17" wheels the same as changing final drive?

R555 · 20th October 2012, 17:10

Hi,

I was reading somewhere that changing to 17" wheels has the same effect as changing the final drive? Does anyone know if thats true?

Also if you are going to change to 17's what offset and width would be best?

stoney · 20th October 2012, 17:13

Due the extra sidewall, switching to 17s isn't as big a jump as an FD change Dave.

If your doing it keep the wheel sizes just like the 18 options, offset/width etc just an inch smaller.

coste1l · 20th October 2012, 17:29

I agree! 35 profile would help i supposr?

Sent from my GT-N7000 using Tapatalk 2

stoney · 20th October 2012, 17:33

35 on a 225 would look meh, I have seen 17s on EP3s with 40 wall and it doesn't look right imo- on FN arches it's be even worse, 45 is a must but means the gain is marginal.

Weight wise though you can shave off a bomb with a good wheel/tyre combo

cvega · 21st October 2012, 21:21

how does fitting 17 inch wheels with 225/45/17 instead of 225/40/18 affect speedo ?

R555 · 21st October 2012, 21:40

Quote:

Originally Posted by cvega

how does fitting 17 inch wheels with 225/45/17 instead of 225/40/18 affect speedo ?

I presume it'll throw out the readings slightly?

R555 · 21st October 2012, 21:42

Quote:

Originally Posted by stoney

35 on a 225 would look meh, I have seen 17s on EP3s with 40 wall and it doesn't look right imo- on FN arches it's be even worse, 45 is a must but means the gain is marginal.

Weight wise though you can shave off a bomb with a good wheel/tyre combo

Oh well, guess I'll stick with the M Factory Final Drive then. Thought it might have been a win / win situation if it had a similar effect to the final drive as I could have got some 17" Pro Race 1.2's and saved weight and had better acceleration.

stoney · 21st October 2012, 22:02

Do it with the FD

The speedo can be retuned via Flashpro too

R555 · 21st October 2012, 22:19

Quote:

Originally Posted by stoney

Do it with the FD

The speedo can be retuned via Flashpro too

Got one on order from Stevie

stoney · 21st October 2012, 22:21

It's on the cards for me too Dave when I crack the box open down the line

R555 · 21st October 2012, 22:36

Quote:

Originally Posted by stoney

It's on the cards for me too Dave when I crack the box open down the line

Colin raves about his so I'm hoping it'll be a good mod. Just wondering it'll make any difference to where my power comes on?

BRM · 21st October 2012, 23:27

17"s on our FN2 bring only advantages!!!!!

Im running 235/40 up front on my Advan RZ and its still smaller than the OEM 225/40 18.

The bigger wall, bring confort aswell as better cornering on slight bumpier roads. Its just alot better overall.

Highly recomend.

Madcaddies · 21st October 2012, 23:53

Sorry for jumping in but where in the UK do I buy 17" Gold Ultraleggera for my FN2 CW? Any good shops I should know about?

stoney · 22nd October 2012, 02:43

Quote:

Originally Posted by R555

Colin raves about his so I'm hoping it'll be a good mod. Just wondering it'll make any difference to where my power comes on?

It feels like the whole car is lighter

Grayfox · 22nd October 2012, 07:12

Quote:

Originally Posted by cvega

how does fitting 17 inch wheels with 225/45/17 instead of 225/40/18 affect speedo ?

All boils down to circumference
A 225/45/17 tire has a circumference of 1992mm
A 225/40/18 tire has a circumference of 2001mm
A 225/35/19 tire has a circumference of 2011mm

While the 18" tire has a circumference that is larger by 9mm which is small it is enough to throw out the speedo by 0.5km/h at 100km/h, and if you go for the 19" option your speedo will be thrown out by 0.9km/h or 1km/h

But if you were to have a 225/45/18 tire equipped it's circumference would be 2072mm.

This would make you travel 104km/h when your speedo says 100km/h(which is enough to get you fined these days)

To counter this and have some leeway for other things speedos over read your speed by 4% or so.

When i am going 100km/h on my cars speedo i am going 96km/h as seen on my SII GPS.

The Official Site for the Best Online Tire Size Calculator

Relic · 22nd October 2012, 12:20

You can fit...
225 35 r17 = 1851mm circumference (not much tyre choice though)

225 40 r18 = 2002mm circumference

With a 5.1 you will end up with the equivalent of...
5.1 * 2002 / 1851 = 5.516 final drive

But there is a weight saving too.

ghost_bhp · 22nd October 2012, 17:55

Quote:

Originally Posted by Relic

You can fit...
225 35 r17 = 1851mm circumference (not much tyre choice though)

225 40 r18 = 2002mm circumference

With a 5.1 you will end up with the equivalent of...
5.1 * 2002 / 1851 = 5.516 final drive

But there is a weight saving too.

I just love how you always have a formula to hand!!

Sent from my iPhone.

coste1l · 22nd October 2012, 19:15

Its how his brain works. Its the words between the formulas he struggles with

Sent from my GT-N7000 using Tapatalk 2

cvega · 22nd October 2012, 21:16

Brilliant, thanks for that info! Considering 17s for the winter time.

Relic · 22nd October 2012, 22:29

The diameter will be 2" less.
So you will have a 1" bigger arch to tyre gap.
Coilies would be good.. avoid speed humps

20th October 2012, 17:10	#1 (permalink)
R555 Supporter Car: 2007 CTR, Milano Red Join Date: 17th November 2009 Location: North Yorks Posts: 5,142 Thanks given: 819 Thanked 403 Times in 376 Posts iTrader: (6)	17" wheels the same as changing final drive? Hi, I was reading somewhere that changing to 17" wheels has the same effect as changing the final drive? Does anyone know if thats true? Also if you are going to change to 17's what offset and width would be best?

22nd October 2012, 12:20	#16 (permalink)
Relic Cockup Specialist Car: 2007 2.2 Type 'S' GT, Bronze Join Date: 31st August 2009 Location: uk Posts: 12,187 Thanks given: 740 Thanked 1,466 Times in 1,283 Posts iTrader: (0)	You can fit... 225 35 r17 = 1851mm circumference (not much tyre choice though) 225 40 r18 = 2002mm circumference With a 5.1 you will end up with the equivalent of... 5.1 * 2002 / 1851 = 5.516 final drive But there is a weight saving too. Last edited by Relic; 22nd October 2012 at 12:27.

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20th October 2012, 17:13	#2 (permalink)
stoney Supporter Car: 2007 FN2 GT Join Date: 24th March 2010 Location: lisburn Posts: 7,199 Thanks given: 160 Thanked 1,082 Times in 917 Posts iTrader: (9)	Due the extra sidewall, switching to 17s isn't as big a jump as an FD change Dave. If your doing it keep the wheel sizes just like the 18 options, offset/width etc just an inch smaller.

20th October 2012, 17:29	#3 (permalink)
coste1l Supporter Car: 09 Suzuki Swift Sport white Join Date: 16th January 2010 Location: Sunderland UK Posts: 17,889 Thanks given: 1,117 Thanked 1,992 Times in 1,879 Posts iTrader: (15)	I agree! 35 profile would help i supposr? Sent from my GT-N7000 using Tapatalk 2

20th October 2012, 17:33	#4 (permalink)
stoney Supporter Car: 2007 FN2 GT Join Date: 24th March 2010 Location: lisburn Posts: 7,199 Thanks given: 160 Thanked 1,082 Times in 917 Posts iTrader: (9)	35 on a 225 would look meh, I have seen 17s on EP3s with 40 wall and it doesn't look right imo- on FN arches it's be even worse, 45 is a must but means the gain is marginal. Weight wise though you can shave off a bomb with a good wheel/tyre combo

21st October 2012, 21:21	#5 (permalink)
cvega Supporter Car: 2007 Porsche Cayman S Join Date: 30th January 2012 Location: Cambridge Posts: 218 Thanks given: 0 Thanked 23 Times in 14 Posts iTrader: (0)	how does fitting 17 inch wheels with 225/45/17 instead of 225/40/18 affect speedo ?

21st October 2012, 22:02	#8 (permalink)
stoney Supporter Car: 2007 FN2 GT Join Date: 24th March 2010 Location: lisburn Posts: 7,199 Thanks given: 160 Thanked 1,082 Times in 917 Posts iTrader: (9)	Do it with the FD The speedo can be retuned via Flashpro too

21st October 2012, 22:21	#10 (permalink)
stoney Supporter Car: 2007 FN2 GT Join Date: 24th March 2010 Location: lisburn Posts: 7,199 Thanks given: 160 Thanked 1,082 Times in 917 Posts iTrader: (9)	It's on the cards for me too Dave when I crack the box open down the line

21st October 2012, 23:27	#12 (permalink)
BRM Join Date: 2nd October 2007 Location: Albufeira, Portugal Posts: 2,250 Thanks given: 8 Thanked 116 Times in 105 Posts iTrader: (2)	17"s on our FN2 bring only advantages!!!!! Im running 235/40 up front on my Advan RZ and its still smaller than the OEM 225/40 18. The bigger wall, bring confort aswell as better cornering on slight bumpier roads. Its just alot better overall. Highly recomend.

21st October 2012, 23:53	#13 (permalink)
Madcaddies Supporter Car: 2010 CTR CWE Join Date: 1st October 2011 Location: Denmark Posts: 777 Thanks given: 185 Thanked 65 Times in 62 Posts iTrader: (11)	Sorry for jumping in but where in the UK do I buy 17" Gold Ultraleggera for my FN2 CW? Any good shops I should know about?

22nd October 2012, 19:15	#18 (permalink)
coste1l Supporter Car: 09 Suzuki Swift Sport white Join Date: 16th January 2010 Location: Sunderland UK Posts: 17,889 Thanks given: 1,117 Thanked 1,992 Times in 1,879 Posts iTrader: (15)	Its how his brain works. Its the words between the formulas he struggles with Sent from my GT-N7000 using Tapatalk 2

22nd October 2012, 21:16	#19 (permalink)
cvega Supporter Car: 2007 Porsche Cayman S Join Date: 30th January 2012 Location: Cambridge Posts: 218 Thanks given: 0 Thanked 23 Times in 14 Posts iTrader: (0)	Brilliant, thanks for that info! Considering 17s for the winter time.

22nd October 2012, 22:29	#20 (permalink)
Relic Cockup Specialist Car: 2007 2.2 Type 'S' GT, Bronze Join Date: 31st August 2009 Location: uk Posts: 12,187 Thanks given: 740 Thanked 1,466 Times in 1,283 Posts iTrader: (0)	The diameter will be 2" less. So you will have a 1" bigger arch to tyre gap. Coilies would be good.. avoid speed humps