Front wheel bearing torque for racing

Suspension, including wheel, tire and brake.
Sleepys-14
Posts: 434
Joined: 03 Mar 2011 11:26
Location: Appleton, WI

Front wheel bearing torque for racing

Postby Sleepys-14 » 09 Feb 2016 05:43

I was just wondering what you racing guys use for front wheel bearing torque strictly for racing purposes. I have been running my car for a few years, and have had pad kickback issues with these front bearings (280zx). It seems to get worse the hotter the brakes get. I have tried torqueing the bearing a little tighter which help a little, but I don't want to get crazy with the bearing torque and cause a failure. I also understand that when you tighten the bearing preload, you will essentially shorten the life of the bearings, but my car mainly sees the track, so replacing bearing every once in a while is not a big deal. I currently have the bearings set to just slightly over hand tight. Stock is 25ftlbs then back it off 60*, which makes it just about hand tight.

To combat the issue of heat causing the kickback issues, I have upgraded to a 2 piece rotor. That should take quite a bit of heat out of the hubs to reduce the kickback, but now my rotors are 12.2" vs 10.8", so the kickback will be increased from the rotor size, but maybe the heat will counteract the kickback. I was going to try torqueing the wheel bearings tighter to see if some of the kickback goes away.

First step is just to replace the races and bearings, but I doubt that will do anything...
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

User avatar
zKars
Supporter
Posts: 383
Joined: 15 Aug 2013 14:19
Location: Calgary Alberta Canada

Re: Front wheel bearing torque for racing

Postby zKars » 09 Feb 2016 06:42

Bearing torque is critical. Too tight and all you're doing is squeezing the crap out of the inner/outer parts of the bearing making them fail sooner, and increasing rolling friction. Maybe you have crappy chinese bearings?

There is a circle track supply company that makes a spacer that goes between the inner and outer race that allows you to torque them up and keep rolling friction at a minimum. Someone on hybridz found they have one that fits the 240/280z hubs. No clue if the 280zx spindle/bearing spacing is the same. I'll see if I can find that link for you.

Aha!

http://forums.hybridz.org/topic/122454- ... try1145230

The discussion begins with sourcing highest quality bearings, then leads into the need for a spacer to allow proper torquing.

DRP Performance is the source.

http://store.drpperformance.com/bearing-spacers/

Sleepys-14
Posts: 434
Joined: 03 Mar 2011 11:26
Location: Appleton, WI

Re: Front wheel bearing torque for racing

Postby Sleepys-14 » 09 Feb 2016 07:52

Very good information. I looked up the legends bearing spacer and confirmed the measurements, so it looks like it will work. I do use good quality bearings, but taper bearings seem to always have some runout even when they are preloaded... Thanks for the info zKars!

http://store.drpperformance.com/bearing ... ble-steel/
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

User avatar
S15DET
Supporter
Posts: 2561
Joined: 03 Dec 2004 17:02
Location: Waxhaw, NC

Re: Front wheel bearing torque for racing

Postby S15DET » 11 Feb 2016 05:37

I love the idea of this spacer, wish I had thought of it. Please let us know if it works for the 280ZX spindle/bearings.

Sleepys-14
Posts: 434
Joined: 03 Mar 2011 11:26
Location: Appleton, WI

Re: Front wheel bearing torque for racing

Postby Sleepys-14 » 11 Feb 2016 11:07

The Z cars use the same wheel bearings as the 280zx, so I would assume so. I am going to get a new set of bearing and see if I can grab set of spacers soon.
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

User avatar
bertvorgon
Supporter
Posts: 9971
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: Front wheel bearing torque for racing

Postby bertvorgon » 13 Feb 2016 07:52

Morning Gang,

I fought this also. I tighten my bearings pretty snugly too, never checked the torque thought, just get it finger tight, then give it a bit of a turn tighter on the crescent wrench. Seems to work fairly well, with minimal pad knock back .

One thing I do do, is keep my pads square ( flat) Andy made a jig for a dedicated belt sander, to true up the pads, works like a hot damn, keeps taper wear to a minimum.

What calipers do you run? I eliminated 90% of my perceived knock back when I went to the forged caliper, flex was gone, as that was my biggest issue with the old JFZ/WILWOOD Mini GN calipers.

Here is a picture of my brake cooling duct, which properly blows air into the center of the rotor.
Attachments
hose attachment.JPG
hose attachment.JPG (172.8 KiB) Viewed 1372 times
IMG_2524.JPG
IMG_2524.JPG (172.3 KiB) Viewed 1372 times
bend in sway bar.JPG
bend in sway bar.JPG (170.91 KiB) Viewed 1372 times
280zx cooling duct.JPG
280zx cooling duct.JPG (171.68 KiB) Viewed 1372 times
aircraft duct hose.JPG
aircraft duct hose.JPG (155.41 KiB) Viewed 1372 times
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

User avatar
bertvorgon
Supporter
Posts: 9971
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: Front wheel bearing torque for racing

Postby bertvorgon » 13 Feb 2016 07:57

The aluminium face sits a few thou' off the rotor edge.
Attachments
IMG_7973.JPG
IMG_7973.JPG (115.4 KiB) Viewed 1371 times
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

Sleepys-14
Posts: 434
Joined: 03 Mar 2011 11:26
Location: Appleton, WI

Re: Front wheel bearing torque for racing

Postby Sleepys-14 » 13 Feb 2016 09:44

Thanks for the suggestions. With the addition on the 2 piece rotors, i have also changed from the old style wilwood dynalites to the new dyna-pro, which is a forged billet caliper with a bridge bolt to decrease caliper flex. I also have brake ducts that blow air to the hat area of the rotor, then the curved vane rotor pulls the air the rest of the way through. I will replace the front bearing and races next week and set where that gets me.

I also set the bearings to slightly tighter than hand tight, but it didn't help much with the play.

Thanks for the info again!!
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

User avatar
bertvorgon
Supporter
Posts: 9971
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: Front wheel bearing torque for racing

Postby bertvorgon » 13 Feb 2016 10:16

I hear yah, I will ask Andy at Specialty about the bearing spacer, I seem to remember he did something like that for the GT3 cars. I know we did have a discussion about pad knock back, it is after all one of the MOST annoying things a racer deals with. The "comfort" tap on the brake just becomes so standard, I do it on all my cars.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

Sleepys-14
Posts: 434
Joined: 03 Mar 2011 11:26
Location: Appleton, WI

Re: Front wheel bearing torque for racing

Postby Sleepys-14 » 16 Feb 2016 05:43

Thanks for asking. I am used to doing the love tap before each corner just to make sure the pedal is at the highest spot, but on 2 of our tracks we have a small chicane into a braking zone which really is hairy when coming in hot and left foot braking to keep the pedal high... And don't say just go slower, because that's not going to happen!
Beer... The cause of, and solution to, all of lives problems- Homer Simpson

User avatar
bertvorgon
Supporter
Posts: 9971
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: Front wheel bearing torque for racing

Postby bertvorgon » 16 Feb 2016 06:48

Cold day in hell when I say go slower...... :lol:

I will be going by Specialty on the way home tonight.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

User avatar
bertvorgon
Supporter
Posts: 9971
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: Front wheel bearing torque for racing

Postby bertvorgon » 16 Feb 2016 16:44

So, this is Andy's take.

He makes his own basically, torquing the wheel bearing till it is close, then machining off whatever is needed get to the to the proper torque. Or, uses a shim.

He says they work quite well if installed properly.

I do know that any of Andy's race cars have impeccable brakes.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

User avatar
funwithmonkeys
Supporter
Posts: 870
Joined: 05 Sep 2013 09:34
Location: Vancouver, BC

Re: Front wheel bearing torque for racing

Postby funwithmonkeys » 16 Feb 2016 21:43

It makes me happy that Andy is doing the brakes on mine.
If no one from the future comes back to stop you from doing it then how bad of a decision can it really be?

User avatar
bertvorgon
Supporter
Posts: 9971
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: Front wheel bearing torque for racing

Postby bertvorgon » 17 Feb 2016 06:48

When is your car going into Andy's?
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

User avatar
funwithmonkeys
Supporter
Posts: 870
Joined: 05 Sep 2013 09:34
Location: Vancouver, BC

Re: Front wheel bearing torque for racing

Postby funwithmonkeys » 17 Feb 2016 08:05

He already has it, work should be starting this week on it as I understand. It is in the hanger next door hanging out with the helicopters till he starts on it.
If no one from the future comes back to stop you from doing it then how bad of a decision can it really be?


Return to “Suspension”



Who is online

Users browsing this forum: No registered users and 2 guests