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Old 07-01-2019, 06:04 AM   #1
Dibdob62
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5"/6" lowered, Tyre size ?

I have fitted a static 5"/ 6" lowering kit to my 77 C15 and Im now have clearance issues on the front with the 275/60/15 tyres fitted at the moment. What size tyres are you guys using with this much lowering ?
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Old 07-01-2019, 06:28 AM   #2
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Re: 5"/6" lowered, Tyre size ?

What wheels are you running?
Jimmy
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Old 07-01-2019, 06:30 AM   #3
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Re: 5"/6" lowered, Tyre size ?

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What wheels are you running?
Jimmy
15" Rallies think they are 8" wide
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Old 07-01-2019, 09:52 AM   #4
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Re: 5"/6" lowered, Tyre size ?

I run a 235/70 15 on a 7 inch rim and a 255/70 15 on a 8 inch rally and no troubles. I wish they made a 245 thou, the back is a little tall
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Old 07-01-2019, 10:35 AM   #5
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Re: 5"/6" lowered, Tyre size ?

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Originally Posted by Dibdob62 View Post
I have fitted a static 5"/ 6" lowering kit to my 77 C15 and Im now have clearance issues on the front with the 275/60/15 tyres fitted at the moment. What size tyres are you guys using with this much lowering ?
275/60-15 = 27.99" tall for your front tires.

This is the mathematical calculation but sizes can/do vary per manufacturer. That being said, blazer2007's combo doesn't help unless the clearance issue is caused by width/back spacing vs. height:

235/70-15 = 27.95" for his front tires.

To recommend a solution, more info is required. Where is the 'clearance issue'?
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Old 07-01-2019, 02:09 PM   #6
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Re: 5"/6" lowered, Tyre size ,

Its rubbing the inner wheel tub and catching the wheel arch.

Been looking at 235/60/15, 26.10" high and 9.30 wide or 225/60/15 25.60 high and 8.90 wide but would like to know what you guys recommend ?
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Old 07-01-2019, 04:25 PM   #7
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Re: 5"/6" lowered, Tyre size ,

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Its rubbing the inner wheel tub and catching the wheel arch.

Been looking at 235/60/15, 26.10" high and 9.30 wide or 225/60/15 25.60 high and 8.90 wide but would like to know what you guys recommend ?
Still plan on the same wheel @ 8" wide? If so, 255/60 @ 27" tall is a common front side for 4 or 5" drops.
There's always the aftermarket inner wheel tubs to (like Slosh Tubz).
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with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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Old 07-02-2019, 08:55 AM   #8
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Re: 5"/6" lowered, Tyre size ?

8 in. rims are too wide, I could,t make them work up fr. went to a 7 in.
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Old 07-02-2019, 11:07 AM   #9
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Re: 5"/6" lowered, Tyre size ?

Back spacing, diameter, & overall OD of the tire all play a role. An 8" wheel can fit w/no issues @ 5" of front drop & stock inner wheel wells...
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Building a small, high rpm engine
with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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Old 07-02-2019, 12:41 PM   #10
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Re: 5"/6" lowered, Tyre size ?

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Originally Posted by SCOTI View Post
Back spacing, diameter, & overall OD of the tire all play a role. An 8" wheel can fit w/no issues @ 5" of front drop & stock inner wheel wells...
Is that a 255/60/15 on the front then ?
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Old 07-02-2019, 02:00 PM   #11
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Re: 5"/6" lowered, Tyre size ?

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Originally Posted by Dibdob62 View Post
Is that a 255/60/15 on the front then ?
In the pic? No.
It's a 245/45-18 @ 26.75" OD on an 18x8" wheel w/5.25" of back spacing.

A 245/60-15 @ 26.57" on your listed 8" wheel size would be another option that's slightly shorter than the 255/60-15 I recommended above.

Also..... How is it lowered? Soft spring rates can contribute to buzzing on the tops of the inner wheel wells. Back-spacing can have an impact as well.
Your 8" Truck Ralleys should work but you need the right height of tire & the right spring rate/shock combo to live a quiet life.
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Building a small, high rpm engine
with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....

Last edited by SCOTI; 07-02-2019 at 02:05 PM.
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Old 07-02-2019, 08:58 PM   #12
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Re: 5"/6" lowered, Tyre size ?

He mentioned it was a 15 x8 inch rally is what I was talking about. The 235/70 offers a taller tire for clearance on a static drop but clears the inner wheel wells on a 7 inch rim. I,ve tried a 60,s profile but with crappy roads and summer construction it is to low on the A-arm . Embarrassing when you have to use a 2x4 to get over a cut out asphalt.
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Old 07-03-2019, 06:44 PM   #13
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Re: 5"/6" lowered, Tyre size ?

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Originally Posted by blazer2007 View Post
He mentioned it was a 15 x8 inch rally is what I was talking about. The 235/70 offers a taller tire for clearance on a static drop but clears the inner wheel wells on a 7 inch rim. I,ve tried a 60,s profile but with crappy roads and summer construction it is to low on the A-arm . Embarrassing when you have to use a 2x4 to get over a cut out asphalt.
Understood & all good. I just wanted to educate others to understand there are multiple factors to consider. While switching to 15x7's worked in your application, just doing that may not work for someone else. This is especially true when it comes to where & when rubbing occurs.
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Building a small, high rpm engine
with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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Old 07-08-2019, 03:59 PM   #14
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Re: 5"/6" lowered, Tyre size ?

Quote:
Originally Posted by SCOTI View Post
In the pic? No.
It's a 245/45-18 @ 26.75" OD on an 18x8" wheel w/5.25" of back spacing.

A 245/60-15 @ 26.57" on your listed 8" wheel size would be another option that's slightly shorter than the 255/60-15 I recommended above.

Also..... How is it lowered? Soft spring rates can contribute to buzzing on the tops of the inner wheel wells. Back-spacing can have an impact as well.
Your 8" Truck Ralleys should work but you need the right height of tire & the right spring rate/shock combo to live a quiet life.
3" lowered spindles, 1" lowering springs. Going to put new bump stops back on to stop it hitting the wheel tub for now until I can source some reasonably priced tyres but still not sure about what size to go for, don't want to go to small so most lightly go for the 255/60/15.
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Old 07-08-2019, 04:37 PM   #15
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Re: 5"/6" lowered, Tyre size ?

I have 3" drop springs and 3" drop spindles up front on my 86 C10. I am running 8" rallies with 255/60 up front and 275/60 in rear, no rubbing anywhere. Your truck looks so clean man!
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Old 07-08-2019, 04:42 PM   #16
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Re: 5"/6" lowered, Tyre size ?

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Originally Posted by Dibdob62 View Post
3" lowered spindles, 1" lowering springs. Going to put new bump stops back on to stop it hitting the wheel tub for now until I can source some reasonably priced tyres but still not sure about what size to go for, don't want to go to small so most lightly go for the 255/60/15.
My wheel choices are typically staggered (7's in front; 8's in back). I had a similar problem when using 3" spindles w/the stock cut coils up front on my 74 so I went w/a 215/70-15 because I was running a narrower Van Ralley (6.5"). The 215/70 = 26.85" (very close to the 245/45-18's) & didn't cause issues. I used the same size tire on my 90swb for the same reason. If you're sticking w/the 275/60 rears & still utilizing the 8's on the front as well, the 255/60 will allow more travel room before contact is made while keeping the tire/wheel proportions similar.

I tried no bump-stops (crazy bad w/o anything) & then trimmed-stops (much better but would still buzz more than I liked) so I went back to unmodified stops. Mine only buzzed @ the top of the inner well so I knew I needed to limit travel if I wanted to run a decent height tire. Some guys will opt for a shorter tire but I don't like the way it looks (well... I can't stand it is more appropriate). The ride was rougher because it was on the stops more but I preferred that over the buzzing/contact @ the wheel-well.

If I do one now for someone, I'll explain my past experience & highly recommend purchasing an aftermarket/new replacement spring w/a KNOWN spring-rate. A "drop spring" isn't good enough. You need to know the spring-rate.

If you utilize a higher rate spring that has the desired 1" drop along w/a properly valved shock, you're much more likely to have a better drive quality & it will help keep it off the bump-stops. Modified (taller) inner fender-wells are worth considering as well. My trucks were budget builds so I went w/the combos I did because of my budget @ that point in time. These days, I wait & get the right spring for the best ride @ the new lowered ride height.
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Building a small, high rpm engine
with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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Old 07-09-2019, 03:43 PM   #17
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Re: 5"/6" lowered, Tyre size ?

Ordered some 255/60/15 tyres today then fitted the new bump stops but I don't think they will work
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Old 07-09-2019, 05:46 PM   #18
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Re: 5"/6" lowered, Tyre size ?

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Ordered some 255/60/15 tyres today then fitted the new bump stops but I don't think they will work
If the bump-stop is touching while the truck is stationary, the springs are more than 1" drop or they're too soft.

I had a full coil removed off of my >100k HD small block springs in my 74swb pictured above which is >/= 2" coil drop & still had about 3/8" gap between the bump-stop & the bottom of the x-member. It wasn't much, but there was a gap.

Bump=stop contact while sitting still = full time rough ride.
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Building a small, high rpm engine
with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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Old 07-20-2019, 04:32 AM   #19
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Re: 5"/6" lowered, Tyre size ?

255/60/15 front tyres and it looks like its not catching anymore I also swapped the -1" springs for -2" springs because the ride was the same on both but the -2" springs were stiffer plus I have made up some bump stops giving me some movement now.


Next up I need to lower the rear a bit (hard to see in this picture but there's a good rake) to level it out so I have some 1"/2" drop shackles on there way.
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Old 07-20-2019, 06:40 AM   #20
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Re: 5"/6" lowered, Tyre size ?

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Originally Posted by SCOTI View Post
Back spacing, diameter, & overall OD of the tire all play a role. An 8" wheel can fit w/no issues @ 5" of front drop & stock inner wheel wells...
Whats your rear setup on that Scoti ????
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Old 07-20-2019, 12:28 PM   #21
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Re: 5"/6" lowered, Tyre size ?

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Whats your rear setup on that Scoti ????
That 74 had a Western Chassis flip-kit, WC C-notches, lower shock extension brackets, & Bell Tech shackles. Later in its history, a driveway fabricated AOL set-up added.
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Building a small, high rpm engine
with the perfect bore, stroke and rod ratio is very impressive...
like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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Old 07-21-2019, 08:30 AM   #22
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Re: 5"/6" lowered, Tyre size ?

Scoti, what's the difference between the HD small block spring and the 454 spring?

Rick
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Old 07-21-2019, 03:20 PM   #23
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Re: 5"/6" lowered, Tyre size ?

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Scoti, what's the difference between the HD small block spring and the 454 spring?

Rick
I don't have the info in front of me but recall the HD sbc springs were like 940# & the bbc springs were 1018#.
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Building a small, high rpm engine
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like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar.

Cubic inches is like Indiana Jones with a cheap pistol....
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