Well, I dun goofed up. It clearly won't be the last time, but this one stings a bit because I deprived a very clever man named Miloš Musil,
@mmbike68 on Pinkbike, out of some well-deserved attention. I'm talking about the wild looking single-sided suspension fork that popped up on Spaziale Compositi's Instagram feed awhile back, a fork (strut?) that very much looked like it came from the admittedly strange Italian company. But it didn't. In fact, not only did I get the company wrong, I even flubbed the country that it came from - the Czech Republic.
Thankfully, the real story of this single-sided carbon strut-type thing is far more interesting than what I originally put together, so let's get this straightened out.
Fifty-year-old Miloš Musil originally built his odd creation six years ago, and back then it had 120mm of travel and was bolted to the front of Musil's 26'' wheeled RB Speedster (pictured at right). Until he broke the frame, that is. His new ride, a 145mm-travel Propain Twoface, has 27.5'' wheels and much more travel than the Speedster, so he had to bump up the fork's stroke to a full 160mm to balance things out. That's where it sits right now, but how the MM fork came to be is a whole other story, one that involves Musil using components from four different suspension brands - and a bunch of homemade carbon fiber - to build what you see here.
Musi started with an aluminum crown and tapered steerer unit from a Suntour fork and then bonded in the carbon-wrapped legs from RockShox. The two legs, which look like a single piece once they've been wrapped in carbon, are also joined at the bottom by an aluminum piece that ties them together and serves as home for the Enduro fork seals. The stanchions, also from a Suntour fork, are only 32mm in diameter, but they're both clamped by a massive, CNC'd aluminum lug at the bottom, and the titanium axle is from a Lefty. Talk about mixing and matching.
The fork's chassis is a mix of Suntour and Rockshox components, along with a few homemade parts and some carbon fiber.
Things are just as odd internally, too. Musil has kept the Suntour damper in the leading leg, but the trailing leg houses a Dual Air system from RockShox that allows for independently adjustable positive and negative air spring pressure. If you look closely, you can see the negative air valve on the CNC aluminum lug, and the positive air valve is at the fork crown.
As far as weight goes, Musil leaned more towards reliability than trying to shave grams - probably a smart approach when building your own fork - and he says it weighs about as much as a RockShox Recon, which is still under 5lbs.
The two separate legs are joined by an aluminum span that's home to a set of Enduro fork seals, and the whole thing is wrapped in carbon fiber to increase strength and rigidity.
Musil's completed fork looks wild, but it appears to be finished so well that it could have come off of a (strange) production line.
How does it perform? I'll let Miloš fill us in via Google Translate: ''
The behavior is the same as a conventional telescopic fork. Thanks to the UD [upside-down design], it's better at lubricating bushings and seals, and inner legs are not contaminated from the shell. The fork has great torsional rigidity that's comparable, maybe even better, to Lefty, and it does not flex when pedaling or braking; curves can be ridden much faster than a conventional fork. Another advantage is that it is jednokorunková [single sided], so you can seamlessly mount tires on the wheel.''
I can't tell you if Musil's wild creation is any better than an off-the-shelf fork, but one thing that I am sure of is that, better or not, it's pretty freakin' cool. Much like
Jean-Francois Boivin and his Insolent downhill bike, Musil has used a mix of existing components, carbon fiber, and ingenuity to build something that he couldn't purchase.
actually, you translated it wrong, but you got the point.
"Another advantage is that it is single sided, so you can seamlessly mount tires on the wheel.""
Milos said it incorrect. In czech "jedno/dvou korunkova" means "single/dual crown". He just misspelled.
just think how would single crown (normally expected as 2 legs) would help you with changing tires without unmout wheel.
Kinda like how Rockshox, Fox, Suntour, Manitou, DVO et al all have their take on bi-stanchion (I want credit for this word) and are trying to be better than their competitors. All of these forks (DVO comes to mind) come from people who dreamed them up or were working for one and left for another because they thought they could do it better.
I particularly like this design as it appears you could service it with "regular" tools and service kits. I'd give this thing a try for sure.
I'll be more than happy to test ride the prototype, Mr. Musil!
@Rasterman It sounds like you don't quite have a good understanding of dynamics or fork design... if that's the case it would probably be a good idea that you don't comment on things like this...
Belittling people is just trolling. Only one suspension expert on here, he made those forks.
Waki provides intelligent alternative views and encourages and engages debate. Again never heard him say don't post comments.
You lose your respect for others in this community just because you have been granted anonymity on the Internet.
Why not just cut down an MX coil spring fork? You've got a damping cartridge and spring in both fork legs, so you can pick either and go to town. I think one 49mm stanchion would be plenty for a mountain bike
I’ve seen the exact opposite! People, usually the …spoiled brat’s variety, demonstrate hate when the see something new / homemade / personalized…
The usual words are:
“Kill it with fire!” (Sometimes followed by the most copied, “it looks like a session”!!!)
As for the companies, there IS a great difference. They are supposed to provide mass produced products that will work along with other so we might have a working bicycle. When the various companies introduce strange new sizes and more, they owe first, at least out of respect for the client, to sit down and agree on the new standards.
The rest of us (people), we are free to create. After all these creations made our sport what it is today…
Nothing. That's why they hate new & different things.... This guy is creative, that only makes him a... minority.
Mr. Milos.
If you're going to answer questions, you have to do some seriously filtering. Your design and craftsmanship are, at least, superior.
Thanks for sharing
And, yes. If you can, you ought to do! After all that’s how the whole mountain bike sport stepped into existence…
Great work Milos…
-Borat
But two stanchions on a single sided fork?Why!
It seems to me to be an easier way to manufacture a "lefty" without having to figure out how to package a spring and damper in the same leg and still achieve rideable stiffness.
lots of companies have made internal damping for lefties, not just manitou! easy to service, the telescopic action runs on bearings so they don't wear like conventional forks do. they are stiffer, lighter and stronger than conventional forks..
Either way this does seem like an easier way to build a "lefty." Which begs the questions, why did the lefty get built in the first place? And why do we need any easier way to make one?
Awesome project though.
I also had friends with Lefties and they seemed very hit or miss. Some worked great with little maintenance forever, but others needed constant maintenance. I think the product required tighter tolerances than CDale could deliver at the time. Plus, while spring and damper service was the same as any other fork, bearing maintenance was a royal pain in the ass when needed. Hopefully they've fixed the issues, I'd love to try one again.
Why is this design not universally accepted, patent issues?
Again, what you say is true, some lefties are trouble from the get go, i have been lucky, but we must remember that there are a lot of lefties out there, from an engineering perspective they are the 'rolls royce' of front suspension. Bearing maintenance is a simple gaitor up, clean and smear grease, much easier than replacing stanctions, bushings and seals on regular fork, and much cheaper! The huge benefits and cost saving in the long run make the lefty a wise investment, especially if you ride as much as i do!
You get it, rear shocks perfect example.
Lefties run on needle bearings, two square tubes so no twist, super sensitive, very smooth, no stiction, massive stub axle so stiff and strong, dual crown.
Yes again, patent power! there are adapters now so lefties can be used on most frames.
> yes i have heard/experienced bearing migration, i don't mind doing a quick 'reset' the latest lefties don't have this set up.
The fix is quick, no big deal, but the thing that sucks is you lose travel on big hits and either have to finish your ride with less travel or pull to the side of the trail and fix it.
> Bearing maintenance is a simple gaitor up, clean and smear grease, much easier than replacing stanctions
I'm not sure you've actually performed this service. The Lefty has 4 sets of bearings, each of which has 2 races. All 4 bearings and 8 races will fall on the floor in a heap when you drop the lowers to gain access to these for maintenance.
Now you have to measure all of the races with a micrometer, since they all have different thicknesses depending on the tolerances of your specific fork. You regrease them or order new races and bearings and are ready to put them back in? I hope you wrote down the exact position of each of the 8 races, because the fork won't work properly if you accidentally swap a 0.025" race from one side of the fork with a 0.020" race from the other side.
Ok, you remember to write everything down and have carefully positioned each of the 8 races in the correct place, now you find that you don't actually have enough fingers to hold all of this together as it's reinstalled into the fork, and you have to call a friend for help.
Granted, bearing maintenance intervals are long, and this service is infrequent, but when it needs to be done it is a giant pain in the ass, no doubt about it.
the bearings and races DO NOT NEED STRIPPING FOR MAINTENANCE, if/when the lefty develops fore/aft movement then this can be done simply. nothing 'falls on the floor' unless you have no idea as to what you are doing. i'm not going to waste time explaining, you can make this a big deal or if you are mechanically minded it all makes sense, i won't be asking you to rebuild my motorbike engine! lol.
tools are available for complete rebuild or just make use of elastic bands and a balloon, RTFM (read the flipping manual), a little thought before hand goes a long way and saves you calling on friends!
difficult for some people, a piece of cake for others, depends where you are skilled.
It is significantly more difficult than any maintenance on a traditional fork, which don't require "elastic bands and a balloon", and even if you've done it before and successfully remove the bearings and races, you still need to carefully record the position of all 8 races due to the different thicknesses. It's not a "piece of cake", I worked in a CDale shop in college and have performed the operation dozens of times. Most shops in the US won't even do it anymore, they will send it back to CDale instead.
Nearly a 100% failure rate with our customers that ride often and aggressively. Not happy people.
100% failure rate goes against my over 15 years of lefty use, not to mention countless others, if 100% of lefties fail, surely Cannondale would of stopped producing them? The older models are renowned for being reliable, there is a great lefty following for good reason, even being used on fatty bikes, I've covered thousands of miles on my Ti litespeed with a lefty...maybe your workshop was setting the lefties up wrong and CAUSING the 100% failures..
so whats your deal? lefty idolizer? own a cdale shop? you don't seem to have a grasp of the overall picture, even if yours have been flawless, I am not the only one with bad experiences with these.
You have been on pinkbike 10 years, 2 followers, it doesn't add up, you probably bought an abused lefty and couldn't rebuild it and that sent you on the lefty hate mission. I am a trained mechanic, welder, painter, panel beater, engineer, health and safety inspector and lots of other things, i find lefties to be very well designed, light, strong, stiff and easy to work on. From an engineering perspective, they are fantastic. I say it like it is and i can back up what i say, you say lots of stuff but offer no proof. I am still using a DLR 2, original bearings, smooth as silk, lefty max 140, original bearings, only done 1 damper service, perfect, i run a speed 110 on my rush, done damper service and air spring, perfect, also speed 110 on my litespeed i built for touring, rode through 8 or so countries on that bike, all weather etc. Show me some repair receipts, back up what you are saying!
What are these 'bearing failures' you keep on pushing? The air springs take 5 mins to strip and fit new o rings, the dampers take under an hour to strip, rebuild and refil with oil, i really can't see your problems, hence my comment about you trolling. Prove me wrong.
Guess I’m not a social media mogul like you. I’m glad you have had a terrific experience with your lefties. There are
Plenty of folks out in the world that havn’t, that is all @baggyferret:
you've never owned a lefty but have lots to say about them....stop posting ffs.
As for 'leaving me out there' lol I think i'll be fine thx. I've been riding mtb since 1984 in Vancouver, I haven't seen everything, but there isn't much that phases me either. my relative silence and lack of followers is likely that In the shop days I would look for trends and product opinion info. there is shop politics to avoid on the web. and this thread is an example of some of the bs that was always best left alone.
wow, some of my early videos of 'dangerous dan' and the boys in vancouver suddenly flashed before my eyes, what a place that is..and you ride there, i have always dreamed of going there, this is one of the reasons i love pinkbike so much, seeing all of the world through other bikers eyes in their edits etc...Wales has a lot to offer the mountain biker, where i ride mostly, is miles from others, only logging roads to get into the heart of the forests and soo easy to get lost or hurt..love it!