[SILVY968]

My 1995 cab has 18" "twist" style wheels. The rubber is Dunlop FM901's.

The rears are 265/35ZR18 and fronts are 225/40ZR18's.



The ride quality sucks when driven on downtown streets with rough terrain. Even on a smooth road, the occasional seam or manhole cover is noticable. As a daily driver, she is shaking herself apart. I am forever chasing rattles and loose screws.



The stock wheels were; rear 8J X 16", front 7J X 16".

Stock rubber was; rear 225/50ZR-16, front 205/55ZR-16.



Having never driven a stock wheeled 968, I do not know if the ride quality is the exclusive result of the wheel/tire combination, or just the nature of the beast. My last Porsche was a 911 with stock factory shoes and it was WAY more comfortable.



Front shocks have been replaced before I got her and have been tested by my PM as OK. Rears were replaced with a small improvement.



I run the tires at 36#.



Other that going over to Park Place Ltd to test drive another 968, I am in the dark when it comes to "stock" ride comfort.



I love the way the car sits with the 18's, as well as the looks of the twist wheels, but I drive my cab way too much to let the ride quality stay the way it is.



Forum opinions and comments, please

Partial Post: Please Login or Register to read the full post.

[BruceWard]

I have driven my 968 on similar 18s and on 16s. The ride quality is much softer of the 16" wheels. In both cases I run similar air pressure to yours. I did have 225F/245R on the 16s.

Partial Post: Please Login or Register to read the full post.

[Greimann]

I went the full route from stock 16's and worn out shocks to 18's, and then Konis and HR springs. The jump to 18's made a small increase in ride harshness, but by far the Koni's and HR springs gave it a sharp (but desirable in my mind) ride and response.



In stock form, I think the car is quite soft. Do you have the Konis and aftermarket springs?

Partial Post: Please Login or Register to read the full post.

[sasilverbullet]

My 968 has 17" wheels with Michelin Pilot Sports all around. We have this road surface in Texas called "chip seal". This road surface with these tires is LOUD! But, I wouldn't change the tires out because of the handling characteristics it gives the car.

When I bought my car, it had kumho's up front that were one size to big. The ride was smoother, but it hanled like a cow.

In all of my cars I've had over 30 years, the brand and kind of tire definitely make ALL the difference in the world in handling, quietness, and safety.

I prefer to always opt for the handling and safety...



Oh, and in my opinion the best tires for a Porsche are Michelin Pilot Sports, or Michelin Pilot sport cups if you want to run on a track. The pilot sports have awesome handling with about the quietest ride you're gonna get in a high performance tire.

Partial Post: Please Login or Register to read the full post.

[Harvey]

No doubt..when I went from 16" wheels to 17" the ride got stiffer. Also, Z rated tires are stiffer.



Harvey

Partial Post: Please Login or Register to read the full post.

[Harvey]

Park Place Ltd of Seattle has some cool cars. I came within $500 of buying a 968 there last year...but I'm glad I didn't since I got one better, and fewer miles for for $4,500 less....if you don't count expenses for flying to Atlanta and driving it back to Idaho. I'm going to drop by Park Place again next week. Nicer than a museum and they have nice rigs to drool over.



Harvey

Partial Post: Please Login or Register to read the full post.

[SILVY968]

[quote name='Greimann' date='Nov 9 2005, 07:53 PM']I went the full route from stock 16's and worn out shocks to 18's,  and then Konis and HR springs. The jump to 18's made a small increase in ride harshness, but by far the Koni's and HR springs gave it a sharp (but desirable in my mind) ride and response.



In stock form, I think the car is quite soft.  Do you have the Konis and aftermarket springs?

[right][post="12249"]<{POST_SNAPBACK}>[/post][/right][/quote]



She is bone stock except for an upper KLA strut brace.

The rear shocks that I put on are KONI sport model.

Partial Post: Please Login or Register to read the full post.

[flash]

not a lot of good news here - sorry



dunlops have traditionally had very stiff sidewalls - try dropping the pressure to 35 front and 34 rear - it may help a bit



this is not an uncommon complaint though - it happens way too often - many people don't consider the physics when putting wheels on the car, and just go by looks and fit



i was trying to explain this to another guy the other day - wheel weight is incredibly critical here - increases in wheel weight can quickly exceed the suspension's ability to compensate - the increased impact force on each and every jounce is dramatic - it doesn't seem like much when out on a wheel that is a pound or two more, but add to that the much heavier tire (tires are heavier than wheels) and youcould easily add 6 or 7 pounds at each corner - that's huge!



the further bad news is that it also increases load on every single suspension bushing - be preapared to have to go in there later to start replacing stuff



the reduction of sidewall also increases bounce and rebound issues



you have a cast rim (heavy and stiff), low profile tires (stiff), larger tires (heavy), and dunlops (stiff) - that's a lot of road force increase to deal with



to make matters worse, those wheels are very likely costing you acceleration and braking, due to the increased rotational mass that you must overcome



18s can be great looking, can help handling and really make the car more fun - you have to be careful what you choose though, and take into consideration the use of the car



if you are stuck on those wheels, and the dropping of pressure doesn't help, try a softer sidewall tire, like the michelin pilot sport

Partial Post: Please Login or Register to read the full post.

[Jacks968]

Brian,



I have to agree with Flash - and add my own experience - you know my car - stock 63,000 miles - still on original shocks - with factory 17" wheels. If your issue is not the Konis bing screwed down to firm my guess is you would be happy switching to 17"s. I have read many road test reports on these cars and often the testers comment that the 17" wheels improve road holding but the ride suffers - and they also note increased Tramlineing. I also have two sets of 17" Cup IIs. The original 968 wheels are 7.5 inch front w 225/45 Bridgestone tires- and I have 7" fronts from a 993 w 205/55 Contis (on the car now & for sale ;-)).



Having had both sets on the car I can say for sure the 55 aspect Conti rides better then the 45 Brgstn. I can also say that the 968 rides much better that my former 964 which had run on the 993 wheels w Contis.



If you would like - PM me & come over and drive mine and see for your self. I think you would find the ride very acceptable with 17" and a little taller tire set.

Partial Post: Please Login or Register to read the full post.

[SILVY968]

[quote name='Jacks968' date='Nov 13 2005, 12:15 AM']Brian,



I have to agree with Flash - and add my own experience - you know my car - stock 63,000 miles - still on original shocks - with factory 17" wheels. If your issue is not the Konis bing screwed down to firm my guess is you would be happy switching to 17"s. I have read many road test reports on these cars and often the testers comment that the 17" wheels improve road holding but the ride suffers - and they also note increased Tramlineing. I also have two sets of 17" Cup IIs. The original 968 wheels are 7.5 inch front w 225/45 Bridgestone tires- and I have 7" fronts from a 993 w 205/55 Contis (on the car now & for sale ;-)).



Having had both sets on the car I can say for sure the 55 aspect Conti rides better then the 45 Brgstn. I can also say that the 968 rides much better that my former 964 which had run on the 993 wheels w Contis.



If you would like - PM me & come over and drive mine and see for your self. I think you would find the ride very acceptable with 17" and a little taller tire set.

[right][post="12364"]<{POST_SNAPBACK}>[/post][/right][/quote]



Jack,



Thank you for the offer.

Actually, I had the same idea, so I went over to PARK PLACE LTD this afternoon. I test drove a 1992 968 tip cab ($19,995.00) that they had on the lot. It had OEM 16" wheels and tires on it. It had no balls at all and leaked water into the cabin, but the ride sold me on changing to 16's.

I bought LeeDye's OEM 16" chromed, Conti set and they will be on the way to me next week.

I am going to keep the 18" twists as well.

If my 968 was a second car or trailer queen, I would keep the 18" on all the time; but since she is my daily driver I want the comfort of the 16's. With the winter approaching, I think that the 18"s will live in the garage until the first spring day.

Partial Post: Please Login or Register to read the full post.

[apex]

I should add that my 17" wheels with Yoko dbII tires are a very nice combination - almost perfect combination (for me) of good looks, ride, quiet, and stickiness. So far, so good! Mine is also a daily drive.

Partial Post: Please Login or Register to read the full post.

[Anchorman]

I have 18" wheels with Yokohoma AVS ES-100. I've never had anyone comment about a harsh ride. Several multi-hours rides with my wife as a passenger gave rise to no complaints at all - and, trust me, she's no enthusiast. It certainly is a firmer ride than when I have the 16" with winter tires mounted, but I would not characterize it as harsh. Certainly firm, though. From what's been written, on this thread and others, it seems to be as much an issue of tires as it is with wheel size.

Partial Post: Please Login or Register to read the full post.

[flash]

yeah, i don't think "harsh" is necessarily the right word either, though i hear it a lot in the description



as i have said, it's a very subjective thing - as an example, ron compains about the scuttle shake, while i notice nothing out of line - having driven an mg for years, this car is comparatively very smooth, yet it drives him nuts - he would hate 18s



it's really all part of a package - doing it in concert with other accompanying component changes is the key to success - it just means more money



like everything, no free lunch

Partial Post: Please Login or Register to read the full post.

[SILVY968]

I received the chrome OEM 16's with CONTI's on them.

They are on the car now and the ride is the same but the harsh "stop at the bottom end of the bump" are gone. She still corners very well and I still have the road feel that I want. The height of the car is the same and the new wheel/tire combo still fills up the wheel wells nicely.

It is more smooth through the bumps on the road, and provides a more enjoyable ride.

A more pleasant P car experience. The 18's look great, but you must be willing to give up some ride comfort.

Partial Post: Please Login or Register to read the full post.

[taporite6]

have a tip with 265 40 18 on rear 225 35 18 on frt came with car have khumo's.

I think the ride is a bit harsh. can feel bumps and such. would like a softer feel

Mine is a daily driver. I like the look of 18's but would not like to feel every bump in the road. have stock springs and shocks.

Partial Post: Please Login or Register to read the full post.

[flash]

lol - if you think that's bad, you should drive mine - i got rid of most of the rubber suspension bushings - you get to feel a lot now - handles great, but going to be a lot more careful with my coffee now



18s are definitely not for everybody, for a number of reasons - before running out and buying them, drives somebody's car with a similar wheel (primarily for weight reasons and how it affects the feel) - then decide if you can deal with it, before you drop all that dough

Partial Post: Please Login or Register to read the full post.

[taporite6]

definately have to test drive a 968 with 17's or 16's. also i guess have to change bushings again.

Partial Post: Please Login or Register to read the full post.

[6spcab]

[quote name='SILVY968' date='Nov 26 2005, 02:08 PM']I received the chrome OEM 16's with CONTI's on them.

They are on the car now and the ride is the same but the harsh "stop at the bottom end of the bump" are gone. She still corners very well and I still have the road feel that I want. The height of the car is the same and the new wheel/tire combo still fills up the wheel wells nicely.

It is more smooth through the bumps on the road, and provides a more enjoyable ride.

A more pleasant P car experience. The 18's look great, but you must be willing to give up some ride comfort.

[right][post="12826"]<{POST_SNAPBACK}>[/post][/right][/quote]





Glad to hear Brian. Enjoy them and put up some pics.

Lee

Partial Post: Please Login or Register to read the full post.

[smshirk]

Anyone interested in a trade.........my 18" twists for OEM cups

Partial Post: Please Login or Register to read the full post.

[SILVY968]

[quote name='LeeDye' date='Nov 26 2005, 08:14 PM']Glad to hear Brian. Enjoy them and put up some pics.

Lee

[right][post="12834"]<{POST_SNAPBACK}>[/post][/right][/quote]



Had her out last weekend. Sure rides nice, but the Dunlop 901's are wider and can be pushed MUCH harder on the corners than the OEM sized Conti's.

Partial Post: Please Login or Register to read the full post.