DNM-USD-8S

Does this suspension fork require a standard hub or boost hub? The axle is 20*110mm
I emailed DNM directly and the only information they give me is the size of the axle but not sure if I should use boost hub or Standard?

So I have a downhill fork on my ebike now but it’s super budget and I don’t trust it. I don’t think it’s strong enough to support the weight of my E bike. Well the DNM is budget as well but it seems to be built strong. So I’m considering buying this DNM and building a new front wheel. My current front wheel is also budget and just don’t trust my current fork wheel combo. Now being I laced up my hub motor which was my first wheel build I would like to go for my second build. have an halo sas rim. Just need to get a hub and spokes and lace it up! Looking at the Hope pro4 hub. If anyone would like to add their 2cents that would be great!

Also there’s many topics on es about the USD but I can’t seem to find an answer if hub should be boost or not.

110 mm is the width of the fork.

https://www.dnmshock.com/upload_files/products/7/usd-8coil.pdf

Standard hub width is 100 mm
Boost hub width is 110 mm

You need the hub to match the axle size and width of the fork of course, that would be 20X110.

Yet, don’t expect much of it. It is a fake Chinese DH fork, that has nothing to compare with common DH racing forks, even the old ones 10-15 years old. They are OK for the streets, but more a matter of looks and style than performance.

E-HP said:

Standard hub width is 100 mm
Boost hub width is 110 mm

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Really? they sell Standard hubs that are 20mm by 110mm.
From everything I’ve read online boost has wider hub flanges for the spokes to create a better angle. It also has a wider mount for rotor. That’s what makes it confusing is because the boost hub and standard hub can have the same exact axle diameter and width.

MadRhino said:

You need the hub to match the axle size and width of the fork of course, that would be 20X110.

Yet, don’t expect much of it. It is a fake Chinese DH fork, that has nothing to compare with common DH racing forks, even the old ones 10-15 years old. They are OK for the streets, but more a matter of looks and style than performance.

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Right, I know it’s not a real DH fork and it’s no fox 40 :lol: I’m just looking for something stronger than my other fake Chinese DH fork :lol: I just can’t kick out $1800 for the fox 40. Also don’t do any extreme riding Just some mountain bike trails but no jumping on this bike setup.

Since the standard hub and boost hub can be the same size it makes it confusing. The hope pro4 hub comes in 20 x 110 both standard and boost

OP, I take it that you have what I'll call the "original standard" DH front hub...110mm spacing with a 20mm axle. This boost thing in newer hubs doesn't change the spacing but does change the offset as already pointed out. You can use the old standard 20 X 110 hub on the newer boost 20 X 110 with a spacer kit, but if I under stand correctly you can't go newer boost 20 X 110 hub on an older 20 X110 standard fork. Surprisingly at this point, the older standard 20 X 110 hubs are still readily available, and there are still a few new forks using it.

On your initial request about a better budget fork for your 20 X 110 fork, I'd suggest the RST Killah dual crown. These are often installed on the Sur-Ron e-motorcycle. Luna has them for $500. You can also find them from Sur-Ron owners who have replaced them with Fox 40's and similar DH MTB forks. That's what I did. Have you seen the vid from Luna where they have a comparison on the forks offered on the Sur-Ron? It's about the forks and not so much about the Sur-Ron. It's quite informative about the RST in particular.

And like you stated earlier, the RST is not a Fox 40. However, it is head and shoulders above the DNM. It is an actual cartridge for with low/high compression tuning and single rebound tuning. It can be tuned with Rock Shox Boxxer springs if you don't like the OEM spring weight. I have an RST Killah on an '08 Santa Cruz Nomad with a Bafang BBSHD mounted. I'm a coil fork and shock guy personally. This fork performs above its price range IMO. It is not a Chinese pogo stick like some of these offerings. If you do a Youtube search for "servicing the RST Killah fork", you'll see a vid from the Outline Downhill Shop where one is completely disassembled and serviced. You can see how the fork is built and the internal components. While it is not a Fox 40 and such, it is a surprisingly decent fork as long as you don't intend to do the Red Bull Rampage and World Cup Tour...LOL!

OP on an unrelated point, it sounds like you're running a hub motor bike for what sounds like an aggressive mountain bike...since you're running a dual crown fork. Just curious, what kind of bike is this? I would think a mid-drive would be better suited to an aggressive MTB. Not an argument, just curious.

TNC said:

OP, I take it that you have what I'll call the "original standard" DH front hub...110mm spacing with a 20mm axle. This boost thing in newer hubs doesn't change the spacing but does change the offset as already pointed out. You can use the old standard 20 X 110 hub on the newer boost 20 X 110 with a spacer kit, but if I under stand correctly you can't go newer boost 20 X 110 hub on an older 20 X110 standard fork. Surprisingly at this point, the older standard 20 X 110 hubs are still readily available, and there are still a few new forks using it.

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OK great thanks for the info, so it sounds like I need the older standard 20 x 110 hub, Correct?

TNC said:

On your initial request about a better budget fork for your 20 X 110 fork, I'd suggest the RST Killah dual crown. These are often installed on the Sur-Ron e-motorcycle. Luna has them for $500. You can also find them from Sur-Ron owners who have replaced them with Fox 40's and similar DH MTB forks. That's what I did. Have you seen the vid from Luna where they have a comparison on the forks offered on the Sur-Ron? It's about the forks and not so much about the Sur-Ron. It's quite informative about the RST in particular.

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Yes I looked into the RST dual crown but I’m running 27.5 and it looks like the max wheel size is 26”

I tried to find the video you’re referring to about the comparisons but I couldn’t find, if you have a link that would be great.

TNC said:

OP on an unrelated point, it sounds like you're running a hub motor bike for what sounds like an aggressive mountain bike...since you're running a dual crown fork. Just curious, what kind of bike is this? I would think a mid-drive would be better suited to an aggressive MTB. Not an argument, just curious.

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Yes that’s correct hub motor. I’m running a mxus 3k 5T. I’m pushing right under 6kW. The reason I run the dual Crown is to create extra space between the bikes down tube and the front wheel. I have the battery installed on the bottom side of the Down tube and then I made an ABS plastic case for a cover. The battery case also has some storage at the very top with a removable lid. That’s the main reason for using a downhill style fork is just so I can have the clearance. Also I love the upright riding position as well 8)
Now with full compression the tire can actually rub the battery housing but I could limit the travel by installing stoppers. Current fork I don’t have stoppers installed as I don’t push the bike where it ever goes to full compression.

And yes I completely agree with you that mid drives are better for aggressive mountain bike riding. That being said I do light trail riding and most of the time is on either tarmac sidewalks greenways etc. So yeah I ride on mountain bike trails as well but nothing crazy with that heavy hub motor in the back :lol:

The bike is a Schwinn, it’s called protocol 2.7
The bike frame itself is budget as well but as you mentioned I don’t plan on doing any Red Bull Rampage or World Cups either :lol:
I bought the bike brand new for around $400 and then converted it. The bike frame is the only thing that is original.

Also thanks for sharing the bike picture! I love seeing other peoples custom built bikes. So I guess your battery goes in a backpack?

Yes, I use a battery/backpack setup.

On the hub for your fork, I'm pretty sure DNM has not moved to the "boost" hub. And on the RST Killah, the 26" dual crown will take a fairly large 27.5 tire and wheel. Mine accepts a 2.35 X 27.5 with plenty of room. The RST uses the original standard 20 X 110 hub. Here's the link to the fork comparison from Luna:

https://www.youtube.com/watch?v=LJ33aqBfS48&t=278s

Here's the one on the internals and service:

https://www.youtube.com/watch?v=N3vWy9Ph6IQ

TNC said:

Yes, I use a battery/backpack setup.

On the hub for your fork, I'm pretty sure DNM has not moved to the "boost" hub. And on the RST Killah, the 26" dual crown will take a fairly large 27.5 tire and wheel. Mine accepts a 2.35 X 27.5 with plenty of room. The RST uses the original standard 20 X 110 hub. Here's the link to the fork comparison from Luna:

https://www.youtube.com/watch?v=LJ33aqBfS48&t=278s

Here's the one on the internals and service:

https://www.youtube.com/watch?v=N3vWy9Ph6IQ

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Thanks for clearing the RST Fits 27.5. Now I see that after researching the RST more. I can’t seem to find the measurement diagram for the RST though. The the axle to crown measurement is super important in my situation because of the battery clearance. The DNM axle to crown measurement is 563mm, slightly longer than my current fork so that would give me more clearance. I’m not sure if you seen any diagrams for the RST or if you could measure the axle to crown measurement?
My current axle to crown is 21 5/8”

I just measured mine. It's 22.75" from the center of the axle to the top of the crown at max extension. I run mine with .75" pushed up through the top of the top triple clamp. It works with the geometry of my bike.

Eastwood, can you clarify something? I see the thread seems to be about the DNM-USD-8S. I thought you meant you had that fork on the bike. I'm guessing you meant you're considering that fork? I've seen the internals on that DNM, and I wasn't that impressed. However, for the reason you're using a dual crown and how you'll use it, it's not extremely critical to reach Fox 40 performance.

Learned a lot from this thread :thumb:
Will come in handy in the future.

TNC said:

I just measured mine. It's 22.75" from the center of the axle to the top of the crown at max extension. I run mine with .75" pushed up through the top of the top triple clamp. It works with the geometry of my bike.

Eastwood, can you clarify something? I see the thread seems to be about the DNM-USD-8S. I thought you meant you had that fork on the bike. I'm guessing you meant you're considering that fork? I've seen the internals on that DNM, and I wasn't that impressed. However, for the reason you're using a dual crown and how you'll use it, it's not extremely critical to reach Fox 40 performance.

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Great, thanks for the measurement!

Yes I’m considering the DNM. My current fork is the one I’m concerned about, it was super cheap. It works great but it’s just not designed for a 85 pound eBike