Bump steer issue

Ok, brand new here and in need of some technical help. I have an 09 DCSB 4x4 with a toytec 3" lift and LR UCA. I was running 265/75/16 on a 16x8 (4.5BS) wheel. This set up has been no issues for the past 30k miles. I recently got a set of FJ trail teams wheels (16x7.5 4.25BS I think) and upgraded to 285/75/16. Ever since, I immediately noticed a fairly significant bump steer issue. I have since checked all front end (susp/steering) and had a re-allignment. No improvement. I then had the speedo calibration corrected thinking related to stability control. Again nothing. Can anyone please help me as I'm completely frustrated. Could it be the difference in wheel width and offset, though marginal? Any help advice would be greatly appreciated!!

 

First of all Brett tacoma, welcome to TW!

A major cause of bumpsteer is unequal tie rod lengths. Try measuring the exposed length of the treads on both tie rods from the jam nut to where the threads end in a direction inboard along the tie rod. They should be even.

 

Awesome!! I'll check that next. I'm completely discouraged with this and considering going back to 265 tires.... Could this be a cause? Thank you again for the advice!

 

Sometimes hack alignment techs will adjust just one tie rod as a quick and dirty way to get you out of there. Is your steering wheel centered or are the steering spokes crooked?

Also have you seen an alignment sheet? A rear thrust angle will create all sorts of problems that a tech tries to correct by monkeying with the tie rods. Were the tie rod ends ever replaced that you know of?

I don't personally think the tires have much to do with it. I do not have a lift or large wheels/tires. Perhaps one of the gurus here that has a bunch of experience with changing wheels/tires can chime in and let us both know if bump steer developed.

 

I don't have the allignment sheet with me now but from my relollection, the numbers were basically 0 with the exception of caster +2.0.... I agree about the tires not being the issue but the only change was the wheels/tires when the bump steer began. I greatly appreciate all the advice!!

 

Ok friends, I have come to a solution to my issue. The new 285 tires I had were the Toyo MT. After going through just about everything, the tire shop recommended changing out the tires. Installed were a set of Toyo AT 2 in the same 285/75R16 tire. Results were no bump steer, smoother and quieter ride. Shop told me it was most likely due to the much stiffer side wall and higher weight of the MT tire. It makes sense but I know lots of people run MTs in this size with no issues. Maybe it's simply Toyo MTs are just stiffer/heavier than other manufactures or it's my truck. Either way, I'm perfectly content with the ATs. Thank you for the warm welcome and help. Hope my solution helps another down the road...

 

Good to know, lol! At 40 years old I can't handle swampers (boggers) any more.