State of the art: MX vs DH MTB suspension

[flat tire]

TL;DR off the shelf MX vs downhill MTB suspension...which one's better / more advanced? Why?

I'm pretty ignorant on suspension. I've mostly learned by doing and until I first swung a leg over a motocross bike a couple years ago I didn't really understand that "full suspension" can provide an extremely wide range of actual user experience. Wow! That suspension is __AMAZING__ compared to the 4" travel on my Gary Fisher.

Motocross suspension is unbelievable if you haven't experienced it, and a wonder if you have. You get good adjustable damping, great stiffness, and really easy rebuildability. OE level race bikes you or I can buy off the showroom floor come with fully adjustable high and low speed damping front and rear and for the class leading bikes, technology that is at most only a few years old. There are lots of air forks although they have not completely worked out all the issues. Also, MX suspension gives 12" of wheel travel which is amazing. I consider it the benchmark by which all other suspension should be judged, since it's developed and proven by dudes going as fast as possible and doing jumps on the most crazy and rough terrain in existence.

Anyway recently I got a Orange 322 with Rockshoxx Boxxer World Cup fork and Vivid rear shock. 8" travel front and 9.5" rear. Since I don't plan to do any triples or anything on the bike that should be enough. Haven't electrified it yet so I can't really tell much about how it rides. I can't pedal it fast enough to make anything interesting happen. The fork is not optimized for low unsprung mass and max stiffness, and it seems that upside down forks haven't really taken over yet in MTB. I guess this is because the advantage is marginal and more importantly DH MTB may be mostly dominated by talent and conditioning.

Barring any severe injuries this is slowly changing, but I'm not a skilled rider so unless the suspension on my bike is downright deficient I won't have a problem keeping it. At the same time, I'm a gear slut so upside down forks with 4 way damping adjustment are definitely on the radar.

If my bike has top end off-the-shelf downhill MTB suspension, how good will my suspension be compared to a MX bike? Obviously both will be tuned by a person of equivalent skill.

 

[flat tire]

93 views and nobody has anything to say about this highly interesting topic? I don't believe it.

 

[boytitan]

Because the mx suspension designed for faster speeds, bigger jumps and more weight would be better.

 

[macribs]

I know of only one that already has a mx shock in the rear of an electric bike, check out his radical carbon frame with and insane QS 273 motor. Try asking him about the shock he is using and how it performs compared to DH rear shock.

One thing I've noticed is that when using a heavy hub in a heavy mx rim with mx spokes and tires the weight adds up a little too fast. For daily riding around town DH shock is just fine, but if I ride dirt roads with several deep bumps in a row at speed the rear shock struggles to keep the wheel down, and 3 or 4 bumps in the rear wheel is bouncing up too high and too fast to my liking, and I can't seem to be able to dial that away. I think for such settings a better shock n spring would help a lot. I think the huge mass of the wheel/motor/tire is too much for the shock, as both bike and rider are heavy too.

Click the pic to read all of his thread, 6 pages long as of today.

 

[Offroader]

93 views and nobody has anything to say about this highly interesting topic? I don't believe it.

I did some research into this a while back. It does make sense to use an MX shock in the rear because it is built more for a heavier MX rear wheel than a light weight bicycle rear wheel.

I believe the stealth bike bomber uses an MX rear shock or a pit bike shock.

The front fork you are better off going with a downhill fork because an MX fork is too heavy and a downhill fork works fine.

There are not many people interested in suspension on the forum, so you don't get many people experimenting with this. The other issue is using an MX rear shock will require you to have different mounting hardware and also you will have to match the right travel. This is kind of out of many peoples hands here as frames are designed for bicycle shocks.

If you are willing to do the research and testing, would be great to hear your results. I can tell you that switching to a 5lbs lighter rear hub motor has made a big difference in the rear. Maybe it is possible a rear shock would also make a big difference. My issue is that the rear will get thrown up violently when hitting objects at higher speeds, I assume this is because of heavy mass being bounced upwards.

 

[Offroader]

One other option may be to have someone make a custom ebike shock.

The problem with an ebike is that it is in between a MX bike and a downhill bike in weight. What happens is that MX parts are built too heavy for an electric bike, and MTB/downhill parts are built too light.

What if there was a shock designed specifically for an ebike?

I always thought of contacting a shock company like avalanche who makes custom shocks and tunes for bicycles, and see if they can design a shock built for an electric bike.

This would possibly have them tune the shock for the heavier rear wheel of an ebike.

http://www.avalanchedownhillracing.com/index.html

 

[E-geezer]

A custom tune will make a world of difference in suspension, most mtbs, even those with high quality suspension components are not set up correctly and ride OK, but not as good as they would if done right. I bet Avalanche or any of the other suspension shops would be able to build you a rear shock that can deal with the extra weight.

I'd venture that a top shelf DH bikes could give you a ride similar to a mx bike, just scaled down due to less travel and lighter components. Bike suspension systems are also compromised by trying to provide a pedaling platform that you don't have to worry about with an ebike.

Check these out if you want to learn how to tune your suspension.

https://www.youtube.com/channel/UCIF1fjRe-xXWztlig1TiT5g