Opentracker's UCA mod

John, could you do a little write-up on this if you have the time please. It looks you welded in reinforcement plates on the bottom, correct? Does moving the perch cause the spring to interfere with the outer spring housing, especially if it has been modified for tire clearance as in a previous write-up of yours? Does it lower the front end at all as the base of the triangle is lengthened while being countered by an improved spring ratio? Any alignment issues?

I'm doing some front end work and want to take advantage of the down time as much as possible. I run a machine shop, so doing the work myself (I'm doing roller perches as well) isn't a problem.

If you have time please I'd really apreciate it and it would be a good tech thread for the other members, I'm sure.

Thanks, Krash.

Opentracker said:
.....you can improve the motion ratio by moving the spring perch forward on the upper arm.

2005upperarmodd3.jpg

2005upperarmod8.jpg

The spring perch location has been moved 1 1/4" on these arms. With this mod the motion ratio goes up from ~0.6 to ~0.73, making the wheel rate 1.5 times stiffer. Not bad for an almost free mod.
 
I did an upper arm mod post a while back but it got lost with the server crash we had. About 6 months of threads got lost if I remember right. I plan on doing another one when I have the time to take some good photos and do a nice write up. There is some info. here.

I'll be glad to help by email till I get the new UCA mod post done.

John
 
Thanks DB, I had forgot about that thread. And thank you again for hosting info. and photos about my Mods. Now that I have a web site, I should be able to do some myself. IF I can figure the HTML thing out. Wow! that is a lot of work.

John
 
Opentracker said:
IF I can figure the HTML thing out. Wow! that is a lot of work.
LOL...from a guy who rebuilds/redesigns/rewelds UCAs that just sounds backwards to me :D

In that one photo it looks like the modded arm is longer than the other. Is that an optical illusion from the photo?
 
Well, we all have our own place on earth. I guess mine is in front of a welder. Reading HTML looks easy while other people are doing it, but it's not easy for me. I'm learning though. I wish I could weld my web site together.

They are a matched set of arms. I have not ran these on the track yet. I still have to work out the spring rate and shock valving. I found out after making these arms that the perch can be moved 1 1/2" or 1/4" more than these arms. The adjustable upper arms I made have holes in the stock location, 3/4" out and 1 1/2" out.
adjuca05.jpg



John
 
I'll help OpenTracker

I will help with the HTML if you need it OpenTracker. I am a C++/C# programmer by profession so I look at code ALL day. HTML is easy once you get the hang of it. Just shoot me a PM if you have questions. As helpful as you have been it's the least I can do.
 
Edbert said:
66MP, you can't be a coader, you speel two well...LOL.

(inside joke from a guy with 17 years IT-systems experience)

I have been learned about 6 different programming languages and sometimes it does screw with you....For example, when I number a list of things to do I start at 0. Only a C programmer would get that.... :rlaugh:. You are in Austin I see, been down there a few times to talk to Cisco guys. Enjoyed my trips.