the wrong tyres

100turbo c · 14-01-09, 09:49 PM

on the 90 quattro i have just bought it has the wrong tyres fitted they are 60 profile instead of 50, could this make the car a lot slower as it does feel a bit slugish or is it just me

Emjay · 14-01-09, 09:58 PM

if the profile is incorrect then you will get incorrect speedo readings. So if the profile is too high then the speedo reading will read too high and the car will be going slower. For example sppedo reading reads 70 but you are in reality travelling at 65 mph. So the car will feel sluggish. If the profile is too low then the opossite effect applies and you run the risk of speeding. Eg sppedo says 70 but in fact you are travelling at 75mph.

I use this as a great reference site http://www.carbibles.com/tyre_bible_pg2.html

pimpdriver · 14-01-09, 10:04 PM

you have no turbo and only 136bhp. And the extra quattro weight.

Isimmo · 14-01-09, 10:49 PM

I suspect you should be running around the 195/55/15 mark for the tyres, maybe 205/55/15... But remember the wider the tyre the '50' or '55' is the % profile of the width. So the gearing is altered accordingly. However, I'd suggest you're looking at maybe another issue/aspiration as the profile alteration to acceleration is marginal from 55 profile to 60 profile.

I’d sling all the excess weight out (ask Puglife, he’s a man on a mission with scales), pump the tyres up, and check when there was a change of the plugs, leads, oil, filter, air filter, rotor, distributor cap. (coil maybe) and try again.

Gaz · 15-01-09, 01:22 AM

Quote:

Originally Posted by Emjay

if the profile is incorrect then you will get incorrect speedo readings. So if the profile is too high then the speedo reading will read too high and the car will be going slower. For example sppedo reading reads 70 but you are in reality travelling at 65 mph. So the car will feel sluggish. If the profile is too low then the opossite effect applies and you run the risk of speeding. Eg sppedo says 70 but in fact you are travelling at 75mph.

I use this as a great reference site http://www.carbibles.com/tyre_bible_pg2.html

id of thought if the car had a higher profile, the speedo will read 'less' ??? and likewise if you fitted very tiny wheels, the wheel would have to rotate many more times than normal to cove the same distance, so a smaller wheel/profile would give a false 'high' speedo reading respectively.

However, a taller wheel/tire will be harder for the engine to rotate. But having a 60 instead of a 55 wouldn't make a huge difference, as already stated.

20vcqdriver · 15-01-09, 11:30 AM

Standard 90 quattro tyres were 205/60/15. Only the S2 with 16" rims had a lower profile..

Gib · 15-01-09, 11:59 AM

STD 90 tyres are 50 profile , 60 are for coupes i had a look at these and asked the , then current owner at CC if he had any rubbing issues as these are coupe wheels and also have the wrong ET. i have used coupe wheels before and it depends on the tyre as to if you get issues. From memory rubbing was only on the rear upper edge of the inner wing..

Emjay · 16-01-09, 09:34 AM

Quote:

Originally Posted by Gaz

id of thought if the car had a higher profile, the speedo will read 'less' ??? and likewise if you fitted very tiny wheels, the wheel would have to rotate many more times than normal to cove the same distance, so a smaller wheel/profile would give a false 'high' speedo reading respectively.

However, a taller wheel/tire will be harder for the engine to rotate. But having a 60 instead of a 55 wouldn't make a huge difference, as already stated.

Your probably right, anyway it's one way round or the other and none the less wrong profile tyres will have an effect on speedo readings...I was high on a bottle of red when I posted

and look at the state of my spelling too, thats a comprehensive education for you!!

Jabber · 16-01-09, 10:55 AM

I had 205/60/15s on mine when I first bought the car and when I had people in the back it rubbed on the rear arches, the B3 models never had 205's they run 195/50/15s and hey I don't rub no more!

pimpdriver · 16-01-09, 02:31 PM

look in side the filler cap or the handbook to find out what options should be fitted.

14-01-09, 10:49 PM	#4
Isimmo Super Moderator Classic Audi Club Member Join Date: Jul 2007 Location: Sissix-by-the-sea Posts: 15,218	I suspect you should be running around the 195/55/15 mark for the tyres, maybe 205/55/15... But remember the wider the tyre the '50' or '55' is the % profile of the width. So the gearing is altered accordingly. However, I'd suggest you're looking at maybe another issue/aspiration as the profile alteration to acceleration is marginal from 55 profile to 60 profile. I’d sling all the excess weight out (ask Puglife, he’s a man on a mission with scales), pump the tyres up, and check when there was a change of the plugs, leads, oil, filter, air filter, rotor, distributor cap. (coil maybe) and try again. __________________ 1985 WR quattro, 1985 20vT RallyRep, 1993 MTM ABY S2 Avant. 2010 S3 Sportback.

15-01-09, 11:30 AM	#6
20vcqdriver 4 ring whore! Classic Audi Club Member Join Date: Dec 2007 Location: Wirral Posts: 3,910	Standard Standard 90 quattro tyres were 205/60/15. Only the S2 with 16" rims had a lower profile.. __________________ Coupe quattro 1986:-~450bhp + loooong list of mods! Audi A7 Bi-TDI SLine Black edition 2015 mapped to produce 600lb/ft torque! Audi S4 4.2 V8 cabriolet 2004:-

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14-01-09, 09:58 PM	#2
Emjay Man Fettler Extraodinaire Classic Audi Club Member Join Date: Jul 2008 Location: Up my own arse blowing smoke Posts: 7,417	if the profile is incorrect then you will get incorrect speedo readings. So if the profile is too high then the speedo reading will read too high and the car will be going slower. For example sppedo reading reads 70 but you are in reality travelling at 65 mph. So the car will feel sluggish. If the profile is too low then the opossite effect applies and you run the risk of speeding. Eg sppedo says 70 but in fact you are travelling at 75mph. I use this as a great reference site http://www.carbibles.com/tyre_bible_pg2.html

14-01-09, 10:04 PM	#3
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	you have no turbo and only 136bhp. And the extra quattro weight.

15-01-09, 11:59 AM	#7
Gib Grown up member Join Date: Jul 2007 Location: Abingdon in a boat about 15 foot above the roof of my house Posts: 221	STD 90 tyres are 50 profile , 60 are for coupes i had a look at these and asked the , then current owner at CC if he had any rubbing issues as these are coupe wheels and also have the wrong ET. i have used coupe wheels before and it depends on the tyre as to if you get issues. From memory rubbing was only on the rear upper edge of the inner wing..

16-01-09, 10:55 AM	#9
Jabber Newbie! Join Date: Jan 2009 Location: West Dunbartonshire Posts: 7	I had 205/60/15s on mine when I first bought the car and when I had people in the back it rubbed on the rear arches, the B3 models never had 205's they run 195/50/15s and hey I don't rub no more!

16-01-09, 02:31 PM	#10
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	look in side the filler cap or the handbook to find out what options should be fitted.