Rear shock movement

Ron Gusack · 09-01-2016, 02:15 PM

I took video of the rear shock movement when leaving the line, but I don't know what it should look like. My logger says it didn't spin and I guess I could have tightened the compression. Can you tell me how this looks? There's both slo-mo and regular speed and also from the outside of the car. Thanks for any help.

Bob Mulry · 09-01-2016, 05:24 PM

OK Ron,

I guess that I have to give up one of my old guy tricks...........

Measure the roll out on your rear tires, with the car staged take a look at the name on the side of the tire or a paint stripe on the side wall......

If it's a 94" roll out, that tire should turn exactly 94" and move the car forward 94"........

With your eyes you should be able to read the name on the sidewall for 1 complete tire revolution..

If you use a camera during testing put a chalk mark on the tire and ground at the spot they touch the track, measure 94" forward and put a chalk mark on the track. This way you see if it is hooked up 100%

I know about loaded radius, but the tire tread still has to rotate 1 revolution....

Hope this helps sort it out,
Bob

ironside68 · 09-04-2016, 10:41 PM

I'd start with tightening the extension on the shock. It's extending way too fast and bouncing right back up "into the car". What type of rear and front shocks do you have, both DA?

Ron Gusack · 09-05-2016, 12:28 PM

Both are DA. Rears are Strange, fronts are Menscer/Afco. Rear extension was set 3 from full loose and compression 3 from full tight. That was from a previous day on a track I couldn't get consistent 60's.

ironside68 · 09-05-2016, 09:59 PM

I would tighten them to full stiff on ext, and 3-4 from full soft on compression and start there. Fwiw I've had Strange DA's on my car and had stiffer valving put in about the 3 or 4th time I ran them because I was always at full stiff on ext and still extended too fast.

The front looks to move decent and transfer, if it's a good hooking track I'd start with the rear changes first and compare videos.

Ron Gusack · 09-05-2016, 11:02 PM

Thanks, I'll give it a try. Should the rear plant, stay down and then gradually come up as it gets close to the gear change? I've been told to make the adjustment as tight as possible until it spins and then soften a little. The guys at Merscer told me that they don't like Strange shocks but didn't want to bad mouth them, so no real detail. My logger showed no spin on the run in the video, but my RT's were late on every run. Mostly .040's with one 020, and that was deep staging. I kept tightening the front.

09-01-2016, 02:15 PM	#1
Ron Gusack Member Join Date: Feb 2009 Posts: 244 Likes: 1 Liked 7 Times in 6 Posts	Rear shock movement I took video of the rear shock movement when leaving the line, but I don't know what it should look like. My logger says it didn't spin and I guess I could have tightened the compression. Can you tell me how this looks? There's both slo-mo and regular speed and also from the outside of the car. Thanks for any help.

09-01-2016, 05:24 PM	#2
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	Re: Rear shock movement OK Ron, I guess that I have to give up one of my old guy tricks........... Measure the roll out on your rear tires, with the car staged take a look at the name on the side of the tire or a paint stripe on the side wall...... If it's a 94" roll out, that tire should turn exactly 94" and move the car forward 94"........ With your eyes you should be able to read the name on the sidewall for 1 complete tire revolution.. If you use a camera during testing put a chalk mark on the tire and ground at the spot they touch the track, measure 94" forward and put a chalk mark on the track. This way you see if it is hooked up 100% I know about loaded radius, but the tire tread still has to rotate 1 revolution.... Hope this helps sort it out, Bob __________________ Bob Mulry 7516 STK A & M Motorsports

09-04-2016, 10:41 PM	#3
ironside68 Junior Member Join Date: Oct 2010 Posts: 49 Likes: 9 Liked 19 Times in 6 Posts	Re: Rear shock movement I'd start with tightening the extension on the shock. It's extending way too fast and bouncing right back up "into the car". What type of rear and front shocks do you have, both DA?

09-05-2016, 12:28 PM	#4
Ron Gusack Member Join Date: Feb 2009 Posts: 244 Likes: 1 Liked 7 Times in 6 Posts	Re: Rear shock movement Both are DA. Rears are Strange, fronts are Menscer/Afco. Rear extension was set 3 from full loose and compression 3 from full tight. That was from a previous day on a track I couldn't get consistent 60's.

09-05-2016, 09:59 PM	#5
ironside68 Junior Member Join Date: Oct 2010 Posts: 49 Likes: 9 Liked 19 Times in 6 Posts	Re: Rear shock movement I would tighten them to full stiff on ext, and 3-4 from full soft on compression and start there. Fwiw I've had Strange DA's on my car and had stiffer valving put in about the 3 or 4th time I ran them because I was always at full stiff on ext and still extended too fast. The front looks to move decent and transfer, if it's a good hooking track I'd start with the rear changes first and compare videos.

09-05-2016, 11:02 PM	#6
Ron Gusack Member Join Date: Feb 2009 Posts: 244 Likes: 1 Liked 7 Times in 6 Posts	Re: Rear shock movement Thanks, I'll give it a try. Should the rear plant, stay down and then gradually come up as it gets close to the gear change? I've been told to make the adjustment as tight as possible until it spins and then soften a little. The guys at Merscer told me that they don't like Strange shocks but didn't want to bad mouth them, so no real detail. My logger showed no spin on the run in the video, but my RT's were late on every run. Mostly .040's with one 020, and that was deep staging. I kept tightening the front.