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The mkiv Supra Owners Club

Offset limits


Terminator

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I have searched but so far have not found the answer I am looking for.

 

Stock offset is 50mm so a perfect replacement wheel should be 50mm. What I am interested to know is how far away from this a wheel can go before effects are felt/noticed in handling or wear other components. What I am getting at is there a safe window of mm’s not cm’s which would be acceptable as a compromise without impacting upon safety.

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This interests me too, i'm venturing into the aftermarket wheels area for the first time and will soon be running 41mm offset fronts and 45 offset rears (possibly with a small rear spacer if it looks 'wrong')

 

So in a few weeks I could tell you what if anything i notice good or bad compared to the stock 16's.

 

Neil (HISUPE) has the most away from stock offsets ( i think 31 front and 37 rear?) that i know of and has no major complaints as far as i know.

 

Not sure myself on the extra wear / strain on other parts though?

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Mine are 32 front and 38 rear IIRC, this makes both wheels sit flush with the wings, on stock tyre sizes (17s). Car came over like that, it does look good ;) but on a previous thread CW said this would probably put undue stress on suspension components. I can't afford to change them though so they'll have to do for now.

I must admit, I do think the car doesn't handle great (but I've come from a chuckable scoob with eibachs, bumpsteer and geom done). I've had the Lance Alignment done at Micheldever, but I still think the RLTC cuts in quite quickly (eg the car loses grip too quickly not the RLTC being over eager!). I've not driven a stock wheeled supra back to back though so I can't be sure it doesn't handle normally, and its been a while since I did a test drive at JIC!

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Originally posted by HISUPE

Mine are 32 front and 38 rear IIRC, this makes both wheels sit flush with the wings, on stock tyre sizes (17s). Car came over like that, it does look good ;) but on a previous thread CW said this would probably put undue stress on suspension components. I can't afford to change them though so they'll have to do for now.

I must admit, I do think the car doesn't handle great (but I've come from a chuckable scoob with eibachs, bumpsteer and geom done). I've had the Lance Alignment done at Micheldever, but I still think the RLTC cuts in quite quickly (eg the car loses grip too quickly not the RLTC being over eager!). I've not driven a stock wheeled supra back to back though so I can't be sure it doesn't handle normally, and its been a while since I did a test drive at JIC!

 

I went from a Supra with 18"x8" rims with a 38 offset on koni adjustables to one with stock wheels on Toyota Eibach/Bilsteins.

 

The stock setup is UTTERLY better at handling, grip, braking, accelerating, not tramlining - everything. It's so much better it's not even funny.

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OK we are getting somewhere here. At 38mm OS there is a noticeable difference to stock but the shock set up may have contributed there too Ian.

 

I take it this was 38 front and rear?

 

I am looking at Front OS 48mm 18x9.5 Rear OS OS 50mm 18 &10.5. They fit fine and felt fine for the week I had them on the car, TBH it felt better than stock.

 

I just thought it would be a good area for discussion and get some data that may help others in the future.

 

If we get more contributors may be we can find some acceptable limits albeit based on subjective comments. My big wheels are summer wheels due to finish my stock are winter wheels so ~ I will have good experience of both.

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Originally posted by Terminator

OK we are getting somewhere here. At 38mm OS there is a noticeable difference to stock but the shock set up may have contributed there too Ian.

 

I take it this was 38 front and rear?

 

I am looking at Front OS 48mm 18x9.5 Rear OS OS 50mm 18 &10.5. They fit fine and felt fine for the week I had them on the car, TBH it felt better than stock.

 

I just thought it would be a good area for discussion and get some data that may help others in the future.

 

If we get more contributors may be we can find some acceptable limits albeit based on subjective comments. My big wheels are summer wheels due to finish my stock are winter wheels so ~ I will have good experience of both.

 

They sound fine, what's 2mm between friends? ;) Should give very acceptable performance if you insist on an 18 inch rim. (I add that it's not the RIM diameter that necessarily causes bother, but the very low tyre profile needed to run the big diameter wheels.

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Originally posted by Nick

What is it about a lower profile tyre that causes problems?

 

The lower the sidewall height relative to tread width (profile) the less flex there is in the sidewalls. This means the tyre relies more and more on suspension kinematics that keep the tread flat on the road during roll and suspension rise and dive. A car will (or at least should) be designed to have good camber control suitable for its designed tyre profile, whether that camber control is good enough to operate a very low profile tyre depends on many factors, and good as the MKIV's is, it is not THAT great. Also the suspension bushes compliance is designed around certain tyre loadings and frequencies, change the tyre for something radically different and this may become a problem. The front end of the Supra has poor arm movement control when loaded higher than the stock tyres manage, and is one of the reasons a very low profile tyre causes tramnlining. It's even worse / diabolical on a wrongly offset wheel rim.

 

It's a LOT more complex than i can even touch on here, but that's a couple of the more basic reasons.

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Originally posted by Chris Wilson

They sound fine, what's 2mm between friends? ;) Should give very acceptable performance if you insist on an 18 inch rim. (I add that it's not the RIM diameter that necessarily causes bother, but the very low tyre profile needed to run the big diameter wheels.

 

I thought 2mm would be negligible, but it would be interesting to see if there is a point where handling deteriorates dramatically.

 

I will stick to my 17's for top performance and track days, I got the 18’s for looks in the summer, I understand the compromise in handling, but to be honest UK roads don’t allow us to use the potential of the MKIV, legally anyway. I was surprised how little extra un-sprung weight they added considering how much wider than stock they are. I am sticking to a 35 profile as 30 is too low IMHO.

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I have BBS wheels on mine - they're 38 offset I think. The car has very good grip, but I wouldn't say the handling is that spectacular (I don't have Bilsteins though). However, it is *much* better since I had the geormetry done and fitted a set of Eagle F1s to the rear. It is definitely over-tyred at the front - turn in is instant and there is no understeer but there is quite a bit of tramlining. However, I agree with Phil that it is very hard to push these cars to the limit anyway, and it is certainly still "fun" as it is. The most important thing for me was that UK brakes fit under them :)!!!!

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Well, cars been in with Dude this weekend and I asked him to take it out for a spin to see what he though of the handling/grip. So he did, and he said the car handled fine, plenty of grip, even with RLTC set to off. So the offset on mine doesn't seem to have adversely effected handling and grip, though will prob have an effect on suspension component life..........

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Originally posted by HISUPE

So the offset on mine doesn't seem to have adversely effected handling and grip, though will prob have an effect on suspension component life..........

more and more it seems to me that for road cars as long as the tyres are good most of us won't really notice that much difference.

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