Omega Owners Forum

Chat Area => General Car Chat => Topic started by: Field Marshal Dr. Opti on 03 July 2020, 13:30:11

Title: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 13:30:11
285/30/20 as standard but I always seem to struggle for grip, especially in the wet.

Will the 295 section tyres from the XFR-S fit standard XFR rims?

Does anyone know?.....




Title: Re: Rear tyres are 'donald ducked'
Post by: Sir Tigger KC on 03 July 2020, 13:42:04
Your Kwik Fitup fitter will be able to tell you!  :y
Title: Re: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 13:46:19
Your Kwik Fitup fitter will be able to tell you!  :y

Oh, silly me......yes of course. A spotty 17 year old knuckle dragging neanderthal will have all the information. ;D
Title: Re: Rear tyres are 'donald ducked'
Post by: Andy B on 03 July 2020, 13:56:00
I can't see 10 mm wider being a problem

but will 10mm make much difference to the amount of grip?
Title: Re: Rear tyres are 'donald ducked'
Post by: Sir Tigger KC on 03 July 2020, 13:56:08
Well given that you seem to be willing to entrust your expensive car to said spotty 17 year old knuckle dragging neanderthal for the brakes, why not the tyres?  :P  :)
Title: Re: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 14:00:04
I can't see 10 mm wider being a problem

It's  strange but at times larger tyres can be cheaper than smaller tyres.

Standard fit tyres on the mighty Signum are an oddball 215mm. They are hard to source and about £30 a corner more expensive than the 225mm tyres I replaced them with.
Title: Re: Rear tyres are 'donald ducked'
Post by: Andy B on 03 July 2020, 14:09:58
I can't see 10 mm wider being a problem

It's  strange but at times larger tyres can be cheaper than smaller tyres.

Standard fit tyres on the mighty Signum are an oddball 215mm. They are hard to source and about £30 a corner more expensive than the 225mm tyres I replaced them with.

I wasn't thinking cost .... you asked if they'd fit  ;) You just need to be aware of the rolling diameter being too far from original otherwise you'll upset the ABS etc

The 17" tyres for the 17" rims I bought for my Omega were cheaper than the original fitment 16" because they were more common  :y
Title: Re: Rear tyres are 'donald ducked'
Post by: Marks DTM Calib on 03 July 2020, 14:26:12
285/30/20 as standard but I always seem to struggle for grip, especially in the wet.

Will the 295 section tyres from the XFR-S fit standard XFR rims?

Does anyone know?.....

A quick look on 'the system' shows the alloy dimensions are pretty much the same  :y
Title: Re: Rear tyres are 'donald ducked'
Post by: Marks DTM Calib on 03 July 2020, 14:27:55
I can't see 10 mm wider being a problem

It's  strange but at times larger tyres can be cheaper than smaller tyres.

Standard fit tyres on the mighty Signum are an oddball 215mm. They are hard to source and about £30 a corner more expensive than the 225mm tyres I replaced them with.

I wasn't thinking cost .... you asked if they'd fit  ;) You just need to be aware of the rolling diameter being too far from original otherwise you'll upset the ABS etc

The 17" tyres for the 17" rims I bought for my Omega were cheaper than the original fitment 16" because they were more common  :y

ABS wont care, it might upset a car which uses the rotational speed to provide tyre deflation guesses (as the front and rear tyres are different sizes).

Most of the ESP and ABS functions are based on delta calcs rather than absolute  :y
Title: Re: Rear tyres are 'donald ducked'
Post by: Marks DTM Calib on 03 July 2020, 14:28:55
Pop the two dimensions into here to see the changes

https://tiresize.com/comparison/
Title: Re: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 14:29:20
285/30/20 as standard but I always seem to struggle for grip, especially in the wet.

Will the 295 section tyres from the XFR-S fit standard XFR rims?

Does anyone know?.....

A quick look on 'the system' shows the alloy dimensions are pretty much the same  :y

Thanks, Mr DTM.

I'll check the price difference.

She currently runs on Michelin Pilot Sport 4S rubber.......which I like.
Title: Re: Rear tyres are 'donald ducked'
Post by: Marks DTM Calib on 03 July 2020, 14:31:50
285/30/20 as standard but I always seem to struggle for grip, especially in the wet.

Will the 295 section tyres from the XFR-S fit standard XFR rims?

Does anyone know?.....

A quick look on 'the system' shows the alloy dimensions are pretty much the same  :y

Thanks, Mr DTM.

I'll check the price difference.

She currently runs on Michelin Pilot Sport 4S rubber.......which I like.

The general view on those at work is that they are a bit hard for anything with decent torque and tend to spin up a bit to easy (they are predictable and wear well).

The guys here tend to go for something a softer  :y
Title: Re: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 14:32:21
Pop the two dimensions into here to see the changes

https://tiresize.com/comparison/

Looks like 1.1% extra diameter.
Title: Re: Rear tyres are 'donald ducked'
Post by: Marks DTM Calib on 03 July 2020, 14:34:24
Pop the two dimensions into here to see the changes

https://tiresize.com/comparison/

Looks like 1.1% extra diameter.

So bugger all, less than 1mph difference at 70mph
Title: Re: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 14:35:18
285/30/20 as standard but I always seem to struggle for grip, especially in the wet.

Will the 295 section tyres from the XFR-S fit standard XFR rims?

Does anyone know?.....

A quick look on 'the system' shows the alloy dimensions are pretty much the same  :y

Thanks, Mr DTM.

I'll check the price difference.

She currently runs on Michelin Pilot Sport 4S rubber.......which I like.

The general view on those at work is that they are a bit hard for anything with decent torque and tend to spin up a bit to easy (they are predictable and wear well).

The guys here tend to go for something a softer  :y


I'll go with that.

According to Viezu torque has gone from 461 lb ft to about 530 lb ft following the remap.

No idea what that is in NM.
Title: Re: Rear tyres are 'donald ducked'
Post by: Marks DTM Calib on 03 July 2020, 14:55:45
720 ish
Title: Re: Rear tyres are 'donald ducked'
Post by: Field Marshal Dr. Opti on 03 July 2020, 15:19:07
720 ish

It doesn't seem lacking in twist although Starship Enterprise gearing can blunt the acceleration in top at almost 50MPH/1000 RPM.