Toyota Tacoma Drive Shaft Tech
Toyota Tacoma Drive Shaft Tech
On this page we'll try to as briefly as possible explain some of the concepts that are important with Toyota Tacoma rear drive shafts.
- The reason the carrier bearing is there on the stock shaft is to hold and support the drive shaft. It is not there for ground clearance. It doesn't actually help ground clearance by much if any. Here's why the carrier bearing is there. Imagine your drive shaft is a big pvc pipe, the faster spins the more likely it is to start to flex and bow under its own centrifugal force. The same thing can happen with a steel drive shaft just not as dramatic. The carrier bearing is there to prevent this from happening. The RPM at which the drive shaft might start to flex is basically what we'd call the "critical speed" of the drive shaft. From a technical engineering perspective this is probably not 100% accurate but that's the general concept.
- Removing the carrier bearing and converting to a single piece shaft changes the critical speed of the shaft. Even though the the single piece shaft works great, it is not without limitations. Namely, critical speed. This can become a problem if the drive shaft is spinning exceptionally fast. How fast the drive shaft is spinning depends on 3 things, vehicle speed, tire diameter, and ring and pinion gear ratio. We have a calculator below you can use to calculate drive shaft RPM at various speed. If you have re-geared to 5.29 gears and you live somewhere that has high speed limits your drive shaft RPMs may be too high for the single piece shaft.
- Increasing tube diameter increases the critical speed. The larger a shaft is in diameter the higher the critical speed, because a bigger diameter tube is more rigid. Normally we build these shafts using a 3.5" diameter tube. If you expect regular drive shaft speeds of above 3,500 rpm a 4" diameter tube is required. If you expect regular drive shaft speeds of above 4,000 rpm the stock carrier bearing style shaft is the type of shaft you should be running. These are already pushed limits!
- These bigger tube diameters won't always clear your carrier bearing bracket. Especially on a 2nd gen Tacoma the carrier bearing mount may rub on the drive shaft tube. The higher your truck is lifted the less likely it is to rub.
- The double cardan design is introducing a greaseable moving part that wasn't there before. I'm talking about the center ball (cv center ball). The shaft we make works great on lifted Tacoma trucks with geometry related vibrations and shudders. The trade off is that now there is a part that needs to be greased that wasn't there before. Many people overlook this part and don't grease it. Make sure you know it is there and make sure you grease it. This applies even if you get the shaft built with non-greaseable u-joints, the center ball still needs grease. Don't rely on the guys at the oil change place to know or care enough to grease it. It should be greased at least once a year. More on that here.
- You need to measure. We do have enough experience to expect that most 2nd gen trucks will use the 66mm bolt pattern flange at the transfer case and the 60mm flange at the axle. 3rd gen trucks should be 66mm bolt patterns at both ends. But you should measure your truck and make sure. The lengths are much more variable. The length of the shaft on one 3rd gen truck might be 1.5" longer than it is on another 3rd gen truck. Measure the length of your truck, don't worry about what your buddy or the dude on the forum has on his truck. And don't sweat the length too much, if you are off by a half an inch the shaft will still fit and function perfectly, there's some room for error on the length.
- Most of the time our shaft works great, sometimes it doesn't. We are trying to fix a problem that Toyota couldn't get perfect, that's a tall order. 95% of the rear shafts we build for Toyota Tacoma trucks work great and people are happy with them. That means 5% don't, around 5% end up getting returned for a refund. While still good, this is a much lower success rate than we have with drive shafts for other applications. It sucks for us and it sucks for the customer when a shaft gets returned for a refund. The reason we still offer these shafts is because when it works it often works really well. Many of our customer reviews on this shaft say things like "Best thing I ever did to my truck". We want to keep this shaft as an option and a solution for the people who have been going crazy due to their stock drive shaft problems so we accept that we have to take the bad with the good, and that more of these will be returned than we would like to see get returned.