Got some new wheels: Boss 338's in 20x10 and 20x8.5 - Page 10 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**lolife99** · 09-20-2009, 03:21 PM

These are my measurements from the two rotors:

1" ROTORS:

-Hub Diameter: 2.650"
-Hub height: 1.750"
-Total height from wheel flange to end of dust cover: 2-11/16"
-Height from disc face to lugnut flange: 1-7/8"

1.25" ROTORS:

-Hub Diameter: 2.895"
-Hub height: 2"
-Total height from wheel flange to end of dust cover: N/A (No cap on my rotor)
-Height from disc face to lugnut flange: 1-9/16"

Looks like the thinner rotor has a taller "hat",... and a shorter hub.

And here's the wheel mounted!

**lolife99** · 09-20-2009, 03:40 PM

Here's the final dimensions.
(excuse my crappy skills in "paint")

71'tahoe · 09-20-2009, 04:37 PM

Nice!! Now I got to figure how to get them to work on my 97' truck!!

smashingchuck · 09-20-2009, 05:42 PM

Nice work Keith.

**lolife99** · 09-20-2009, 06:46 PM

This won't solve everyones issues,... but at least they will fit something.
And,... I don't have to return mine or wait for the new design.

djracer · 09-20-2009, 08:18 PM

I hope I don't have these issues on a mustang II rotor. I bought these in a 18x8 and a 18x9.5 for my brothers 59 truck. We have the rears on and haven't done the fronts yet.

71'tahoe · 09-21-2009, 09:33 AM

I did some digging and ithink the 88-98 trucks are like the 73-87 trucks they used 2 different rotors depending on the option or the gvwr. i may head to the parts store and pull a few rotors and measure..

72BlckButy · 09-21-2009, 02:17 PM

Awesome FAQ Keith!

**Hart_Rod** · 09-21-2009, 02:46 PM

Keith - quick questions, I'm getting ready to buy new spindles and am thinking about going with the LD ones. What else has to be changed besides the rotors and spindles to make the LD stuff work? Thanks,

R/

Benji_1802 · 09-21-2009, 04:54 PM

Great feed back man...i got the 20x8 & 20x10 set up for my 72 c10, so i only need to get the 1" thick rotors? or will i need the drop spindles for 1" brake rotors as well? will caliper from my stock 1.25 rotors work on the 1" rotors? any feedback will help. Thanks.

**lolife99** · 09-21-2009, 06:08 PM

Rob and Benji,... the only thing I'm not sure about is the calipers.

I need to stop by the local auto parts store and check that out tomorrow,... but I'm sure they are a different part number.
If I had DSL,... I'd look online,... but it's not worth the effort. (And the slow internet, driving me crazy)
My frame is a 1983,... so that's the application I will use.
(Hint, hint dsl guys)

Last night I ordered a set of 73-87 Belltech 3" drop spindles (part #3200 for the LD version), for my '86 Dropmember project.

Anyone else running 63-70 conversion spindles will have to swap to the 73-87 version and change balljoints.

I think the upper and lower balljoints of the 71-72 trucks will work with the 73-87 spindles,... but I'm not 100% sure.
(another cross reference item for you dsl guys)

I'm pretty sure there is no 1" spindle for the pre '73 trucks,... so a balljoint/tie rod switch will be in order.
(with maybe the exception being the 71-72 trucks)

mentlmidget · 09-22-2009, 05:37 AM

GUYS! please remember that going to a 20" wheel combo is going to be double, if not triple the weight per wheel. Braking distance IS INCREASED. Before ordering all the brake hardware, think about increasing the rotor diameter, which would also include a different caliper/spindle setup. I am all for the GO GO GO, but we also need to STOP STOP STOP.
I didn't think there was going to be that much of a difference from the 15" 165/50/15 combo I had until I went out to do this measuring. Holy cow was that wheel heavy. I am a school teacher who used to work at a few tire shops in my younger years. I equal the weight to about a split rim set up for a box truck. Maybe not quite that bad, but heavy enough.

I AM looking into getting a bigger brake combo for my rig.

Just keep the longer stopping distance in mind.

**lolife99** · 09-22-2009, 05:48 AM

Good luck finding a rotor,... ANY rotor,... that will fit this wheel.

So far the Light Duty version of the stock rotor is the ONLY one that will work.
And that's what you have right now.
Let me know if you find another rotor/brake system that this wheel will fit.

brossow · 09-22-2009, 07:37 AM

Quote:

Originally Posted by mentlmidget

GUYS! please remember that going to a 20" wheel combo is going to be double, if not triple the weight per wheel. Braking distance IS INCREASED. Before ordering all the brake hardware, think about increasing the rotor diameter, which would also include a different caliper/spindle setup. I am all for the GO GO GO, but we also need to STOP STOP STOP.
I didn't think there was going to be that much of a difference from the 15" 165/50/15 combo I had until I went out to do this measuring. Holy cow was that wheel heavy. I am a school teacher who used to work at a few tire shops in my younger years. I equal the weight to about a split rim set up for a box truck. Maybe not quite that bad, but heavy enough.

I AM looking into getting a bigger brake combo for my rig.

Just keep the longer stopping distance in mind.

Let's not get into a panic here. Do you upgrade your brakes if you're going to have a passenger in your vehicle? Didn't think so. The rims weigh more, but the tires weigh less. And we're talking about a 2-ton vehicle, not a 500-pound motorcycle. Yes, there's a difference in rotational mass, but overall the weight difference is negligible in the big scheme of things on a vehicle this size. (If you want to do the math, an increase in rotational mass equates to about a 10x increase in static mass -- for example, adding 40 lbs at the wheels is roughly the same as adding 400 lbs of cargo.) If your braking system is so close to its limits that the weight of the wheels means life or death, you've got bigger problems than wheel selection.

I agree that brakes need to be a MUCH higher priority than just about anything else on a vehicle. But I don't see adding a few pounds per corner as something that necessitates a $2000 brake upgrade. IMHO, of course.

Brent

*vegaschevy* · 09-22-2009, 08:26 AM

Quote:

Originally Posted by brossow

Let's not get into a panic here. Do you upgrade your brakes if you're going to have a passenger in your vehicle? Didn't think so. The rims weigh more, but the tires weigh less. And we're talking about a 2-ton vehicle, not a 500-pound motorcycle. Yes, there's a difference in rotational mass, but overall the weight difference is negligible in the big scheme of things on a vehicle this size. (If you want to do the math, an increase in rotational mass equates to about a 10x increase in static mass -- for example, adding 40 lbs at the wheels is roughly the same as adding 400 lbs of cargo.) If your braking system is so close to its limits that the weight of the wheels means life or death, you've got bigger problems than wheel selection.

I agree that brakes need to be a MUCH higher priority than just about anything else on a vehicle. But I don't see adding a few pounds per corner as something that necessitates a $2000 brake upgrade. IMHO, of course.

Brent

I laugh when people make this argument. Like when they pull that 2 ton trailer, or load the bed that the truck was okd to haul. or when you put the 5 passengers in the vehicle. better upgrade your brakes ASAP

**lolife99** · 09-22-2009, 12:07 PM

I'm good with a brake upgrade,... but until they redesign this wheel,... they won't fit anything except the factory LD rotors.

I guess I was just happy to get them to bolt on with no modifications,... finally.

You guys keep me posted if you find another rotor that will work,... or a new part number for the redesigned wheel.

mentlmidget · 09-22-2009, 03:13 PM

I am not panicing, nor am I suggesting there be a panic. I am only stating, since I have put the 20's on my truck, my stopping distance has increased. I wouldn't consider myself a maniac on the road, but then again, this is subjective.

brossow · 09-22-2009, 03:18 PM

Quote:

Originally Posted by mentlmidget

I am not panicing, nor am I suggesting there be a panic. I am only stating, since I have put the 20's on my truck, my stopping distance has increased. I wouldn't consider myself a maniac on the road, but then again, this is subjective.

Yup, and that's an expected occurrence -- same as if your fat cousin Cheeto is along for the ride. Something to be aware of when you're driving around getting used to the new wheels, but not something that should necessitate a brake system upgrade.

DrtyJack75 · 09-23-2009, 09:34 AM

well I was just looking at the ECE page and the brake conversion they sell (and I bought) have a 1.25" rotor.

So is it possible to just go back to the 1" or is there something to do with the newer spindles that you have to have the 1.25" (or heavy duty)?

SCOTI · 09-23-2009, 10:41 AM

Quote:

Originally Posted by DrtyJack75

well I was just looking at the ECE page and the brake conversion they sell (and I bought) have a 1.25" rotor.

So is it possible to just go back to the 1" or is there something to do with the newer spindles that you have to have the 1.25" (or heavy duty)?

You can machine the HD 1.25" rotors & use spacers to work w/these wheels if you can accommodate the slight increase of track width.

DrtyJack75 · 09-23-2009, 10:59 AM

Id rather not use spacers? Sorry if I missed it but is there any word on the release of the new wheels?

**lolife99** · 09-23-2009, 11:57 AM

Quote:

Originally Posted by DrtyJack75

well I was just looking at the ECE page and the brake conversion they sell (and I bought) have a 1.25" rotor.

So is it possible to just go back to the 1" or is there something to do with the newer spindles that you have to have the 1.25" (or heavy duty)?

The only way to use the 73-87 1" LD rotor is to change ball joints and outer tie rod ends.
Your ECE "conversion spindle" eliminates all that.

It may be better to wait for the "new" design on the wheel itself.

**lolife99** · 09-23-2009, 11:58 AM

Quote:

Originally Posted by DrtyJack75

Id rather not use spacers? Sorry if I missed it but is there any word on the release of the new wheels?

I haven't heard anything yet.

**nlped** · 09-23-2009, 04:36 PM

I haven't heard anything good, just "it should be soon".

DrtyJack75 · 09-23-2009, 11:23 PM

I talked to Jeff from ECE today and he had another option but I dont think it's worth it..

He said I can take my spindles off they can press out my PIN (Axle) and he can press in the smaller one that accomidates the standard rotor...

to much work if you ask me..

So Ill just wait for the wheels to come out..

hey NLPD, How was it you can tell the new design? I thought you said soemthing about part # or something.

THANKS!!

09-20-2009, 03:21 PM	#226
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,699	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 These are my measurements from the two rotors: 1" ROTORS: -Hub Diameter: 2.650" -Hub height: 1.750" -Total height from wheel flange to end of dust cover: 2-11/16" -Height from disc face to lugnut flange: 1-7/8" 1.25" ROTORS: -Hub Diameter: 2.895" -Hub height: 2" -Total height from wheel flange to end of dust cover: N/A (No cap on my rotor) -Height from disc face to lugnut flange: 1-9/16" Looks like the thinner rotor has a taller "hat",... and a shorter hub. And here's the wheel mounted! Attached Images __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 Last edited by lolife99; 09-20-2009 at 03:53 PM.

09-20-2009, 03:40 PM	#227
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,699	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Here's the final dimensions. (excuse my crappy skills in "paint") Attached Images __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

09-20-2009, 04:37 PM	#228
71'tahoe Registered User Join Date: Feb 2004 Location: lynchburg ohio Posts: 736	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Nice!! Now I got to figure how to get them to work on my 97' truck!!

09-20-2009, 05:42 PM	#229
smashingchuck It'd be alot cooler if you did Join Date: May 2003 Location: Three Rivers, MI Posts: 2,345	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Nice work Keith. __________________ 78 Build Thread 4Runner Build

09-20-2009, 06:46 PM	#230
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,699	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 This won't solve everyones issues,... but at least they will fit something. And,... I don't have to return mine or wait for the new design. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 Last edited by lolife99; 09-22-2009 at 05:49 AM.

09-20-2009, 08:18 PM	#231
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I hope I don't have these issues on a mustang II rotor. I bought these in a 18x8 and a 18x9.5 for my brothers 59 truck. We have the rears on and haven't done the fronts yet. Attached Images __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

09-21-2009, 09:33 AM	#232
71'tahoe Registered User Join Date: Feb 2004 Location: lynchburg ohio Posts: 736	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I did some digging and ithink the 88-98 trucks are like the 73-87 trucks they used 2 different rotors depending on the option or the gvwr. i may head to the parts store and pull a few rotors and measure..

09-21-2009, 02:17 PM	#233
72BlckButy Tot Roddin' Join Date: Apr 2005 Location: Mid-MO Posts: 24,461	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Awesome FAQ Keith! __________________ -Nate 1969 CST SWB - Project Blank Slate (4.5/6" ECE Static Drop, 6-lug disc brake upgrade (manual), Billet Specialties Vintec 20x8.5 255/40 (F) 20x10 295/40 (R), 250 I-6) 1960 AMF Skylark - Tot Roddin' (Lowered with custom frame; soon to include custom push bar and interior) 2008 Silverado CrewCab 1LT (5.3L, 3:73, 4x4, LT1, Z-71, Towing Package)

09-21-2009, 02:46 PM	#234
Hart_Rod ************* Join Date: Apr 2005 Location: Pensacola, FL Posts: 17,856	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Keith - quick questions, I'm getting ready to buy new spindles and am thinking about going with the LD ones. What else has to be changed besides the rotors and spindles to make the LD stuff work? Thanks, R/ __________________ Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3

09-21-2009, 04:54 PM	#235
Benji_1802 Registered User Join Date: Sep 2009 Location: Oakley Ca Posts: 13	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Great feed back man...i got the 20x8 & 20x10 set up for my 72 c10, so i only need to get the 1" thick rotors? or will i need the drop spindles for 1" brake rotors as well? will caliper from my stock 1.25 rotors work on the 1" rotors? any feedback will help. Thanks.

09-21-2009, 06:08 PM	#236
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,699	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Rob and Benji,... the only thing I'm not sure about is the calipers. I need to stop by the local auto parts store and check that out tomorrow,... but I'm sure they are a different part number. If I had DSL,... I'd look online,... but it's not worth the effort. (And the slow internet, driving me crazy) My frame is a 1983,... so that's the application I will use. (Hint, hint dsl guys) Last night I ordered a set of 73-87 Belltech 3" drop spindles (part #3200 for the LD version), for my '86 Dropmember project. Anyone else running 63-70 conversion spindles will have to swap to the 73-87 version and change balljoints. I think the upper and lower balljoints of the 71-72 trucks will work with the 73-87 spindles,... but I'm not 100% sure. (another cross reference item for you dsl guys) I'm pretty sure there is no 1" spindle for the pre '73 trucks,... so a balljoint/tie rod switch will be in order. (with maybe the exception being the 71-72 trucks) __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 Last edited by lolife99; 09-21-2009 at 06:10 PM.

09-22-2009, 05:37 AM	#237
mentlmidget Registered User Join Date: Jun 2005 Location: Fort Lauderdale, FL Posts: 30	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 GUYS! please remember that going to a 20" wheel combo is going to be double, if not triple the weight per wheel. Braking distance IS INCREASED. Before ordering all the brake hardware, think about increasing the rotor diameter, which would also include a different caliper/spindle setup. I am all for the GO GO GO, but we also need to STOP STOP STOP. I didn't think there was going to be that much of a difference from the 15" 165/50/15 combo I had until I went out to do this measuring. Holy cow was that wheel heavy. I am a school teacher who used to work at a few tire shops in my younger years. I equal the weight to about a split rim set up for a box truck. Maybe not quite that bad, but heavy enough. I AM looking into getting a bigger brake combo for my rig. Just keep the longer stopping distance in mind.

09-22-2009, 05:48 AM	#238
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,699	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Good luck finding a rotor,... ANY rotor,... that will fit this wheel. So far the Light Duty version of the stock rotor is the ONLY one that will work. And that's what you have right now. Let me know if you find another rotor/brake system that this wheel will fit. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

09-22-2009, 12:07 PM	#241
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,699	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I'm good with a brake upgrade,... but until they redesign this wheel,... they won't fit anything except the factory LD rotors. I guess I was just happy to get them to bolt on with no modifications,... finally. You guys keep me posted if you find another rotor that will work,... or a new part number for the redesigned wheel. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 Last edited by lolife99; 09-22-2009 at 12:08 PM.

09-22-2009, 03:13 PM	#242
mentlmidget Registered User Join Date: Jun 2005 Location: Fort Lauderdale, FL Posts: 30	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I am not panicing, nor am I suggesting there be a panic. I am only stating, since I have put the 20's on my truck, my stopping distance has increased. I wouldn't consider myself a maniac on the road, but then again, this is subjective.



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09-23-2009, 09:34 AM	#244
DrtyJack75 Registered User Join Date: Feb 2008 Location: West Sacramento, CA Posts: 417	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 well I was just looking at the ECE page and the brake conversion they sell (and I bought) have a 1.25" rotor. So is it possible to just go back to the 1" or is there something to do with the newer spindles that you have to have the 1.25" (or heavy duty)?

09-23-2009, 10:59 AM	#246
DrtyJack75 Registered User Join Date: Feb 2008 Location: West Sacramento, CA Posts: 417	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 Id rather not use spacers? Sorry if I missed it but is there any word on the release of the new wheels?

09-23-2009, 04:36 PM	#249
nlped Senior Member Join Date: Jul 2009 Location: Hayden, Al. Posts: 4,148	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I haven't heard anything good, just "it should be soon". __________________ Carter 1968 Chevy SWB Fleet... Walt 1963-1/2 Ford Falcon Futura...Martha

09-23-2009, 11:23 PM	#250
DrtyJack75 Registered User Join Date: Feb 2008 Location: West Sacramento, CA Posts: 417	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I talked to Jeff from ECE today and he had another option but I dont think it's worth it.. He said I can take my spindles off they can press out my PIN (Axle) and he can press in the smaller one that accomidates the standard rotor... to much work if you ask me.. So Ill just wait for the wheels to come out.. hey NLPD, How was it you can tell the new design? I thought you said soemthing about part # or something. THANKS!!

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