Help me choose tires. Non eco project.
 

Hello everyone,

I have a non Eco project car I am restoring and need some help deciding on what series tires to run.

I have no experience with low profile tires so I have no idea how they ride. I know a lower sidewall will be stiffer, but I was hoping that with newer tire technologies, they may have improved from what I have read. So the question is this. Can anyone clue me in on how a 45 or 40 series tire might ride? I know there are many other variables involved (tire compound/tread/width/etc.) but I'm looking for more of a general idea. I definitely want to limit the road noise for the long highway cruises and worry about how the lower profile tires will handle road imperfections. I have found 40 and 45 series tires in 16" and 17" and that will give me plenty of wheel options to compliment the car. I could also use 15" tires and comfortable go to a 60 series tire, but it will limit my options on wheels. I don't want to molest the body so I am limited to a maximum 25" tire and that may even be to tight. I would like at least a 225 width for those occasional (cough cough) times I "might" want to get on the go faster pedal. it will only see 3 seasons (no snow ever) so probably a touring tire of some sort.


Car is a 1976 Triumph TR7 that will have a GM L33 V8 truck engine. I'm not building this to be a great eco car, but definitely a highway cruiser that I can still open some eyes with from the in-town stoplights. Roughly 325+ rwhp when all is said and done. Probably a 60%-70% highway car.

Any advice?

I am no tire expert. I remember the TR7: "The Shape." Great project!

Personally, I would be against really low profile tires, unles the rims are carefully matched to the look of "the shape." I think low profiles are more prone to blowouts and rim damage in potholes, especially if you run lower tire pressures to soften the ride a little.

You burried the lede! The thread title should be Pick low profile tires for my '76 TR7... that'll get lots of clicks.

I ran 245/45-ZR17s on my ‘68 Mustang. 45 is about as thin as I’d ever go. They replaced some (I think) 205/65r14 or 15’s. It did stiffen up the ride, but it wasn’t a dramatic change - it probably helped that the old tires were cheap no-names, they tend to not be quite as nice riding.

The shorter sidewall should improve turn-in. I've nothing else to offer, as 165-50R15 (Federal Formoza) is the lowest profile I've run.

But, pix please? Or at least tell us what color it its. :)

For the moment I am thinking these might be my choices, but more research is in order.

235/45/16
245/45/16
225/50/16
225/55/15
245/50/15
235/50/15

And as requested some pics. I haven't had much time to start with the pull out and it is definitely going to be a long term project. Still has the original pinstripes on the body and around the trunk (boot) latch. Last one is similar to the engine going back in.

With a relatively light weight wheel, a 45 isnt too bad. My wife's car has 45's but the tire wheel combo is around 100lbs. My car has 50's also a much more refined suspension and far lighter wheels. I think both are very comfortable to drive.

The one thing I will add: low profile tires suck on rough roads.

Important to keep in mind the tire width changes the sidewall height even if comparing two tires that are "low profile". My wife's 285/45/22's are or near low profile, but due to the width actually have a taller sidewall than my 235/50/17's.

And yes, my volt handles absolutely amazing!

I talked to a guy behind the counter of a tire store who thought aspect ratio is absolute instead of a ratio. I didn't try to convince him, I just got the tires somewhere else.

Just to throw it in, I have General Gmax AS-05 tires and love them. I had the AS-03 before that on my CTS, loved them as well. Really great wet traction.

I'm under the impression that 45 isn't all that thin nowadays, relatively speaking. There are plenty of new cars on the road today with 30 aspect ratio tires.

That said, I personally prefer a little bit more sidewall.

I wish there was a general rule of thumb for this. XXX cm of sidewall is good for comfort. YYY cm is good for handling but harsher ride. ZZZ cm is super comfortable but has a lot of side wall roll.

The closest I could find was a reference to a luxury package tire size for a Cadillac CTS that had 123 cm of sidewall height. I do the math with certain combinations of sizes that keep me under the 25" total diameter and almost all are auto cross or track use only. At least at TireRack. To get that sidewall height in a 16" tire is nearly impossible and the 15" ones are track tires.

Miata's and RX7's must have a similar tire size. I wonder what those guys are using for daily drivers and highway cruisers?

According to TireRack the only size with multiple choices that fit my criteria is a 225/50/16. Nothing available in a 15" tire that isn't Pirelli (read super expensive) or a track tire (basically slicks and not for rain)

225 width would be good for aero but I have to wonder how they would do if I decide to put my foot into it.

I just bought a set of 225/40/19 Bridgestone Potenza at 4wheelonline for my sedan. The ride isn't bad at all although the speedometer is a bit off.