Bottoming out

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Nov 5, 2006 | 09:32 AM

happiedazs

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From: Norwalk CT and Boynton Beach FL

Bottoming out

I just did a front and rear suspension rebuild on my 75 roadster with grand touring parts from VBP (front springs 460 lb, rear mono spring 330 lb and KYB GR2 shocks). I find I am bottoming out in the rear when I hit some bumps. I probably should have gone to a sitffer rear spring, but it's too late for that now. Can I solve this problem with a stiffer rear shock --- or are there any shocks available with helper springs to give me additional rear support? Looking for suggestions other than replacing the rear spring again --.

Thanks

Nov 5, 2006 | 09:46 AM

wombvette

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From: New Hill NC

Just add a few spacers under the spring bolt pads if its too low.

Nov 5, 2006 | 09:53 AM

happiedazs

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From: Norwalk CT and Boynton Beach FL

I can raise the rear easy enough, but i don't want a rear end rake if I can help it

Nov 5, 2006 | 09:54 AM

mbeeman350

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From: Auburndale Florida

2025 C2 of the Year ('64-'66) Finalist - Unmodified

St. Jude Donor '03-'05-'06-'07-'09

Quote:

Originally Posted by happiedazs

Thanks

It all depends on what you are going to do with the car...a cruiser or racing, auto x etc. For me I wanted a good all around cruiser, with good manners. I had the GR2's on my 72 with about the same front spring and I found the KYB's to be way too soft. I just put a pair of Bilstein HD's on the front and it made huge difference.

Re the rear if you are bottoming out ...it has to be the shocks. I just received the same spring and have not installed it yet. So I am researching what shocks to use. Do a search there are several threads going on re "SHOCKS". It's down to the Bilsteins either HD's or Sports (sports are more off road and performance oriented).

Call VBP and take their advise, assuming everything is installed correctly and the spring is not defective. You need better shocks to control the spring.

Do you experience any bouncing in the rear with the glass spring?
best of luck...Mark

Nov 5, 2006 | 10:08 AM

wombvette

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From: New Hill NC

The car was designed for a rear rake. If you have it set up low already and the rear to match, its too low for its design parameters. Then if rear alignments ie. camber settings are much negative, it is even lower. No doubt it bottoms. A 330 rear spring should hold the car up.

Nov 5, 2006 | 10:10 AM

mbeeman350

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From: Auburndale Florida

2025 C2 of the Year ('64-'66) Finalist - Unmodified

St. Jude Donor '03-'05-'06-'07-'09

Quote:

Originally Posted by wombvette

I agree with womvete. He is correct. The spring should hold the car up and the camber will change with the height of the car

Nov 6, 2006 | 08:53 PM

happiedazs

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From: Norwalk CT and Boynton Beach FL

I crawled under the car this weekend to see where the road hit the bottom. I was on one of the clamps which attached the muffler to the exhaust pipe and I rotated this clamp bolt and stud verticle so that I got about another 1/2 inch from the ground to the clamp. I also raised the rear about 1/4 inch. I think this may do it. If not I will raise the rear another 1/4 inch ad if that doesn't do it then it will be bilsteins!

Thanks for your input and I've also contacted VBP for their suggestions. Otherwise car rides tight and responsive.

Nov 6, 2006 | 10:00 PM

mandm1200

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From: New Cumberland PA

Quote:

Originally Posted by happiedazs

The exhaust seems like a common area to bottom out. I think you did the most obvious thing by rotating the exhaust clamp. The 330lb spring should be enough of a spring rate, and stiffer than most factory spring. The composite spring seems to allow the suspension to travel more even though its stiffer. Shocks may help but I would suggest checking the ride height and possible making a slight adjustment higher if needed. Raising it 1/8" will hardly be noticeable. 330lb x 2 = 660lbs Divide that by 1/8 is 82lbs. That’s the equivalent of 3/4 tank of gas. If the car does not bottom out when the tank is empty but does on a full tank, then an raising an add'l 1/8" will help out