My Tundra mods for stable towing

Nice feedback. Which color Sumos did you use? What do you not like about them vs stock? I see you cut them down which sounds like a good idea so you aren’t riding them constantly, but looking for more specific feedback. Thank you.

 

Had a long shakedown trip last weekend, about 400 miles round trip between Austin and Dallas. Notes below.

ATX to Dallas
- Moderate traffic, driving after dark
- Fairly strong tail wind (~15 MPH)
- Incredibly smooth drive, I could easily take my hands off the wheel when going 70MPH and have a big rig pass me, not even feel it
- Stayed behind other large vehicles most of the way, probably got 12MPG on the way up
- Handled some fast ramps well, notably the I35 split as it forks to Ft Worth and Dallas. Google maps told me about the turn rather late and I had to speed up to about 80MPH to get in there, then brake moderately hard as I hit the ramp (it's surprisingly tight in the Ft Worth direction.) No understeer or oversteer.
- Truck stayed between 1800-2000RPM most of the time, even at 70MPH

Dallas to ATX
- Tons of traffic due to ending of spring break
- Fairly strong wind either directly from the side or about 45 degrees at the front (15-20 MPH)
- Meager 8MPG gas mileage, wind like that makes a massive difference in mileage and handling
- RPM anywhere from 1800-3000
- Decided to cap out at 65MPH due to the wind. No sway, but could feel the buffeting.
- Noticed some other campers, eg. a large Forest River behind a chevy 2500. He wasn't going any faster than me.

At our KOA my neighbor had a 2WD Tundra double cab with regular bed, so ostensibly the same length as my 4x4 CM. He was towing a 30ft trailer, 33' from ball to bumper. Didn't ask how it towed, but because those campers sit above the wheels without any wheel wells, he had a riser on his truck hitch to meet the trailer coupler. Can't imagine it being a very good combo.

Came to realize that road conditions vary in the USA. The Autobahn in Germany is over very high quality and is consistent. Here our roads can indeed be just as good but usually this is a short stretch. You'll find cracks and potholes, but on freeways the worst part is 'swells.' The surface simply isn't level. Sometimes those swells/dips are intermittent and your rig merely has to absorb it at high speed. Other times those swells are more regular and lead to a harmonic effect on your drive. Usually one must slow down since speeding up is seldom and option. It doesn't affect individual vehicles very much but for a 50ft trailer combination they are apparent.

Important Note: Turns out I had a flat tire at some point during/after my trip to the CAT scales! I have no idea if I got it at the start of the day or the end, but discovered it later. The truck drove like crap on my way to the scales, that's all I know. Now I do a quick walk around every time I take a break just to make sure all the lugs are in place, tires look good, no wheels are hot, my WDH is all set - can't take anything for granted.

I have the Blue sumos. I started with the Black but didn't install, they are rock hard. And yes I did cut the top donut since I didn't want constant contact between axle & frame. To me they seemed to provide too much connection, I prefer to rely upon my WDH setup to 'level' the truck & trailer. As I have it now, the sumos function as a progressive version of the bump stops rather than a helper spring.

 

Did you have any issues with fitment on the sway bar? Sparks Parts list the genuine Toyota hitch as a possible conflict.

 

No issues at all. No idea why they'd say that, they even include an extra set of washers for those who _don't_ have the factory hitch. If you have a hitch, you leave those washers out.

 

Great! Thanks

 

Great write-up showing depth of prep @BrakeDust!

 

Can we see some pictures of this setup? How long to you plan to keep this setup?

 

So, you mentioned ditching the Sumo springs, suppose you do or did. If you keep or kept the cb shackles and the springs flex due to terrain or load and hit factory bump stop would that not be compromising the spring because at that point it would be forced down by the long shackle beyond factory design limits? I mean this is why I think you better keep the taller Sumo springs and not bend over your leaf packs.

 

I didn't ditch them, I just cut off the top donut. IMO they're a little 'tall' straight from the factory. After initial install they appeared to allow some space between the bumper and frame but after a week of driving my mods settled a little (bilsteins, shackles.) There was now only a quarter inch gap even when unloaded and with a load the sumos were already compressed. After deleting the top ring I now have about an inch of clearance when unloaded and a quarter inch when loaded. This allows some articulation and the sumos are progressive when being worked. The stock bumpers are pretty short, quite a bit less than even the 'reduced' sumo. I've towed multiple times with the setup and haven't seen my leafs turning into a 'W', pretty sure it's ok.

But if I were to do it all over again I could stick with just the OEM tundra stops. The WDH already balances the load, anyone with the factory Bilsteins could pretty much run their truck bone stock. (ie. TRD off road for example.)

 

I understand that you kept them but I think you might be misleading others by implying that they could just use the shackles. I believe if the Sumo springs were not in place the shackles would force the springs down further than the factory design allows for which would then be possibly compromising to the springs. Maybe I'm wrong but I don't think so.

 

I imagine Toyota knew what they were doing when designing the oem suspension. Sumo springs help prevent squat and can help give extra support in turns when the truck leans.

I do not have a anti roll bar on my rear axle.

I also cut my top donut as I didn’t want to hit the spring under normal driving. When loaded for a trip with the wdh setup properly I am just off of mine now.

before it would be almost touching when unladen.

 

I got the smallest CB shackles on purpose. The Bilsteins I put on are set to the lowest perch and still give about a half inch lift. Similarly the short CB shackles should only 'lift' the rear by a half inch. I measured the rake before and after, this was indeed the case both front and back. A half inch is nothing, the width of my pinkie. I don't think it's an issue. I wanted to preserve the factory rake while running better shocks.

 

Are you going to remove your Sumo springs and go back to factory bump stops?

 

No, they've been in a landfill for months! And even if I had them it's not worth the trouble. I'd have to get fresh U-bolts for the install since I already reused the OEM bolts for the sumos - supposedly they stretch and many recommend brand new bolts for each install.

FWIW I did order the 'black' Sumos at first - they felt so hard I returned them without installing. Rated for 1500 lbs in the bed, they were as firm as the OEM stops and didn't compress at all. At least the blue type has a little give.

I ran my 2008 Tundra for years with the factory stops and was perfectly happy. Did have Bilsteins and the short CB shackles, those were the only mods.

Anyway I'm happy with the blue sumos at my "-1" setting, no complaints. The rear sway bar makes the biggest difference that I can actually feel, and the E-rated tires.

 

@BrakeDust
Curious, did you consider the Roadmaster active suspension setup rather than the CB shackles and sumo bump stops? I have read that the Roadmaster kit increases the unloaded rear height a bit and provides better towing support like the shackle/sumo combo. Just curious if you researched Roadmaster when preparing for your build and, if so, why you chose this route.

 

I did not research them, but I've since seen good reports on this forum.

 

More pics from central Texas

 

Getting a 2020 Globetrotter 25' in a few weeks from Colonial in NJ.

SPP

 

I second that suggestion. Ditch the Sumo's and install RAS HD. They work very well and also act similar to the TRD anti sway bar. Feels very solid and sporty when not towing and still a comfortable ride. I had them on my 2016 and putting on my 2021.