Now I know what you’re thinking, but first let me explain! Bumpstop spacers are spacers that you add between your suspension bumpstops and the vehicle frame. These spacers lower your bumpstops so that your suspension will bottom out sooner. Yes, this means reduced overall suspension travel and this is why some people will laugh at me for even suggesting them. Normally, I am also against limiting suspension travel for the sake of reduced tire rub and this whole article is based around clearing big tires throughout the suspension’s entire travel range. HOWEVER, in the case of running 37” tires on the tundra, I am making an exception by adding some tiny bump stop spacers and here is why:
With a 37” tire jacked up to full compression using the method given in this article, the tire will not hit the top of the fender but it will be within a couple millimeters of it. Remember that ‘small caveat’ I mentioned earlier on? When you are out in the wilderness and encounter a hard suspension bottom-out situation, such as bumping a ledge obstacle to get up it or hitting an unexpectedly big dip on an FSR a little too fast, the suspension will compress (just as we simulated in the shop). Plus, there will also be flex in the vehicle chassis, body mounts, suspension bushings, etc that will result in the tires compressing a little bit further than what we can replicate in the shop. For this reason, its important to ensure that we give the tires at least an extra ½” of space to account for the additional flex and movement that will occur within the vehicle during a hard bottom out. My solution is to add a 3/16” thick front bumpstop spacer and a ¼” thick rear bumpstop spacer. Due to the relationships between the suspension pivot points, bumpstop locations, and tire location, this will result in a wheel travel reduction of just about ½” which is perfect.
So yes, you will theoretically lose ½” of wheel travel, but this is wheel travel at the very end of the travel range that will only be reached during hard bottom-out situations. If you’d prefer to avoid the bumpstop spacers, the alternative is to cut and re-seal the vehicle’s outer fenders and remove the inner fender liners altogether. This adds a lot of work to the overall procedure, as well as visible cutting and modifications to the vehicle’s outer fenders that risks premature rusting if not sealed properly. If I was running an expensive long travel setup, I absolutely would do this. However, if you are running stock lower control arms with a typical lift or “mid travel” kit, you’re not losing any real suspension performance by limiting that last ½” of fender-crunching wheel travel.
