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How much fender clearance beyond the oem tire size do I have before I need to roll fenders to make space for wider wheels?

6.9K views 13 replies 4 participants last post by  Camreeeee  
#1 ·
I'm gonna go junkyard hunting tomorrow through ford explorers/fusions for some 17x7.5+44mm wheels to stick 235/45/17 tires on. I figure I'm going to gain around 3/4" of wheel backspace so I ordered 1" bolt on spacers for suspension clearance. Problem is that the tools I used to calculate tire clearance indicate the tires are going to stick out over 1.5" than stock when I have everything mounted.

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Does anyone who has upgraded to wider wheels know if this much extra outside width will require me doing something to my fenders with a stock tire height and -3 degrees camber in the front and -1.5 in the rear?

Is it possible to just cut them a bit or is the wiring inside of them problematic for that approach?

I have no idea how to roll fenders but if that's necessary I can learn. I don't care how it looks but I don't want to damage the wiring inside the fender/tires or do more work than is necessary.
 
#2 ·
Jackpot! $130 for all 4 from my favorite outdoor shopping center. Came off a 2003 ford exploder.

They're in crazy good shape for junkyard wheels, no dents, lip corrosion, mount corrosion, or curb rash on any of them; and only one has any noticeable scratches.

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I checked with my local discount tire to make sure they would put 245s on a 7.5 wheel, and they said as long as it's listed in the rim width range for the tire specs they will install it; so I'm going to return the 1" spacers and order 1.5" bolt on 60.1mm hubcentric spacers with hubcentering rings for these ford wheels.

When I'm less broke I plan on ordering these thicc sticky meats off tire-rack and breaking some sway bars links.

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As far as fender clearance that's not happening.

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I'm going to just cut them with some sheet metal shears and use a hand seamer to fold the lip over, seems less complicated than anything else. If the wiring gets in the way I'll relocate from the fender to the chassis with brackets but it appears far enough forward that I should be ok; no way to tell until they're installed though.
 
#4 ·
Will rub, almost guaranteed. With 5mm spacers and about -1.75 camber, I had 225/45-R17 on17J7 ET+50 rims rub on the strut just a smidge in corners. 235 is gonna be even taller, and you're getting way too large a spacers. If you had the spacers just the perfect size you MIGHT be able to get away with it, but there would be no room at all for error, so count on them rubbing.
There's no wiring on the outer fender, it's all on the inner fender. Should not be a problem at all.
Fender rollers are available starting at $40 on eBay. I'm sure the quality is crap, but ought to be good enough for one job. You can also ask around to see if anybody would lend you one. If you're really tight on funds, you can do a ******* fender roll with a piece of lumber (though a bat works batter). It ain't pretty but it works and should look waaaay better than whatever level of craftsmanship you will achieve with snips. I've done it in an emergency on track - basically stick a piece of wood of appropriate size b/w the wheel (bolted to the car) and fender and "roll" it back and forth.
 
#5 ·
Will rub, almost guaranteed. With 5mm spacers and about -1.75 camber, I had 225/45-R17 on17J7 ET+50 rims rub on the strut just a smidge in corners. 235 is gonna be even taller, and you're getting way too large a spacers. If you had the spacers just the perfect size you MIGHT be able to get away with it, but there would be no room at all for error, so count on them rubbing.
There's no wiring on the outer fender, it's all on the inner fender. Should not be a problem at all.
Fender rollers are available starting at $40 on eBay. I'm sure the quality is crap, but ought to be good enough for one job. You can also ask around to see if anybody would lend you one. If you're really tight on funds, you can do a *** fender roll with a piece of lumber (though a bat works batter). It ain't pretty but it works and should look waaaay better than whatever level of craftsmanship you will achieve with snips. I've done it in an emergency on track - basically stick a piece of wood of appropriate size b/w the wheel (bolted to the car) and fender and "roll" it back and forth.
Thanks for the reply, for the $40 eBay ones I'll likely go that route after looking at how they work if they would suit the job, if you don't mind answering them there are a couple things I'm unclear on.

Although anything I choose to do is at my own risk, but I'd like your opinion on this since I have zero experience with this kind of thing.

Do you think the 245s on 1.5" spacers (giving aprox .5” clearance from front struts, less on rear with these wheels offset) which are essentially the stock tire diameter would have issues rubbing after rolling them with one of these tools?

I get the concept of rolling the lip so its not cutting the tire, but under hard cornering - especially with no front sway bar, won't the body roll cause the rolled fender to come down far enough to hit the tire sticking out beyond the fender? Are these tools able to push the push the fender outwards and upwards so that this wouldn't happen?

Another thing I'll need to look more into but hopefully you could shed some light on - Hypothetically does a wider wheel/tire with the same diameter and backspacing have a wider arc?

I don't have front fender liners and there is tons of open air beyond where they were so that's not a concern if I can bring the outside fenders far enough upwards, but would a wider tire with the the same backspace and diameter come closer to the rear liners? I don't really understand the geometry of this very well - I'm not very good at mentally picturing things but need to figure it out before purchasing tires.

I'd be grateful if you're willing to explain how this would effect inside clearance when turning.
 
#6 ·
There is a set amount of space between the strut tower and the fender. You can take a tape measure, and measure that distance - this is how wide, in theory, the tire the car can take. Let's say this number is 240mm - enough to accommodate a 235/45-R17 tire.
Wheel offset (ET) will dictate how far to the inside or outside the rim will offset the tire. If you bolt on a spacer, it will push the wheel to the outside. If you get wheels with different offset, that will also push the wheels either in or out. In any case, if you have 240mm of space and 215mm tire, you have room to spare. If you have 235mm wide tire, the rim offset and spacers have to line up perfectly or you will rub either on strut or fender.
With the rims you got having the same offset, I would first try to bolt them on. 1" or more spacers will push the wheels way out. Maybe you can get away with just a hub ring rather than the whole spacer.

Another thing to keep in mind: don't get wheels that are too big, or you run the risk of the rite rubbing on he strut seat. There really isn't that much extra space there. If you wanted to go for 245 wide tires, get 245/40-R17 rather than 245/45.
 
#7 ·
I get the fender clearance thing, that's why I was thinking shears to just lop 4-5 inches of them off and then add flares higher up after folding the sharp edge over itself - but if rolling them can move the fenders high enough up that spring compression won't allow tire contact that's preferable - I'm just not sure how far you can bend the sheet metal upwards without cutting.

I did already calculate the backspacing/offset for strut clearance before I even went looking for wheels, a 1" spacer wouldn't work for the rear with 245s, but 1.5s will work for both axles while maintaining ~.7" front coilover clearance and ."4 rear coil spring mount clearance. 245s are only available with a 45 sidewall on 17x7.5" wheels, I'd squeeze 40s on but nobody would mount them.

I'm mainly wondering about if the arc of a wider tire will come closer to the front and rear fender liners when turning the wheel lock to lock if I've already compensated for the increase in backspace for suspension clearance by moving the wheel outwards.

Idk if that makes sense, I'll have to dig more into it.
 
#8 ·
Not sure what you're calling a fender liner. Fender liner is the plastic "inner fender" that I thought you said you've already removed.
The wheel will rub on the inner frame at full lock with bigger than stock wheels. This is generally only a problem in parking lots, as that's the only time you ever have the wheel at full lock. I had that problem with 225" tires I mentioned earlier, it torn off the rubber liner and paint on my frame rails where the wheel touched it. Oops.
That said, with 1" spacer, I would imagine you moved it away enough to where it will not rub for you.

Also, I don't understand why you're saying nobody will mount 245/40's on 7.5" rims - the sidewall makes no difference on the tire width, only the height. Yea, sure, lower profile tires are more difficult to mount, but usually shops will just charge you more rather than refusing to mount. Why are you obsessed with 245's though? Even when I had 225's mounted on 7" rims, it was too wide a tire for the rim and there was this weird momentary float when I would change direction, like a pause while the rim made it over to the other side of the tire. I really didn't like it and went back to 215's (same tire) that would not have this problem. I would stick with 225's for 7.5" rims and get stickier tires, you'll have way more fun. Just my 2c.
 
#10 ·
Thanks for the reply.

What I meant by fender liner was the plastic bits you mentioned, I have them in the rear of the tire but I'll just remove them if they're rubbing on then.

Main reason I'm pretty intent on 245/45s is that they will have more grip than anything skinnier and they're the widest tire I can fit on these wheels. 40sidewalls would be mountable, the is finding a shop willing to mount a tire on a wheel that is outside of the tire manufacturers specs, which all 245/40s are for 17x7.5, so a couple millimeters more sidewall doesn't bother me. Tire grip is all I really care about cause I can't see the fenders from the drivers seat.

You're right about them being less responsive than something skinnier. The weird floaty feeling when changing direction back and forth is the bead shifting side to side on the lip from a combination of too low air pressure/sidewall stiffness/rim width for the tire. Increasing any of those 3 things can reduce it. Its not dangerous if you aren't running ridiculously low tire pressures but many people hate it for the reason you mentioned.

200tw sidewalls seem stiff enough that I have to drop under 28 psi with 215s on 6.5" rims (not in manufacturer spec)/to even notice the delay so I want 245s (in spec) because they're the widest tire I'd feel safe running 28psi on the street on these wheels and will likely still be less floaty than my current tires (which is not at all).

Keep in mind everyone prefers different things, I prefer having more grip over looks or comfort and am willing to sacrifice a lot of stuff to turn even a little faster. 10mm isn't much on the average tire but on rt660s that's a non negligible increase in corning and braking grip.