jscobey

i hear so much talk on here about how the hawk has alot of flex all around the bike. Skinny forks, an unbraced swingarm, the frame has flex etc... but im wondering what all this means. and really how rigid/flexible is it compared to other bikes?

from what i understand "race replica" bikes are very rigid and dont have much flex just like their racing counterparts. on the other hand the hawk has what i understand to be quite a bit of flex. i see a bike like the 916, 996, 998, series of ducatis which have a steel trellis type frame which has very thin spars making the frame. and those bikes which were road trim race bikes that dominated in bsb, sbk, etc.. to me surely the hawks chassis is more rigid than that? or maybe not since the ducs were steel and hawk is alum. and then there is bikes like the panigale's which have no frame at all. so how could that be more rigid than a bike with a frame.

im not sure what people mean when they say it has flex. where is the flex occuring? ive seen how the moriwaki bikes had their frames stiffened by an extra spar, at the head, and at the back of the frame. plus ive seen the ears on some spondon frames which is more for a high HP bike, not rigidity. ive never really felt "flex" except for before i did the RC51 front end swap. but now even at the track i dont really feel flex. maybe is because ive never riddin a "rigid" bike? just wanting to know a little more about the subject

VTR1000F

Maybe "tuned flex" became an engineered-in "feature" when the bean counters determined a cheaper, un-braced swingarm would be used. And, oh yeah, use these skinny forks we have laying around. What fuel gauge? Fuel gauges cost yen.

mikstr

First of all, the "Spondon ears", as they are called, was an attempt to fix a high-speed instability problem which, it turns out, was caused by an overly long rear shock (do a search on the vtr1000.org site, there is a post about this very subject, a historical overview, by Roger Ditchfield, the man who inherited development of the VTR and who diagnosed and corrected the problem).

Tuned flex helps to address the issue of suspension inefficiency when the bike is leaned over. At one point, bikes were made to be stiffer and stiffer, and got to be too stiff (Wayne Rainey having complained about his YZR500 being unpredictable when leaned over, for example), so engineers began engineering some "give" in the chassis to compensate. Notice how swingarms now are constructed of tall and narrow box sections? This is designed to give rigidity in teh vertical plane but somne fexibility in the horizontal one.

The VTR was built with flex in mind, though Honda perhaps went a bit too far (example: the 1996 CBR900RR was also built along these lines but Honda made the next gen CBR, the 98, significantly stiffer). So, it can be fixed though the VTR was never designed to be a world-beater (that duty was assigned to the RC51). There are things that can be done to help remedy tthe stiffnesss issue if it`s problematic for you, including bracing the steering head area.

jscobey

maybe its because i only way a buck fifty but i havnt event thought man this thing is flexing. the reason i wanna brace the swingarm is because i wouldnt want the swingers flex to lead to a crash or something. i feel like once people start stiffing up the front with new forks and brace the rear, maybe the flex in the frame becomes more noticable where as stock it all flexes together and its hard to notice. all i can say is i deffinatly could feel the front flex under hard riding up until i swapped forks. all interesting stuff tho.

Wolverine

Try riding an RC51 for a while, then switch back to your Hawk. Night and day difference. The RC feels like it's made from 1 piece of billet aluminum. When I got back on mine all I could think about was a wet noodle. My friend that used to own the RC felt very uncomfortable on the VTR when we did switch up.

jscobey

yea id like to. unfortunately i dont know anyone with one well enough to ask to ride it. those things are becoming more of a collectible now. so then i assume bikes like R1's and CBR's are very stiff as well?

bmidd

I'm 260# in full leathers and I have owned several R1's 2002 and up and they are a world of difference from this bike. My last daily was an 01 FZ1 and it was very flexible, the frame is a 2 piece bolted together. I haven't put many miles on this Hawk, but I can't push it at all because the suspension sucks *****. When I work it out this spring I will be able to get a better feel for it.

smokinjoe73

I had a race buddy who raced the hawk put the hrc kit on it. Bigger rads etc. He filled in the frame diamonds with weld. Said it made a huge difference.

Even just putting on the cbr1000rr forks makes it feel way stiffer, as I figure the braced fork would too.

jscobey

ya i deffinatley could feel the flex in the front before i did the RC swap. it wasnt till after i did the swap tho and rode it that i really noticed how much it actually flexed. hoping that a braced swinger will provide the same effect for the rear. the rc51 forks made the front feel so planted and inspired confidence in the front wheel. thats what im hoping to gain for the rear with a braced swinger.

so filling in the diamonds, is that just a plate covering them or is it filling in each individual space?

kenmoore

I can assure you that the braced swinger makes a world of difference.

I don't have a USD front end but my forks are modded with Ohlins springs and a couple of other tricks.


When I fitted the CBR600F4i calipers my front end was flexing so I fitted a Coerce fork brace.


That's when I realised that the Swingarm was flexing like a Russian gymnast warming up for the Olympics, and that necessitated the braced swinger.


Now everything works together, not against itself.


This brings me to the conclusion after fitting Dunlop D209 Sportmax qualifiers which are old technology, and the bike handling the best it ever has that maybe the latest greatest tyres are not the best for our bikes.


Could it be that our frames are not compatible with the latest tyre options because frames on the latest bikes do not flex as much as they do on our bikes?


Just a thought, but I now have another set of Dunlops waiting to replace the ones on my bike when they wear out.


I had Michelin 2 CTs on it and whilst they had good all round performance and wear the Dunlops eat them for feedback, comfort and wear.


I have tracked them and currently have 6,000Ks on them and reckon I will get another 1500-2000 out of them.




Just a thought that the latest and greatest tyres are not the best for our bikes, and yes I know that 2Cts are not the latest but the D209s have been around for longer than the 2Cts.

jscobey

thats really an interesting thought. ive wondered about similar things. i run michelin pilot power 3's on the street and dunlop Q3's for the track. but i wonder if modern tires designed for stiff chassis' highlight the flex in the hawk. is there any articles or professional research on the matter? it deffinatley makes sense as the Q3 was designed for modern CBR's an the like. BUT i would think manufactures take into cosideration not everyone buyin tires has the latest and greatest machines. but then again what do i know

VTR1000F

I very much doubt that. Unless a manufacturer is marketing a tie for older machines, I doubt they give a crap about how it works on anything but the latest hot selling models.

I seem to remember kenmoore's idea about newer tire technology not being suitable to our older bikes being discussed on here before. Maybe by kenmoore???

jscobey

well my reasoning is that if they only made tires based on the 2013/14 models then people that own prevoius bikes wont be satisfied with the performance if it doesnt work well with their bike, hence they wouldnt buy the tire hence the company wouldnt make money. youve gotta remember a companys sole purpose is to make money. they want the broadest range of customers to bring in the most money. im sure that within the tire companys somewhere there are engineers thinking about bikes made over the last 10 years or so. because if i had to guess less than %10 of riders have the most recent model bikes.

sjscicluna

you forget marketing and salesmen by the time we realise we have the wrong tires the next model will be out and you have already spent your cash. and the company docent care about it as they are now making a profit, if they did they would offer a money back guarantee if the product is **** for you they will give you your money back or supply a more suitable product for your needs, but that is axing too much.

Apple is a good example of this it may or may not be the best product but there marketing and sales says otherwise.

kenmoore

I did discuss tyres and frames somewhere on here.

After changing to an older spec of tyre I found the storm to be totally different.


It could be the fact that I refurbed the suspension and that these tyres that I had fitted were just more suitable for my riding conditions, however my inner voice tells me that the frame likes the older tyres better.


I could be wrong, but "Zen And The Art Of Motorcycling"tell me that I am not!!

7moore7

It would seem that if indeed tires were optimized for the newest bikes this would especially be the case with sport tires. If you look at how 600rr bikes are bought by many: by looking at a chart of horsepower numbers buying the one at the top, then tires would probably fall into the same mindset. By looking at a chart of best new tires and buying the one with four stars. Then you have people who buy the rr bikes who use them as intended, and they have every reason to buy tires to fit their bikes.

Now, you buy a Honda shadow VLX that didn't have any major changes for nearly 20 years and the tires for that style of bike are not only probably the same exact model... those people are also not bracing their frames to fix flex issues that aren't as apparent in modern small cruisers.

A bike first sold in 1997 and designed to be nice to ride on the street is certainly going to feel its age when pushed compared to much newer bikes designed to be ridden on the track.

smokinjoe73

Using the older dunlops will give a more connected feel of the road since they are stiff carcass and sidewall tires. This means a bumpier ride but solid feel.

Going to a squishy carcass michelin or pirelli would isolate the small bumps and imperfections. They are meant to act like the first step of suspension. It takes some getting used to.

Most racers who do the switch pull back into the pits complaining of a flat tire. The rim moves around the contact patch that much.

The big trade-off on the street to me is lifespan. The pencil eraser soft tires wear out in half the time. (a day or 2 of racing).

jscobey

so your saying that the "older" stiffer type tires are better suited for the hawk? i feel like the stiffer the tire the more you will highlight the flexing in the frame. it seems like, as you said the softer tires act as the first step of suspenion and would allow the hawk to not flex as much compared to a stiffer sidewall and carcas. am i wrong here?

smokinjoe73

I think "better" is preference. I run the dunlops but for longevity. For me I would give up comfort to not have to swap as often.

Yes the softer mich and pirelli are better for smoother ride etc, but you will have to swap em often. (plus the cost more).

Gotta pick you poison.

jscobey

im not talking about personal preference of tires in terms of millage, comfort, grip, etc...

im talking about the hawks chassis and weather older style tires like kenmoore stated work better with the hawk as it was designed at a time when those were the standard.

what i was geting at is that it seems like a harder tire would only add to the hawks chassis flex where as a softer carcass might compensate a little bit for it. i really dont know so thats why im asking.

the idea totally of older tires being a better fit makes sense as dunlops Q3's werent even in the womb sorta speak in 97. i just wonder if this were true, would the quality of the latest and greatest tires be a worth while trade off although the hawk wasnt desgined for tires of that spec.

smokinjoe73

Just cuz its old dosnt matter. Lots of things can be improvements, headlights, suspension, tires, seat, etc.

Newer better tires will be newer and better. But again, newer dunlops and bridgestones are quite stiff still. (except the brand new dunlop 211).

They designed the bike with those tires but that doesnt mean they will always be best.

Many older bikes benefit from new tires.

7moore7

+1

I would agree definitely that tire technology is better now, but I'd guess that components of the technology are better for all bikes and components are better for newer bikes that may adversely affect the way the Superhawk was designed. Maybe not (maybe all newer tires are 110% better), but I would guess there's a happy medium in there somewhere.

You wouldn't buy a perfectly round tire for a Harley and put it on the superhawk and say it's better for the sole reason that it's a newer tire.

VTR1000F

That last part went right over my head.

Could you dumb it down a skosh?

7moore7

Sorry, I put a value beyond infinity in there. Probably didn't compute and overrode some circuits. Are you a robot?

Here's a disctraction:

VTR1000F

It is a known fact that yellow tires are faster and offer better traction than any other color.

jscobey

found this in an article on motorcycle.com about the VTR when it was first released

"The "pivotless" twin-spar frame was designed around the VTR's OEM radial tires, which use a softer construction than that found on other sporting machines. Mounting different treads, according to Honda, will upset the "tuned" balance of the Super Hawk's chassis."

really interesting article on the VTR that i havnt seen before.

also thought this picture was pretty cool