Going a bit OT, but Ungn is correct.
Think about it: the spring meets the lower arm some way in from the hub centre line. Therefore there is some mechanical advantage due to the distance between those two points.

Adding a spacer increases the mechanical advantage slightly (as it extends the distance), so the same weight will result in more force compressing the spring. The larger the distance between those two points, the greater the effect.

Wont be much and will be dependent on the spring compression rate, but it will happen.



Mike

Edit: Sounds plausible but on reflection my logic is wrong. Bladerunner is correct here. See his explanation below.

 

Anyone here want to buy my spacers to experiment for themselves let me know!!!!!

 

That would only be correct if the spacer was added between the fulcrum and the point at which the force is being applied. Your mistake come from suggesting that in this instance the force is applied at the point where the wheel meets the road, whereas it is actually exerted by the weight of the car at the spring, which is in the same place relative to the fulcrum of the wishbone.

 

In order to get my wire wheels to fit, I needed to install wheel adapters, which are 1.25 inches thick. What it did was put my wheels out further, and put more tension on my springs and wheel bearings. The front springs were affected the most.

So far with 15,000 miles on them I haven't had any wheel bearing problems, and since I bought the car used, I don't know how many miles are on the wheel bearings. I did need to put a rubber ring in each front spring, so the front end wouldn't bottom out on fairly severe dips in the road. The rear springs have shown no issues......Hope this helps.....Mike

 

Good for you finally getting a Jag you like.

Correct, the 19" wheels IMHO just make for a harder ride. Some say they look better and perform better due to less sidewall flex. Personally I'll take ride comfort over extream performance which I don't need.

Changed out my 19's for 18's awhile back and have a noticeable smoother ride,
See here for my odyssey.
https://www.jaguarforums.com/forum/x...-shoes-144124/

 

Michael,
Great to hear that you've finally pulled the trigger. Welcome to the club; enjoy your new cat and don't forget the piccies.

My apologies for hijacking the thread earlier.

Mike

 

No apology needed. You guys are as great as the Land Cruiser bunch I also run with.

 

Way to go, Mike.

I would never discourage anyone from buying anything, but something about that other car just gave a bad vibe. Your list of issues and concerns clearly outweighed the pros of owning this amazing car.

Post some pictures of the beauty, and keep us posted.

 

I'll start anew thread

 

Spacers are now off and I am glad I did, for if I had had a flat not the road i would be in deep do-do. It took a power hammer wrench, a 4 lb mallet, solvent and four hours. The spacers and the rim just meld into one when the lugs are tightened! Thanks for all the input.

Now for tires. I'm thinking and I said this somewhere else I think, of Bridgestone serenities for a smooth ride to compensate for the 19' rims. What yer think?

 

UPDATE: Took her for a ride today and in my option she drives MUCH BETTER WITHOUT the spacers. Better controlled steering on corners by far. With the spacers I had feelings of under or over steer. Definitely I do not recommend spacers.
FOR SALE 4 matching 30mm spacers for XK8.......... LOL

 

Not knowing much about this stuff.... Wondering why someone would put spacers on in the first place?

BTW... Those rims / tires look pretty nice on your car.
You sure you want to get rid of them?

 

No not now. With the spacers gone and new tires I think i will be happy. thanks.

 

The longer the lever arm, the more force is applied to the spring.

As the wheels are moved outward, the lever arm compressing the spring is lengthened.

Ever used an L-bar spring compressor when re-doing heads? The longer the moment arm is, the easier it is to compress the springs.

Foot Pounds is meaningful as a measurement because the length of the lever arm matters. You can double the force applied or double the length of the lever arm and the effect is the same.

I think this concept is taught in the first week or two of a Statics class. This class is one of the first to separate the Engineers from the Business Majors.