968 Caster Blocks on a 944 Question!

[Its_Scott]

I apologize for this noob question as I am not very mechanically knowledgeable. By the way, I love this forum and everyone is very helpful. I feel bad that all I've been doing is asking questions. I hope one day I'll be able to give back to the community as I get more experienced.

Anyway, I heard about if you want to upgrade wheels sizes (17"+), it is a good idea to upgrade to 968 caster blocks on the control arms. I've seen pictures of the caster blocks and I don't understand how it works, what it is for and where it fits. Is it hard to install yourself and how much does it run for? How much will it cost to have someone install it? If it isn't hard to install myself, I wouldn't mind getting my hands dirty, but I just need some reference on how everything looks like and placed. Any advice and direction on this would be appreciated! Thanks!

[JivenJim]

You can find them for about 100$+. They are more stable, but mainly for running wide tires on track (265+) Never heard of issues regarding wheel diameter. If you change ,you will probably throw off you allignment a bit. They are sloted. You could mark with paint or White out before you remove the old. Easy to slide on and off A Arms. Little WD40 helps.

[flash968]

you will definitely need an alignment after installing new castor blocks - .010" different, and you are going to see a castor change - also, worn units do not position the same as new ones - that is why these cars need an alignment every year

as to wheel size, there is a lot to consider - weight is the most significant - extra wheel weight means more wear and tear on all suspension components - it also means less acceleration and longer braking - larger wheels also mean larger tires - larger tires weigh a lot more - a 5lb per corner difference can easily be felt - keep that in mind when choosing wheels

[Aslet]

Another note, larger the tire, more they cost. I have looked into doing this, larger wheel with 968 castors, but I have realized its not worth it. If you want to get larger wheels just for the look when you drive around, it should be fine without the new castors. Then all you would need to do is keep stock wheels and put them on if you want to autocross or track (higher stress driving), not to mention this would be better performance then the larger wheels. Also, what year 944? I have an early, so that was another factor, I would need spacers for most wheels (993 cup wheels) I would like to get. So is investing easily over $1000, so the car looks maybe a little sportier, worth it? Like I said, I decided that its not worth it for my car which I bought for around $3000...

-Randy

[gtroth]

--great upgrade even on stock 15" wheels, IMO. Whole suspension seems tighter and more precise (you'll feel more "confident"). Easy installation.

[Spidey944]

I have a set of like new used avail for half the price if you decide to go that route. I have them on my 16" BBS's and just replaced them for piece of mind. Not to hijack, just an option.

[flash968]

you have a set of castor blocks on 16" bbs's?

[Spidey944]

Originally Posted by flash968

you have a set of castor blocks on 16" bbs's?

Yes, these are a great upgrade regardless of wheel size. The OE blocks have a huge rubber section, the 968 blocks have more support, and less rubber for stiffer reenforcement. The OE style is no longer avail anyway.

[flash968]

lol - i was just poking fun at the wording - i was trying to figure out how to attach castor blocks to a wheel

obviously upgraded castor blocks will improve any car

[rickharrison]

you can run 18's like these....

[Its_Scott]

I have an 89 944 turbo. I'm not an expert on this but wouldn't increasing the diameter of the wheel make the tires actually weigh less due to having less rubber and material since the rims will take up that space? (sorry for the run-on sentence lol). Yes, the rims will weigh more but the tires would weigh less? The overall outer diameter of the the tires will stay the same.

.... Oh wait, I just remembered that by increasing rim size, it MOST likely will increase the width of the tires as well. Hmm... I guess it can be heavier.

I'm don't race, track or autocross with my car. I just want some 18's so the car looks more contemporary. I plan to stick with OEM wheels since they are lighter than replicas and other aftermarket wheels so I've heard. So is it still a good idea to upgrade the castors or will it just run fine without them? Thanks!

[Aslet]

18 inch wheels may be pushing it with these cars, although if you don't push the car hard on the street, you shouldn't have an issue. As far as weight, metal is heavier than rubber and you have to remember that the tires are just filled with air, so the amount of rubber you will lose going to low profile is next to nothing (tire sidewall compared to tread is thinner). From my point of view (being cheap), I would say use the castors you have now... Worst case they will ware out quicker then with oem size wheels and you can upgrade then...

[Tidybuoy]

Originally Posted by Its_Scott

I'm not an expert on this but wouldn't increasing the diameter of the wheel make the tires actually weigh less due to having less rubber and material since the rims will take up that space?

I recently sold two sets of phone dials on eBay - both with tires. The 16's weighed 24.5 lbs each and the 15's weighed 21lbs each.

I thought the same as you but I think the metal around the lugs is thicker, besides the wheel being taller. Go figure......Vern

[flash968]

metal is not necessarily heavier than rubber if your wheels are aluminum - as an example, my 18 x 10 rim in the rear is 22.5lbs - my 285/30 tire on it is 30 lbs - the front is similar at 20 and 28 respectively

in stock 16" sizes, they are about even - in stock 17" sizes the tire starts outweighing the wheel

you can go to tire rack and see tire weights - you'll be surprised

[Its_Scott]

How do I know when the castors wear out? I actually don't even know what they are for.

Yea, I did hear about some wheels being lighter due to it being made from aluminum. On tirerack there were some rims that onl weighed 18 lbs at 18". Pretty amazing!

[flash968]

while you have the car in the air, if they wiggle, have cracks, or are separated, they are due for replacement

what they do is positively locate the rear point of the front lower control arm - they have an eccentric on them that allows for castor adjustment - castor is what keeps the car going straight