📓 Journals kitkat's Emira
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Orchardbike
Emira Fanatic
But you have ‘more’ tyre (tire). So what is the weight benefit specifically? And why is the trend, by the manufacturers, to bigger wheels?
I've mentioned this before, Tire rubber is dense and heavy. Overall, you largely end up around the same weight. I think for real track rats, the benefit is usually a broader selection of track oriented rubber. You have a heck of a lot more choices at sub 20" diameter.
You’re saying the marginally greater tire sidewall + more air volume offsets the savings of a smaller circumference metal wheel barrel, plus shorter wheel spokes? I would find this surprising although I can’t say I’ve compared it personally.
This all assume that total rotating diameter remains constant, thusly a greater aspect ratio w more tire sidewall. It’s certainly possible to run a smaller set up, although it requires a bit of coding to adjust for.
Some cars have this preloaded, since they are offered with various wheel/tire size options which are never exactly equivalent rolling diameter, and/or different winter tire specs.
Ppl likey big wheels bc they “look cool.”Bigger is better etc
Manufacturers can charge more for them, and shareholders likey profits.
Also, and more rationally, sometimes brakes are too big and require larger wheels
That's exactly what I'm saying. Just go to your friendly neighborhood tire shop and grab the OE tire size (20") and then grab an 18" tire size equivalent (I.e., rolling diameter equivalent will have a higher sidewall also make sure it's a width equivalent). When and if you do this, you will be shocked at how much heavier that 18" equivalent tire is.
- Thread starter
- #288
Hoosier Track Attack Pro 295/30/20 -- Overall Diameter 27" -- Weight 24 lbs
Hoosier Track Attack Pro 295/40/18 -- Overall Diameter 27.28" -- Weight 25 lbs
Differences when moving down:
- 1 lbs heavier tire
- Wheels are way more than 1 lbs lighter each moving from 20" to 18"
- tire costs drop
You're looking at an overall weight drop not gain -- and more money in your pocket for consumables.
I'm planning for a set of magnesium 18" but you don't need to spend that money you can just as well buy a $1000 set of forged 6061-T6 wheels weighing in the 18 lbs range.
Hoosier Track Attack Pro 295/40/18 -- Overall Diameter 27.28" -- Weight 25 lbs
Differences when moving down:
- 1 lbs heavier tire
- Wheels are way more than 1 lbs lighter each moving from 20" to 18"
- tire costs drop
You're looking at an overall weight drop not gain -- and more money in your pocket for consumables.
I'm planning for a set of magnesium 18" but you don't need to spend that money you can just as well buy a $1000 set of forged 6061-T6 wheels weighing in the 18 lbs range.
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You also have to consider the specifics. kitkat is right, on "slicks" the weight increase is certainly less (1 lb. in his specific case). However, if you take the more common threaded "streetable track" tire options and compare equivalent diameter and widths, the weight addition is likely closer to 1.5 to 2+ lbs. This would be approximately the same drop in weight changing aluminum wheel diameter (for like wheels). Now, if you are going from the OE anchors (oops, I mean wheels) to an aftermarket 18" light wheel, yeah, it's a much bigger difference.
I'm referring to an equivalent 20" light wheel option vs. a similar design (if not identical) 18" wheel. The delta won't be that much more of what you add in additional tire weight. Overall, let's say you do come up with a pound a wheel savings. Most will tell you, they likely did it for the increased tire options for tracking, not any net weight savings. Ultimately, just go on Tierrack and look up the tires you are interested in. The specs. usually list the weight. That way you will know the weight add of the heavier tire. Then go to whatever wheels you are buying and look up that weights vs. what you have now. You'll know if you are saving, net neutral or perhaps adding. My experience (probably 7-8 wheel sets over 5 cars), is you largely end up in the same spot from an overall weight perspective.
I'm referring to an equivalent 20" light wheel option vs. a similar design (if not identical) 18" wheel. The delta won't be that much more of what you add in additional tire weight. Overall, let's say you do come up with a pound a wheel savings. Most will tell you, they likely did it for the increased tire options for tracking, not any net weight savings. Ultimately, just go on Tierrack and look up the tires you are interested in. The specs. usually list the weight. That way you will know the weight add of the heavier tire. Then go to whatever wheels you are buying and look up that weights vs. what you have now. You'll know if you are saving, net neutral or perhaps adding. My experience (probably 7-8 wheel sets over 5 cars), is you largely end up in the same spot from an overall weight perspective.
No, a drop in weight from a 20 to an 18 is like. 4 lbs.
You are still dropping 3lbs and that's over an identical design, comparing an 18 aftermarket light wheel to a stock 20 inch? you are going to be dropping like 8lbs or more per wheel. 1 MAYBE 2 LBs of tire weight isn't making that a bad decision.
You are still dropping 3lbs and that's over an identical design, comparing an 18 aftermarket light wheel to a stock 20 inch? you are going to be dropping like 8lbs or more per wheel. 1 MAYBE 2 LBs of tire weight isn't making that a bad decision.
TE37 20x9.5, weighs 22 lbs, according to Showstoppers USA.
TE37 Saga (18x9.5 +38): 19 lbs
For one of the industries lightest wheels in its given sizes. Weight drop to 18s is an advantage. Tire selection will be the biggest advantage though.
Go look it up for yourself. Michelin Pilot Sport 4 S. in 245/30/20 is 22 LBs. 245/40/18 is 23 lbs.
TE37 Saga (18x9.5 +38): 19 lbs
For one of the industries lightest wheels in its given sizes. Weight drop to 18s is an advantage. Tire selection will be the biggest advantage though.
Go look it up for yourself. Michelin Pilot Sport 4 S. in 245/30/20 is 22 LBs. 245/40/18 is 23 lbs.
- Thread starter
- #293
Yeah I'm just going to have to disagree with you on just about all points @F1 SML8R
- Those tires I posted aren't R-Comps -- lots of street tires in the same range of 1 lbs increase from the sizes I compared.
- A theoretical wheel OEM wheel in 18" doesn't exist and it isn't apples to apples but in the end this doesn't matter, what matters is the actual net effect of doing this modification.
- Your overall weight will indeed drop 24+ lbs with track focused 6061-T6 wheels
- Your overall weight will indeed drop 30+ lbs with track focused AZ80 wheels
Additionally if you really want you can always run a 35 series 18" wheel and then you are diving deeper into weight loss on both tire and wheels. If you're also budget oriented about it you can also break even on the price of track wheels and parking brake relocation in about 3 to 4 sets of track tires all while going faster.
This mod isn't for the street guys.
- Those tires I posted aren't R-Comps -- lots of street tires in the same range of 1 lbs increase from the sizes I compared.
- A theoretical wheel OEM wheel in 18" doesn't exist and it isn't apples to apples but in the end this doesn't matter, what matters is the actual net effect of doing this modification.
- Your overall weight will indeed drop 24+ lbs with track focused 6061-T6 wheels
- Your overall weight will indeed drop 30+ lbs with track focused AZ80 wheels
Additionally if you really want you can always run a 35 series 18" wheel and then you are diving deeper into weight loss on both tire and wheels. If you're also budget oriented about it you can also break even on the price of track wheels and parking brake relocation in about 3 to 4 sets of track tires all while going faster.
This mod isn't for the street guys.
geoffbland
Emira Fanatic
There's way more to it that just wheel weights too. The saving on wheel weight is unspring mass so it affects the momentum in the suspension usually a positive affect in responsiveness (usually more meaningful the the change in rotational momentum which is negatable against the weight of the car).
There's also a change in longitudinal contact area (not transverse assuming same width tyres) this can make a difference to both grip, steering and breaking - larger tyres have more grip. Even with the same callipers this will make a difference.
Then there's the diameter of the tyre - assuming this also alters, so you will cover more distance per rotation of the wheel - a small difference but this will affect acceleration and top speed.
Only by trying these things out would anyone know the benefits (or lack of) and even then it is likely to be different for every driver.
All that said, usually it is done as 18" tyres are more plentiful so cheaper and regular tracking will go through many sets of tyres.
There's also a change in longitudinal contact area (not transverse assuming same width tyres) this can make a difference to both grip, steering and breaking - larger tyres have more grip. Even with the same callipers this will make a difference.
Then there's the diameter of the tyre - assuming this also alters, so you will cover more distance per rotation of the wheel - a small difference but this will affect acceleration and top speed.
Only by trying these things out would anyone know the benefits (or lack of) and even then it is likely to be different for every driver.
All that said, usually it is done as 18" tyres are more plentiful so cheaper and regular tracking will go through many sets of tyres.
FWIW my "take" on larger tires/rims (street use) for some time has been:
I. Pros
a) looks;
b) looks.
II. Cons
c) price: larger tires and rims typically cost more;
d) road noise: larger tires usually have smaller side wall width and generate more highway noise;
e) ride quality: feels bumps more, due to low profile (less sidewall width);
f) risk of flat tire: increased, with the smaller sidewall width; (I experienced this ++ with Mercedes low-profile tires, which kept getting flats or side wall bulges, due to all our potholes)
g) gas mileage: uses more fuel.
A long time ago and while shopping for a family SUV (for my spouse, to replace a Suburban), I fell in love with an Acura MDX which had large aftermarket chrome rims, larger low profile tires and matching chrome running boards. The tires/rims alone added at least $6,000.00 onto the stock price. While waiting at a set of lights, my wife would often get compliments ("NICE ride!") from younger drivers next to her. Our first road-trip in the MDX (to the West Coast) was a shock for me. I HATED the road noise, then couldn't believe the gas mileage (about the same as the larger/heavier older Suburban) and HATED the rough ride, so it was a big wake-up call and the entire vacation, I ++ missed the smooth ride of the Suburban. I got rid of the MDX larger rims/tires, after that trip. Since then, I've continued to purchase street vehicles with top-line trim, to get all the bells/whistles, however I've had their tires/rims "downgraded" to the smaller tires/rims sold with the lower trim lines, even though I've lost money doing this. My 2 cents.
I. Pros
a) looks;
b) looks.
II. Cons
c) price: larger tires and rims typically cost more;
d) road noise: larger tires usually have smaller side wall width and generate more highway noise;
e) ride quality: feels bumps more, due to low profile (less sidewall width);
f) risk of flat tire: increased, with the smaller sidewall width; (I experienced this ++ with Mercedes low-profile tires, which kept getting flats or side wall bulges, due to all our potholes)
g) gas mileage: uses more fuel.
A long time ago and while shopping for a family SUV (for my spouse, to replace a Suburban), I fell in love with an Acura MDX which had large aftermarket chrome rims, larger low profile tires and matching chrome running boards. The tires/rims alone added at least $6,000.00 onto the stock price. While waiting at a set of lights, my wife would often get compliments ("NICE ride!") from younger drivers next to her. Our first road-trip in the MDX (to the West Coast) was a shock for me. I HATED the road noise, then couldn't believe the gas mileage (about the same as the larger/heavier older Suburban) and HATED the rough ride, so it was a big wake-up call and the entire vacation, I ++ missed the smooth ride of the Suburban. I got rid of the MDX larger rims/tires, after that trip. Since then, I've continued to purchase street vehicles with top-line trim, to get all the bells/whistles, however I've had their tires/rims "downgraded" to the smaller tires/rims sold with the lower trim lines, even though I've lost money doing this. My 2 cents.
I dont think they do that anymore.
Tracked Emira
Emira Fanatic
Funny. Not Funny.!
My fat challenger on 18 inch slicks had new rotors and pads that caught on fire due to heavy braking, but thank God I didn’t have magnesium wheels.
Always have a fire extinguisher in the car.
You can always get forged magnesium wheels.
Now I have to get a fire extinguisher if I get the magnesium wheels.
The other benefit of 18s is a wider selection of slicks, better grip and lap times.
Are forged Less vulnerable than cast?
I just assumed all mag wheels were forged but perhaps erroneously
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