Literature FAQs (Frequently Asked Questions)

The following questions are those that are typically asked about ConMet Hub Assemblies.
Additional information is available by calling ConMet Customer Service at 800-547-9473.

1. The pilots don’t look like they can support the axle load, why?
2. Why do stud-piloted front hubs come with two different stud sizes?
3. I have a wheel for a stud-piloted mounting system. Does it work for both 3⁄4-inch and 1-1/8 inch studs used on front hubs?
4. Can I convert my stud-piloted hub to a hub-piloted hub?
5. Do I have to service my hubs? When and how?
6. I have a Q-spindle drive hub. What is the replacement?
7. Can I take the spacer out of my PreSet hub?
8. My hub is aluminum. It’s a ConMet hub right?
9. I have a spun bearing cup in my front hub. What causes this?
10. I have a ConMet front hub for an inboard-mounted brake drum.  Is there a replacement?
11. What is LMS™?
12. What lubricant should I use in my hubs?
13. I can’t find replacement parts for my PreSet hub. What do I do?
14. My hub is running very hot. Should I be concerned?
15. Can I convert my hub-piloted hub to a stud-piloted hub?
16. A ConMet representative said I have a “small-backface” hub. What does that mean?
17. Can I convert from dual wheels to a super-single (wide-base) wheel?
18. Is my spindle nut compatible with your PreSet hub?
19. I replaced a competitor’s hub with your front hub and now the ABS bushing on my spider interferes with your hub. How can it be fixed?
20. Why do wheel studs break?
21. What is the part number of my hub?
22. I can’t find replacement bearings for my PreSet hub. What do I do?
23. There is rust all over my spindle, and the hub was difficult to remove. What can I do about it?
24. Someone told me I can’t service the special bearings in your PreSet hub. Is this true?
25. My drum pilot is damaged. How did that happen?
26. What hubcap should I use?
27. Do I have to replace the PreSet spacer when I service the hub?
28. I’m using a super-single wheel or a singled-out dual wheel on my drive or trailer axle. Does that affect my hub load rating?
29. Where do I find parts for my hub assembly?
30. What is the warranty for ConMet hubs and what is covered?
31. Where can I get more information?
32. Will a ConMet wheel stud or axle stud fit my non-ConMet hub?  Can I use a ConMet fastener in my design?
33. I'm experiencing vibration and/or tire wear. How much runout is allowed on my hub?


1. The pilots don’t look like they can support the axle load, why?
The purpose of the pilot bosses is to guide and align the drum and wheels at time of installation. For stud-piloted hubs, the wheel nuts are used to guide the wheels in place. Once the wheel nuts are torqued, the tire load (and braking load) is transmitted to the hub by friction through the mounting interface. The pilots take no load during service and only support the weight of the wheel and drum at installation. (Figures 1 and Figure 2)

back to top

2. Why do stud-piloted front hubs come with two different stud sizes?
The standard sizes are 1-1/8 inch and 3⁄4-inch studs. The larger studs were created to give the same outer wheel nut as used on the drive hub. The 3⁄4” stud uses a different nut than the drive hubs but the same installation socket. The reason the smaller studs are used is to save weight.

back to top

3. I have a wheel for a stud-piloted mounting system. Does it work for both 3⁄4-inch and 1-1/8 inch studs used on front hubs?
Yes. For the 1-1/8 inch stud, the same nut can be used as for the outer wheel of a drive or trailer hub dual-wheel application. A different, unique nut is used for the 3⁄4-inch stud.

back to top

4. Can I convert my stud-piloted hub to a hub-piloted hub?
Stud-piloted front hubs can be converted to hub-piloted hubs only if they originally came with “convertible” 3⁄4-inch studs, which have the same diameter shank as the studs for the hub-piloted configuration. When converting, verify the drum pilot diameter on your hub matches the pilot diameter needed for the drum you will use. The current standard drum pilot diameter is 8.78 inches. Verify there is a wheel pilot on the hub beyond the drum pilot. Contact ConMet Customer Service at 800-547-9473, if you require assistance determining the drum pilot diameter on the hub. Contact your drum manufacturer for their pilot diameter.

back to top

5. Do I have to service my hubs? When and how?
ConMet Service manuals are available which detail the service required for PreSet ® hubs. For oil-lubricated hubs and hubs using semi-fluid grade 00 grease, see manual 10005642. For non-PreSet hubs, refer to your OEM for service requirements.

back to top

6. I have a Q-spindle drive hub. What is the replacement?
ConMet no longer manufacturers Q-spindle drive hubs or an equivalent replacement. Contact your dealer for replacement options.

back to top

7. Can I take the spacer out of my PreSet hub?
Yes, if you are willing to convert to a manual-set bearing configuration. The spacer is required to properly space the bearings of a PreSet hub. It is clamped between the two bearing cones with a high spindle nut torque. Once removed, the hub can be used by setting the bearing endplay manually as you would any other hub.

back to top

8. My hub is aluminum. It’s a ConMet hub right?
Not necessarily. There are some other manufacturers that make or have made aluminum hubs. Check for a ConMet logo cast into the hub, or verify the part numbers stamped or cast into the hub with ConMet Customer Service at 800-547-9473, to be sure.

back to top

9. I have a spun bearing cup in my front hub. What causes this?
Axle overloading is the most common cause, but a low lubricant condition can also cause this.

back to top

10. I have a ConMet front hub for an inboard-mounted brake drum.  Is there a replacement?
ConMet hubs with a 6.12" flange offset for use with an inboard-mounted drum (drums mounted to the inside of the hub flange) can be replaced with a hub having a 5.44" flange offset and an outboard-mounted drum.

back to top

11. What is LMS™?
LMS, or “Low Maintenance System”, is a Dana designation for a series of products designed for low maintenance. ConMet manufactures some hubs used by Dana under this designation. Consult Dana for warranty, service, and maintenance for LMS hubs. The hubs are usually identified by a yellow ring present in the spindle nut assembly or they may be identified by an LMS hubcap.

back to top

12. What lubricant should I use in my hubs?
For PreSet hubs, contact either your OEM or ConMet Customer Service at 800-547-9473, for an approved lubricant list based on seal compatibility. Refer to ConMet service manual 10005642 for recommended filling practices. For non-PreSet hubs, consult your trailer or tractor OEM for approved lubricants and filling recommendations.

back to top

13. I can’t find replacement parts for my PreSet hub. What do I do?
ConMet sells parts kits for each PreSet hub type. See ConMet service manual 10005642 for a complete parts list, or by calling ConMet Customer Service at 800-547-9473, for assistance.

back to top

14. My hub is running very hot. Should I be concerned?
There is no concern unless the hub is hotter than 150°F above ambient temperature. Hub temperature will run a little warmer than usual for a new hub while bearings are “running in”. Variation is also due to axle load, hub endplay, low lubrication level in the hub and braking variations in service. An overheating hub is an indication of a failing bearing, overloading, or heavy braking application. To determine the cause, check the hub after runs without excessive braking or axle loads.

back to top

15. Can I convert my hub-piloted hub to a stud-piloted hub?
ConMet hub-piloted hubs can be converted to stud-piloted 3⁄4-inch studs using “convertible” studs, if available. Front hubs cannot be converted to 1-1/8 inch studs. Compare the drum pilot diameter on your hub with the pilot diameter needed for the drum you will use. The current standard drum pilot diameter is 8.78 inches. Contact ConMet Customer Service at 800-547-9473, if you require assistance determining the drum pilot diameter on the hub, and for availability of convertible studs. Contact your drum manufacturer for their pilot diameter. If you have an 8-stud hub, there is no conversion, as the stud-piloted hubs only exist with 10 studs. A stud chart is included below for reference. Measure the thickness of the flange through which the wheel stud is mounted.

STUDS TO CONVERT FROM HP (hub piloted) TO BSN (ball seat nut-same as stud piloted)
SYSTEM (NOT APPLICABLE FOR SUPER-SINGLE WHEELS)

16. A ConMet representative said I have a “small-backface” hub. What does that mean?
A small-backface hub has a flange outer diameter that is slightly smaller than usual. Hubs of this type were made specifically to clear the inside of certain drums that do not meet SAE J1671 recommendations. Most drums do not require this special modification.

back to top

17. Can I convert from dual wheels to a super-single (wide-base) wheel?
Yes, but there are several considerations:

1) The required stud length may be different.
For hub-piloted applications using 22mm 2-piece flange nuts, a minimum length is required for proper thread engagement to the nut. All ConMet trailer and drive axle hubs designed for dual wheel applications can be used with wide-base wheels. This assumes a 1/2" brake drum thickness, 1.13" wheel disc thickness and a 1.19" nut height, giving a minimum required stud standout of 2.94 inches from the hub flange. A longer stud, while affecting appearance and socket fit, is also acceptable. Some available nuts include: Metform 39627 (1.06" height) and Hayes Lemmerz 90846 (1.19" height).
For stud-piloted applications on drive and trailer hubs: All ConMet trailer and drive axle hubs designed for dual wheel applications can be used with wide-base wheels. Standard ball seat cap nuts for single or outer dual applications can be used for steel wheels. The thread size is ¾"-16. For aluminum wide-base wheels, ConMet recommends Alcoa 5995R/L cap nuts, or equivalents, which have been engineered to fit wide-base wheels.

2) For super-single (wide-base) wheels on drive and trailer hubs the hub will be derated for load for wheels over 1" offset. See ConMet Technology Bulletin 1009934 "Wheel End Load Ratings for Hubs Used in Single Tire Applications" for further details.

IMPORTANT: Outset wheel may decrease the load rating for other components such as axles and bearings. Manufacturers of those components should be consulted for approved load ratings. Many manufacturers of axles wheel end components recommend that the P type spindle be used in conjunction with outset wheels.

back to top

18. Is my spindle nut compatible with your PreSet hub?
All PreSet hubs require a spindle nut torque of 300 ft*lbs, with increasing torque as necessary to advance to the next locking interval. ConMet does not specify or recommend specific spindle nuts. The nut manufacturer should be consulted to verify the nut can withstand the specified torque.

back to top

19. I replaced a competitor’s hub with your front hub and now the ABS bushing on my spider interferes with your hub. How can it be fixed?
The bushing can be tapped back using a soft-faced mallet. It will then clear the hub.

back to top

20. Why do wheel studs break?
The cause of wheel stud breakage is almost always incorrect torque on the wheel nuts, either too high or too low. ConMet wheel studs meet or exceed SAE grade 8 specifications and should not fail when proper torque is maintained at 450-500 ft lbs.
back to top

21. What is the part number of my hub?
There are potentially 4 part numbers applicable to the hub. In order of usefulness, they are: PreSet number, Assembly number, Machining number, and Casting number. The first 3 numbers are stamped into the hub, usually on the inboard or outboard of the flange, or on the outer diameter of the flange. Sometimes the number will be stamped into the barrel of the hub. The number will be 6 to 8 digits long, followed by a revision designation of either a dash or a letter. The assembly number is usually included in a string of other identifying numbers. The casting number is cast in to the hub and is present on either the inboard or outboard side of the flange. It also is a 6 to 8 digit number with a revision letter. Contacting ConMet Customer Service at 800-547-9473, with any of these identifiers will aid in identifying your hub.

back to top

22. I can’t find replacement bearings for my PreSet hub. What do I do?
ConMet’s PreSet line of hubs use specially-toleranced bearings having tighter tolerances than industry-standard bearings. That aside, they are interchangeable with industry standard bearings. ConMet sells bearing kits for each PreSet hub type. See the chart below. If necessary, industry standard cups or cones can be used, but the hub must be converted to a manual-set bearing configuration by removing the bearing spacer and setting the bearings manually. The hub can be converted back once the specified PreSet bearing for PreSet is obtained and installed.

23. There is rust all over my spindle, and the hub was difficult to remove. What can I do about it?
Aside from outside contamination, this is normal fretting corrosion and is related to the small movements of the bearing against the spindle in service. The effect of fretting can be greatly reduced by applying a coating of grade 2 grease to the spindle bearing journals before installing the hub. In severe cases, the bearing cones will adhere to the spindle and require a special tool to remove the hub. The spindle can be reconditioned with emery cloth or a fine sand paper to remove the excess rust before installing the hub. Consult your tractor or trailer OEM, or the axle manufacturer in cases of severe spindle damage.

For more information, refer to the Field Service Bulletin entitled "Removing Frozen Hubs from the Spindle".

back to top

24. Someone told me I can’t service the special bearings in your PreSet hub. Is this true?
No. ConMet’s PreSet line of hubs use specially-toleranced bearings having tighter tolerances than industry-standard bearings. That aside, they are interchangeable to industry standard bearings. ConMet sells bearing kits for each PreSet hub type. See the chart above. If necessary, industry standard cups or cones can be used, but the hub must be converted to a manual-set bearing configuration by removing the bearing spacer and setting the bearings manually. The hub can be converted back once the specified PreSet bearing is obtained and installed. All PreSet bearings are marked with their part numbers by laser or stamping.

back to top

25. My drum pilot is damaged. How did that happen?
A damaged drum pilot is usually caused by installation damage, where wheel studs are torqued with an unseated drum. The drum is not allowed to rise over the pilot and slides into it, destroying the pilot surface. This can be prevented using proper installation techniques described in ConMet service manuals: One pilot aligned on top of the hub, tighten the top wheel nut first to seat the drum. Pilot damage can also occur when the drum or wheels slip in service, as allowed by insufficient wheel nut torque.

back to top

26. What hubcap should I use?
PreSet hubs must use an approved PreSet hubcap to maintain warranty. See chart below. For PreSet front hubs refer to your OEM tractor manufacturer for requirements. ConMet does not specify hubcaps for Non-PreSet hubs. For non-PreSet hubs, refer to your OEM for requirements.
Axle Applications:
Meritor - TN, TQ
Hendrickson HN
Dana Spicer - D-22
Ingersoll - A22

Axle Applications:
Meritor - TP
Fruehauf - ProPar
Dana Spicer - P-22
Ingersoll - A24
Hendrickson HP

back to top

27. Do I have to replace the PreSet spacer when I service the hub?
The PreSet spacer is reusable. It does not crush or deform in normal service. If the hub was accidentally run with manually set bearings, the spacer should be replaced as wear on the ends has likely changed its length which is critical for proper endplay. Contact ConMet Customer Service at 800-547-9473, for a replacement.

back to top

28. I’m using a super-single wheel or a singled-out dual wheel on my drive or trailer axle. Does that affect my hub load rating?
Yes. For super-single (wide-base) wheels on drive and trailer hubs the hub will be derated for load for wheels over 1" offset. See ConMet Technology Bulletin 1009934 "Wheel End Load Ratings for Hubs Used in Single Tire Applications" for further details.

IMPORTANT: Outset wheel may decrease the load rating for other components such as axles and bearings. Manufacturers of those components should be consulted for approved load ratings. Many manufacturers of axles wheel end components recommend that the P type spindle be used in conjunction with outset wheels.

back to top

29. Where do I find parts for my hub assembly?
For a list of ConMet Hub Parts Suppliers in your area call ConMet Customer Service at 800-547-9473, or visit the Sales and Service section of our web site.

back to top

30. What is the warranty for ConMet hubs and what is covered?
ConMet Hub Warranty

back to top

31. Where can I get more information?
Call ConMet Customer Service at 800-547-9473, or browse our Hub Literature Section.

back to top

32. Will a ConMet wheel stud or axle stud fit my non-ConMet hub? Can I use a ConMet fastener in my design?
No.  ConMet studs are designed for use only in ConMet hubs and should not be used in any other brand of product.  Aftermarket sales of ConMet studs is intended for replacement of parts in service.  Hardware for general use should be obtained from aftermarket stud manufacturers.

back to top

33. I'm experiencing vibration and/or tire wear. How much runout is allowed on my hub?
Up to .008 inch axial and radial flange runout is allowed relative to the axle. The wheel and drum pilots can be confirmed by measuring the outer flange since they are machined at the same time. During measurement the bearings must be set with zero endplay. The PreSet ® or LMS™ spacer between the bearings, if one is present,  must be removed to accomplish this. Take care not to misalign the seal when the outer bearing cone is removed to access the spacer.  Apply light torque to the spindle nut while rotating the hub to assure there is no endplay. When measuring radial runout, take readings between the wheel studs, as there will be a slight bulge in the flange near the studs. Make sure all surfaces are clean and in good, undamaged condition, or the resulting value could be in error. The gage should be mounted rigid relative to the spindle or to ground (See images). Hubs returned for warranty consideration with excessive runout from a manufacturing defect will be honored if the runout is verified to exceed .008 inch.

Radial Runout	Axial Runout

back to top