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Discussion Starter · #1 ·
OK, I've searched because I think it's been addressed but for some reason I'm not finding it. Chalk it up to being hot outside while working in the yard...

I want to buy an Ascent Limited. It has 20" wheels. After some discussions here, with a local shop and LP Adventure directly, the vehicle can be lifted 2" and the 20" wheels can be swapped for 18" wheels with more rubber.

I'm told that the spare cannot be swapped for an identical 18" wheel and tire. Is that true? Can it be aired down a bit? Won't fit underneath? So what then, put it on a rack on top of the vehicle?

The reason why this is so important is that I want to travel with a small overland trailer that the Ascent can tow easily enough (confirmed here) for 1000's of miles and this will include lots of forest roads and dirt highways in Alaska. I do not want to be stuck without an appropriate spare.

I'm trying hard to not buy a truck. FWIW, imo, the entire mid size truck category is a complete [email protected]#$%^&*.

Thank you everyone.
 

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with more rubber.
where are you implying is the more rubber? If you downsize to 18s, but run the "stock" size of 245/60R18, then you can reuse the factory spare. If you are going a different size which affects the overall diameter of wheel and tire, then you will need a different option. You can buy an extra rim and place it in the factory spare space, but you will need to have it deflated in order to fit, and it may cause other clearance issues while out on the trail. You will also need to pack an inflator in the event you need to use the spare. If that location does not suffice, you can buy a hitch mounted carrier, but since you are towing, why not carry the spare within the trailer?. Sure you can also put the spare on the roof, but that sounds like a pain to get up and down.

*** edit ** should the worst happen with the factory spare, be advised that you cannot tow with it, and it must be mounted in the rear locations as opposed to the front locations.
 

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Discussion Starter · #3 ·
Thanks for the reply. I have forgotten the size of the 18" tire recommended but I was thinking that if changed to an 18" that the overall size would need to be about the diameter of the original 20" rim plus tire thus more side wall height ("more rubber") on the 18".

While it thankfully has been a long time since I've had a flat, I would not want to be 200+ miles away from support and having to run the factory spare which would be a 20" anyway.
 

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Thanks for the reply. I have forgotten the size of the 18" tire recommended but I was thinking that if changed to an 18" that the overall size would need to be about the diameter of the original 20" rim plus tire thus more side wall height ("more rubber") on the 18".

While it thankfully has been a long time since I've had a flat, I would not want to be 200+ miles away from support and having to run the factory spare which would be a 20" anyway.
2 different issues here. As long as you stick with the 245/60R18, you're at "stock size". You are correct that you will have "more rubber" (aka sidewall) with the 18s compared to the 20s, which is critical for off-roading and (I think) most soft-roading and the like. If you stick with that size, you can in fact fit a full size spare underneath. The downside is that it will hang down and mess with your departure angle and clearance compared to the donut. This will be less of an issue with a lift, but will still be a potential problem.

Options are:
1. Keep the donut (bad option IMO)
2. Get a 5th wheel/tire combo and mount it in the spare tire spot either full (with reduced clearance) or aired down for better (not perfect) clearance.
3. Put a full size spare on the roof, in the car or on/in the trailer when you tow.

Note that if you decide to truly upsize the tire (as some have done), you need a full size spare anyway. You'll also need to work with a good tire shop like @Discount Tire to make sure the fitment works.
 

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Discussion Starter · #5 ·
2 different issues here. As long as you stick with the 245/60R18, you're at "stock size". You are correct that you will have "more rubber" (aka sidewall) with the 18s compared to the 20s, which is critical for off-roading and (I think) most soft-roading and the like. If you stick with that size, you can in fact fit a full size spare underneath. The downside is that it will hang down and mess with your departure angle and clearance compared to the donut. This will be less of an issue with a lift, but will still be a potential problem.

Options are:
1. Keep the donut (bad option IMO)
2. Get a 5th wheel/tire combo and mount it in the spare tire spot either full (with reduced clearance) or aired down for better (not perfect) clearance.
3. Put a full size spare on the roof, in the car or on/in the trailer when you tow.

Note that if you decide to truly upsize the tire (as some have done), you need a full size spare anyway. You'll also need to work with a good tire shop like @Discount Tire to make sure the fitment works.
Thank you pd...wouldn't the width of the 245/50/R20 be almost the same as the 245/60R18? That's what it seems to show on the tire calculator I'm looking at. If so, why would it hang down lower than the 20"?
 

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Thank you pd...wouldn't the width of the 245/50/R20 be almost the same as the 245/60R18? That's what it seems to show on the tire calculator I'm looking at. If so, why would it hang down lower than the 20"?
The spare under there now is a donut, not a full sized 255/50R20. Test it yourself with a swap now if you like.

What matters in one case (swapping a flat for the spare) is the diameter. What matters in the other case (storing a full size spare under the car) is the width.

The donut is a lot narrower than the stock tires, but has the same diameter as the stock ones. Which is why you can use it and not destroy the transmission.
 

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wouldn't the width of the 245/50/R20 be almost the same as the 245/60R18?
Not almost..."the same". 245mm is the width. (any minor variances would be due to tread design and manufacturing process)
 

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If you go to a full size spare, be sure to include it when rotating tires. You don't want the spare to get too far off the wear rate than the rest of the tires or you could wind up needing to buy 4 tires if a flat destroys one tire.
 

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Discussion Starter · #9 ·
Thanks everyone. It's all clear now. Does anyone here do such a thing as I was thinking about successfully? It seems that it's somewhat complicated, has potential problems and frankly, just a big 'ole hassle. About the last thing I want to worry about is damaging a tire/wheel under the vehicle which potentially causes other damage. Can't carry it in tow vehicle for daily driving.
 

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Thanks everyone. It's all clear now. Does anyone here do such a thing as I was thinking about successfully? It seems that it's somewhat complicated, has potential problems and frankly, just a big 'ole hassle. About the last thing I want to worry about is damaging a tire/wheel under the vehicle which potentially causes other damage. Can't carry it in tow vehicle for daily driving.

So I'm kinda looking at the same thing. I have talked a little bit with this guy on Instagram who carries a full sized larger spare under his lifted ascent. If I remember right he says it's the same aftermarket tire and wheel as he runs on all fours. The screen name is "Ascent Overland" and if you look in his photos you can see this spare under the car. You might contact him and see what he says and ask specific questions. I know the main thrust here is that it isn't a good idea, but on a lifted vehicle it might give it a little extra space.

 

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Thanks everyone. It's all clear now. Does anyone here do such a thing as I was thinking about successfully? It seems that it's somewhat complicated, has potential problems and frankly, just a big 'ole hassle. About the last thing I want to worry about is damaging a tire/wheel under the vehicle which potentially causes other damage. Can't carry it in tow vehicle for daily driving.
If I"m not mistaken, Robert carries a full size spare when off-roading/overlanding, but it's mounted on a rear carrier or up top,
 
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If I"m not mistaken, Robert carries a full size spare when off-roading/overlanding, but it's mounted on a rear carrier or up top,
Yes, he uses a hitch mounted carrier. It would certainly be another good option, if @Hawkeye weren't already using the hitch receiver for a trailer.
 

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@Hawkeye - I have a full-size 18" spare where the OEM donut used to be. The donut is "full size" in diameter. It is just thinner. This means a full-size spare will fit in that well, but it will stick down a bit further. I air my spare down to 20 PSI. I have Falken wildpeak A/Ts. Good for soft roading. Their tread block isn't aggressive. If you get a tire with larger thread blocks, it may not fit.
 

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ai2160, can you post pictures showing from the rear of the car?
Here. It impacts departure angle. Ground clearance remains the same as it still isn't the lowest point. This picture was taken before I lifted (~1.5") with Eibach Springs. I keep the spare inflated at 25 PSI.
Wheel Tire Automotive tire Tread Vehicle
 

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Anybody remember the $200-300 Goodyear donut tire that was discussed in previous month(s)? Then someone suggested used one from some SUV.
 

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Anybody remember the $200-300 Goodyear donut tire that was discussed in previous month(s)? Then someone suggested used one from some SUV.

I believe you're talking about this thread!

175/90D18

And it looks like the price has dropped on it a bit since the convo!
 

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I'd suggest carrying an inflator in any case, as pressure can drop over time and you don't want to be 200 miles from a pump. They can be pretty small-mine is an older one from Harbor Freight and is much quieter than any other I have owned (so it might not scare away the bears). I also carry a tire plugging kit incase it is something you can fix without using a spare. (I am a flat tire magnet). Enjoy the trip and good luck.
 

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If you go to a full size spare, be sure to include it when rotating tires. You don't want the spare to get too far off the wear rate than the rest of the tires or you could wind up needing to buy 4 tires if a flat destroys one tire.
That is really good advice that I had not considered. I'm getting a Forester Wilderness and I'll make sure to do this. Probably good to rotate every oil change too since one of the tires rotates into the trunk.
 

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That is really good advice that I had not considered. I'm getting a Forester Wilderness and I'll make sure to do this. Probably good to rotate every oil change too since one of the tires rotates into the trunk.
Just be sure to get some tire crayons and label your tires including the spare if someone else is rotating for you. I like the shop too see that I'll be checking their work. I sign my oil filter too.
 
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