I am pretty sure that I am finally getting caught back up in life after the Thanksgiving 30 hour driving weekend last week. What a nitemare. Two years ago I said I would never travel again for Thanksgiving, so i guess I lied to myself.

Anyway...Here are the final 2 weeks of the 25 Days of Robby Items. We'll get that wrapped up by the 19th so everyone can get their Christmas gifts.

It's the middle of the offseason now, and plans for 2009 are starting to be executed. All the teams are hard at work figuring out sponsorship (still) and trying to get a good peice for Daytona. The testing ban will be a releif for the mechanics as the Daytona testing in years past was so boring it was stupid. There were only 2 drafting sessions in the 3 days and in those you just crossed your fingers that you didn't get your car wadded up. Even though the banquet was boring (I heard) and there are no races, teams are still pounding away behind the scenes.

A couple of weeks ago I wrote about how a cup team goes about deciding what spring to use, and I want to revisit that topic a little bit. Before I talked about just the spring choice, and now I want to talk about how the bumpstops come into the equation.

In the early days of the COT, there were a few different configurations of bumpstops that people tried. Many of the teams at the first COT race ran chassis mounted bumpstops. These were a piece of rubber on the end of a screw to adjust the height. When the lower control arm of the suspension moved up it would hit it and stop the car from traveling. The other way was to mount some foam or rubber or whatever on the shock shaft. When I worked for RG, we were one of the only teams at the Bristol race with the shock mounted stops, and now everyone mounts them this way.

The purpose of the bumpstop is to stiffen the suspension in the last fraction of an inch of travel, so that you can run as soft of spring as possible and still keep the car from hitting the ground. For example, running a 400 lb spring in the RF would be desireable at say Chicago to keep the car low and the aero attitude right, but is too soft to keep the splitter from eating the track. So you put a bumpstop on that will make the RF spring feel like a 1500 lb spring for the last 1/4 inch of travel, and now you are good to go (theoretically). So you try to get all of the good benefits of running soft springs without hitting the ground.

Now...There are alot of ways to try to achieve this, and alot that I can't talk about. Speaking in general terms, probably the most common bumpstop is some kind of foam rubber that is stacked in some sort of aluminum can. There are hard plastic "packers" that can be slid in and out to adjust your "packer gap" which will determine at what shock travel the bumpstops engage and how far the car will travel. In 2007 people started coming out with aluminum canisters that could be charged with pressurized air to make a sort of airspring for the car to ride on. I think these were legal for all of about 7-8 races before NASCAR put an end to that. So there are always people that are pushing the envelope with bumpstop designs. The teams have had alot of time to work on them now, so they are becomign more and more refined. Here is a picture of some different foam/rubber peices that are sold for use as bumpstops.

I hope that helps demystify bumpstops somewhat. You can ask many of the smartest NASCAR people around what the best bumpstop curve looks like, and they can't tell you. In the end you just have to test stuff out at the track and see what feels good to the driver. Of course 7-posting can help get it sortof close (maybe) before you hit the track too.