect that larger tires and rims that have a wider offset is the stress to the front wheel bearings. However, the dynatrac doesn't use the unit bearing style so that concern is decreased. Unit style bearings tend to wear out faster just given their design.

[Twoxentrix]

Have 35's with 4:56 gear ratio and was considering going to 37's not too long ago. I found this article very helpful. Wont answer your question specifically, but certainly makes you think through the selection process (Provided more factors to take into consideration than I initially anticipated):
How to Pick Pickup Truck Axle Gear Ratios to Improve Performance

[Jack K]

Thanks for the info, guys. I'll be springing for 35s. Still don't understand why SMB West refused to install them with their conversion.

[TomsBeast]

Originally Posted by Jack K

I've read that the larger tires can produce premature worn ball joints, worn wheel bearings and suspension and steering system wear. Those of you using these larger tire sizes, have you had any issues with premature front end wear over the long term, since the larger mass and wider footprint add greater rolling resistance and weight on the machine

I'm not positive your front axle is a Dana 50 or 60, but my Dana 60 out of a 2001 F350 uses "unit construction" or "Modualar style" non-servicable wheel bearing and hub assembly. Worse, the wheel bearings are too close together to offer the kind of extra duty support needed for larger offset and bigger diameter tires and wheels. Said another way, those OEM assemblies are marginal with factory tire/wheel combinations, and under rated for lager tires and wheels that give the van a wider stance for this reason, leverage

This young man I met that had 37" and wheels that increased the width on his F350 4x4 truck, told me he'd been replacing wheel bearing hub assay at the rate of a new set every 14k miles or so

There are replacement, fully serviceable wheel bearing and hub assemblies available, but they are not cheap, just a tick under $1800 for the parts I think. Then there is the Dana axle balljoints, another underrated component that Ford used. Some guys say they need replacement every 40-60k miles of moderate fireroad and washboard road use. Again, there's an aftermarket, heavy superduty balljoint kit available, also $$$$, but I understand it's replacable while on the van/truck if then get loose.

[Jack K]

The front axle is a Dynatrac Pro Rock 60 with Warn hubs, so it's beefier than OEM. I wonder how or if that configuration is adversely affected by larger tire sizes.

[TomsBeast]

Originally Posted by Jack K

The front axle is a Dynatrac Pro Rock 60 with Warn hubs, so it's beefier than OEM. I wonder how or if that configuration is adversely affected by larger tire sizes.

Dynatrac makes a replacement heavy duty (serviceable) "free-spin" hub, bearing and spindle retrofit kit with the wider bearing spread, forged spindle, etc. (do a search). It fixes a lot of the weaknesses the OEM Dana axle has. I think the free spin kit requires their proprietory Dynatrac manual locking hubs and stub axles. You'd have to find out if your Dynatrac axle was fitted with the kit, or if they used the less expensive OEM Ford/Dana kit (fine with smaller tires/wheels), which are interchangeable.

I'm not sure how you'd tell without removing the manual locking hub assembly, and getting a look at the wheel bearing lock nut. The Dana lock nuts are peened over if I remember right, are obviously not rebuildable (there's no parts available even if you get it apart), once you get the locking hub parts out of the way.