Dragster chassis types pros and cons

[offroadr]

New member here and I am curious and learning about the different types of chassis. I am aware of 4 kinds, hardtail, slip joint, swingarm (mono shock) and 4 link. What makes one more favorable over the other? Horsepower, track conditions, etc?

[offroadr]

Wow, over 100 views and not one response?

Not many dragster owners here?

[Chris Williams]

Hardtail: old school and fine if all you ever race on is NHRA-quality and national event prepped tracks. Any bumps or poor prep will make it a tough car to get consistent. And at tracks with bumpy shutdowns can be downright scary. Advantages are mostly the simplicity of the car and the drivetrain.

Slip-tube: the next generation, helps with some of the above issues, but can't react fast enough to make a significant difference on tough tracks. Someone recently said that they think most of these cars joints don't actually slip anymore because they're too tight or rusted stiff. Advantages are that is has the simple drive train, and few moving parts.

Swing-arm: the next generation after slip-joint. The idea being, if sliding tubes work better, a hinge should work better than that. It's reasonably true, and because the hinge is in front of the engine, the drivetrain remains simple. But the unsprung weight is the entire back half of the car, the engine and everything else back there, and it just can't react very fast. It does help with the big whoop kind of bumps you get on shutdown, but doesn't do much for the little ones you see down track.

4-link: the bulk of the newer cars you see out there today. At one point people worried about the reliability of u-joints, but that's not the case anymore. Advantages include the speed that the rear-end can react and the ability to adjust them. Really helps on bumpy tracks and shutdowns, and the nice squat at the start means most have little or no tire spin a the hit. One key disadvantage is that people often don't have them adjusted right and the torque squat (one side goes down much further than the other) can make that worse.

Fully triangulated 4-link: this is what we're driving. Ours is made by Joe Monden and looks like a regular four-link but it has a lower triangulated setup at the bottom of the four-link setup that prevents the torque problem mentioned above. The rear end only moves together up and down, and it has only one shock to adjust. It has proved to be really smooth and very consistent for us.

Hope this helps,
Chris

[offroadr]

Thanks for the response!

[Bill Baer]

Hey I was out in the garage!
Chris is right on target as usual what he didn't metion is the cost difference a four link car is approximately 50% more money than a hard tail and their resale value is also higher.

[offroadr]

Originally Posted by Bill Baer

Hey I was out in the garage!
Chris is right on target as usual what he didn't metion is the cost difference a four link car is approximately 50% more money than a hard tail and their resale value is also higher.

Seems that higher HP (TD vs SC) cars are solid or slip as well?

[Chris Williams]

Originally Posted by offroadr

Seems that higher HP (TD vs SC) cars are solid or slip as well?

Quite the contrary. With more HP, you have an even bigger interest in planting the tires right. I know people running well into the 6's in and over 200 in TD and into the 180s in SC with four links. You don't get back into slip tubes until you get into the fuelers where the components (u-joints) can't handle the HP.

[offroadr]

Interesting , I have yet to see a suspended TAD car. My buddies TD is a slip car, so far best of 6.09 231 but its an ex TAD car.

[Chris Williams]

Of course you're right about TAD, but you asked about TD/SC. There, at least today, suspension rules. I bet if you went down the top 50 in national points in those two classes you'd find little more than a handful of un-suspended cars. You can do it, and have a lot of fun racing, but hard to be consistent and win a lot.

We just moved from a hardtail to a suspended car, and there is nothing that would take me back. The difference is amazing: the car is a pleasure to drive and vastly more consistent.

[offroadr]

Originally Posted by Chris Williams

Of course you're right about TAD, but you asked about TD/SC. There, at least today, suspension rules. I bet if you went down the top 50 in national points in those two classes you'd find little more than a handful of un-suspended cars. You can do it, and have a lot of fun racing, but hard to be consistent and win a lot.

We just moved from a hardtail to a suspended car, and there is nothing that would take me back. The difference is amazing: the car is a pleasure to drive and vastly more consistent.

You are correct, just good discussion. Thanks for the input.