Has anyone replaced their 245/50/20 with a 255/50/20? I'm looking to add a little more rubber for ground clearance. I went up in size on my old Sienna which helped since my van sits lower being converted for the wheelchair.
Bigger Tire
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The issues for bigger tires is a lot more than just friction , suspension components , extra weight , increased stopping distance , speedometer that’s incorrect , etc , etc .
And warranty issues as well, since the mileage cannot be accurately verified, factory can deny warranty coverage related to engine or other crucial parts.
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Honestly if you used the oem rim and stuck bigger tires on it I bet dealers would even know
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If your coming in for suspension , alignment , brakes and have different rims then def . But if your coming in for other stuff its going unnoticed
In theory, the ride should be better. But I doubt anyone would want to downgrade their wheels only for that purpose.
I haven’t finalized my decision yet but I’m leaning in the direction of keeping them. The changeover would cost more than $1,000 and then there’s the aggravation of what to do with the 20’s. I’ve been looking at tires also. A Michelin is going to cost somewhere between $260 to $290 per tire. And guess what at around 30k miles their not the same. So, I’m lookin at a tire for $129 with mileage rating of 40k miles. So, it is a soft tire which also should provide a better ride on a 20 inch wheel than an expensive tire with an 80k mile rating because it is a harder tire. Stay tuned, I’ll let you know how this experiment turns out.
Well I just installed Firestone SureDrive tires which were $139 per tire. They are quiet and take the bumps much better that the Falcon Ziex tires that were on the van. At this price I can replace them twice and still be less expensive than buying one set of Michelins'
Perhaps some numbers will illuminate this discussion and the magnitude of the diameter changes we're talking about:
Wheel diameter for stock 245/50R20 is 753 mm or 29.6".
Diameter for the 255/50R20 will be 763 mm or 30", which is 10 mm (0.4") wider, and 0.4" larger diameter, but will only increase your ride height by 0.2". Speedometer/odometer will be out by 1.3%, likely not enough to affect warranty. I don't know how much Chrysler allows for tire size variation, but Honda allowed up to 3% when I had my Odyssey. Lots of folks up here go up more than the OP's proposed 1% to increase winter ground clearance in the snow. Some Mitsubishis can go +5%, Jeeps a lot more.
Note that @BB21's 255/45R20 are 738 mm or 29", 10 mm wider but SMALLER diameter, similar in diameter to the stock 17" and 18" setups.
Stock 17" is 235/65/17 = 29.0". Chains allowed: Max dia 29.7"
Stock 18" is 235/60/18 = 29.1". Chains allowed: Max dia 29.8"
As noted, interference with suspension components is a concern more than speedo calibration. For my snow tires, no chains allowed here so I went with 225/75/17, 30.3" and a bit narrower, which works better in the snow. No interference.
However, would this be counter-productive on a wheelchair van? Isn't it lowered on purpose? Would raising the ride height make the ramp steeper on deployment?
With respect to ride quality, tire quality makes a difference, but I will say that I noticed a clear improvement in ride quality switching from 18" to 17" when I got a deal on 17" take-offs. My dad has the 20" rims with even worse ride quality and he is going to 18's or 17's if he can find some cheap take-offs like I did.
One other note: When your tires are worn, higher profile 17" (smaller rim, taller rubber, same outer diameter) tires can be a lot cheaper to buy, pretty much paying for new 17" rims with the difference. That's what I found with my Mitsu - the 17" tires & rims weren't much more than new 18" tires & the $$ selling my old 18" rims was bonus.
Wheel diameter for stock 245/50R20 is 753 mm or 29.6".
Diameter for the 255/50R20 will be 763 mm or 30", which is 10 mm (0.4") wider, and 0.4" larger diameter, but will only increase your ride height by 0.2". Speedometer/odometer will be out by 1.3%, likely not enough to affect warranty. I don't know how much Chrysler allows for tire size variation, but Honda allowed up to 3% when I had my Odyssey. Lots of folks up here go up more than the OP's proposed 1% to increase winter ground clearance in the snow. Some Mitsubishis can go +5%, Jeeps a lot more.
Note that @BB21's 255/45R20 are 738 mm or 29", 10 mm wider but SMALLER diameter, similar in diameter to the stock 17" and 18" setups.
Stock 17" is 235/65/17 = 29.0". Chains allowed: Max dia 29.7"
Stock 18" is 235/60/18 = 29.1". Chains allowed: Max dia 29.8"
As noted, interference with suspension components is a concern more than speedo calibration. For my snow tires, no chains allowed here so I went with 225/75/17, 30.3" and a bit narrower, which works better in the snow. No interference.
However, would this be counter-productive on a wheelchair van? Isn't it lowered on purpose? Would raising the ride height make the ramp steeper on deployment?
With respect to ride quality, tire quality makes a difference, but I will say that I noticed a clear improvement in ride quality switching from 18" to 17" when I got a deal on 17" take-offs. My dad has the 20" rims with even worse ride quality and he is going to 18's or 17's if he can find some cheap take-offs like I did.
One other note: When your tires are worn, higher profile 17" (smaller rim, taller rubber, same outer diameter) tires can be a lot cheaper to buy, pretty much paying for new 17" rims with the difference. That's what I found with my Mitsu - the 17" tires & rims weren't much more than new 18" tires & the $$ selling my old 18" rims was bonus.
Our touring L came with 18" rims, and i attest to a very luxurious ride. I have been running Goodyear comfort-tred for the past128k miles and the are know as a quiet ride.
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You get more tire so it rides a bit softer, handling might not be as good but really are you gonna notice it on a minivan?
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