7000# vs 8000# Axles and Brakes

News flash...For those of us with 7000 lb axles, they seem to max out with the 2.5" shoe pads.

For those with the 8000# axles, you get 3.375" shoe pads for extra braking power.

I have sent off to a couple of brake dealers to see if you can put the 8000" backplates and drums on the 7000# axles. If it is possible, it still may prove too cost prohibitive compared to installing Disc brakes.

We'll see...

I think that there may be an issue as the 3.375" shoes and drum may stick out into the fender skirt. As is, it looks pretty close. There may also be a problem with bearings fitting.

One thing for sure, if it is possible, I'll bet the braking is significantly better but still less than Discs...

When I had my 08 KZ , I had the IS installed along with the 3-3/8 brakes... They make a HUGE difference over stock brakes...
I cannot answer whether or not they fit on the 7K axle , but id so they are a winner.

For those who cannot do the disc conversion they are a good second choice if they fit.

I don't believe that drums would out perform the disc brakes; however. it would be interesting to see the price difference between the two, and performance gain in using the wider brake pads.

I agree... BUT - For those who cannot make the discs happen , they are a good alternative . .

The last 2.5." complete backing plates with every attached was just over $400, if the larger ones are much more I'd go with the disc.

7000# vs 8000# Axles and Brakes

News flash...For those of us with 7000 lb axles, they seem to max out with the 2.5" shoe pads.

For those with the 8000# axles, you get 3.375" shoe pads for extra braking power.

I have sent off to a couple of brake dealers to see if you can put the 8000" backplates and drums on the 7000# axles. If it is possible, it still may prove too cost prohibitive compared to installing Disc brakes.

We'll see...

I think that there may be an issue as the 3.375" shoes and drum may stick out into the fender skirt. As is, it looks pretty close. There may also be a problem with bearings fitting.

One thing for sure, if it is possible, I'll bet the braking is significantly better but still less than Discs...

Are you sure about the stock brakes being 2.5 inches wide by 12 inch diameter? I changed out my backing plates and the brakes on my 7000 lb axles are 2 inches by 12 inches.

7000# vs 8000# Axles and Brakes

News flash...For those of us with 7000 lb axles, they seem to max out with the 2.5" shoe pads.

For those with the 8000# axles, you get 3.375" shoe pads for extra braking power.

I have sent off to a couple of brake dealers to see if you can put the 8000" backplates and drums on the 7000# axles. If it is possible, it still may prove too cost prohibitive compared to installing Disc brakes.

We'll see...

I think that there may be an issue as the 3.375" shoes and drum may stick out into the fender skirt. As is, it looks pretty close. There may also be a problem with bearings fitting.

One thing for sure, if it is possible, I'll bet the braking is significantly better but still less than Discs...

Are you sure about the stock brakes being 2.5 inches wide by 12 inch diameter? I changed out my backing plates and the brakes on my 7000 lb axles are 2 inches by 12 inches.

You are absolutely correct...I went back to the receipt and they are 12x2. With the 12x3.375's, there would be a lot more surface for braking. I'm still awaiting the answer back from the dealer I contacted.

I am concerned that the price of drums and back-plates may quickly reach disc cost...

Look to pay around $125.00 per wheel per backing plate... And add about $250.00 per for the drum.. $375.00 per wheel---roughly $1500.00 + labor .. Now, they are high estimates going off websites I know .. Disc kit from Ron $1800.00... Just add labor... Too close to NOT to do The discs...

And on edit... I think you will find that they are 12-1/4 X 3-3/8.....

I always wondered why, if disc brakes are so good, that 85% of the commercial trailers on the highways are still using drum brakes? Just saying!

Apples and oranges... The big rig drum brakes are far superior to any small size drum system... Between the air system, the large/thick pads, and the huge drum , they are not even in the same league.. I could lock up ( did ) my brakes with a total of 90,000 pounds under me... Yea, I was 10K overweight , but that's another thread...

The spindle on a 7k and 8k axle are the same so the bearing I.D. has to be the same. The increased bearing load come from the O.D. and the length of the roller, all related to the Hub/Drum. I see no reason why the larger 8k brakes will not fit. The biggest expense will be the new drums.

The next thing to look at is the added overall length of the axle and new hubs (if we go that way). The standard 2" shoes and drums clear the fender wheel by only a tight few inches. The 3.375" shoes and drums will add about 3" to the overall length.

I still have not heard back from my dealer just yet about the overall price. They are very good to deal with and I look forward to their comments as well.

Disc brakes may still be the best option. This will help determine if that is correct.

Thanks Titan Guy!

Greetings Titan Guy!

Great to see you again at the Texas regional rally!

I have what I think is the last question on your disc brake conversion...

As you know, I have the 7K axles at the moment. If I have the disc conversion put on with the current 7K axles and later switch to 8K axles, will this effect your installation? It's the last thing I think I need to know to move forward.

BTW...You really put things into perspective at the rally. That cleared up a lot of questions I would have never thought to ask! (Both brakes and tires)!

Many, many thanks!

If you install disc brakes now on your 7k axle and change to a 8k axle in the future, the only thing that would need to change is the Caliper Bracket, about $120 for all 4. The 7k brake flange on the axle is 5 bolt 3/8". The brake flange on the 8k axle is 4 bolt 7/16".

PERFECT!

I'll be in touch for the next rally to line this up and the wheels as well (H rated).

We're just trying to decide which rally to catch up with you...