Spacers, scrub radius, etc? (1 Viewer)
- Thread starter razzyrazz
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Kenda kr28
Automotive Tires, Passenger Car Tires, Light Truck Tires, UHP Tires | Automotive | Kenda Tires | Klever A/T Truck Tires | Find a Tire | Kenda Tires
Need all terrain truck tires? Check out our Klever A/T truck tires. Durable build + total traction make these all terrain tires a solid performance pick. Try 'em!
Pskhaat
Tourer
And I just read there they make a 275/80r18. That is bloody near perfect width with a proper aspect ratio. Good on them!!Kenda kr28
Automotive Tires, Passenger Car Tires, Light Truck Tires, UHP Tires | Automotive | Kenda Tires | Klever A/T Truck Tires | Find a Tire | Kenda Tires
Need all terrain truck tires? Check out our Klever A/T truck tires. Durable build + total traction make these all terrain tires a solid performance pick. Try 'em!automotive.kendatire.com
Only non bias ply in that size I could find. They’re running well about 3000 miles in. Normal AT noise, starts in at 35 mph and barely noticeable. Just normal tire noise. On par with the passenger radials on my minivan.
taking them on the snow tomorrow will report how they perform.
Admittedly I'm not sure running +60 offset stock wheels gets you a 0 scrub radius. I just assumed that's probably the case (or at least very close to it)
Did fine in snow. Perhaps a touch less inspiring than the Duratracs, which I thought were fantastic on snow.
Pskhaat
Tourer
They were stunningly fantastic in snow and ice. ...for the first 2000 miles
. It's like they have magic compound that then turn into making the traction of cafeteria trays.
Funny. I got some used ones with some wheels and ran the duratracs for about a year. They had only 6 to 8 32 and were getting close to wear bars. However my alignment is good and I mounted them high side out, previous owner had a bad lift and they were about 2/32 run out. I think this contributes to them tracking very straight. Anyways good in snow for a hybrid for sure. A shame about the sidewalls.
Ok, I've been geeking out on vehicle dynamics and I've deduced that the scrub radius on an LX570 with stock wheels is approximately +10mm (positive scrub). Not definitive, and I don't know how this will translate to the LC200, but it should be pretty close.
In lieu of published numbers (which I can't find anywhere) we've been using a 0 scrub as our baseline. However, modern double-wishbone suspension systems almost always have a positive scrub. I used a couple of methods to try to find the actual scrub, including some practical experimentation and some measurements and calculations based on an SAI of 13 degrees. The results were consistent with graphing out the previous recommendations on offset vs wheel-size.
Most interesting to me is that it goes a long way to explain the squirrely ride and more difficult steering dynamics I experienced when I had 275/70R18 BFGs mounted on +60 offset Tundra wheels with no spacers. That 33" size and 60mm offset translates to close to 0 scrub radius, which turns out to be no-bueno in a double-wishbone setup.
I know there are those of you with real-world experience with this stuff, so feel free to pile on.
In lieu of published numbers (which I can't find anywhere) we've been using a 0 scrub as our baseline. However, modern double-wishbone suspension systems almost always have a positive scrub. I used a couple of methods to try to find the actual scrub, including some practical experimentation and some measurements and calculations based on an SAI of 13 degrees. The results were consistent with graphing out the previous recommendations on offset vs wheel-size.
Most interesting to me is that it goes a long way to explain the squirrely ride and more difficult steering dynamics I experienced when I had 275/70R18 BFGs mounted on +60 offset Tundra wheels with no spacers. That 33" size and 60mm offset translates to close to 0 scrub radius, which turns out to be no-bueno in a double-wishbone setup.
I know there are those of you with real-world experience with this stuff, so feel free to pile on.
Last edited:
Interesting. Means my+13mm scrub is really +3mm.
Oh I use this tire size calculator. I always assumed zero was the target (ie 285/50r20 on a 8.5 rim at 60mm)
i put it in again and it’s 8mm even better.
www.wheel-size.com
i put it in again and it’s 8mm even better.
Rim & Tire Size Calculator. Custom Offsets
Tire Tech Information - The Wheel Fitment, Tyre Stretch, Rolling Radius and Speedometer Error Calculator. Play with specs, try different settings, compare results
www.wheel-size.com
Ah, yes. I fiddled with that too. Fun calculator! The only issue I've had with it is that it requires a correct suspension clearance to properly calculate the scrub. It took me awhile to figure out why it wasn't accurately predicting scrub until I realized its reference is a McPhearson strut setup. The steering axis inclination (SAI) in our double wishbone suspension setup is determined by the angle of the imaginary line between the control arm pivots. The calculator also pivots the virtual strut at the hub/axle, which is totally different than the DWS. I haven't found an online calculator yet that does DWS. Let me know if you know of one.
This calculator looks like it will calculate DWS scrub. You have to subscribe though. Not sure if we know all the required measurements.
www.racingaspirations.com
Suspension Geometry Calculator
Quickly and easily see the affect movement has on your suspension set-up and adjust on the fly using the drag and drop editor.
www.racingaspirations.com
Last edited:
Pskhaat
Tourer
THANK YOU. So, I run Tundra steelies with 275/79R18 tires as well, and I’ve added 7mm spacers in order to correct scrub to my earlier and errant calculations! So I’m not too far off?
