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I am somewhat puzzled with the following topic:
I have Conti GT Gen1 and wanted to equip it with 21'' wheels.
I have purchased the original 9.5J x 21ET41 3W0 601 025DK.
With the recommended tires on these wheels: 275/35.
Issue #1: After I mounted them as-is, they rub from inside on the front size.
Solution #1: I had to put 12mm wheel spacer rings on the front.
Which triggered issue #2: they became too wide, and when the car goes in the normal mode, the outer size of the tire rubs on the car fender. If I put suspension in the high mode -- its ok, there is enough space.
I am puzzled: why do I need the spacer ring at the first place? They make the wheel effectively from 9.5J x 21ET41 into 9.5J x 21ET29 -- I have not seen this spec anywhere.
Another solution could be to change the tires, from 275/35 to 265/30, which make them lover and narrower. But I also did not see any spec for Bentley 21'' wheels.
Third solution, is to calibrate the normal mode of the suspension to make it higher by default.
Looks like I am missing something trivial, but can't understand what.
As far as your tire and wheel issues, I can only say that I believe that you went with the incorrect tire size selection, and as you do not state the year of you 1st Gen, I will use my 2005 wheels as comparison.
The 2005 GT wheel is a 19" X 9J - ET 41, so therefore your newly purchased 21" wheels are a half of an inch wider now at 9.5J, that adds to clearance problems inside and outside, the 2005 GT had 275/40/ZR19 tires.
Now the tire size you selected for the 21's is to large in diameter compared to the 275/40/19.
See chart below, I believe the 275/30/ZR21 would be a much better fit, same width as the original 275/40/19, and only 2/10ths of an inch smaller in diameter.
Johnny
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Last edited by Johnny Hotspur GT; 10-03-2021 at 02:37 PM.
Reason: Spelling
many thanks for your insights. My Gt is 2005 as well.
Indeed, I missed the 0.5 inch difference in the wheels width.
I still have one question/concern regarding the 275.
I am enclosing the tyres photo, which gives a sense of the rubbing pattern, when the wheel was mounted without the 12mm spacer ring.
Do you think the smaller diameter but with the same width will solve this issue?
I'm running 21 inch 9.5J wheels with an ET of 35 on my 2005 GT. Fitted with 275/35/21 tyres and I don't have any rubbing. The car is lowered 20mm all round too.
Perhaps your need a spacer to bring the offset to ET35 so it matches my wheels?
Looks like the smaller diameter should fix the tire rubbing issue without spacer, from what I can see. The diameter will be 1.1" less, going by the above, half of which will be the reduction all around, so that looks like it should easily clear whatever is gouging the inside shoulders on your tires.
I'm running approximately the same diameter tire as the suggested 30 profile 21" (I'm running 275x35x20 on 9.5" wide et 41mm speed wheels) and have no rubbing, even with the car lowered about 1" or on sharp turns.
Thank you all for the ideas. It looks like indeed lowering diameter should be a solution. I had a closer look today, and it looks like that the front suspension was lowered in this car, as it is visible lower as the back. Which might explain why 275/35 causes an issue while everyone else does not have it. Tomorrow I am going to try to adjust the suspension height, to make it 10mm higher at the front, which should solve the rubbing, hopefully.
The root cause was that the front of the car was lowered by 30mm by the previous owner. We have reprogrammed the suspension and now the original ET41 wheels with 12mm spacer and 275/35/21 fit just great.
The root cause was that the front of the car was lowered by 30mm by the previous owner. We have reprogrammed the suspension and now the original ET41 wheels with 12mm spacer and 275/35/21 fit just great.
Hello @DrGigabit ,
I an glad you got it figured out !
I will add, I should have made my setup clearer earlier in my previous post, as said, my 2005 GT stock wheels are 19 X 9 X ET41 with 275 / 40 / ZR19 tires, of course all fit fine even when lowered, my new wheels and tires as seen in my avatar are 20 X 9 X ET25 and 275 / 35 / ZR20's, no spacers, they fit fine also with lowering links installed, so, as I stayed with the 9" width wheel, but went with a ET25 which moves the backspacing outwards from the suspension, and it gives a more flush outward look, I have no clearance issues with the 20's even when lowering because I went with the 275/35 which is 1/10th on an inch or 3 MM smaller in diameter then the stock tire size, but is the same width,
whereas you stayed with the ET41 offset and went with a wider 9.5 wheel and a 275/35 tire, which in turn reduced your backspacing clearance for suspension and other items, and hence the need for a spacer on your 2005, so as Sam08861 has 275/35/20's and lowered 1 inch without issue, I can only think that if you used a 275/30/21 you would not have any issue, and most importantly would not need the spacers, or as Lewis Barwick noted, he has 21's at 275/35 on ET35 wheels, and no issues, so in theory you only need 6MM spacers for clearance.
BUT: As I sit here typing this, it came to mind how you mentioned "Gen 1", so I just looked up the part number you posted, and it states that they can fit 2011 and up, now depending on which 2011 they are referring to, NA vs ROW, that could be the issue, as the ROW 2011 is a second generation Bentley GT, and as your part number shows a product description date of May 10 2015, I definitely think that you have some Gen 2 wheels in a size with Gen 2 size tires, that are not meant to fit the Gen 1, most likely because of suspension geometry differences between the two.
Please post some pictures of your B !
Johnny
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Last edited by Johnny Hotspur GT; 10-07-2021 at 02:00 PM.
The 35 profile recommendation for 2nd gen 21" seems to compensate for shrinking sidewalls from increased rim diameters, while width remains the same or similar.
I'm assuming Bentley chose to do this for the purpose of maintaining a level of ride softness (from the tires, at least, as other components have gotten stiffer)
The 3rd gen follow the same pattern, are taller still and also staggered with wider rears. This 'evolution' can be seen below, in the continental section for the GT, with the changes at 2012 and 2019 model years.
10-03-2021 | 04:49 AM
