Upgrading to 18inch

MrCypherr

Veteran Member
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Sep 3, 2012
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Ontario
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Mk6 Wagon
Currently running 16" wheels on my wagon and thought about upgrading to 18 inch. Now I was looking at the 18" prisma wheels that come off the Atlas but also noticed that they weigh 32lbs (just wheel, no tire) each. Which would be around 128lbs just in wheels alone and not tires. Kind of heavy and was also looking at a set of wheels that were 108lbs total. Knowing that they are this heavy i am expected a drop in fuel economy but was wondering if anyone has ran similiar wheels that weighed around the same. Just trying to get some insight cause I do alot of driving, I fill up every week or so and Im getting around 950km-1000kms (590-620miles) and would like to keep around that per tank or atleast 900kms.

Thanks!
 

oilhammer

Certified Volkswagen Nut & Vendor
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Location
outside St Louis, MO
TDI
There are just too many to list....
Cannot comment on the weight, but know this: the bigger the rim size, the lower the profile tire, which means harsher ride, higher tire cost, and shorter tire life. In addition, the rim size seems to correspond to a substantial increase in bent wheels. Like, for each inch increase, the likelihood of bent wheels goes up by a factor of ten.

Just telling you what I see daily in our shop. Looks aside, for a daily driver I'd want the smallest (diameter) wheels available myself. I drive a lot, too.
 

hskrdu

Top Post Dawg
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Oct 17, 2003
Location
Maryland and New England
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2003 Golf GLS 4D 5M, 2015 GSW SE 6M
My OE VW 17"s are listed in the club classifieds. Outstanding fuel economy with them. Of course, your location doesn't really reveal where you are.
 

hskrdu

Top Post Dawg
Joined
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Location
Maryland and New England
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The seats from my 2003 Golf went to Marcus, who lived in Wisconsin. It's all just an excuse for a TDI road trip...
 

JELLOWSUBMARINE

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yes
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2011 Jetta Sportwagen, 6M, red/tan, navi, pano, 83 5m diesel pickup, 82 p/u trailer,.04 5.5 TDI Passat wagon (gone), 80,81,82 diesel p/u (gone), 80,82 sportruck (gone), 59 passthru bus (long gone), 79&87 westy (gone), 57 baja bug (long gone), 73 914
Yep, check Tirerack. they're really reasonably priced too. I've got them on my A3.
What mpg difference did you see?
 

tjg

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What mpg difference did you see?
So I think I've mentioned this before, but I put them on right around when stations switched over to winter fuel. I'll have a better idea once it warms up a bit, but I think maybe 1-2mpg at best. The A3 is Stage3/CP3/CR170 so it will never get the mileage that my stage 2 sportwagen gets.
 

pipesta

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Mar 15, 2020
Location
Chicago, IL
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'14 JSW TDi 6MT
I drive 5-600 miles a week (a lot more in the summer), I have 18" Forgestars and they're not too harsh in the Chicagoland ridden with potholes. I do a lot more dodging of the potholes though lol. My Kerma tuned non-deleted car still gets upper 40mpgs (yes ,that's calculated) 70% highway driving.
 

66fasty

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Ca
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2012 tdi Sportwagen
I drive 850mi a week and went from 17’s to 18” New Beetle Disc wheels, no noticeable loss in mpg’s.
 

MrCypherr

Veteran Member
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Sep 3, 2012
Location
Ontario
TDI
Mk6 Wagon
Thanks for the info. I'm deciding between 18" Prisma wheels (Atlas) at 32lbs each and a set of 18" audi wheels that are around 27lbs each. Obviously I know the lighter ones make sense, but was just seeing if made that much of a difference on a diesel.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
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Location
South of Boston
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'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Short answer is yes, weight matters. When it really affects MPG when stopping, and starting. Wheel weight doesn't really have an impact when driving a consistent speed. But lighter wheels are also easier to stop, change direction, and are easier on steering and suspension components.

Remember, 18" tires are going to weigh more, too, although maybe only a pound or two compared to 17s.

I can't help but be surprised at the wheel weights you're sharing. I have 15" Kosei K1s on my MKIV, they weigh 13 lbs. And I just bought new tires, General Altimax RT43s, 215/60-15s, which weigh 20 lbs. So wheel and tire combo is 33 lbs. Compare that to the 48-52+ lbs. of the setups you're looking at. 20 lbs. per corner on what's a very similar car is significant.
 

lamsv

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Jan 17, 2019
Location
Bellingham, WA
TDI
JSW
I recently installed a set of 18x8.5 wheels with 225/40. I'm am consistently getting 50 miles less per tank than before.
 

taleAwaggin

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The Atlas wheels are probably rated for some ungodly amount of carrying capacity. Maybe look at some OE Passat 18's..

I actually don't like the way large diameter wheels look either.. even if I could get some that were as light and rode as well as smaller wheels. Don't understand the obsession with having large wheels, but then I'm not young.

I'd run 13's or 14's if I could fit them over the calipers.
 
Last edited:

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
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There are just too many to list....
Sadly, you can no longer find decent brand 14" tires let alone 13". Your choices there are a couple of garbage Chinapop no-names typically. I actually remember going to get another set of Michelins for my '79 Rabbit.... nada. Nothing for my '91 Jetta anymore, either. Although the Jetta I can still get a couple name brands (Firestone, Uniroyal) in addition to all the Asian garbage.
 

IndigoBlueWagon

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'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I'd love to go back to 14s on my Passat (15s now) but tire selection is just terrible. And the one thing that the Prius has done for me is ensured decent selection of 15s for the MKIVs, as long as you don't want any kind of a performance tire.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Prius does not use the same speed and load rating, though. Although a lot of people ignore that anyway. The way we have been replacing engines on them lately, and the general ownership tendency for George Constanza-ism that would make a TDI owner seem lavish, would make me think it would do nothing more than to insure plenty more low end Asian garbage tires and not the good stuff.
 

IndigoBlueWagon

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I can find H and S rated tires with 91 load rating, I think that's correct for a MKIV. Maybe not...I've been buying tires for these cars for so long that maybe I've just adjusted to buying the wrong ones.
 

ttcheung

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Location
Sudbury, MA
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2011 TDI Sportwagen 6MT
Besides the diameter, you might also want to think about the width of the wheel / tire and how well they fit in the wheelwell. You wouldn't want the tires to hit your fender liners nor the fender itself.

I think 17" fits nicely on the JSWs, and the 45series tires are probably as road-friendly as it gets.
 

taleAwaggin

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I would look at some Jetta/Golf/Passt used OE options.. It might be cheaper to find SUV takeoffs, but again those SUV wheels are designed to carry 6000+ pounds max capacity. Of course they are going to be heavier when they are designed that way. Its a waste on a car that cannot carry that much weight. All that mass is just going to screw up your suspension's ability to control movement properly.

Sadly, you can no longer find decent brand 14" tires let alone 13".
Right, it makes sense that this would be the case since no car makers use the sizes any longer. Point being.. I would run 12" wheels if I could. What is so bad about a gigantic sidewall on a car where all I do is commute over potholes and maybe take it camping through some trails once in a while? I'm not a BTCC driver is what I'm getting at. Don't need to look like one! /BoomerRant
 

IndigoBlueWagon

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What is so bad about a gigantic sidewall on a car where all I do is commute over potholes and maybe take it camping through some trails once in a while? I'm not a BTCC driver is what I'm getting at. Don't need to look like one! /BoomerRant
I think the only people who really like big wheels are the marketing folks who generate the computer images of cars for web sites (since no one uses photos any longer). And tire sellers and wheel straightening services. I've only got one set of 16" wheels for my MKIV cars which I used on the track. The rest are 15s. And I'll eventually get 15s for my MKVII.
 

taleAwaggin

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Bet you can achieve better fuel economy with a lowered car on 18's versus a stock car on factory 16's. As long as the tires are similar width to factory. Heavy wheels should only hurt your city economy, hwy mpg "should" only be hurt by offset and width (aero). Lowing is common with the people who get larger wheels, which is why I bring it up. Lower cars get better fuel economy.


As for boomer..
I want my 26" tires to look like this basically... I think I'd need 8's or 10's.
 

MrCypherr

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Ontario
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Mk6 Wagon
Ive scraped the idea of using Atlas wheels are decided to gear towards something OEM like. I've found a set of 18" Audi peeler wheels, as I mentioned they are around 27lbs each without tires. I've thought about doing OE 18" passat wheels, just hard time finding something OEM like around here that arent $1000+.
 

hskrdu

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Some observations: You can achieve better FE by improving Cd/CdA, and you can improve CdA by (to some extent) lowering the car, but for the same car at the same height, the lighter wheel-tire combo with better CRR will typically net better FE. Here I'm speaking about a car lowered via the suspension, since most OE VW wheel-tire combinations maintain similar overall diameters, so going to an 18in combination does not necessarily lower the car. Many swaps to 18in wheels will result in an increase in diameter, raising the car height, and countering (to a greater or lesser extent) the effect of lowering via suspension. Suspension itself can be a factor in FE, but the factors are complex enough I'll leave it out. Obviously production vehicles are tuned for the marketplace, but manufacturers do a lot of testing to improve the FE numbers on most vehicles (or for fleet averages). Not that the results are always accurate, but cars such as the e-Golf, Prius, or Insight are good indicators of what works to maximize FE, which is (one reason) why we don't see those cars excessively lowered, or with wider, low profile tires. The Cd is often improved though underbody panels, which mimics the FE found where some lowering might improve Cd , but allows for a taller and more narrow tire, which is key in these cars FE numbers.

Although the weight penalty of 18in wheels and the accompanying heavier tires hurts FE most in city driving, it still hurts FE on the highway, although all-highway trips may mask this, or may render the difference as negligible. If the 18in wheel-tire combo falls behind the 16in combo in any area of efficiency, the penalty of the 18's will grow. These factors go beyond offset and width (aero and resistance penalties), and include the Cd of the wheel itself, the FE loss or gain due to sidewall height, the FE loss or gain due to LRR tires, and FE losses or gains due due to the impact of height on RPM. It may also be more difficult to find better LRR tires in 18in which maintain the right diameter, and here we lose additional FE. Also, rolling resistance typically increases with speed rating, so if the 18in tires have a higher rating than 16's, they may also increase RRC, and lower FE.

I won't pretend I know the magic elixir, but from my experience, and tests here (going all the way back to Ernie Rogers) and elsewhere, the same car, under the same conditions, will see better FE with wheels that are more aero, weigh less, and have tires that are LRR, narrower, and lighter than the opposite factors. I initially also said "taller," but skipped it because I would then want to discuss other factors such as sidewall flex. That being said, there is also obviously diminishing returns, compromises, and the impact of one factor on another (such as taller tires raising ride height, increasing CdA, but lowering highway RPM, improving efficiency).

To the OP: Free bump.
 

taleAwaggin

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Right, steady speed highway it shouldn't matter one iota if your wheels are zero pounds or 50 each. Even if you pulse up and down in speed it shouldn't matter too much because energy is for the most part retained. Just the engine load is a little higher. City driving on a car without regen brakes.. that is where you will see the difference. 100% of that energy turns into brake heat every stop light.

From what this old fart has seen around these parts.. The younguns that put huge wheels on tend to lower their cars to a point that even with their huge wheels, they are still lower overall than factory height. I've also read some data which suggests offset has a huge effect on highway speed aero, but nobody every talks about that.
 

hskrdu

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Part of my post was saying that wheel-tire weight does matter, regardless of city or highway driving. It's just that you see the FE impact less in highway driving. Weight matters as an overall factor in how much fuel is required to obtain or maintain speed, but weight at the wheels is also a factor. If we agree that, of the energy that makes its way past other losses (sinks) as mechanical energy to turn the wheels, there are three types of losses (sinks): aero drag, rolling resistance, and braking (not concerned with driving conditions like acceleration or slope, etc). We know that braking, as a sink, is a higher percentage in stop and go driving, and that aero drag, as a sink, is a higher percentage in highway driving. Rolling resistance, however, as a percentage of overall energy loss does not vary as greatly as the others. Rolling resistance, as discussed earlier, is complex, but one factor is mass, which is why small changes in mass at the wheel-tire can impact efficiency. (Just a note, the specific rolling resistance associated with tires also does not vary greatly by speed unless the tires are severely underinflated or speeds go well above the legal limits).

Sometimes members post that they are unhappy with their new tires because their FE immediately declined. It is common to respond that there are many factors associated with the impact of tires on FE, and brand/width/height/weight/compound, etc. will all play a role. It is also not uncommon that the response is "My new tires are the exact same brand, model, and dimensions, but my FE went down." Here a common explanation is given: First, the new tire (of the same size) has a larger diameter, and so the odometer will record fewer miles, lowering FE calculations (and the opposite is true of the worn out tire). But more importantly, the newer tire is generally at its highest rolling resistance, while the worn out tire is at a low point for rolling resistance. This RR change over time (not changes in condition, such as temp or type of travel) is most associated with the loss of outer tread, which does two things: First is reduced hysteresis (energy lost as the tire deforms and recovers), second is reduced mass, which also lowers RR. (Here I just want to note that my focus was the initial question of comparing weight. I'm purposefully leaving out the other interrelated factors: when diameter increases, rolling resistance decreases, and larger diameter tires may show a lower RRC {as the deformation of travel is less of a percentage impact on the tire}, but larger tires generally have greater RR, etc.).

Owners who drive mostly on the highway don't may not notice FE losses with larger/heavier wheel-tire combos because, as we know, aero drag is the greatest sink at highway speeds. Despite this, weight does contribute to lower FE, even for highway travelers. In the end it may not matter to owners, as they are choosing wheel-tire combos based on a variety of factors, but it may be helpful to be aware of where the energy sinks are occurring, and how to reduce them if desired.
 

jonhmat

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Mar 19, 2021
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Vilnius
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VW
I was thinking about upgrade to 18inch too, but my golf now its chassis ride, that after upgrade need to drive only soft road...
--
autoera
 

MrCypherr

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Sep 3, 2012
Location
Ontario
TDI
Mk6 Wagon
I'm trying to stick to a OE 18" wheel weight when choosing. Currently trying to seek out some OE wheels or wheels around the same specs. I will be lowering the car but on some springs. Not as low as you see all these cars that are sitting on the ground. An outlook on a tank of diesel is usually 95-98% highway which is about 1000kms a week give or take. So highway driving is what I would be looking at when it comes to FE. Tire wise, I'm looking for something close to an OE option that isnt too harsh or has a hard side wall. Not really needed if I'm not making lots of power of course. Does anyone have any good tire brands/models that they are happy with when it comes to highway driving? Like road noise, FE, wear etc.?
 
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