Why the TELESCOPIC FORK keeps WINNING-Alternative front suspension FAILS! 

Could you imagine being a young rider with an older well used bike (we’ve all been there) and having Mark Hoyer as your neighbor? Lucky dude.

Between Kevins seasoned first hand technical experience and Marks exquisite tactile references to the riding experience, you guys are a winning team. Been a reader since the 70s with the candle after mandatory bedtime.

Geez, the show gets better with every episode. I love Kevin's dry sense of humor. Keep up the great podcasts!

Marks comment about his arms being an extension of the front suspension - while showing his loose-hands gesture we've seen him do here so many times - is something I visualize often in mid-corner. Kevin and Mark ride along with me quite often since I started watching this series.

Bought a cheap Yamaha GTS 1000 a a commute bike to haul between Isle of Man and England every weekend for 10 years. It was so stable and over 40,000 miles never changed its stability. I say stable I also mean across the islands TT mountain course, crazy hard breaking into rough ragged corners whilst leaned over. It was so good I took the ABS off the front, you could break with it in a skid. Obviously this took a few years and 10,000 miles to master but it showed the true ability of the strange front end. At the time I also ran a GSXR 1000 K5 with carbon wheels and that was the definitive sensitive steering machine over the same roads. With the bloated (heavy) under powered 100HP Yamaha it still outshone the GIXER on ragged corner braking but you realy had to put trust in that difference (remote) feel.

Mark Thank you for helping your young neighbor. I’m sure it means the world to him. Philip

Over 15 years as a motorcycle tech, mostly Honda, Kawasaki, and Suzuki. Some of the strangest feelings during servicing was a bike that had developed a "detent" function in the steering head bearings. Weirdest feedback to the rider and ironically, not perceived by the owner which made for challenging negotiations with the owner as to why they needed to be replaced.

These conversations between you...are priçeless!! Insightful and informative.. good entertainment... I own ALL Kevins books! Some i bought twice as i would loan them...and people would move away with out returning them! Had to buý them again!! He is only person whose perspective i trust! Also C Everett koop... Kevin explains things so well... And mark...i always read everythi g you wrote...but the intelligence and passion are more apprent on you tube videos

I had a brand-new 1972 Steen (a small, 100cc Hodaka-powered, American-made bike) with a 'leading-link' front suspension (like a Greeves). The LL setup was basically a swingarm and two shocks pivoting in a conventional steering head, and made of tubular steel. It did have a certain plushness in its feel, and I'm convinced its geometry saved me from going over the handlebars once or twice. But, steering was vague, sloppy, and just weird compared to conventional bikes. It was a lot of work keeping that thing on the correct heading - it wiggled all over the place. Part of the difference was the cumulative slop in all of its moving joints, part of it was the arcing motion of the front wheel in travel, and part of it was excess weight. I was only ten years old and I had a blast riding it for a couple of years, so not exactly a hardship! Besides, I only really found out how bad it was after I graduated to a 1974 125cc Honda Elsinore, which simply blew it away in every dimension, except low-RPM grunt. In the 1970s, though, _every_ dirt bike squirmed and wiggled around under pressure, I suppose because _everything_ in their chassis and suspension was so flexible. By the early 1980s, it was a completely different world where even your run-of-the-mill, affordable dirt bike was a masterpiece of engineering and refinement. One of the last dirt bikes I rode seriously was an original Kawasaki KDX 175 (from, what, 1982?), and that thing was just incredible in its poise, performance, and all-around competence.

Another fantastic conversation. I would love to hear you both talk about the evolution of reliability and serviceability in motorcycles.

No BrittenV1000? 🙂

This is best show, content, lessons, history, technical on M/Cs ever !!! Thanks guys ride on !!!

When I was designing motion-based simulators for aircraft pilot training. We solved the stitching problem early in the design phase. It is very critical to designing the hydraulic system with Servo valve control for the motion-based platform. Especially on the 84 in platforms. The four cylinders are never completely vertical, and they rotate on an axis as much as 18 to 24 degrees off center. Each end of the cylinder meaning of rod end and the housing end rotate independently of each other. We used a seal design on the piston that did away with the standard polypak design. Which, as you know, expands to seal the piston to the ID of the barrel of the cylinder as the pressure increases to prevent leakage. We changed the piston seal design and the material to decrease breakaway torque by as much as 90%. Consequently, we had some leakage by the seal. By means of an orifice with a zero leakage check valve, we were able to channel that extra hydraulic fluid back to the other side of the piston. Next, we had to face the most difficult problem of eliminating the breakaway torque on the outer seal that comes in contact with the rod. This is a proprietary design that, as far as I know, is still in effect today. In a more private conversation setting, I would be happy to discuss it with you and explain how it operates. Best Regards, James Whitney

I would have liked to hear more about the alternative suspensions and why they are working well enough to continue in production, (BMW and Honda) and less about the alternative suspensions that didn't make production. I think that would have been a better discussion.

You should definitely have Erik on your podcast. He's a approachable guy, he's personable AND he's brilliant. Having Erik on the show would be magnificent!

The inverted fork on offroad bikes also eliminated extension of the lower tube below the axle eliminating contact with ruts/roots/rocks.

“Taco short of two Pedrosas.” Best laugh I’ve had today.

I was working at the local Kawasaki shop long ago when a guy brought in an original 500 triple that he had “customized” with foot-long fork tube extensions. He insisted that I ride it for some reason. In addition to doing very bad things to rake, trail, and cg, it transformed steering inputs into little more than a suggestion with respect to the direction in which the front wheel pointed. I was terrified, and brought it back very quickly. I came in, parked the bike, and said, “You know, only a damn fool would do what was done to that bike.” He looked puzzled, climbed on, and wobbled his way down the street.

The Honda RC45 was a bad example of the 'benefits' of raised center of mass. The general consensus by all observers and Honda team technicians was that the RC45 had the crankshaft positioned incorrectly in the frame. They battled with this design flaw from the beginning until the end of the RC45's racing career as Honda/HRC, in their arrogance, did not homologate adjustable engine position shims in the frame for the engine position or the swinging arm pivot position. They had to compromise, and work around these flawed location positions. The crankshaft was too high in the frame. The bike was born bad.

Really interesting, thanks from the UK

Nice SS in the back!

This has been a fascinating technology (on the front) of motorcycling to spectate, if you will, over 50 plus years. Always inspiring to see innovative adaptation. But i never quite saw the net advantage of this. Great discussion! Long enjoyed (and cherished) Kevin's perspective and appreciate Mark's interaction with him! Thanks guys!

Brake dive is pretty unpleasant in stop and go traffic. Why don't we get anti-dive on commuting bikes, cruisers, and other non-race motorcycles? My impression is a lot of scooters do have anti-dive, at least older ones.

The only motorcycle design to actually be competitive to conventional fork was the Britten…

Girder forks may have been nicer on paved/cobblestone European roads compared with the alternatives at the time, due to very high lateral rigidity. Although they were obviously obsolete by the 60s. Great episode - thank you.

Michael Czysz had an interesting front end on his original gas motorcycle. There were two fluted sliding stanchions incorporating bearings with a separate shock absorber with spring. He was certainly forward thinking.

Thank you for yet another cool topic. As to USD forks - I do not know when they first appeared on motorcycles, but the Triumph Bantam had them at least in the mid-50s.

This show is gold. I've been an enthusiast all my life and used to read these guys monthly. I remember how much I looked forward to the old print editions. Luckily, (I guess, still kinda miss those old prints in so many ways) the net has spoiled us and I am soo thankful for this show. Been a long time listener on Spotify but had to log in to RU-vid to watch the Air episode and couldn't stop watching some of the old stuff. Keep up the great work and I will continue to be spoiled. I'd love to know more about the RC30 and 45s if you guys need content ideas. Those machine are fabled and I'd love to hear your guys breakdown.

Tony Foale did some experiments with centre of gravity, and decided that low CoG is no good for rapidly pitching a bike into a corner, and especially a flick from one side to the other. He found a higher CoG worked better, ideally with mass as close to the CoG as possible. Most short leading link forks have the link roughly horizontal. This results in trail that strongly reduces with compression. This can be 'unhelpful', especially if the brake torque reaction goes straight into the suspension link, as on, say, a Honda step-thru or Vespa. The works Moto Guzzi race bikes (which won multiple world championships) of the mid 1950s had short leading link forks with the pivot below the axle, giving wheel movement roughly in line with the steering axis, and so a more consistent amount of trail. The brake plates were on links to give control of dive. The settings were altered for wet or dry race conditions - they allowed more dive in wet to give more feel. The Vincent Girdrauluc fork definitely has its faults. As its designer Phil Irving admitted, it had far too much anti-dive. The wheel movement gave almost no trail at full extension. The Vincent tendency to tank-slappers was eventually traced to the lack of trail at full extension. Worst case scenario, braking hard (therefore full extension) and hit a bump, and it goes into a tankk slapper. This even spat John Surtees off. The cure is a revised lower fork yoke with the pivot down and backwards, giving wheel movement more like a telescopic fork, and consistent trail. Combined with a ball-bearing pivot for no friction, a hugely improved fork results. The Britten V-1000 race bikes of 1994-5 had an A-arm girder fork similar to Norman Hossack, Claude Fior etc. It gave excellent wheel control and late braking. Some riders liked it, some hated. As mentioned in the discussion, sensitivity of seering feel is a critical factor with all funny front ends. A drag link can allow friction and binding, as well as slop. That makes me wonder if the front fork from a Whyte PRST-1 mountain bike might be the ideal. It had a fabricated alloy box section fork, a lower A-arm, and upper links like a girder fork. This eliminates the separate steering link, and allows the designer to choose a variable amount of trail with wheel movement.

What i found with Honda forks on my 93 XR650L and 88 NT647 Hawk, if you used Showa 5 w fork oil and not the amount somuch but w the cap off and spring out, pour in the suggested oil amount and measure from top of the fork to the oil level inside the fork after you pumped the tube in and out to get out all the air out, the forks feel great and responsive. 45:44

You describe one more place the modern chassis has superior rigidity but where exactly is the still needed flex located? Even Jeremy McGrath describes the aluminum framed Hondas as diabolical and they weren't subject to any high lean angles.

Kevin mentioned a racer from Georgia that was outbreaking Kenny Roberts. First name coming to mind, Dale Singleton? A really nice southern gentleman, lost far too young. Edit: As the show wraps up, I recalled something unique that Kawasaki brought to Daytona in 1983. So the superbikes were now 750s, and Wes Cooley rode in the 200 (still Formula 1 then) one of the KZ1000 based machines in formula configuration with a full fairing. It had a linkage system of some sort on the front end. Still telescopic forks, but if memory serves it was an anti-dive braking set up that was fascinating to see. I've got pics of that and will have to dig those up. Not sure if that lasted the season, I think the only other full national I attended that year was Laguna. I don't recall if it was present there.

so glad about your talks; thank you for that! may you consider a follow-up to this talk? discussing the functions, consumer-available suspension offers today?: low- and highspeed compression-damping in fork and shock. and its limits, for example for shocks above highspeed-dampening speed (hydraulic lock, suspension goes in fixed-frame-mode) and was the industry can offer such as conevalve tech or products as n10z offers or electronic active suspension / sensitive, regulated suspension.

Very insightful observations by both gentlemen.

I never bought into that "The secret is to lower the center of gravity" thinking. I figured out a long time ago that riding, bicycle or motorcycle, is steering the contact patches under the CofG in order to stay shiny side up. (That's why countersteering works: it gets the contact patches out from under the CofG and makes you steer them back under, causing you to turn.) You don't want the CofG way high, that'll have you pulling wheelies and will limit your acceleration, likewise it'll have you pulling stoppies and limiting your deceleration. But "Lower, lower, lower!" isn't the answer, that makes the bike stiff and unwilling to turn.

Was present when the first TESI was raced, Zeltweg 1984, and it ended in the first corner since they had push pull steering handlebars the riders did not understand. The better solution is the Hossack fork as used by Britten and the Swallower Guzzi's but indeed with the UPSD fork most weak spots of the telescopic fork disappeared. Love the podcast guys!

Being part of the bike, i.e. Don't hinder the bikes ability. Cracking show - thanks

Motocross World Champion Brad Lackey first used Steve Simon’s “upside down” fork in the early 80’s much to the dislike of Suzuki. No mention of the front fork on the Michael Czysz MotoCzysz.

[Comes in from cleaning brake calipers]... oo, a cool topic under discussion. I bought my 1290SAS because it comes with anti-dive.

I would have been interested to hear Kevin's explanation as to why only the "leading link" front fork is acceptable in sidecar racing applications.

The biggest axle I ever saw was on front end of Britten's racer! Looked like a soda can being inserted!! Also evolution of klr650 axle retention is perfect example of details making difference..Gen 1 straight thru ..no pinch either side.. Gen 2 similar to Gen I BUT TWO PINCH BOLTS PER SIDE... STRONGER? Yes Gen 3..3mm larger axle ..THREADED into one leg.pinch bolts on one side...strongest!! I tried to find a Bolger front end for my bmwk100RS...was unsuccessful... This made me aware of the corporate opportunistic sin that BMW committed. They waited till Joe could no longer afford to defend his patents ..and took the idea... THEN THEY TOLD THE WHOLE WORLD BLATANTLY HOW THEY GOT THE TELEVER!!! JUST BUSINESS!? BUT A SIN to brag about it!

Gentlemen, if ever there was a discussion that required some diagrams and pictures, this is it! (Tricky on an audio-only podcast, I know, but you could have inserted some images into this RU-vid version!). From your descriptions, I could not imagine what the Nico Bakker system looked like, although I’m sure I must have seen photos of it at the time. Unlike most of your viewers and listeners (I suspect) I’ve ridden bikes with most of the alternative steering systems you’ve mentioned. I haven't ridden a Tesi, but I have ridden many bikes with hub-centre steering systems, including those by Difazio, Tait, and Creasey, none of which you mentioned. I’ve also ridden a couple of Tony Foale’s machines along with several GTS Yamahas. Since the Foale bikes and the GTS Yams like the Parker design (and all the Elfs) are single-sided, I would not describe them as ‘like the Tesi’ (as Mr Hoyer did) since that is double-sided. I’m glad Mr Cameron knows the difference between a girder fork system and a Hossack because Mr Hoyer seems confused about that too; (girders still use a headstock, Hossacks don't). It’s a shame you don’t seem to be aware that Norman Hossack’s first two racebikes won a whole host of races and many championships before he started converting road bikes. (See CW March 1983!). The Britten front end - which you didn't even mention - was also a straight copy of the Hossack design. I'm glad you mentioned the Hossack-ish steering on the Gold Wing which was a late adoption of the design, compared to BMW’s Hossack Duolever which predated it by more than a decade. Personally, I’m puzzled by BMW’s perseverance with Telelever (which was of course a copy of Nigel Hill’s Sax-Trac/Saxon/Motodd design) when they could be using the Duolever system instead. I’d also love to see a BMW S1000RR with a Hossack front end - there’s no doubt that it would be lighter than the super-duper USD teles that are currently fitted. You only have to look at Norman’s superb conversion of his Ducati 800 (in 2014) to be sure of that. I've ridden both Telelever and Duolever BMWs and two Hossack-steered motorcycles that were converted by Norman Hossack himself, both excellent: Norman's own K100RS, in 1987 and in 1993, the Triumph 900 that he converted for Keith Duckworth, co-founder of Cosworth. I rode the latter both before and after it was converted - much for the better. Lots more here: www.hossack-design.com/

BMW still uses their Telelever anti dive front end (on the non superbike models) They have had it since 1994 or so. Even a nose picker like me noticed the negative at track days. At that level you do adapt to it.

A suggestion for an episode (related to your comments in this episode) on the unique front end geometries for the Honda Gold Wing and the BMW K1600): the story of the FLHT front end developed by H-D in the late 1970's where the pivot is off centerlined from the plane occupied by the downtubes. Impacts to low and high speed handling, etc. Perhaps your comments on all three bikes at speed etc. Thanks for the interesting episode today.

How about the Britten?

What about the 'strut' prototype Honda created (in the 90s?)? Basically a single hydraulic cylinder, and serving as or coinciding with the cylinder head, with a single 'fork' wrapping around the wheel. Somewhat similar to front landing gear for airplanes, only simpler. Seemed inherently promising.

Great stuff. I'm an ex-Buell owner (I had 3). I reckon EB was the bike version of the other EB, Ettore Bugatti. Can't wait for you to investigate EB v EB :) .... Patrick from Scotland

Great performance, guys, thank you very much - BUT - can you provide some pictures, intermittently? I am not an english native speaker (but I rode an H2 750, if that counts), and so I didn't get it, what was ment with the Vincent fork, and at the end this Honda invention. Nevertheless, thanks a lot,

My 2012 BMW R1200R is Telever equipped. I can say two things about it. The anti-dive geometry, along with linked front and rear braking through the right hand lever, and ABS have saved me when I thought I was done for. The bad....... The feel that you have through the palms of your hands about what is going at the tire contact patch is missing completely. Just not there. This really does away with a lot the fun of riding a canyon road. No doubt I would like this bike more with a good telescoping fork.

The guy from Georgia was Dale Singleton.

Interesting discussion...could have used some pictures of various forks being discussed and some schematics.

I think of John Britten and his improvement on the front fork. He successfully eliminated stiction while designing in the feel of a conventional fork. It certainly seemed to work quite well, even though it wasn't brought to the apex of racing at the level of Moto GP.

Love this can of worms, nothing better than a good tune telescopic fork, best fifty minutes, thanks

You guys never disappoint! 👍

Hey Mark and Kevin, l haven't tried any leading link, Hossack style front ends, but recently saw one out of Australia called, l think, MotoInno. Not sure if that was the company or the front end design. A vid with Cameron Donald of Isle of Man fame, test rode it. But as Kevin said, theres many solutions to a good front end, but at the ragged edge, .... t.forks win out. Great chat guys, thank you.

It would be nice if some pictures were shown to illustrate the different concepts in the post-editing of the video.

I guess the compromise made with the big front rotor on on a Buell is similar to the compromise we make with high performance tires that only last about a third as long as a harder compound touring tires. I have a question, I've got an old Suzuki GS550L 1980. I've done a lot of modifications or used the wrong parts to fix it up, depending on your point of view. It's got 09 Triumph silencers that fit perfect upside down switched to opposite sides.Everything on the frame is standard but I went to a slightly wider 16 inch Lester rear wheel from the standard wheel which was 17 inch. I did have a 19" Lester wheel on the front with the same tire rotor and bearings as the stock wheel but it weighed 4 lb more than stock and I was always worried that someone was going to steal it so I put the stock wheel back on. I thought since the diameter of the rear wheel was slightly smaller than stock that it would make sense to lower the triple clamp by about 1/2 an inch over the forks . I did the 650e top end swap and I changed the gearing to try to make the most of the overdrive so I've got a 16 instead of a 15 tooth Sprocket in the front and I've got a 45 instead of a 50 in the rear. I tried 43 but I thought it was a little too severe. The bike runs good and it's pretty fast on the highway it's got 60 or 70 hp. When I get up around High highway speed, maybe 80 on Route 80 or 95 North, I get a slight weave, the bike has new bearings all around it's got new wheel bearings and new steering head bearings, the swing arm bearings were in really good shape so I left them in, there was a very slight mark on one of the needle bearings insert spacers, the one on the the right. I get a slight weave so I'm wondering what I should try first.It's very slight like less than a quarter of an inch back and forth from the back of the bike. I made a tool out of couple of feet of half inch threaded rod with two eye lag bolts the type you screw into wood and six nuts and I use that as a caliper to to measure from the center of the swing arm pivot Bolt to the rear axle Center, to make sure that the back wheel is straight so I know that's good. The bike has Michelin Pilot Tires front and rear in good shape and Progressive Suspension and Fork Springs that I bought new in 2010 the bike has probably covered about 30,000 miles since then but the suspension seems good. I want to get it all straightened out before I put the third engine in. I think I'm going to start by putting that half inch back into the length of the forks. I've been reading Cycle World for over 40 years, not continually but often and I appreciate the content and the channel. THANKS !

In the more distant future I expect that with high performance electric motorcycles we will need regeneration brake from the front wheel. I wonder how that will change this conversion about front suspension

The most underrated feature on a BMW is the telelever front suspension. You have to ride it to appreciate and understand it.

Do you have any comments on the front end used by John Britten?

What about the Britten?

Some of us live for..... "Air Time!!" 😮😂

Rough ride guide...on flat clean pavement..." the front tire won't lock until the fork bottoms out or hits a hard spot in stroke.."

I've often wondered why riders complain about brake dive. I've always liked it.

Hi Kevin, why were the P&W R-2800s never used to power the B-29s?

The Yamaha with two front wheels???

The Honda mx leading link looked like they stole the parts off a small bridge.

I wish they would talk about the Britten v1000 a lot more as it was successful and it did beat Ducati.

"When you come to a fork in your suspension, take it!" - Yogi "Bimota" Berra

How does Telelever compare? Ha... you just answered it. 🙂

BMWk1300s

Bimota Tesi ❤ is the best

Need dive on a tele fork motorcycle. . . Gives weight transfer. Unfortunately also changes steering angle and wheelbase.

1 Please Turn On Closed Captions 2 The Reason Telescopic Forks Keep Winning IS Aesthetics, It Just Looks Right!

Funny front ends are like communism. All current attempts have failed, but the faithful swear it just hasn't been done correctly...😂😂😂

I rode a series 1 Bimota Tesi a while ago. It steered like a truck, very slow and heavy and over expansion joins it bumped me out of the seat. I absolutely agree about the braking, it certainly stopped quickly.

Dont forget to discuss the yamaha 450 off road 2 wheel drive system that was driven by a cable like a strong speedo type cable that turned inside a cable casing.and some said it actually worked in certain circumstances, it game just enough to get small amout of traction.

Yes you’re right i stand corrected sorry and if you own one well done keep hold of it i loved the idea of those bikes and they looked cool.

The only motorcycle design to actually be competitive to conventional fork was the Britten…