Benefits of metal hubs

How-Tos & Esk8 mechanics
#41

I know cost was already mentioned but a set of 4 etoxx hubs costs the same as 20 MBS rockstar 2’s.

l brought some metal megastars in the past when I wanted a shiny Street board, but the more I ride off-road the more I appreciate cheep hubs. Lighter & more resilient.

the weight saving is enough to carry a complete spare wheel, and the cost saving is enough to buy an entire extra set with different tyre setup for different conditions (and still have cash left over).

I guess they are not shiny. Plastic hubs do not win dick waving contests.

13 Likes
#42

True. They win in every other metric though. The best hubs I have ever used are MBS Rockstar 2! You just cannot beat them - they are symultaneously the cheapest and also the highest performing hub available in my opinion, really it just doesn’t get any better for eMTB.

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#43

fivestar, lighter and take 9" tyres :rofl:

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#44

Lighter the hanger, motors and wheels are, (unsprung weight) the quicker the axel will recover when unwanted action is introduced.

I would like to see the motors be remote from the hanger some day.

11 Likes
#45

Speed rings and spacers ABSOLUTELY have a lot to do with squareness to the hub. When you lock it all up as a package, it runs true. It also ignores the imprecision of the axle not being true and to size. They all must however be flat. And correct dimensions.

As far as I know, all plastic wheels, are in two parts. Or more.

1 Like
#46

HAving light hubs, plastic, makes the ride a lottttttttt more busy. UNSPRUNG suspension, does NOT take advantage of lower unsprung weight.

#47

Doesnt that also raise the resonant freq, and thus initiate a speed wobble easier?

#48

Hmm maybe I’m missing something. Isn’t this all about how much weight is effectively below the suspension (meaning not held up by it), which causes the truck to react more slowly because of additional weight, hence @MoeStooge’s desire to move the weight to the board?

Could you clarify what you mean by “unsprung suspension?”

#49

Generally electric skateboards dont have a suspension. So, a heavier hub will ride smoother. Particularly on stutter bumps. Might not have as good a grip at the limit. But I cant get my board to slide anyway.

Mine is a street board.

#50

OK, I think I get you. I was thinking about the design of the Apex trucks. That hanger can move up and down, though I realize with bushings there’s not much travel to say the least and most of the “suspension” if coming from the deck and our knees so the best place to lose weight is on my body. :sweat_smile:

#51

Probably not lol. You can try though. I want video.

1 Like
#52

But look worse with an 8 inch tyre on them. 9 inch tyres are fun but ultimately too heavy for proper eMTB imo = beginner mode.

@goodmove yeah we have found that the lighter trucks make a huge difference to the way the board reacts. It makes the trucks more nimble and allows them to react to the terrain with less lag which increases control and grip.

4 Likes
#53

Agreed: when you stack hanger + spacer + bearing + spacer + bearing + speed ring + nut, you get a rigid (non-rotating) assembly.

But no, if your axle is not a precise diameter or is out of round , a spacer isn’t going to magically make your bearings not wobble all over the place from a loose fit. Again, spacers space - they only constrain the degree of freedom of side to side movement. If you’ve got precision bearings on sloppy axle, your wheels are going to bounce up and down.

Show me a spacer with tighter dimensions than a Swiss/Japanese ball bearing inner race and I’ll show you a guy who spent too much on spacers.

To get a wheel to run true, you need (among other things) a precise and rigid hub bearing seat, high quality bearings, and a precise axle. You do not rely on cheap aluminum spacers to stop your hub from wobbling, while your bearings float in mid-air. You’re arguing that spacers and speed rings are doing the job of the axle.

To your original claim - you could run high quality plastic (nylon, PTFE, delrin, etc) spacers and be fine as long as the assembly was rigid enough.

2 Likes
#54

I can barely get by on 9" tires and my hangers are getting destroyed by rocks.

1 Like
#55

I’m interested in how applicable the techniques of (automotive) motorsports are to our particular motor sport. Whether it’s rally, nascar, motoGP, the local drag strip, or autox, almost everyone uses the lightest possible hubs they can get away with that are still strong enough not to deform when hitting a pothole/bump/curb.

The beneficial effects of smaller diameter and lighter weight wheels have been investigated and debated for decades. A reduction of 10 lbs per corner (on a 3500 lb vehicle = 1.15% change), has a noticeable and measurable impact on steering effort, acceleration and braking distances (quicker to start and stop due to reduced rotational inertia), fuel economy, ride quality (less sensitive to bumps), not to mention the umbrella benefits of less unsprung weight.

When a heavy wheel runs over a bump in the road, its entire mass is sent flying up towards the top of the wheel well. The inertia it carries as it travels is countered by the car’s suspension, forcing the wheel back onto the road surface. The heavier the wheel, the higher it will jump off the road when faced with road imperfections.

On the other hand, a light wheel has less mass. Running over a bump with a light wheel means that your suspension has to counter much lower inertia forces, allowing it to force the wheel back to the road with less effort. More lightweight wheels are much quicker to reestablish grip.

But wait, wheels are just one, albeit a large part of the equation. You also need to account for brake rotors, lug nuts, and just about everything else that is considered unsprung. Once you fine-tune the suspension to perfection, even a hubcap can become an issue.

As far as hitting bumps goes, TKP/RKP/PKP bushings act exactly like a car’s suspension (with a rigid axle to boot) for argument’s sake.

Hub Weight Comparision (Set of 4):

  • RockStar Pros (aluminum) = 677.6g
  • RockStar IIs (nylon) = 567g
  • FiveStar (nylon) = 657.7g
  • Hypa (fancy plastic) = 616g
  • Primo (fancy plastic) = 1128g
  • Megastar (aluminum) = 1144g
  • Deepdish Megastar (aluminum) = 1556g
  • Superstar (fancy plastic rim, alum center) = 746g
  • Phatlads (fancy plastic) = 1080g

On a 15kg (33lb) board, choosing the Rockstar IIs over the Superstars saves you about 180g aka (180/15000 * 100=) 1.2%.

Swapping from the Deepdish Megastar chunky bois to RockStar IIs saves you almost 7%!

Edit:
Related fun fact - if you’re using 170kv motors on a 12s (52V) pack, your theoretical max motor rpm is about 8800 rpm. At 4.0 gear ratio, that’s about 2200 wheel rpm. At 100 km/h (60mph) your car is somewhere around 900 wheel rpm. So the rotational mass/inertia effects are similar or even more pronounced (assuming I’m doing this math correctly)

5 Likes
#56

Imo only the looks of metal hubs outweigh all the negative stuff even if there are any.

#57

I think MBS RockStar 2 are the best 8 inch hubs.

MBS FiveStar et Trampa Phatlads are both good 9 inch hubs and Trampa Phatlads fit 10 inch tyres.

With Trampa, stay away from any hub that uses the aluminium spokes. They fail in making balanced ones. I got rid of my MEGASTAR hubs because of that. They let you use counter balancing bolts but the bearing seat is not centered… It’s crazy.

Yet, I think there is no use of metal in hubs for us. I don’t use high presure for tyres because it’s very unconfortable when going off-road. It’s a lot heavier. If it was relative to sport cars then you’d have to pay a lot more for lighter but still strong nylon hubs.

2 Likes
#58

I never did the maths on this but I’m convinced that for our purposes, the performance impact from differences in hub weight is about as significant as what you ate for breakfast.

In case someone wants to work that out, I run Rockstar II’s and ate Weetabix.

1 Like
#59

Add another 10A of breaking and probably its more than compensated :smiley:

#60

I’m late to that party :man_shrugging:

Well first of all I have 38 hubs at home :rofl:
16 x Superstars, 4 x Rockstar II, 4 x Fivestars, 12 x E-Toxx and 2 wobbly chinese metal hubs.

Superstars, I had 12 in the beginning and was shocked how wobbly they are and how bad the bearing seats are. The bearings are so loose that they rattle and the whole wheel moves sideways. Also the combination of bearing spacer and o-ring makes it much worse. I filed custom spacers for each hub to solve this issue. The rattling bearings I glued with Loctite 641 (medium strength retaining compound). From 16 hubs only 2 run roughly true.

For the Rockstar II i also made spacers but the bearings have a bit play which makes the wheel rattle. I can’t use retaining compound on plastic and also the bearing to bearing distance is wider. That’s why I never used them but I understand why most of you like them. They run (almost) true which is great and they are cheap.

The fivestars are dyed and wavy so never tried them (got them additional when I bought trucks from a forum member).

From E-Toxx I have a set of V1, V2 and V3 offset hubs. V1 was a bit wobbly but V2 and V3 run perfectly true. A set of 4 hubs weights about 0.3kg more than Superstars. V2 and V3 have 3 bearings each hub and no spacer at all which means no rattling, it is like one with the truck. I can’t stand rattling and wobbling (bad for the drivetrain, bearings and my soul) so even this 2 reasons justify the price for me. Not to mention the bad ass look and the wide patch of the tires.

On my 2 MTB’s I use them and haven’t manage to bend or destroy one and I try my best :laughing:
But it’s 7075 alloy so they should last a while.

I have no experience with other metal hubs.

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