LocostUSA.com

My initial plan is to put R888R's in 195/50 and 225/45 tire sizes on 7 and 8" rims respectively. I will be running a 2.5 liter duratec which should output 200-220hp in the initial state of tune. These are the same tire widths I recently saw on a Caterham 420R.

The car will mostly be for the backroads with a track day or two a year. I see people running 100tw slicks, 220tw Avon's, all the way to 340TW UHP tires. I recently had 340tw firehawk Wideovals on my ND miata for street only use at approachable limits compared to the 200TW cheaters I used to slap on my Turbo Miata yearly, but ultimately didn't have a playful character on the road.

I would be interested in hearing what people are running on their cars with regards to Size, TW, and Heat considerations.

I feel the R888's are a great street and track tire, but 225 in the rear may not offer the playfulness on that sticky of a tire off the track, or get up to temp with lighter use. also, 205/50/15 has much better size support, but I worry about steering feel falling off
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I run the same wheel size combination, more track less street. I did not have success with the R888R's, the older R888 was great but when they switched to the R888R's the side wall was to stiff for my liking. I think the RA1 is a better tire for a 7, softer side wall. The Miata racer love them, Toyo have tried to discontinue them more than once but the outcry from the racing has made them continue production. One good thing about the RA1 is the old adage, they go faster and faster until the cords show:) As for playfulness, on the road you cannot get the heat into them to get full stick. Your going to have a fair amount of power so you should be able to get them moving around when you want to.

Graham

Specmiata has switched to Hoosier tires which appear at first glance to be less streetable. There are places that sell 3/4 tread takeoffs for 100 a piece. I am pondering the idea of going with a 205 on 7" rims all around. Maybe on a 200tw tire to start with. I had a lot of experience with 200tw options on my turbo miata which had about 260hp, but weighed 1000 lbs more.

I am after steering response and driving experience more than all out speed I think.

Currently running 205/50/15 Kumho V730's. I believe TW is 200.

To get full contact patch air pressure has to be quite low, around 15-ish
They take a while to warm up
Happy with the grip and overall performance once warmed

I prefer the same size front & rear so they can be rotated as well as having a preference for as much front grip as I can get. My rules are:

1. Make the car go where you point
2. Make the car go where you point
3. Dial in as much rear grip and corner exit bite as possible without breaking rules 1 & 2

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Peace, Ron

I use Federal SS595 P185/60R13 on 13x7's on all four corners.

They are not a "race" tire, but grippy enough, hilarious fun, and give you a VERY predictable slip angle. They LOVE slip angle.

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The Lethal Locost
The Lethal Locost 2 - Even More Lethalerer

How much power do you have?

Two summers on these tires, the first summer was with a mostly stock 1.8L Miata drivetrain so roughly 130. The latter part of this summer I install a mild turbo so best guess is 200-ish. No straight-line wheelspin unless intentionally provoked.

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Peace, Ron

You are happy with the grip at the current power level?

I think grip is very well balanced for the current power level. This winter it's getting a bump in boost so we'll see how that goes, but I'm fully expecting traction to become a challenge at that point.

One thing I forgot to mention is that my wheels are narrow (6"). With a wider wheel you'd probably get a smidge better performance out of them.

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Peace, Ron

I've been running Falken RT-660 205/50R15's on 15x7 wheels. Grip and wear has been good. Gotten to the point where I could use a bit more grip mainly at the autoX, am leaning towards Bridgestone Potenza RE-71RS's. If I was doing track days only I'd try the Goodyear F1 Supercar 3R. Also debating going to a 225 width but that limits choices a bit. I use the Grassroots guide when trying to decide on these: https://grassrootsmotorsports.com/articles/track-tire-buyers-guide/

Because the cars are so light, all-season tires intended for cars weight 2-3 times as much as a Locost will never come up to temperature, and won't have much traction. Of course, if all you do is go out for coffee in your Locost, then it doesn't really matter. Very much use-specific.

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Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

For me it's 4 Yokohama S-Drive tires with 205/40 R17 versions up front and 235/40 R17 tires at the rear. The stock donor engine is right around 150 HP, but a second engine of 250-300 HP is planned.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

Speaking of 17" wheels and tires - it is what it is. Some years ago there were many threads here about how wrong and inappropriate such large tires are on a Locost (and Mini for that matter). Thing is, if that's all that's available, what's the alternative. I say just do the best you can, finding something affordable and somewhat sticky (they'll last forever on such a light car) and call it a day. Going on and on about how they're "wrong" only leaves the alternative of leaving the car on blocks in the garage. Pick and move on.

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Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

My personal approach was to get the smallest wheel that I could get tires for and came in correct offsets and widths. Since I am using Miata uprights and brakes, that puts me at 15 if I use sports brakes. I am fairly concious of unsprung weight as well, but everyone has a different goal.