Tier Motorsports R1 concept

[mdisher]

Article here: https://www.thebikergene.com/concept-bikes/...front-swingarm/

Drool, then discuss...

 

[Ignacio]

Oohh...concept. It looks a bit like an update to the one they produced about a decade ago......the GTS. Many thought it was ahead of it's time and still run them in rally events.

 

[Crash Cash]

Wow, not only is it not just another photoshop-exercise, it's an actual original idea in the front-hub steering. They seem to have done the front hub far better than the Bimota Tesi or anybody else.

It doesn't look like they're actually planning on building one...

 

[Neil San Diego]

An update on the '78 Elf X...?

https://www.elfmoto.us/lub/lubusa.nsf/VS_OP...F2?OpenDocument

 

[jekirby]

Same idea as the Bimoto Tesi.

 

[MotorToad]

Making a swingarm front end from a forked frame is... well, there are ten or so negative comments I could make. "Ridiculous" should suffice.

Vertical steering axis? Someone please tell me how zero trail is desirable.

 

[wfooshee]

The steering axis is vertical, but it's not at the center of the wheel. That's what those "Four-bar" links do inside the hub. The axle is like a tie rod connecting steering arms (the two "U" shapes). The backs of the "U"s attach to the hub, which then behaves like two kingpins welded together. So, not only trail, but adjustable trail.

Rake, that's another matter, and I'm kinda thinking you'll want some rake as the bike leans. Wouldn't you?

Can't tell where the front swingarm attaches. Did they just put bracket at the bottom of the front of the engine?

 

[MotorToad]

The steering axis is vertical, but it's not at the center of the wheel. That's what those "Four-bar" links do inside the hub. The axle is like a tie rod connecting steering arms (the two "U" shapes). The backs of the "U"s attach to the hub, which then behaves like two kingpins welded together. So, not only trail, but adjustable trail.

Ah, missed that. It looks like they took Audi's "floating hub" front suspension idea.

Rake, that's another matter, and I'm kinda thinking you'll want some rake as the bike leans. Wouldn't you?

Rake is just the means to achieve trail. I don't think you'll miss it.

Can't tell where the front swingarm attaches. Did they just put bracket at the bottom of the front of the engine?

This is what made me dismiss the whole thing as a photoshop exercise in stupid, hence my not reading it closely. One thing you'll notice about the Tesi and GTS is the absence of about 60% of the conventional frame. The mere hint of the idea of retrofitting a conventional beam frame with a swingarm front end is ridiculous.

Something else that made me dismiss it is that this is the ultimate expression of Code's "no BS" bike. I don't see any steering mechanism at all. Even assuming a steering arm, I'm not seeing is how they're dealing with bump steer. You'll see on the Tesi that they have an equal-length arm to keep the front wheel axis perpendicular to the steering arm. Since this wheel pivots around a moving imaginary point, I don't see how the steering is going to be fixed about that point while the swingarm goes up and down.

 

[spalkin]

I'm crazy about the concept but the limited turn arc could really hurt in slow speed maneuvers.

The look alone is incredible.

 

[wfooshee]

This is what made me dismiss the whole thing as a photoshop exercise in stupid, hence my not reading it closely. One thing you'll notice about the Tesi and GTS is the absence of about 60% of the conventional frame. The mere hint of the idea of retrofitting a conventional beam frame with a swingarm front end is ridiculous.

Yeah, the frame doesn't have to go up to the steering head, you just have another subframe to carry the handlebars. A conventional frame fitted with a front swingarm would be pretty heavy up front, or at least excessively bulky.

Pics of my Tamiya 1/12th Bimota TESI to illustrate (click pic for larger image):





I wonder if I can find a pic of the Yamaha GTS unfaired somewhere. You can see in Iggy's pics that the frame is an inverted "U" on each side, similar to the Bimota.

Edit: Hey, look! On this page, I found this picture (linked here, not copied and re-hosted.) Instead of the tie rods parallel to the swingarm, they used an upper A-arm. In my ignorance I do not know if that's a shock from there to the steering head or merely a sliding sleeve to carry steering down to the hub. The spring is in the big silver can on the side, but I don't know if that's just a spring, or a coil-over shock.

Edit II: Consulted the Yamaha on-line parts fiche. The upper piece is a steering link, the shock is in the spring assembly at the side of the swingarm.

 

[Crash Cash]

Pics of my Tamiya 1/12th Bimota TESI to illustrate (click pic for larger image):

Holy crap, manbat! Where the hell did you find one of those?!? And are they still available? The Tesi at Art of the Motorcycle was in the same state of undress.

 

[wfooshee]

Got the kit off an eBay vendor out of Hong Kong. Search eBay for Tamiya TESI. Hobbylink Japan might have it, although it shows backordered right now.

And yes, the handlebars steer the front wheel on the finished model.

 

[MotorToad]

Yeah, the frame doesn't have to go up to the steering head, you just have another subframe to carry the handlebars. A conventional frame fitted with a front swingarm would be pretty heavy up front, or at least excessively bulky.

And you'd have to find some place to put the engine, or at least the exhaust. One of the problems with the GTS was that the engine width made the rear of the swingarm too wide and it was the first thing to touch. (It was also a touch too heavy and they detuned the Fizzer 1k engine too much.)
I'd forgotten you had that Tesi. Keep your eye on it if I come over... :assassin:

BTW, linky to some more reading on front ends. I happened across that earlier today before I saw Foale was mentioned in the original article about the imaginary R1.

Has anyone figured out yet how this thing is actually supposed to be steered?

 

[PapaUtah]

The GTS was not merely ahead of it's time it was applied to the wrong platform. The inverted "U" frame was given the dubious name of "The Omega Chassis". Yep, last one of its design before it was discountinued. I had the good luck to own a 1993 GTS w/ABS. It was a wonderful bike, but not for it's intended purpose. The detuned motor was always needing help help with the right gear, shifting was constant around town. The turning radius at slow speed was just a little better than the Queen Mary. Would have been a wonderful touring bike platform. Had they made it slightly larger they could have wrapped the early Venture body work around it and they may have had a GoldWing fighter. Eerily smooth stops with no fork dive. Bike just liked to settle down into the tires on a quick stop.

 

[Crash Cash]

The inverted "U" frame was given the dubious name of "The Omega Chassis". Yep, last one of its design before it was discountinued.

Actually I think they named it that because it looks just like the Greek letter capital omega from the side.

EDIT: Yup, just actually found my copies of the brochure, where they say that. Yeah, I really wanted one, and a Tesi even more.

 

[MotorToad]

Hehe, it looks like Yamaha got defensive in '95 and actually wrote that on the side of the bike! :rofl:

BTW, there's one for sale in Ohio... boy, I'd like to have it.