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Hello, I have a set of stock factory chrome 17 in is300 wheels.

I bought the set for my gs300.

Was wondering what is the absolute biggest size tire I can run for the best ride? I'm stock height/suspension.

Is it possible to run 235/55/17? Stock tires are 215/45/17.

Not sure if this is possible.
 

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Buy a set of 17 x 8 IS(250/350) rims as the offset, centre bore, wheel nuts etc are correct, and are relatively easy to find. Max width for the front is 225/45 and is flush with the guards and the rear just rubs sometimes with 245/45 and is flush with the guards, this is for a standard IS300. Can't have more offset on the front as rim will be on the suspension, can have a bit more offset on the back, but will be difficult to find rims with more offset than the Lexus ones. Wrong width rubber on the rim gives poor handling.
 

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Hello, I have a set of stock factory chrome 17 in is300 wheels.

I bought the set for my gs300.

Was wondering what is the absolute biggest size tire I can run for the best ride? I'm stock height/suspension.

Is it possible to run 235/55/17? Stock tires are 215/45/17.

Not sure if this is possible.
225/45/17 will work with no issues all the way around on the stock 17x7 wheels.
 

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I edited in above for 7 inch rims. I've tried 225's on 16 and 17 inch, 7 inch wide rims and they feel wobblier than 215's which feel good. I have 3 of these cars and have a stack of rims and tyres which have been swapped around a few times (pic below, plus the 12 wheels on the cars at the moment) . Tried everything from standard 16's to 18 x 9 volks eng rims with 53 offset and slicks but they are not legal on public roads. The stock 16's x 7 from a IS250 give a smooth ride and are OK, but are definitely wobbly with 225's on them. The stock 17 x 7 rims are quite good with 215's, but feel wobblier with 225's fitted (both Potenza RE003's). If you only own one car its difficult to compare wheel combo's like I can. 17 x 8 rims from IS 250/350 come with the same rims back and front, but the tyres are staggered. 225's on the front and 245's on the back. Picture of tyre widths and rims widths from above reposted below. My replies were directed at the numerous times people try and make their cars "look" different by trying to fit wider tyres onto the standard rims or wider than the recommended tyre width for the rim.
I didn't like the 18 x 8 (F) and 18 x 9 (R) Volk's as the car felt planted but didn't feel as good when the roads get rough, the lower sidewalls were making the suspension work harder to try and keep the tyre in contact with the road resulting in less grip. Also, finding a replacement rim is not cheap, the centre bore was different so I had to lathe up some adapters, the wheel nuts are different so you need another set of wheel nuts rattling around in the boot if using a genuine Lexus spare wheel. Having too wide a rear tyre in the wet with a car with a front end weight bias like the IS300 is not good for my wife and she kept complaining about the excessive wheelspin , so sold them.
The best rim and tyre combo from my experience is also one of the cheapest. Second hand IS 350 rims and tyres are easy to find, replace and usually already come with quality tyres fitted. The offset is great, where the car was designed to have its wheel sitting, the centre bore is already correct and the wheel nuts are still the same and they handle great with good quality tyres fitted. They are about as wide as will fit without changing the body work, which I don't like doing as the resale value drops. If good handling is what matters most then buy an Altezza, the IS300 just doesn't have its balance and weight distribution and never will.
Saying you've been to a track means nothing, millions of people have been to the track, and it doesn't change the laws of physics even one tiny bit.
 

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Gosurfun I understand you think you feel the movement. It seems like you are trying to show your experience oryou know better. Just be careful what you say to who.
If you are comparing experience (retired). I have own 3 of this platform and have had several other platforms over the years. From street to track and off. I also worked and was trained by BFGoodrich corp. (AKA: Michelin)
 

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Sorry if your offended Solar, but I can feel it and easily. The centre stack of unmounted tyres has the two 225's taken off the bare Lexus 7inch rims on the far left, they are waiting for when some of the tyres on the 8 inch rims are worn and need replacing. I can feel the difference enough and not like it, to take them off and save them for another day. The two Potenza's on the far left are 215/40's and will go on the bare 7inch rims and on the fronts. They have cobwebs on them as the roads here can be rubbish and low profile tyres and rough roads don't mix, so its been slow to happen, also don't have the thin shims to space the stock Lexus 7inch rims to fit with Fsport brakes.
The other two Potenza's in the stack are 235's and will replace the 245's as the car with them on feels softer in the rear with hard cornering than the other two. I have not compared a 205 and a 215 on 7 inch rims using the same profile, but think I would not be able to tell the difference between them as they are not overextended.

If you understand tyres it would be very useful if you could answer a few questions for me.
1. What is the difference in structure on the inside and outside of a performance tyre? I ask this as they have "inside" written on them but not left and right.
2. What would be the difference between a Potenza RE001, 002, 003, is it just the rubber compound or would there be a difference in the structure? I understand that these are a different brand of tyre to what you mention above and may not know.
3. Why do the front tyres on motorcycles often have a tread pattern that directs the water towards the centre of the tread (pictures below of a sport tyre and semi slick on a R1, both fronts, picture taken from in front of the bikes). While the tyre is on a lean it makes sense, but when it upright it makes no sense at all to me. Have been waiting a while for an answer for this one as the contact patch is smaller and much more critical than on a car, the rears are as you would expect and direct water away from the contact patch in the centre of the tyre. I know its not Lexus related, but it has been bugging me for a while.
I'm not trying to trick you, would be great if you have any answers for me.
134031
134032
 

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Sorry if your offended Solar, but I can feel it and easily. The centre stack of unmounted tyres has the two 225's taken off the bare Lexus 7inch rims on the far left, they are waiting for when some of the tyres on the 8 inch rims are worn and need replacing. I can feel the difference enough and not like it, to take them off and save them for another day. The two Potenza's on the far left are 215/40's and will go on the bare 7inch rims and on the fronts. They have cobwebs on them as the roads here can be rubbish and low profile tyres and rough roads don't mix, so its been slow to happen, also don't have the thin shims to space the stock Lexus 7inch rims to fit with Fsport brakes.
The other two Potenza's in the stack are 235's and will replace the 245's as the car with them on feels softer in the rear with hard cornering than the other two. I have not compared a 205 and a 215 on 7 inch rims using the same profile, but think I would not be able to tell the difference between them as they are not overextended.

If you understand tyres it would be very useful if you could answer a few questions for me.
1. What is the difference in structure on the inside and outside of a performance tyre? I ask this as they have "inside" written on them but not left and right.
2. What would be the difference between a Potenza RE001, 002, 003, is it just the rubber compound or would there be a difference in the structure? I understand that these are a different brand of tyre to what you mention above and may not know.
3. Why do the front tyres on motorcycles often have a tread pattern that directs the water towards the centre of the tread (pictures below of a sport tyre and semi slick on a R1, both fronts, picture taken from in front of the bikes). While the tyre is on a lean it makes sense, but when it upright it makes no sense at all to me. Have been waiting a while for an answer for this one as the contact patch is smaller and much more critical than on a car, the rears are as you would expect and direct water away from the contact patch in the centre of the tyre. I know its not Lexus related, but it has been bugging me for a while.
I'm not trying to trick you, would be great if you have any answers for me. View attachment 134031 View attachment 134032
The long and short on the cycle tires. It has to do with the belt layout and hydrodynamics in braking. In order to keep more contact patch when braking. It gets more complicated. But that is as simple as I can make it.

Fyi. There are variances in tires from brand to brand. Same tire different brands, one could be slightly bigger in width and height. Also in response, do to construction and compound. So I would not be quick to say they are going to be wobblie and such. Unless it is the same exact combo. ( Wheel, tire, suspension, and weight)
 

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I'm fine with getting a more detailed explanation.
When a tyre is made, is the thread material used for the banding put on as a continuous strand around the beads and back over the tyre many many times or is it already made up like a large tape and laid around the tyre and overlapped at the join and glued?
I asked the manager of a car tyre distribution centre about the difference in the structure on the Potenza's today. He said the tyre structure is the same both sides. The tread is different and asymetrical as it is quieter than the traditional V shaped symmetrical tread which has a rotation direction label like the semi slicks and cheaper Asian tyres. The "inside" label is just there to make sure the better water shedding tread is on the outside edge, which makes sense.
 

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I'm fine with getting a more detailed explanation.
When a tyre is made, is the thread material used for the banding put on as a continuous strand around the beads and back over the tyre many many times or is it already made up like a large tape and laid around the tyre and overlapped at the join and glued?
The underlying structure belts are layed out in strands. Then the outer casing (tread) is formed on it. With the tread in the direction. According to belting and purpose. They do make non directional belting. But there is no way to see it. A non directional (slick) non treaded. Could be siped (cut) grooves the way you want. It is a real pain in the butt.
I asked the manager of a car tyre distribution centre about the difference in the structure on the Potenza's today. He said the tyre structure is the same both sides. The tread is different and asymetrical as it is quieter than the traditional V shaped symmetrical tread which has a rotation direction label like the semi slicks and cheaper Asian tyres. The "inside" label is just there to make sure the better water shedding tread is on the outside edge, which makes sense.
Prices are influenced by demand and use.

Why are you so concerned with this? So we do not stomp more on this tread. I would PM me. If you want to know more.
 

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Been running 225/45r17s since the car was a year old. Never any wobble. Maybe people that think they wobble are pushing the car too much thinking they are only much wider tires.
 

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Yes I push my cars and bikes particularly on corners and am sensitive to the feedback from everything, you have to be. I can show how the tyres that are wider than recommended for a rim have a wobbly feeling and this is easy to see if you tuck up behind someone cornering who has done this with their car. Is is easy to see when you are looking for it, explanation below.
First and second picture, when cornering the outside tyre side load is transferred across the tread placing it under compression. The load transfers to the threads within the tyre casing which become under tension. The load is carried through the threads to the bead on the outside of the rim pulling the bead going over the top of the rim down harder onto the rim. Side load shown by boot. Bit of string draped over the tyre to show where a thread at about 45 degrees would run.
134098

134099

Third picture, if the threads just went round and round the tyre at 90 degrees this would not happen and the tyre would try to form the shape similar to a bicycle tyre, a lot of air pressure load would be placed on the steel bands to hold the tread section flat.
134100


Fourth picture, by having the threads at an angle it gets interesting. A cross section cut at an angle across a tyre following a thread as shown in the first picture. The thread is now not trying to go straight across the top of the tyre, it is curved by following the curve of the tyre as it crosss the tread and under tension taking some of the air pressure load off the steel bands as well as carrying the side load of a cornering vehicle. With a correctly fitted tyre the SIDE WALL thread is in a shallow curve like the curve of the thread going over the tread. Over sized tyres put a sharper curve or bulge in the SIDE WALL threads giving them more room to move or bounce or wobble. The greater the over sized tyres on a rim, the more curve it has and the more it moves.
134101


Fifth picture, This is what the rim does when an over sized tyre or a tyre with low pressure (a bit flat) does when side loaded and it goes over undulations in the road. The side wobble is multiplied by the number of tyres which are oversized or under-inflated. Its easy to see when following a cornering car with incorrectly fitted tyres and an uneven road. Its something that is not that hard to feel, I don't know why some people can't feel it, as even my wife can feel it.
Following the logic above its easy to see why the bead is the most solid and rigid part of a tyre. The curve of the side wall threads going at an angle across the side wall would be also controlled by the air pressure within the tyre and some of the reason why the pressure is so important. Makes sense to me anyway. The side load going through the side wall threads on an over sized 2.5 tonne SUV must be enormous when pushed in a corner.
Rushed this a bit as pushed for time, any glaring errors let me know and will change it.
134095
 

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TIRE SIZETREAD TYPETREAD WIDTHSECTION WIDTHAPPROX. DIAAPPROX. CIRC.DESIGN RIMSWT.COMPOUNDS
20.0/6.0-13SS6.07.420.1635-68.5MED,SOFT
20.0/8.0-13SS8.09.620.4646-79.5M-28,M-31,M-32
21.0/7.5-13SS7.58.621.0667-810.5M-28
21.0/8.5-13SS8.59.521.3677-811.5M-31
21.5/10.0-13SS10.010.021.868.58-1012.5M-28
22.5/8.0-13SS8.09.721.6687-816.0M-28,M-32
22.5/8.0-13SS8.310.222.470.57-812.0MD-50
22.5/9.0-13SS9.010.122.0698-917.0SD-48,M-31,MD-50
9.8/22.0-13SS9.510.722.2708-916.0M-28,M-32
22.5/10.0-13SS10.011.422.6718-1017.5M-28
23.5/10.0-13SS10.012.723.6749-1018.0M-28,M-31,M-32
23.5/12.0-13SS12.014.423.67410-1219.0131,M-32
23.5/12.0-13SS12.013.124.175.510-1215.3131


ASPHALT – MINI STOCK

AR782
TIRE SIZETREAD TYPETREAD WIDTHSECTION WIDTHAPPROX. DIAAPPROX. CIRC.DESIGN RIMSWT.COMPOUNDS
20.0/8.0-13SS8.09.620.4646-79.5M-28,M-31,M-32
21.0/7.5-13SS7.58.621.0667-810.5M-28
21.0/8.5-13SS8.59.521.3677-811.5M-31
22.5/8.0-13SS9.510.822.2707-914.7M-28,M-32
22.5/8.0-13SS8.510.222.2707-914.0704
22.5/8.0-13SHS8.210.221.3677-814.0704
23.5/8.0-15SS8.510.323.473.47-815.4704
22.5/9.0-13SS9.010.122.0698-917.0M-31,MD-50
22.5/10.0-13SS10.011.522.6719-1016.0M-28
23.5/7.5-13SS7.59.823.674714.5M-32
23.5/10.0-13SS10.011.323.6749-1216.0M-28,M-31,M-32
23.5/10.0-15SS10.011.023.8759-1015.0M-28
23.0/7.0-13EE7.08.423.573.86-712.6AR782
23.0/7.0-13SHEE7.08.523.272.86-712.6AR782
23.0/7.0-13EE7.08.523.2736-715.7705
23.0/7.0-13SHEE7.08.522.9726-715.8705
23.0/8.0-13EE8.29.323.272.87-816.7705
23.0/8.0-13EE8.09.322.871.87-816.7705
23.0/7.0-14EE7.08.023.473.56-715.8705,MED
23.0/7.0-14EE7.07.923.573.86-712.4AR782
23.0/7.0-14SHEE7.07.923.272.86-712.5AR782
23.0/7.0-14SHEE7.07.823.272.86-715.7705
24.0/7.0-14EE7.08.624.2767-815.0705
24.0/7.0-15EE7.08.424.5777-813.7AR782
24.0/7.0-15SHEE7.08.424.175.57-813.7AR782


Just for educational purposes people.

This one example of what I was referring too. It is a matter of design and construction. Not just sizes. The responce and function is dictated by several aspects.
 
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