Technical 56 chevy truck bolt patterns

Hey guys I’m kind of lost on what to do about my bolt patterns. I have a 56 chevy truck with the dropped axle and front leaf springs. I put the disc brake conversion kit on it from speedway which makes it 5x 4.75. The rearend is a GM 12 bolt which is 5x5. So I have 2 different bolt patterns and I don’t want to carry 2 spares lol. I was looking on speedway and they sell a 5x5 rotor can I just swap out rotors and get the correct bearing for my spindle? My other option is replacing the axles in my rearend but the quote I got was $1500 to do that. I’ve heard of have the rear bolt pattern red rolled to 5x4.75 but I couldn’t find anyone to do that. Thank you any help is greatly appreciated

 

That price is stupid high for replacing rear axles, even if it includes the labor. You can have your axles drilled for the small Chevy pattern by sending them to Moser, and last I checked they wanted $50 per axle. Send your rotors at the same time and they can do both.

 

might want to look at the front rotors....it's possible that there is a 5" bc rotor that is the same size and uses the same bearings as the 4.75 bc rotor, but if it's a stock GM 5" rotor, then it's likely 12" diameter instead of 11" diameter.

If you'd have got a Chevy car rear instead of a truck rear then it would have the right bolt pattern.

Also....when was the last time you needed to use a spare tire? Been a while for me, but I'm pretty good about replacing tires when they get old.

 

Just swapping out the rotors will depend on several factors- rotor diameter, rotor disc spacing, and seals/bearings. Speedway should be able to guide you on what is needed. A lot of GM disc brake conversions use the same spindle spacers and Timken set 3 and 5 bearing sets. Truck spindles may be larger. Big Buicks also used 5 x 5 bolt pattern, and went to disc brakes in 1967. Going from 5 x 5 to 5 x 4-3/4 will also require drilling the rear drums plus new rims all the way around.

 

I contacted speedway and they said they have a 5x5 rotor but it has long 5/8 3 inch studs for circle track racing. So not sure if that could be an option and just swap out the studs for shorter ones.

 

5/8 studs are used in racing . Your wheels won’t work on 5/8 studs.

 

I've used the speedway rotor before, you need to get different studs. Or you can either get replacement axles or re drill yours (which both requires re drilling the drum).

DIY,
https://www.hellsgatehotrods.com/product-category/drill-guides/

 

What is a 4.57 bc ? So you drive around all the screws and nails you might encounter? That could be funny or dangerous.

 

Shop around on the internet. Dutchman , Strange , Currie , Moser etc can help you get where you need to be .

 

some peoples' eyes are dyslexic, my fingers are.

 

This...

 

The common gm 5 inch rotor is a Caprice, Olds 88 Buick electra rotor that is 12 inch rather than 11 inch. GM had both patterns on the full size cars from 88 to the end of the rear wheel drive run. 5 on 4-3/4 on the ones like an 88 and 5 on 5 on the 98.

The simple solution right now is to get a dual pattern spare.
This is the skinny spare out of one of the 80 something Olds Delta 88s that I had here at one time or another, Either the one that I got from my dad or the one I got from my aunt.
Replacement tires are spendy though.

1971BB427 and I can walk into our local Les Schwab and most likely get a 15 inch "snow tire wheel" with both patterns on it new for a pretty reasonable price. ugly wheel but they serve the purpose.

Dutchman moved from Portland to Boise a few years ago but they redrill your axles and rotors pretty reasonable but my guess is that if you hunt around a bit there is a shop in Bakersfield or close by that does it.
You are looking at 65 for the pair of axles and 45 for the pair of drums/rotors to have Dutchaman redrill them plus shipping both ways and all together that will probably end up adding up to around 250 total depending on actual shipping costs.

The last option is get of the probably too wide anyhow pickup axle and put a 70/81 Camaro axle under it. Most of the AD and TF truck guys run one of those rather than the bigger 5 lug 12 bolt truck axle that is usually several inches too wide. 70/81 Camaro rear axle width is 61 inches and 90% of the time that works great for the TF or AD trucks unless you have a wheel/tire combo that doesn't fit without other changes.
Some go with the S-10 4x4 rear axle but at 59 inches you can run into tire sidewall to bed clearance issues with wheels that the offset on the positive side. I've got a 74 Nova rear under my 40 with the same 50 inch bed width and can't run a stock Chevy car wheel on the back because the tire hits the side of the bed. Carried one for a spare for a long time until I had a flat on the rear and had to switch a front wheel to the rear and put the spare on the front to get to the tire store.

 

Why not get one of the aluminum racing type wheels which is basically solid aluminum in the center and drill an extra set of holes in it? You can find used ones pretty cheap. You can find dual patterns already available in 4.75 and 4.5 patterns. Not sure if they make 4.75 and 5 inch. So, if not, make your own.

 

He has a few Les Schwab’s in Bakersfield.

 

I may have a wheel that you can have, have to measure the BP, don’t recall if it was 4.5/4.75 or 4.75/5.
I’ll head out back this evening when it cools down and measure it.

 

Willing to drive just outside of down town Los Angeles?

Cooks Machine Works
4845 Telegraph Rd, Los Angeles, CA 90022
323-268-6571

https://www.motortrend.com/features/shop-visit-cooks-machine-works/

 

Wish you were closer . I have a ‘76 C*m*r* rear that would solve your problem that I could make you a deal on . A different truck I know , on my ‘48 Ford F1 I have a ‘68 C*m*r* 12 bolt under it with 7” wheels and all is well with the world. Under the bench is ‘69 C*m*r* 10 bolt.

 

I have not researched bearings sizes with what you have and what you need , but in 1971 Chevy Impala’s had the 5x5 bolt pattern with the large disc brakes.

 

I contacted speedway but they told me the 5x5 rotors wouldn’t work because the bearings don’t work with the original spindle. I was thinking why couldn’t I just use the inner bearing and sleeve I had to use for the 5x4.75 rotor. But I’m not sure

At this point I’m thinking switching Rearend’s would be the easier option

or I guess if I do have a flat just call AAA lol. And just deal with the 2 different bolt patterns.

Budget if you could check the wheel I would appreciate it. Thank you

 

Or just pick up a wheel spacer/adaptor to make your spare fit the other end.

 

I have zero room for a adapter. My truck is super low as it is. I either have to take the wheel stems out or take the bed off to change the tire lol

 

For the hassle to change a rear end, I’d think shipping the axles to Moser might be more cost effective? For sure less work.

 

Well I just got off the phone with Moser and they said $75 to redrill the axels and $75 to redrill the rotors. That’s not including shipping. I’m sure shipping is pretty pricey these days.

 

Go back to reply #16 and call Cook's.

 

I did. He wants $375 just for the axle plus shipping

 

Most likely the rear axle that he has under it now is wide. 5 on 5 pickup axles with the 12 bolt cover didn't come out until 1973 and those are 63-3/4 WMS to WMS and spacers would put it out around 66 not giving a lot of room between the wheel mount surface and the inside of the fender. Unless he is after that 70's tires five inches out of the wheel well look.

 

Time to be Bakersfield go to guy with... https://www.hellsgatehotrods.com/product-category/drill-guides/

 

But you just need the axles OR the rotors, not both, right?

 

Hello Gate drill guide, I believe he was even a member here $149

 

We re-drilled our own rear axles, with a template, and drill press. Did the same thing, had large BP rear end in a Camaro. Set it up, drilled straight, and installed the studs. Re-drilled the drum to match. Front and rear end were the same.