Apparently the other thread about wheels was shut down. I was thinking about putting Jag Cremona 20" wheels on. Seller says he has 8.5J and 9J x 20" sets. If I go "UN" staggered will this be a problem? Please save the safety issue BS, all I want are real word replies. Thanks -JG

 

 

This one? https://www.jaguarforums.com/forum/s...e-w-str-71568/

Still looks open.

Safety isn't real world(*)? Wow. I hope you don't mean that. Let's imagine you're going to check strength, weight, offset, sizes, effect on suspension & handling, etc.

Speaking of it, what are the offsets of those 20s?

Do the bolt holes fit?

(*) seems you meant that rather than "word"

 

Listen, I dont want to get in an argument with you. What I am asking is that if I put 20"'s on my vehicle, Jaguar fitament, will there be an issue? That is my question. I would wrap them with 255/35/20's all around. I DO NOT know the effect on suspension and sh*t like that, however, there is no reason why this set up would not work. The whole safety BS is mute in my opinion, this car will stop faster than any I have driven and I'm not worried about wheels falling off. FYI bolt holes fit, and I dont know the offset but will figure it out quickly as the wheels are stock Jag Cremona's.

 

Jag V8........god get a grip!!! there are many car manufacturers that use exactly the same suspension/chasis set ups and vary the wheels by way more than 1" that Bull is talking about and yes as an automotive engineer with over 17 years experience i know what i'm talking about. My last Project was the new MINI and we had wheels from 15" to 18" on exactly the same set ups...............does it change handling etc, yes of course it does, but its your personal preference, will it effect safety.....not any more than any other car built today in terms of difference. As long as you get the basics right and the same, PCD, center bore, close offset and the wheels assy does not catch on anything it'll be fine.......i drove round in a 400bhp cosworth which had 4" bigger diameter wheels....2" wider and a 20mm offset difference........OK handling was not as good as standard.....but........did the wheels come off....no.........did i crash it..........no.

 

Those look like wheels for the XK. Not sure though.

There are a few things you need to check. The rest is from experience from playing with different wheel sizes...

First of all. Are they the same bolt pattern and hub bore as the S Type?
Yes? continue... No? I wouldn't even with hub centric rings. I've used them in the past and they can make the wheels difficult to balance. Then again, I'm picky and the slightest vibration drives me nuts..

Staggered wheels.... They are fitted to performance cars to create a larger contact patch for power delivery. Heck... The last generation V8 Pontiac GrandPrix GTP actually had wider tires fitted to the front since it was a front driver. So, if not going with a staggered set, make sure that the width normally fitted to the rear will also fit on the front and not hit any of the steering or suspension. This can get really tricky since you need to accommodate the potential for suspension compression while turning. The other issue is if you go with a wider wheel up front you will potentally increase the front grip to the point that it doesn't handle as you want. These are things to consider.

Another question would be, why do you want to do it. If it is for the look and you can accept the loss of ride quality, then go for it, if they fit correctly they will look pretty mean. If it is to increase performance and improve grip that is hard to answer. 20" might be overkill. I know on the Chrysler I have the factory fitted 20" wheels to the SRT8 cars. Those drivers have found that the cars actually perform better with 18" wheels on a road course. Problem is getting the right offset to accomodate the Brembo brakes and slightly different suspension geometry. I wanted to get 20's for mine but after learning that I am going to go with 18"x8" wheels for a better fitment of wider tires vs those fitted to the standard 7.5" wheel. But, as you know, I look for performance over looks.

The last thing I will mention is the change in ride quality. As you go to a bigger set of wheels the sidewall gets smaller. This will make the ride stiffer as you go up. Again, some cars actually benefit from this but there is a limit. If you go into my photo's I have an album with a couple of pictures of the Honda Coupes I've had. The white one had 18" wheels on it and the silver had 17". With the 18" wheels, it gripped much better but was slower and rode real hard. It also tracked in pavement groves. This was annoying enough that when I went to the silver car I put 17" on it. Much better ride, not as grippy, and didn't look as "mean" as the white car. But I was much happier with the compromise.

I have a link to a very well written article that talks about the effects of upsizing wheels / tires. It was done by Car and Driver.

Effects of Upsized Wheels and Tires Tested - Tech Dept. - Car and Driver

Bull, if you can and are willing, post up a link to the wheels you are looking at. It would be interesting to see some specs on them.

 

Bull,

For ride quality alone, I wouldn't do it....

My wife's 2006 XK8 has staggered 19-inch tires, Michelin Pilot Sports up front and Pirelli P-Zero Rossos in back. I run them at 32 psi all the way around. You feel every pebble in the road. Granted, the Pirellis are done with just over 2/32 of tread remaining (I have a set of two V-rated Yokohamas on order from Discount Tire for the rear axle - they should arrive early next week), but even when the Pirellis had 5/32 of tread remaining, the ride was no better. It's these 19-inch wheels and very low profile (40-series) tires, man....

Our 2005 S-Type has 17-inch wheels with a far less-expensive set of Dunlop SP Sport Signatures (50-series). I run them at 34 psi all the way around. The ride smoothness is light-years better in the S-Type vs. the XK8. Yes, I know they are vastly different models with different characteristics. But the ride in the S-Type blows the ride in the XK8 away, and it is primarily due to the 19-inch wheels and 40-series tires. I can't imagine how much worse it would be with 20s....

 

Short answer, going unstaggered would not be a problem and would they fit? Depends on the offset...

 

I was the one who posted that article in the other thread to help clear the air, but it's a very limited article...As they upsized in diameter, they also upsized both the width of the rim and the width of the tire...There are totally different results if go with skinnier rims and/or tires...

Side note...At one time on a different car, I owned 17x7.5 wheels named Nippon Lightstars, they were cheap and weighed only 13.6lbs!

 

Am I missing something , in that if you are concerned about any clearance issues, would the 8.5 size ones be the best to go for ?