Using 20 mm Narrower Tires ?

Hello,

Have been offered a set of 4 brand new tires. Unfortunately, the size isn't exactly what my car came with.

The offered tires are: 205/60-16

My car came with: 225/60-16 (2009 Buick LaCrosse)

So, I guess my Buick normally has 20 mm wider tires, but the same for the other dimensions.

Would appreciate opinions as to whether this 0.8 inch difference would be a "meaningful" difference ? Caveats, safe, etc. ?

The amount of driving I do now, frankly, due to age, is fairly minimal.

Happy Holidays,

Thanks, Bob

Reply to
Bob
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other dimensions.

Your going to change load rating and diameter. The ride might change a bit, speed odometer a bit faster, more pickup. I think it will fit on rim.

Greg

Reply to
gregz

Speedo will be off by 3.5% FAST / 60mph = 57.9mph

Sidewall 225 - 5.3" 205 - 4.8" Diameter 225 - 26.6" 205 - 25.7"

You shouldn't have a big problem. BUT it might cause a problem if you have the navigation option. The GPS and speedo won't match and could cause a hiccup. Haven't tested it out myself..

Reply to
Steve W.

205/70-16 or 205/75-16 would be a safer option if you want 205 (good for deep snow plowing)

if you have enough wheel well clearance

Reply to
AD

Steve W, G:

The O.P. specically mentioned a change in tire

*width* not diameter. They are both 60-series tires indicating the same height sidewalls, given the information provided.

Width may affect handling(more concentrated weight in snow/ice) but not speedo performance.

Reply to
thekmanrocks

That will affect diameter, the 60 ("series" or "aspect ratio") means that the sidewall height is 60% of the section width. So a narrower tire and same aspect ratio will in fact have a smaller rolling diameter.

I'd be most concerned about weight ratings. That could really only be addressed by looking up the specs of the exact tire in question, and finding out if they're listed for the width rims the OP has and confirming that the tire's max load is greater than the largest GAWR of the vehicle. Some tire shops likely still won't mount them for you if they are not a factory offered size for the vehicle. I had a go-round about this a few years back trying to fit 14" tires to my E28 535i that came factory stock with Michelin TRX tires; several tire stores refused to sell me tires because their book said that a 535i required a V speed rated tire and the 14" tires offered to fit were all H rated. Never mind that the wheels and tires I wanted to use would have been perfectly acceptable on a 528e which is effectively the same car with less power, and that the highest speed limit on the east coast at the time I believe was 70 MPH. They all wanted to sell me a 15" or 16" wheel and tire package, for a small nominal fee of course (at the time, that just wasn't happening with my budget) But I digress...

Dry cornering grip will definitely take a hit with a narrower tire, but it should be predictable and not too great if everything else checks out OK.

nate

Reply to
Nate Nagel

The sidewall heights, and therefore the diameters, are not the same. In order to preserve the 60 ratio, the height must be different.

Reply to
Paul in Houston TX

So you think that a 205 - 60 - 16 is the same diameter as a 225 - 60 - 16?

The 205 will have a 4.8" sidewall height, A radius of 12.8", A diameter of 25.7", A circumference of 80.7" and turn 785 revolutions per mile.

The 225 will have a 5.3" sidewall height, A radius of 13.3", A diameter of 26.6", A circumference of 83.7" and turn 757 revolutions per mile.

The numbers break down as follows

Letters in front of the first number - P - Passenger car tire, LT = Light truck tire, NO letter means it is a European sized metric car tire

205 - The nominal width of the tire measured at the widest part of the sidewall, NOT the tread width. 60 - Aspect ratio. This is a percentage of the section width. In this case 123mm AKA 4.84"

R = Radial tire construction.

16 - Rim diameter in inches (although since the demise of the bias ply tire this is actually in mm equivalent, The actual rim measures 406 mm)
Reply to
Steve W.

205/65 - 16 is the same diameter as OEM

The 16" is actually the narrow tire for the LaCrosse that year. The sport size was 225/55-17

Reply to
Steve W.

55 is comfort these days with many road going near slicks unavailable in 55 profile and 70 is the new 90 :^)

sport seem to have moved into the 25-45 rubber band area

Reply to
AD

No kidding. Apparently the "conservative, comfortable" wheel/tire choice for my "new" car is a set of 225/40R18 front and 255/35R18 rear. Currently it has 225/35R19 and 255/30R19. If you'd told me that would be the case 10 years ago I would have laughed at you!

I have found a set of factory 17" wheels that will clear the brakes, so at least my winter tires are (relatively) inexpensive.

nate

Reply to
Nate Nagel

Nate:

I have to wonder though: How much of this larger rims/lower profile tires trend since the 1990s has been driven by functionality or looks?

Have shock absorption systems(struts, etc) evolved to the point where sidewalls no longer have to share this role with them? Or is it just a "bling" thing.

As far as handling goes, I think more aggressive alignment setups(more caster and/or SAI, negative camber front or read depending on which wheels do the work, etc.) would play more of a role than the height vs side-to-side widths of rims & tires.

Reply to
thekmanrocks

I think it is really appearance driven. The stock 19" wheels on my car look fantastic, but weigh a ton. In the instance of my specific car, the people who actually race them usually use lightweight 18" or even

17" wheels with a "square" (all tires the same size) setup.

Not entirely related, but it's also somewhat common knowledge on the forums that replacing the factory issue run-flats for something like a Michelin Pilot Super Sport will result in better ride, better handling, and longer tread wear. I think the use of the RFTs was primarily driven by the anticipated liability of a motorist getting a flat at ludicrous speed on the Autobahn... but I'm pretty sure the M3 doesn't have RFTs? who knows what the real reason is. In any case I already bought a jack and lug wrench and have a donut spare strapped into the trunk as my winter tires aren't RFTs either. I might pick up another wheel/tire so I can have a full size spare for long trips, I don't like the feeling of being dependent on local vendors for tires when I'm a long way from home. Granted, the last flat I got on the road was in my old Scirocco so that would have been about 2001ish, but still, I am not aware that Murphy's Law has been repealed in the intervening years.

nate

Reply to
Nate Nagel

Sorry to hear that Nate - about looks that is! I thought that the human race would evolve AWAY from trying to impress each other and toward smart appearance inspired by functionality.

Is that the same reason why TLC(the "learning" channel) has lowered itself to the worst denominator with shows like "Honey Boo Boo"?

Reply to
thekmanrocks

(looks like I done shut down yet another thread...)

Reply to
thekmanrocks

Marketing and money. Create a "want, turn it into a "need" and up the profit. Honey Boo Boo, Turtle Man, Repo Man, on and on .... if it plays in Peoria, it'll play anywhere. google documentaries and you will find something worth watching, cut the cable.

Reply to
Fatter Than Ever Moe

there are a few reasons for that, retaining mobility in "bad neighbourhood" would be one. and then there are folks such as myself who would gladly extend a helping hand with a caltrops under the tire of people who routinely park on pedestrian walkways (it's a national sport where I live). Lets just say at $250-400 a "pop" an owner might not be thrilled to replace a tire a caltrops chewed to bits. I guess there is more peace of mind after you have pieced together an RFT tire.

any ideas which explosives would be suitable for destroying the rim for those boy scouts? I feel vehicles have no place on sidewalks and would like to drive it into the sculls of local drivers by any means available.

Reply to
AD

Anecdotally, the RFTs destroy rims as it is, at least on BMWs :( There's a known problem with some styles of factory wheel developing cracks; I asked my local wheel repair guy when I dropped some wheels off to be refinished if he noticed any correlation between using RFTs and non-RFTs; he said there definitely was. Now whether that's because the wheel types that tend to crack just have a natural propensity to crack and they're factory fitted with RFTs, or if the RFTs really do increase the stress on the hoops/barrels, who knows? I'd be interested to know, but I'm probably going non-RFTs when I need tires because of the increased treadwear, traction, and ride comfort of the available non-RFT options (which happen to be less expensive as well.)

As for patching up RFTs, many shops won't do it, their position is that RFTs can't be repaired, period. Bummer!

People really drive on sidewalks where you live? Where the hell is that?

nate

Reply to
Nate Nagel

now that you mentioned I'd only consider steel RFT rims if I ever need them that is. thanks!

frankly I haven't seen an rft tire to be of the same or lower price than the same non RFT tire model (in same size)

I'm sure at $250+ a pop some suv owners would find the shop that does :-)))))

outside the us of a. city mayor is inept and/or unwilling to fix the parking problem so what would normally be a 4 lane stree quickly turns in 2 way street cause 2 lanes are taken by people who parked and in winter when roads are cleaned of snow it's uncommon for the street to narrow down to 1.5 or 1 lane.

do be glad civil engineers are civil and city planners are not stupid where you live.

oh, some businesses f*ck knows how got a permit to do their business despite the fact that the ONLY way to drive to them (for service, delivery, etc) is THROUGH or ON the sidewalk. And it's in the vehicle code since 2007 or so: they are legally permitted to do so.

There is a car dealer close to where I live located such that a vehicle going to service department for maintenance has to cross TWO sidewalks running in parallel to get to the shop.

It's really foobar here. An accident waiting to happen. Haven't seen a comparison of statistics of pedestrian fatalities compared to urban areas in the states but I won't be surprised at all if it's an order of magnitude higher.

Frankly, the way some people jaywalk across the street they probably deserve what's coming to them.

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AD

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