195/50 tyres

EXA_LENT · Post by **EXA_LENT** » Thu Jul 03, 2008 2:47 pm

Does anyone , or can you, run 195/50 series tyres on standard et rims using 10mm spacer plates?
Have 185's now but wanna know before i order the wrong size.
Thanks

et_rider · Post by **et_rider** » Thu Jul 03, 2008 2:52 pm

i dont think they will fit i have 185 as well and was told that is the biggest Tyre you can fit on the rim

70RQE2001 · Post by **70RQE2001** » Thu Jul 03, 2008 2:56 pm

I used to use yokahama A539 tyres on my standartd ET rims with no probs, std ride height etc.
(on my ET)
They were 195/60 or 65 off the top of my head.

et_rider · Post by **et_rider** » Thu Jul 03, 2008 4:48 pm

well then i got told porkys now im mad

Post by **tassuperkart** » Thu Jul 03, 2008 7:45 pm

Remember, a 195 x 50 is considerably wider in footprint than a 195 x 60

195 x 50 is a very wide tyre to try and fit on a pissy stock rim width.

I have 185 x 65 on and thats pushing it.

L8tr
E

TBON12 · Post by **TBON12** » Thu Jul 03, 2008 7:56 pm

Since when has a 195/ 50 been wider then a 195/60?
195 is the width in mm and the 50 or 60 is referring to the aspect ratio of the tyre ( the side wall)

ie 195/50 is 195mm in width with a 95mm side wall which is measure from the outside of the tread to the inner of the bead

Post by **tassuperkart** » Thu Jul 03, 2008 7:59 pm

Nope sorry M8. It aint even close.
do some research and youll be surprised.
L8tr
E

Callumgw · Post by **Callumgw** » Thu Jul 03, 2008 8:22 pm

E
I don't get it. 195 is the width. so 195/60 is the same width as 195/20 and 195/90. The thing that changes is the diameter. The rim width will effect the inner tyre width and a lower profile will make the rate of change from the rim width to the tyre width more sharp. But far as I know the width at the tread block is still 195.

C

TBON12 · Post by **TBON12** » Thu Jul 03, 2008 8:25 pm

what's this about then?
http://www.tyres-online.co.uk/techinfo/aspect_ratio.asp

TBON12 · Post by **TBON12** » Thu Jul 03, 2008 8:30 pm

I think I got it, my brother just explained that a lower profile with have a more squared egde to the side wall, where as a 195/60 or 70 series will have a more rounded edge where the tread meets the tyre wall

Post by **tassuperkart** » Thu Jul 03, 2008 9:02 pm

Not really M8 altho thats what appears to happen.

That article explainbs it quite clearly.

L8tr
E

Callumgw · Post by **Callumgw** » Fri Jul 04, 2008 7:31 am

I'm still not convinced.
The profile is calculated based ont he tyre widtha nd side wall height. Stiffer sidewalls will have less displacement under correct inflation, whether they are 50 or 90 series. Side wall performances is affected by correct rim fitment as is tread performance.
I'm not convinced that tyre manufactures measure all tyre to the same point. For excample, I've had bridgestones that have very rounded tread shoulders and thereby less road contact still quoted to the same width as tyres with very square shoulders. These both had the same profile and same width specified. but the squarer ones rubbed when fitted to the same rim.....

So by my count there isn't consistancy in the measurment of the "width" but once you have it the profile is consistantly calculated.

So I stay with the profile is dependant on width and not the other way.

C

EXA_LENT · Post by **EXA_LENT** » Fri Jul 04, 2008 8:19 am

So 185/60 it is then hey?
(yay for little rims. )
At least they dont aquaplane in the wet i guess.
Thanks for the comments.

Post by **tassuperkart** » Fri Jul 04, 2008 7:24 pm

C you sort of on the mark.

The "width" of a tyre, Ie: 195 x *blah* is a measurement taken that INCLUDES the sidewalls (or some of it(I cant remember exactly at this minute)) and is not a direct measurement of tread face width.

So yes, a rounded shoulder will contribute to an apparently narrower tread width blah.

However i feel you may be reading a little too much into the "stiffness" of the sidewalls.

They have little if anything to do with the actual ride height of the tyre, deflate any tyre and its not too hard to compress the sidewall sos the bead squashes against the tread by hand.
I dont think a couple of extra kilos of support here will have much affect on a 200 odd Kilo corner somehow.
More just the control of flexion, deflection and ultimately tyre slip angle......we wont go there just this minute!

Thats a dissertation for another time!!!

L8tr
E

Callumgw · Post by **Callumgw** » Fri Jul 04, 2008 7:43 pm

Nah E, got disagree again. Sideway stiffness can make a hugh difference. For example, the BridgeS Adrenalines I got ont he exa the other week. apparanetly very stiff sideways to assist turn in and reduce squirm, which is the motion of a tyre relative to the rim. The tyre guy I use normally swears blue that you need lots of pressure, 38 and more. But when I got these on he pulled me aside and says:

"I know I normally recomend 38 but when we were at Phillip Island with Bridgestone releasing the tyres they recommend 28, I didn't believe them and run them at 38 and then the engineer dropped them back to 28. And at 28 they were much better, so when your at the track 28"

Haven't tried em yet but I'll be playing with the pressures for sure.

Also 30-50% of the total deflection of an F1 car comes from the tyre sideway. When considering the total spring/damp set up of a car the tyre is important. In this you have to trust me 'cause I have first hand experience with Stewart GP from '98 when I was doing my masters thesis.

Last story, I had Yoko ES100 on the rear of the MR2 and it went beatifully round corners - no sqirm exccellent feel. When they ran out I went over to BridgeS G111 and immediately you could feel the difference. The car wouldn't set when turned in. The back would sort of sqish and then take up. In the years that ollowed I found out that the ES100 was based on a very stiff racing carcus and the G111 a road carcus. The MR2 with all the weight up back (and apparently Porsches) loved the ES100. But the Comode Ute drivers I spoke with HATED it, cause the stiffness works against their reduced rear weight, reducing traction and make it easu to light up.....

C