Rough Ride?

[ghjedi]

Hi there,

I have a '72 Challenger and I need some advice.  I just got the front end completely rebuilt and in the rear, new KYB shocks are installed with new bushings for the leaf springs.  The leaf springs were still good.  The car rides much better, but it still hits a bit hard in the rear when I go over a speed bumb at 5 mph or so.  I'm wondering if this is normal or if it's due to my really thin tires on custom rims.  I'm about ready to dump the custom 20" rims on the car for more stock equipment.

[MEK-Dangerfield]

Since you don't have air-shocks(thank goodness), I have to look at the 20" wheels. These cars came with 14 and 15" from the factory, so you could put some tall tires back there as far as the amount of rubber goes. The more rubber, the more it will absorb the bumps. I'm just curious, what size wheels do you have up front?

[Bullitt-]

My experience on our 98 GT was going from the stock 225/55-16 to 245/45-17 that while the car was much better driving the ride went to heck... taller sidewalls will make a huge difference.

[72hemi]

My money is on the 20's. My SRT-4 had a 205 50 17 tire stock and when I upgraded to a 225 35 18 the ride got A LOT harsher. I would think that going from a 60 or 70 series profile tire (standard 15 inch profiles) to a 30 or maybe 35 series profile (on 20's) the ride would be horrible.

[Super Blue 72]

   The 20's will do it.  How did you get 20's in there in the first place? 

I heard somewhere that KYB shocks are stiff though.  Maybe someone has experience with this?  I know my friend put KYB shocks on his '68 Charger and made the ride stiffer a lot.

[Super Blue 72]

I fouind this old thread.  Read what the guys said about KYB, especially HP@ about KYB and new suspensions.

http://www.cuda-challenger.com/cc/index.php?topic=60605.0;topicseen

[MEK-Dangerfield]

Phil,

  I just bought 4 KYB Gas-A-Just shocks. I haven't put them on yet, but you are scaring me now.   

[ghjedi]

Thanks for the feedback and yes, the 20s are a tight fit.  I have to be careful when making a sharp turn, otherwise they rub.  I recently bought the car and it would not have been my choice to put the big wheels and low profile tires on it.  Given your feedback and the issues I'm having with the ride quality, I think I'll be switching to a more stock rallye wheel and tire size.

[72bluNblu]

Phil,

  I just bought 4 KYB Gas-A-Just shocks. I haven't put them on yet, but you are scaring me now.   

I have KYB's on mine with my 1.12" torsion bars and XHD rear springs and don't have any issues with them. They are fairly firm, which works decently with the heavier springs I run, but they're not horrible by any means. I'll still be going firmer if I ever get some nicer shocks for my ride.

ghjedi- like most of the others I'm going to say the 20's have a big part of this. The brand new shocks may be contributing as well, they will wear in a little as you get some miles on the car. Also, keep in mind that the weight balance on these cars is pretty heavy toward the nose, so, the rear of the car will tend to "hit harder" than the front since its so much lighter (springs don't compress as much and translate more of the bump to the car). This is still true of my 318 car despite nearly tripling the spring rate in the front, the rear still pops up more on speed bumps.

[Super Blue 72]

Phil,

  I just bought 4 KYB Gas-A-Just shocks. I haven't put them on yet, but you are scaring me now.   

Oops...sorry....

Mike, I think you'll be just dandy with those shocks.  If I perceive your driving style right, I think you'll probably like the KYBs.  Don't think you replaced your front end recently did you?  I know when I get a new set they'll be KYBs because I like a stiffer ride.  Besides, you have 14/15" rims, yes?  That should help dampen the ride a little.  72bluNblu likes em. 

[ghjedi]

I think you guys are right-- the 20s will have to go.  Does anyone have any recommendations on a good wheel and tire kit?  I'm looking for the Chrysler Rallye wheel and perhaps a Coker on it.  I saw one on jegs.com that looked pretty nice.

[the_engineers]

Let's see some pics of the 20's.  Also, your rear tires aren't run-flats, are they?  That will make the ride extremely firm.

[ghjedi]

Here's a shot of the front wheel and the rear wheels are identical.

[MEK-Dangerfield]

The wheels look nice, but yes...low profile tires like that will ride rough.

[drewcrane]

i am running a 17 inch wheel and yes they were harsh ,until i got some adjustable shocks and now run a 275 45 tire ,and that helped alot i didnt want to sacrifice handling for comfort, so if you want more comfort go with 14 inch tires if you want a compromise go with a 17 inch wheel, 20 inch wheels are pretty big for these old cars