What problems will I get running '40 tyres

Robti · 28th March 2017, 18:46

Hi what problems other than speedo would I get putting a set of grid spokes on my 190 with 225x40x18 tyres ?

Thanks

maxi_crawf · 28th March 2017, 19:55

Won't be very comfortable from what I hear.

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Robti · 28th March 2017, 20:02

Thanks that's what I heard also, just got the chance of a set of grid spokes with 4 good 40's so didn't know what to do

steve-45 · 28th March 2017, 20:17

My SAAB 93 Aero is on 40 profile tyres and you can feel every ripple in the road, and potholes loosen your fillings ....

Christopher Price · 28th March 2017, 20:44

Stupid hard ride and a speedo that doesn't read correctly, other than that, fine.

spongeh · 29th March 2017, 08:13

I picked up some cheap Gridspokes with 225/40R18 tyres on them the other week and I've fitted them to the car to see what they're like and how they look & feel.

I've moved from 15" wheels to the 18", therefore the move was about as extreme as you can get.

Slightly more road noise, but not enough to want me to go back to 15s
Cornering improved - mud flaps don't touch down anymore
Pot holes are a painful experience with the 40s, will try 45s soon
Speedo is more accurate than the 15s vs GPS (195/65r15 = 5mph difference, 225/40R18 = 3mph difference)

Looks wise, the 40's are a bit small, but not much.

Dallas · 29th March 2017, 08:35

Quote:

Originally Posted by spongeh

I picked up some cheap Gridspokes with 225/40R18 tyres on them the other week and I've fitted them to the car to see what they're like and how they look & feel.

I've moved from 15" wheels to the 18", therefore the move was about as extreme as you can get.

Slightly more road noise, but not enough to want me to go back to 15s
Cornering improved - mud flaps don't touch down anymore
Pot holes are a painful experience with the 40s, will try 45s soon
Speedo is more accurate than the 15s vs GPS (195/65r15 = 5mph difference, 225/40R18 = 3mph difference)

Looks wise, the 40's are a bit small, but not much.

40's certainly do give a lot lower profile dont they.

Using the kouki.co.uk Tyre Size Calculator, your rolling radius is 0.85cm larger, and your speed is 0.4% greater than indicated.

When your speedo reads 60mph, you will actually be doing 60.3mph.

spongeh · 29th March 2017, 08:44

Quote:

Originally Posted by Dallas

40's certainly do give a lot lower profile dont they.

Using the kouki.co.uk Tyre Size Calculator, your rolling radius is 0.85cm larger, and your speed is 0.4% greater than indicated.

When your speedo reads 60mph, you will actually be doing 60.3mph.

Should have mentioned the ZT is on the correct profile tyres as I've replaced all 4 with 225/45R18s

Speedo as I've said doesn't over read it's 3mph under so an indicated 60mph is an actual 57mph via the GPS

johnpilky · 29th March 2017, 17:23

Quote:

Originally Posted by Robti

Thanks that's what I heard also, just got the chance of a set of grid spokes with 4 good 40's so didn't know what to do

you need 235/40/18 tyres to keep same rolling radius better handling bad ride

Billyuk1 · 29th March 2017, 21:58

will it not affect your insurance?

28th March 2017, 18:46	#1
Robti Posted a thing or two MG ZT-T 190+,Rover 800 vitesse coupe Join Date: Aug 2014 Location: Hamilton Posts: 1,969 Thanks: 616 Thanked 228 Times in 210 Posts	What problems will I get running '40 tyres Hi what problems other than speedo would I get putting a set of grid spokes on my 190 with 225x40x18 tyres ? Thanks __________________ Robert

28th March 2017, 20:02	#3
Robti Posted a thing or two MG ZT-T 190+,Rover 800 vitesse coupe Join Date: Aug 2014 Location: Hamilton Posts: 1,969 Thanks: 616 Thanked 228 Times in 210 Posts	Thanks that's what I heard also, just got the chance of a set of grid spokes with 4 good 40's so didn't know what to do __________________ Robert

29th March 2017, 08:13	#6
spongeh Loves to post MG ZT-T+ 180 Sport Auto Join Date: May 2016 Location: Wyrley Posts: 290 Thanks: 34 Thanked 117 Times in 72 Posts	I picked up some cheap Gridspokes with 225/40R18 tyres on them the other week and I've fitted them to the car to see what they're like and how they look & feel. I've moved from 15" wheels to the 18", therefore the move was about as extreme as you can get. Slightly more road noise, but not enough to want me to go back to 15s Cornering improved - mud flaps don't touch down anymore Pot holes are a painful experience with the 40s, will try 45s soon Speedo is more accurate than the 15s vs GPS (195/65r15 = 5mph difference, 225/40R18 = 3mph difference) Looks wise, the 40's are a bit small, but not much. __________________ https://badges.fuelly.com/images/sma...uk/1095349.png http://badges.fuelly.com/images/smallsig-uk/106569.png

28th March 2017, 19:55	#2
maxi_crawf Posted a thing or two R75 Saloon Conn CDT SE, MG ZT190+ Join Date: Nov 2006 Location: Kingston-upon-Hull Posts: 1,960 Thanks: 823 Thanked 426 Times in 274 Posts	Won't be very comfortable from what I hear. Sent from my SM-J500FN using Tapatalk

28th March 2017, 20:17	#4
steve-45 This is my second home Rover 75 Saloon CDTi Join Date: Oct 2015 Location: Belvedere Posts: 4,076 Thanks: 108 Thanked 1,089 Times in 774 Posts	My SAAB 93 Aero is on 40 profile tyres and you can feel every ripple in the road, and potholes loosen your fillings ....

28th March 2017, 20:44	#5
Christopher Price Banned None at the moment. Join Date: Jun 2016 Location: Lincoln Posts: 753 Thanks: 151 Thanked 230 Times in 152 Posts	Stupid hard ride and a speedo that doesn't read correctly, other than that, fine.

29th March 2017, 21:58	#10
Billyuk1 Avid contributor zt saloon 1800cc Join Date: Apr 2013 Location: in my car Posts: 234 Thanks: 277 Thanked 63 Times in 48 Posts	will it not affect your insurance?