Larger rear wheels and tyres?

[stevenb]

Would larger rear tyres on a mk1 give it better handling? :?

What would be the max. recommended size allowable to keep speedo accurate and maintain optimum handling?

Mk3's had same size all round at 1st then changed to larger rears. Ok I know the wheel diameter was changed too....but for e.g. could you run 14's and 15's or 15's and 16's on a mk1?

[adamh]

for the diameter.. you can run 15/16/17 on the car and just lower the profile of the tyre to keep the same rolling radius, speedo error wont change if you get the same aspect ratio..
the effects of a shorter side wall and wider tread ive not tried my own yet, so i cant comment...

[stevenb]

I heard now that it creates understeer so I think I'll give it a miss. :wink:

[adamh]

we'll have to track day test all these cars with numerous handling modifications one day and settle either way once and for all. :)

[Driftin_AW]

I heard now that it creates understeer so I think I'll give it a miss. :wink:

I think that's a slight misinterpretation.
Imagine you have a neutral handling car, ie both front and rear tyres lose grip at the same lateral loading.
now put larger tyres on the rear, hence increasing rear end grip, reducing oversteer, giving the impression that understeer is worse.

[djdna2000]

I had planned to go 255/40/17 on the back with something like 225/40/17 on the front. Now however after speaking to lots of people, they reckon that 17s will give camber control issues with the stock AW11 suspension geometry (40 profile will be too low) so I'm now thinking 16s. I've got my stock 16x7.5 ST205 wheels and I see from Toyo's website I can go to a 245/45/16 on the back, and then probably a 225/45/16 or similar on the front. I think I will get the 205 wheels drilled for 4x100 (currently they are 5x100), and take this route.

I'll deffo need to get the arches sorted for that though.

[adamh]

toyo are just starting to make 245/35/16 too.. thats the origonal RR back :)
camskill source them.

[Driftin_AW]

stock st205 wheels on an aw11? are you joking mate? :lol: there's got to be something a little bit less tri-spokish that'll work :)

[adamh]

I heard now that it creates understeer so I think I'll give it a miss. :wink:

I think that's a slight misinterpretation.
Imagine you have a neutral handling car, ie both front and rear tyres lose grip at the same lateral loading.
now put larger tyres on the rear, hence increasing rear end grip, reducing oversteer, giving the impression that understeer is worse.

agree, F1's dont use 185's!.
agree with the proportional thing too. it will be at a greater speed when it does understeer, provided fronts are increased from stock also, not drastically, maybe 205/215 max front, will help even the effects.

[djdna2000]

stock st205 wheels on an aw11? are you joking mate? :lol: there's got to be something a little bit less tri-spokish that'll work :)

I've got 6 of em sat in my garage though, and no spare cash!

[lodgeman]

sell em on ebay and then buy some more :lol: :lol:
just bought these for my sons car

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=7999341718&ssPageName=STRK:MEWN:IT

?56 with yoko's

[djdna2000]

A set of decent, strong 16x7.5 will cost more than I can get for the 205 wheels though.

[PsychomIKE]

I heard now that it creates understeer so I think I'll give it a miss. :wink:

I think that's a slight misinterpretation.
Imagine you have a neutral handling car, ie both front and rear tyres lose grip at the same lateral loading.
now put larger tyres on the rear, hence increasing rear end grip, reducing oversteer, giving the impression that understeer is worse.

Well you state that the car originally has a neutral balance so by adding more rubber to the rear will create understeer, no two ways about that!

The black art for you guys who have done the swap is finding a balance to match the new weight properties of your car. Has anyone had a mk1.5 out on a track day? How did it handle?

I've got a very tempting setup in mind but it'd mean ideally fitting some 15 x 8 +35 alloys on... anyone managed to get a 8 inch wide wheel on the mk1 without having to cut a new blouse for her to wear?

Cheers

Mike

[Driftin_AW]

I heard now that it creates understeer so I think I'll give it a miss. :wink:

I think that's a slight misinterpretation.
Imagine you have a neutral handling car, ie both front and rear tyres lose grip at the same lateral loading.
now put larger tyres on the rear, hence increasing rear end grip, reducing oversteer, giving the impression that understeer is worse.

Well you state that the car originally has a neutral balance so by adding more rubber to the rear will create understeer, no two ways about that!

Definitely true, but let's look at it this way-

mid corner the neutral balanced car, right on the limit of adhesion, any more speed into the corner and the car would be 4 wheel drifting around the corner (but the important thing is that it's not going too fast, so it's not sliding at all). Anyway, driver puts foot down to accelerate out of the corner, power goes to the back wheels, pushing them beyond the limit. 2 possible outcomes;
one is that the driver is hardcore + experienced, does a wicked drift with lots of tyre smoke, but doesn't gain any speed.
Scenario 2 is that the driver isn't experienced enough with the car, or gets caught by suprise, and ends up going backward into a tyre wall.

now, lets take the same car and give it more grip in the rear.
at the same speed as the above car, mid corner, the car is right on the limit of losing grip (and more speed into the corner and it would understeer). The driver puts his foot down, now he has "extra" grip available in the rear, so the rear end doesn't break loose, and provided he hasn't gassed it too soon (which would induce understeer), he gets a better exit from the corner, and mr neutral handling car gets left behind on the straight... :D



The black art for you guys who have done the swap is finding a balance to match the new weight properties of your car. Has anyone had a mk1.5 out on a track day? How did it handle?
Well the interesting thing that a lot of people don't believe is that the weight doesn't change all that much, especially if you started with a supercharged model.
Also in the US they had a big MR2 meet recently and the fastest times on the autocross circuit came from a 3sgte powered aw11, (with a 2zz-ge spyder 2nd and I think another 3s aw11 third)

Also, 8" wide wheels should fit fine, depending on the offset. I have 7.5" wheels and they've got about 30mm clearance to the strut and about 10mm clearance to the edge of the guard