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For our cars on the track, I've always thought larger diameter wheels/tires are worse all around because of more weight further away from the wheel's center - and more weight in general. Excessive unsprung weight is a definite issue with the SW20 mostly because of its McPherson suspension setup and lack of real power (400+hp).

From my MR2 track experience, I would prefer a fat 15/16" setup to a 17" combo any day. The problem of course being that tire manufacturers have abandoned wide smaller diameter sizes because of the unprecedented demand of excited men and their obsession with everything bigger, so I've had to sacrifice by using a 16/17 track combo. There's just no money in producing a 345/35-15 tire these days like what the old Lambo Countach used back when wide was more important than large.
 

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For our cars on the track, I've always thought larger diameter wheels/tires are worse all around because of more weight further away from the wheel's center - and more weight in general. Excessive unsprung weight is a definite issue with the SW20 mostly because of its McPherson suspension setup and lack of real power (400+hp).

From my MR2 track experience, I would prefer a fat 15/16" setup to a 17" combo any day. The problem of course being that tire manufacturers have abandoned wide smaller diameter sizes because of the unprecedented demand of excited men and their obsession with everything bigger, so I've had to sacrifice by using a 16/17 track combo. There's just no money in producing a 345/35-15 tire these days like what the old Lambo Countach used back when wide was more important than large.
Well, a larger wheel would increase top end speed, where a smaller tire would decrease it. The smaller the gear in the rear, the faster the wheel will turn and larger the slower it will turn... Lotus had the right idea (they always have), but correct, no one makes tires for 15-16’s anymore... I have 17/18, nothing for matching sizes... well, real limited... I like and run 215-40 and 255-35’s... but I need to pony up to a 225 up front and sadly run a 3mm spacer... 🤷‍♂️.... I have 9.5’s on back, and 255 is real tight...
 

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For our cars on the track, I've always thought larger diameter wheels/tires are worse all around because of more weight further away from the wheel's center - and more weight in general. Excessive unsprung weight is a definite issue with the SW20 mostly because of its McPherson suspension setup and lack of real power (400+hp).

From my MR2 track experience, I would prefer a fat 15/16" setup to a 17" combo any day. The problem of course being that tire manufacturers have abandoned wide smaller diameter sizes because of the unprecedented demand of excited men and their obsession with everything bigger, so I've had to sacrifice by using a 16/17 track combo. There's just no money in producing a 345/35-15 tire these days like what the old Lambo Countach used back when wide was more important than large.
For all that you talk about reducing unsprung weight, I can't believe you haven't (as far as I know) gotten my brake kit yet. Can save 25-35lb of unsprung weight compared to the 93T brakes that (if I remember right) you are running!
 

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Heh heh, it's not like I haven't considered it. My g/f actually wanted to gift one of those BBKs to me a couple of years ago, but I didn't think it was a good idea. Given that the whole thing would cost about US$2K (plus another $500 to have it installed, I have no tools nor any place to work), it just didn't seem cost effective or necessary on a daily that's tracked once or twice a year. My 93t brakes are a track compromise for sure, but are competent and better than my former '91t brakes by quite a bit.
 

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Discussion Starter #28
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For our cars on the track, I've always thought larger diameter wheels/tires are worse all around because of more weight further away from the wheel's center - and more weight in general. Excessive unsprung weight is a definite issue with the SW20 mostly because of its McPherson suspension setup and lack of real power (400+hp).

From my MR2 track experience, I would prefer a fat 15/16" setup to a 17" combo any day. The problem of course being that tire manufacturers have abandoned wide smaller diameter sizes because of the unprecedented demand of excited men and their obsession with everything bigger, so I've had to sacrifice by using a 16/17 track combo. There's just no money in producing a 345/35-15 tire these days like what the old Lambo Countach used back when wide was more important than large.
Haha well said. The one handling benefit to larger wheels though is the added lateral stiffness. With 15" wheels for example you'd need to make sure you're going with a tire with stiff sidewalls or else you're going to give up some lateral rigidity and your tire will flex more. But with a proper tire and smaller wheels giving less unsprung rotational mass I think that's the way to go if you can find them and are willing to spend the money.
 

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Discussion Starter #29
I have the same issue... no hoist... so let’s buy another car with the engine behind 🤦‍♂️
If you can find a one or one and a half car garage even and do all the work with jack stands and jacks it's totally possible. I did my engine swap in front of my garage and only worked on it when there was nice weather last summer. Pain in the ass but definitely possible.
 

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If you can find a one or one and a half car garage even and do all the work with jack stands and jacks it's totally possible. I did my engine swap in front of my garage and only worked on it when there was nice weather last summer. Pain in the ass but definitely possible.
I have a 4 stall, I’m just spoiled... my friend had a huge shop, 5 hoists... gone... thank you Covid 19
 

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larger diameter wheels/tires are worse all around because of more weight further away from the wheel's center
More rotational intertia to be overcome by the engine or brakes. Almost all weight is bad:
Chassis < spun (accel/decel) or unsprung (handling) < spun & unsprung (both accel & handling)

'Weight' without intertia is very good.

The one handling benefit to larger wheels though is the added lateral stiffness.
Lateral tire stiffness comes from lower AR, thicker sidewall and higher pressure. But the latter is a trade-off with contact patch geometry (traction). Pen + Notebook + IR gun are your friends. Until your dust boots catch fire while you're using them. Wilwood for the (track) win. Not street DD IMO, particularly where salt and dirt are prevalent. Opintions may differ (Alex W?).
 

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I've run no-dustboot Wilwoods on the street for over a decade - never seen a problem with o-ring wear. When you're doing pad changes, just give the stainless pistons a quick wipe down before pushing the pistons back in. Even if you don't do this I've never seen a problem.

Now, would I drive them through road salt every day for years on end without changing out the o-rings? Eh - probably not... but I don't even think I'd drive any SW20 in those conditions and lack of maintenance... Keep in mind the Wilwood stainless pistons are WAY more corrosion resistant than the lightly plated (or even no plating!) steel stuff you'll find on an OEM caliper.
 

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Wilwood for the (track) win. Not street DD IMO, particularly where salt and dirt are prevalent. Opintions may differ (Alex W?).
I don't think I can claim quite as much Wilwood experience as DefSport, but I to have never had any issues from the lack of dust seals.

Regarding tires, wheel size, weight, etc: One thing to keep in mind is that fixing the suspension geometry on these cars has significant benefits, but it requires at least 17" wheels in the back (unless you take Eric Hux's approach and build custom control arms with the ball joint inverted). Personally I would trade a few lb of rotating weight for proper suspension geometry any day.
 
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