Just one more inch

[SirRobyn0]

My tyres are 245 wide on the front with a 35 profile and a 20 inch diameter
The rear tyres are 295 wide, with the same 35 profile and 20 inch diameter.

Does that make sense?

You are mistaken.

I can't help with the question about lowering but I can help explain the tire size thing as most of my carrier was working in tire stores either as a tech or managing. Any who, the first number 245 on the front 295 on the back is the width of the tread section of the tire. The last number 20inch is the diameter of the wheel. The middle number 35, is a ratio called the aspect ratio, it does sort of identify the height, but it is the aspect ratio of the height and width combined. So a 35 aspect ratio is not the same height across all sizes, therefore your rear tires will be taller than the front tires. Your rear tires should be about 1 1/4" taller than the front if the tread wear is the same.

That middle number (35 in your case) is sometimes called the series number, profile, and there are a few others, mostly made up by tire manufactures, but aspect ratio is what it actually is.

 

[RecklessWOT]

My tyres are 245 wide on the front with a 35 profile and a 20 inch diameter
The rear tyres are 295 wide, with the same 35 profile and 20 inch diameter.

Does that make sense?

Unfortunately you are mistaken about the size of your tires, but don't feel bad because the whole tire sizing scheme is very convoluted so it barely makes sense to begin with lol.

All 3 parts of a metric tire size work together, unlike the old american size which is simply just a measurement. A 33" tire is 33" tall regardless of what size rim it's on or how wide the tire is. The middle number in your tire size does relate to the height of your tire but it is not specifically a set measurement in terms of height. It is a percentage- the ratio of sidewall height in comparison to tread with.

The first number is width in milimeters, meaning your front tires are 245mm wide (at the tread) and your rear tires are 295mm wide. The 35 profile means that the sidewall height is 35% of the width of the tread. If you have really big 24" rims, a 20 profile sidewall will still be a very big tire. If someone has 15" rims, they may have a 75 series sidewall and it can still be a smaller overall diameter than the 35 profile tire on your 20" rims, it will just have a fatter looking piece of rubber around the wheel. The same goes for width, because your rear tires are wider, that 35 profile means the sidewall is proportionately larger. Because your rear tires are 5cm wider than your fronts, it means the sidewall is also 17.5mm thicker (35% of 50mm is 17.5mm), so overall the tire is 35mm larger in diameter/taller than your front tires are (the 35mm height is purely a coincidence, it's just how the math works out in your specific tire size). 35% of an inch is much smaller than 35% of a mile. Obviously that is an extreme example, but it should help put it in perspective because I know sometimes I am horrible at explaining what I can so clearly understand in my own head.

Source: I worked at a tire shop when I was younger and had to explain this sh!t to customers all the time...

 

[Sovereign]

EDIT: I typed this all out before realizing others had replied before me.

Yes, the second number is the aspect ratio. It's a percentage of the width. In this case, 35% of 295mm and 245mm. To calculate tire diameter, you take the width multiply by two times the aspect ratio as a percentage and then add the diameter of the rim.

295 x 0.7 = 206.5mm/25.4mm to make inches= 8.13 + 20= 28.13 inches

245 x 0.7 = 171.5/25.4= 6.75 + 20= 26.75 inches

To make matters worse, tire sizes are like clothing sizes and not exact even though they have actual measurements in their size. That's why I say your tires calculated out to these diameters. It's always best to physically measure or to check the manufacturer's information for actual sizes. I use Tire Rack's website for that typically.

 

[bucket]

EDIT: I typed this all out before realizing others had replied before me.

Yes, the second number is the aspect ratio. It's a percentage of the width. In this case, 35% of 295mm and 245mm. To calculate tire diameter, you take the width multiply by two times the aspect ratio as a percentage and then add the diameter of the rim.

295 x 0.7 = 206.5mm/25.4mm to make inches= 8.13 + 20= 28.13 inches

245 x 0.7 = 171.5/25.4= 6.75 + 20= 26.75 inches

To make matters worse, tire sizes are like clothing sizes and not exact even though they have actual measurements in their size. That's why I say your tires calculated out to these diameters. It's always best to physically measure or to check the manufacturer's information for actual sizes. I use Tire Rack's website for that typically.

I'd say that tire sizes are even worse than clothing sizes. At least clothing brands are somewhat on the same page with themselves. With a single tire brand, they could have two different tire models of the same size and one could be an inch or so wider than the other.

 

[Sovereign]

Well, I finished up getting the rear shock extenders on and was able to go drive. I rub in certain situations but it's not too bad. I will be altering my bump stops in the front to gain more travel before hitting them. I think I'll try trimming the stop first. This may cause the rubbing to be worse. We'll see what the future holds. Overall, I'm happy with everything on the front end. I may drop the rear another 1/2" with a block. I'm at a hair under 27" in the front and right at 28" in the rear for the wheel well openings.

Here's the good stuff:

 

[MelbGMC]

Very Nice Mate

 

[RecklessWOT]

Looks pretty sharp, but personally I feel like ANY rubbing at all in any situation would be completely unacceptable. Your vehicle is having trouble getting down the street normally because of the modifications. I understand form over function, but once the styling makes the thing less derivable in everyday scenarios, that's a sign to me that there is a problem that needs to be fixed. Don't forget, this is not a Corvette here it is a 35 year old pickup truck we're talking about, there's a limit to what it can do regardless of how bad you want it to be a certain way it was never designed to be...

Also, why is it a problem that the rear is slightly higher than the front? We're talking half an inch here. I bet if someone put a new roof on your house and one side was half an inch lower you wouldn't notice or care, yet a truck that has suspension that moves and changes as you drive even whether or not you park on level gorund, now a half inch is this huge deal? What a minute measurement, these trucks were so poorly built from the factory some of them have more than a half inch ride height difference just to begin with. Everyone with a lowered truck seems to want it dragging a$$, IMO having the rear up just a tad gives it more of an aggressive stance, like a race car is always slightly up in the rear. There is something unnatural about a vehicle that is dead level or even lower in the rear. As soon as you get on the gas it should straighten out (especially with the missing leafs, I bet under even light throttle it's all nose in the air looking), unless you plan to just sit there and look at it parked all the time...

You got a good truck there, just be happy with it. You can try to chisel it into a work of art but it will likely never be good enough, will probably cause more headache down the road, and realistically most people will not even notice one way or the other so save yourself some grief and just enjoy what you got.

 

[Sovereign]

I understand what you're saying, Kevin, and you're right to a large extent. The truck is a toy for me and spending time tweaking it isn't a chore, it's my hobby. So while most people won't notice the extra 1/2", I will because I stared at it long enough to know what I want it to look like. It will still have a slight rake even being 1/2" lower in the rear.

As for the rubbing, it's only when turning tightly so far. If it gets worse with my driving and more situations that I come across, I'll get Slosh Tubz. I figured I would have to get them eventually anyway. The fact I can drive the truck now without them is a bonus really.

Thanks!

 

[RecklessWOT]

I understand what you're saying, Kevin, and you're right to a large extent. The truck is a toy for me and spending time tweaking it isn't a chore, it's my hobby. So while most people won't notice the extra 1/2", I will because I stared at it long enough to know what I want it to look like. It will still have a slight rake even being 1/2" lower in the rear.

As for the rubbing, it's only when turning tightly so far. If it gets worse with my driving and more situations that I come across, I'll get Slosh Tubz. I figured I would have to get them eventually anyway. The fact I can drive the truck now without them is a bonus really.

Thanks!

That's cool man, I really wasn't trying to sh!t on you, your truck, or your taste. Do whatever it is that makes you feel good, I'd just hate to see you stressing over something that really doesn't matter that much in the scheme of things. But if tweaking it into perfection makes you happy then who am I to say not to? You got a good truck there, I hope you can at least appreciate that much. If you want to keep working at it then that's up to you, but don't for a second get down about the way it looks. Anyone who sees that truck and knows f,uck all about cars will realize that you've put a ton of effort into it, just realize it's good the way it is and anything beyond that is just your hobby at play.

 

[Sovereign]

I appreciate it, Kevin. I absolutely agree it's great the way it is. I'm always tinkering though so I'll be making changes here and there along the way.

 

[MelbGMC]

I’ve finally got around to measuring from the wheel centre to the lip on the guard, it’s 375mm or 14 and 3/4 inches.
I want to drop it at least another inch or 2

 

[Sovereign]

I'm right at 13.5" from hub center to wheel arch. I would say you can go one more inch before you start getting into all the issues associated with going very low. Issues such as needing Slosh Tubz and maybe changing control arms or at least modifying the bumpstop on the factory arms, etc. If you're ok with this, as I am, then, I think you can make it work.

Coming down one more inch should put the top of your tire right at the wheel opening or just a hair below. It'll look good. Make sure your shocks can handle the extra one inch drop and even another two inches. That way, if you decide you want two, you can just cut a little more out of the one inch drop spring.

Good luck and post pics when you're done.

 

[MelbGMC]

You must be registered for see images attach

Front shocks will be fine, I have installed these along with shorter shocks

 

[John Nes]

@Sovereign hey dude, just FYI, Ricks truck is on 22’s…him n I got the same drop set up too, axle flip in the back, DJM dropped lower A arms (3”) and drop coil springs (2”)…although he did just drop the rear a lil more with some hangers.

 

[Sovereign]

I appreciate it, John. Yes, I'm aware Rick is sitting on 22s which is why I was looking at the tire and not the rim itself. I love how tucked his rear wheels are but I prefer thicker tires so I'll most likely never go large than 20s.

Marcus, did you have to cut the inner fenders to make the shock mount work? I see that note mentioned with those brackets but haven't investigated if it's actually needed or just a way for them to cover their butt.